SI Tutorial, Phase 1 - Building a Single Cylinder
Model
Step 1 - Starting WaveBuild, Setting General Parameters, and
Creating a Simulation Title
In this step we will open WaveBuild and establish some preliminary
settings that are important for every simulation.
Chapter sections Example Input File:
1.1 Starting WaveBuild
.\examples\engine\TUT_si\tut_si1.wvm
1.2 Setting General Parameters
Windows:
From the Start menu select Programs > Ricardo >
WAVE > WaveBuild 8.0
Linux/UNIX:
Type wb at the command prompt
Once the application opens, the WaveBuild GUI should have a blank
canvas and appear as in Figure 1.
Figure 1: WaveBuild window at startup
The title bar is across the top of the WaveBuild GUI window. It
lists the name of the currently open file
( NoName.wvm by default, until renamed). If changes
have been made to the file and haven't yet
been saved, an asterisk (*) will appear next to the filename. See
Figures 2 and 3.
Figure 2: Title bar when WaveBuild application first opens
Figure 3: Title bar with unsaved changes to the model
The pull-down menus are listed across the top of the GUI, beneath
the title bar (see Figure 4). Clicking these with the left mouse
button will open up menus with selection items.
New Executes the File > New... function.
Open Executes the File > Open... function.
Save Executes the File > Save function.
Undo Executes the Edit > Undo function.
Redo Executes the Edit > Redo function.
Find Executes the Edit > Find function.
Select Puts the cursor in select mode.
Place Element Puts the cursor in element placement mode, which
places an instance of the element selected in the Elements Tab for
every mouse click on the canvas.
Cut Executes the Edit > Cut function.
Copy Executes the Edit > Copy function.
Paste Executes the Edit > Paste function.
Constants Table Executes the Simulation > Constants > Table
function.
Run Input Check Executes the Run > WAVE > Input Check
function.
Run Screen Mode Executes the Run > WAVE > Screen Mode
function.
Run Batch Mode Executes the Run > WAVE > Batch Mode
function.
WavePost Executes the Run > WavePost function.
WNOISE Executes the Run > WNOISE function.
Text Editor Opens the Text Editor specified in the Tools >
Options tab.
Favorite Application Opens the Favorite Application specified in
the Tools > Options tab.
The canvas is the main portion of the WaveBuild window and where
the flow network will be assembled and described (see Figure
5).
The canvas is a customizable surface. You can customize the
properties for the WaveBuild canvas by selecting the Canvas
Properties... option from the Edit pull-down menu or by
right-clicking on the canvas background and selecting the Edit
Canvas Properties... context menu item. Customizable
options include canvas size, annotation display, and grid
appearance.
Figure 5: The WaveBuild canvas Figure 6: How to Edit the Canvas
Properties
The Case Manager is at the bottom of the canvas. The and buttons
allow you to the add and delete cases while the arrow buttons allow
you to navigate between existing cases (first case , previous case
, next case , last case ). The text
field tells you exactly which case you are in and how many cases
there are in total. You can type directly into the text field and
press enter to jump to a specific case. In any case other than Case
1, the background of the text field turns red as a reminder that
you are not in Case 1. Switch back to Case 1 if you wish to make
any changes to the model geometry. The Run checkbox allows you to
select whether or not WAVE should execute the current case in the
simulation. By default, the checkbox is checked for all new
cases.
1.2 Setting General Parameters
With any new model, the first step should always be to define the
general parameters for the simulation, specifically the units
system to initialize all data entry. Open the General Parameters
Panel by selecting General Parameters... under the
Simulation pull-down menu.
For this tutorial, all units will be defined in the SI system with
mm as the basic unit of length. Select SI [mm] from the
Units option menu. Wherever an input is required in WaveBuild,
the units for that input will be displayed next to the entry field.
When a numeric input is provided, if it is in another unit than the
initialized unit, the user can change the units for entry. Changing
the selection in this option menu at a later point will not convert
previously-entered values between units systems!
Under the Start Options section of the panel, note the toggle
button next to Reinitialize Flowfield Between Cases. Turning this
on will cause WAVE to start from the user-imposed initial
conditions for
wall temperatures, gas temperatures, pressures, velocities, and
species concentrations in every subsequent case when multiple cases
are defined (Case #1 is unaffected by this setting). This option is
turned off by default because in most instances the final
conditions for a converged case are closer to the final conditions
of the following case than the user-imposed initial conditions.
Assuming this is true, each case will converge to the final
solution quicker. For this tutorial, the toggle button should
remain off.
In the General Parameters section of the panel, type 30
in the Simulation Duration text field. We will be simulating
an engine and this number will define the number of engine cycles
to simulate. Since we don't know how many cycles our simulation
will take to converge, we will set a typical number for a gasoline
engine and note the convergence behavior at run time. If our number
is higher than required, auto-convergence will stop the
simulation.
Note that the background of the Simulation Duration field
turns yellow. This is because the units are listed as s for seconds
and 30 seconds far exceeds the recommended value for simulation
duration in the intelligent defaults settings. WAVE, by its nature,
simulates fluid flow using a timebase of seconds. When a cyclic
process is introduced to the simulation (such as an engine
cylinder, an oscillating flow source, etc.) WaveBuild knows to
change to a cyclic timebase. Once we place the engine cylinders on
the canvas, this units field will automatically change to cycles
and the background of the text field will change to white. "Behind
the scenes" the WAVE solver will still be solving everything in a
seconds timebase, but user entry fields are changed to cycles for
convenience.
button to open a file browsing window and select the properties
file to use. This will fill the text field with an absolute file
reference, using pointed brackets, <>, to surround the entry,
denoting a filename.
Figure 7: Selecting the INDOLENE tag
In WAVE, five species are used and transported throughout the
model. These are Fresh Air, Vaporized Fuel, Burned Air, Burned
Fuel, and Liquid Fuel; numbered Species 1 to 5 respectively. All
properties for these species are defined in a single properties
file (with a .fue extension) that
contains information on how the fuel and air react at different
temperatures, pressures, and
concentrations. The appropriate properties file should be selected
for the fuel being used in the model. For simulations using only
air, any properties file may be specified since all contain
information on the properties of air. Ricardo ships numerous
pre-made properties files and all are selectable from the default
tags list. The user can create their own file if desired by
clicking on the Create Properties File button to use the
pre-processor.
Note the End of Cycle Angle text field. This field is used to
specify the crank angle that WAVE will use to denote the start/end
of subsequent engine cycles. By default (setting of auto), WAVE
uses
the IVC of cylinder #1 as the end of cycle. This is acceptable for
almost all engine simulations except when VVT is employed and
continuity between cases is important. In that case, a crank angle
can be specified and should be just after the latest IVC for
cylinder #1 in the simulation. For this tutorial, the default
setting of auto is appropriate.
When finished, the General Parameters should appear as in Figure
8.
Figure 8: Completed General Parameters Panel
Click on the Convergence tab. This tab allows the user to
activate the auto-convergence mechanism, which tells WAVE to end
the simulation if it converges to within the specified tolerance
value for the specified number of consecutive cycles (default of 1%
for 1 cycle) regardless of whether or not it has reached the
specified duration. Turning this option off will cause WAVE to run
to the full specified duration for each case in the
simulation.
For this tutorial, the toggle button should remain on and
the default values are acceptable. When finished, the Convergence
tab should appear as in Figure 9.
Figure 9: Convergence Tab
Press the OK button to close the General Parameters Panel and
save the settings.
1.3 Creating a Simulation Title
operations on constants may be used and will be evaluated when
placed inside curly brackets, { }. Pre-defined WAVE constants are
convenient to use sometimes and
include $file,$case, $subcase, $fullcase, $version, and $date. Also
useful are user-defined
the top of the WaveBuild canvas and is fixed in this location. When
finished, the WaveBuild canvas should appear as in Figure 10,
below.
Save your model
Click on the Save button in the toolbar to save the file.
The first time the file is saved, you will be prompted for a
filename and directory where the file will be written (the file is
saved with a .wvm extension, for "WAVE model"). You will
also be prompted to add
comments for the file (this option can be deactivated via the File
tab on the Options Panel located under the Tools... pull-down
menu). When the save button is subsequently clicked, or if the file
is not
a newly created file (opened from a pre-existing file), the
currently open file will be overwritten. To save the file elsewhere
or with a different name, select the Save As... option
from the File pull-down
menu. Save this file with a descriptive name, such as
tut_si1.wvm .
Proceed to Step 2 - Building the Flow Network on the WaveBuild
Canvas
Show
Step 2 - Building the Flow Network on the WaveBuild Canvas
In this step we will layout the junction and duct entities that are
required for the single cylinder model on the WaveBuild
canvas.
2.1 Placing Required Junctions
.\examples\engine\TUT_si\tut_si1.wvm
2.2 Connecting the Junctions with
Ducts
.\examples\engine\TUT_si\tut_si1.wps
2.1 Placing Required Junctions
The basic geometry of the system we will model in this phase is
shown in Figure 1. In order to model this, we will have to
represent both the intake port and exhaust port using two duct
elements, one for the tapered section and one for the un-tapered
section. We will use simple orifice elements to connect the two
ducts (one orifice on each side of the cylinder). The open ends of
the ports will be represented using standard ambient
elements.
Figure 1: Single Cylinder Layout Sketch
Move the mouse over the Ambient junction icon listed in the
Elements Tree. Hold down the left mouse button and drag it onto the
WaveBuild Canvas, dropping it anywhere. This will place one
junction of the simple ambient type onto the model canvas (see the
WaveBuild HELP on how to work with the Elements Tab). To place
additional junctions without continually dragging and dropping,
click on the place
element + button in the toolbar across the top of the
WaveBuild
GUI. The mouse pointer changes to a "+" sign when the mouse is
moved over the WaveBuild canvas.
The mouse pointer is now in junction placement mode. In
junction placement mode, a junction of the selected type will
be placed on the canvas every time you press any mouse button. The
mouse will remain in junction placement mode until you click on
the
Select button on the toolbar across the top of the WaveBuild GUI or
hit the Esc key to return to select mode, at which point the
mouse pointer will return to appearing as an arrow when moved over
the canvas.
Place two of the Ambient junctions on the canvas approximately 12
grid squares apart horizontally. Note that when placed on the
canvas, junctions "snap" to the nearest grid intersection point.
This behavior can be modified via the Edit > Canvas
Properties... menu item.
Drag and drop two Orifice elements from the Elements Tree on the
canvas between the ambient
junctions. Finally, drag and drop an Engine Cylinder element
from the Elements Tree between the Orifice junctions. When finished
the WaveBuild canvas should appear as in Figure 2.
Figure 2: Junctions placed on the canvas
2.2 Connecting the Junctions with Ducts
convention (remember, the Left to Right convention doesn't
necessarily mean Left to Right on the screen, it is merely a
coincidence in this case!). When finished, the canvas should appear
as in Figure 3.
NOTE: The ducts connecting the junctions appear as yellow lines.
This is an indication that some geometric property of the ducts
(i.e. diameter) has not been properly defined. Also, as you connect
the two ports of an orifice junction, the icon of the orifice
disappears because the ducts
Save your model
Click on the Save button in the toolbar to save the file.
This overwrites the .wvm file with the new information
and backs up the previous .wvm file to a file
with the extension .wvm_bak1. WaveBuild will create up to 9 backup
files with the .bak extension,
all of which can be opened and viewed using WaveBuild.
Proceed to Step 3 - Defining Ambients, Ducts, and
Orifices
Step 3 - Defining Ambients, Ducts, and Orifices
In this step we will select all of the elements (ducts and
junctions) on the WaveBuild canvas, and define their geometric
values and initial/boundary conditions.
Chapter sections Example Input File:
3.1 Defining Ambients
.\examples\engine\TUT_si\tut_si1.wvm
3.2 Defining Ducts
3.1 Defining Ambients
With the general parameters defined (specifically a units system)
and all of the relevant ducts and junctions placed on the
canvas, it is time to define the geometric characteristics of the
model as well as specify the initial conditions and boundary
conditions.
We will start by defining the Ambient junctions. As stated earlier,
the left-most Ambient junction will be the intake ambient.
Double-click with the left mouse button on the left-most ambient
junction. This will open the Ambient Panel. In the Ambient Panel,
the user can specify the conditions of the ambient atmosphere
(Pressure, Temperature, and Species Concentrations) as well as
specify the properties of the orifice at the end of the attached
duct.
Temperature and Pressure fields on the Ambient tab and
all inputs on the Initial Fluid Composition tab are used to
specify the fluid conditions of the atmosphere around the attached
duct. The default values of 1.0 [bar] and 300[K] and a
composition of 100% fresh air are suitable for this simulation and
don't need to be changed. In some simulations, the user may choose
to dramatically change the temperature and pressure and/or adjust
the composition to model a boundary that is either not atmospheric,
like the outlet of a compressor or inlet of a turbine, or is not at
sea level, such as an engine operating at high altitude.
The Diameter , Discharge Coefficient, and Acoustic End
Correction fields are used to model the
orifice created where the duct ends at the ambient. The Diameter
field has a default value of AUTO to
assume the same diameter as the attached duct (no restriction
created). The Discharge Coefficient can be set to AUTO to
have WAVE calculate this value internally during the simulation.
This is only
applied to flow going from the Ambient into the attached duct and
should be a value between 0 and 1 if specified. The Acoustic End
Correction is only used for acoustic simulations and is discussed
in detail in the Acoustics Manual.
The ambient's diameter value can never be larger than the diameter
of the attached duct as it would have no physical meaning, however
a value of 0 (zero) makes the ambient junction behave like a closed
end to the attached duct (an end-cap).
The selection of Fixed or Floating Solution Type is discussed in
detail in the Acoustics tutorials. The default
setting of Floating is appropriate in almost all cases and should
not be changed.
For this simulation, the default values are all appropriate and we
only need to change the name of the junction. Type
Intake in the ID text field (name for the junction as
displayed on the canvas and in the output files). When finished,
the Ambient Panel should appear as in Figure 1, below. Do the same
for the right-most ambient junction and type Exhaust in the
ID text field.
3.2 Defining Ducts
Next we will define the ducts. Assume that all the geometric data
for the system has been measured and recorded and that a labeled
sketch is provided as in Figure 2. Minimally, a duct is defined by
Left and Right Diameters,Length, Discretization, and Initial
Conditions.
Figure 2: Single Cylinder Layout Sketch
The middle of the Duct Panel is the Schematic section which
will update the drawing of the duct to reflect the entered
geometric dimensions (Bend Angle is not drawn in the
schematic as it has no physical meaning in a 1-D model, it is
simply used to calculate a pressure loss based on the angle and
bend radius). Fuel Injectors, Spray Impingement Points, and
Thermocouples will also appear in the schematic if present in the
duct.
The bottom of the Duct Panel is reserved for two layers of tabs
which hold entry fields in which the user will specify all
information relevant to that duct. Of all of those tabs, there are
three of primary importance that we will use in this tutorial.
Under the top level tab of Duct Data, the Dimensions tab, the
Coefficients tab, and the Initial Conditions tab are
particularly relevant in all ducts and are the only tabs we will be
editing during the course of this tutorial (see Figure 3).
Figure 3: Required Duct Data Tabs
On the Dimensions tab, with the Shape selected as
Circular , type the dimensions given for duct1 in Figure
2 into the appropriate entry fields (Left and Right
Diameters and Overall Length). The engine bore for this
example is 78.1 [mm] so, following the general recommendation for
discretizing the model for performance simulation, set the
Discretization Length to 35 [mm] (click here to read a
sidebar on Discretization). When completed, theDimensions tab
for duct1 should appear as in Figure 4.
Figure 4: Duct Panel Dimensions Tab for duct1
simulation. The Left and Right end Discharge
Coefficients will be automatically calculated by
WAVE when left as auto based on the diameter of the duct at
the relevant end and the diameter of
the neighboring duct/orifice. If desired, this can be overridden by
typing in a value for the Discharge
Coefficient from 0.0 to 1.0. For the purpose of this tutorial,
the default value of auto is suitable and
should not be changed. When finished, the Coefficients tab should
appear as in Figure 5.
Note that the Friction and Heat Transfer Coefficients have
default values of 1.0. These values are multipliers for the
standard calculation. Thus values of 0.0 imply that there is no
pressure loss due to friction and no heat transfer occurring along
the length of the duct while values of 2.0 imply that twice the
standard pressure loss due to friction and twice the standard heat
transfer is occurring. These multipliers may be used as "tuning
knobs" to adjust friction and heat transfer and should be changed
according to the surface roughness of the material and flow
conditions in the duct. Keep in mind that surface roughness will
affect BOTH of these parameters and that pressure loss due to
increased heat transfer can be much greater (expansion/contraction
of the gas) than pressure loss due to friction!
Figure 5: Duct Panel Coefficients Tab for duct1
On the Initial Conditions tab, type the conditions given for
duct1 in Figure 2 into the appropriate entry fields
(Pressure, Temperature, and Wall Temperature). In the case of
duct1, all of the default settings are correct for our model. When
finished, the Initial Conditions tab should appear as in Figure
6.
Note that initial conditions of Pressure and Temperature
need not be extremely accurate in an engine simulation as the gas
will quickly move through the system and conditions will be re-
calculated frequently. The initial conditions as set will be
flushed out within the first few engine cycles of the simulation.
Default settings of 1.0 [bar] and 300 [K] are appropriate for most
engine
simulations. Turbo/Supercharged simulations should have more
appropriately set conditions to reflect the "boosted" state of the
fluid and avoid start-up calculation errors.
Note that if the Structural Conduction model (discussed in
later tutorials) is not active for a duct, not only is the Wall
Temperature value as entered the initial Wall
Temperature, it is also the fixed Wall Temperature for the duration
of the simulation! Thus, special attention should be paid to
setting Wall Temperatures throughout the model to ensure that heat
transfer is accounted for appropriately, especially in the exhaust
system. If reliable wall temperature data is not available, the
Structural Conduction model should be activated and the wall
temperature will be calculated during the simulation to give
reasonable results.
Click the OK button to close the Duct Panel for duct1. As
above, edit duct2, duct3, and duct4 and enter the relevant
information according to the schematic shown in Figure 2. Use a
Discretization length of 35 [mm] on the intake and
40 [mm] on the exhaust. Make sure to set the
Friction coefficient to 0 (zero) and the Heat
Transfer coefficient to 1.5 for each duct and do
not enter Bend Angles for duct2 and duct3!
Figure 6: Duct Panel Initial Conditions Tab for duct1
3.3 Defining Orifices
Click the Undo button in the toolbar to return the Right
Diameter of duct1 to 35 [mm] again.
Now double-click on the orif1 junction and note the only editable
fields for an orifice junction are the ID of that junction and the
junction Diameter (diameter of the orifice plate) if one exists. If
an orifice
junction is simply used to join two duct ends together, than
the default setting of auto is sufficient. The auto setting implies
that the diameter of the orifice is equal to that of the smaller of
the two attached ducts. If a restriction is to be modeled, a
Diameter smaller than the smallest of the two attached ducts should
be used. Type 20 [mm] in the Diameter text field and hit the OK
button. Note the orif1 junction now appears as if an orifice plate
is reducing the diameter at the junction.
Click the Undo button in the toolbar to return the Junction
Diameter to auto again. For this
tutorial all orifice junctions will have a Diameter of
auto unless otherwise specified.
Orifice with no change of area
Orifice with contraction Orifice with restriction
An orifice diameter can never be larger than the diameter of
the smallest attached duct as it would have no physical meaning,
however a value of 0 (zero) makes the junction behave like a closed
seal between the attached ducts.
When completed, the WaveBuild canvas should appear as in Figure
7.
Figure 7: Completed WaveBuild Canvas
Save your model
Click on the Save button in the toolbar to save the file.
Proceed to Step 4 - Defining the Engine
Step 4 - Defining the Engine
In this step we will input all of the required data for the engine.
The Engine currently is not an entity on the canvas. It physically
would consist of all engine cylinders represented on the WaveBuild
canvas (currently only one) but also includes physical sub-models
for combustion, friction, heat transfer, etc.
Chapter sections Example Input File:
4.1 The Geometry Tab
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
4.2 The Operating Parameters Tab
Example Output File:
4.3 The Heat Transfer Tab
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
4.4 The Combustion Tab
4.1 The Geometry Tab
To define the engine, open the Engine General Panel by selecting
Engine... from the Model pull- down menu. The Engine
General Panel consists of numerous tabs, each used to define the
characteristics of the engine or the physical sub-models associated
with the engine.
There are four primary tabs that are important for every engine.
These are Geometry, Operating Parameters, Heat Transfer , and
Combustion.
On the Geometry tab, under the Configuration section
enter the relevant data for this engine as shown in Table 1.
The No. of Cylinders field does not automatically
update when cylinders are placed on the screen (this allows for
definition of the engine before the model is built). The user must
enter the correct number of engine cylinders manually.
The Strokes per Cycle field is used to define the engine as a
2-stroke or 4-stroke engine (optionally a 6- or 8-
stroke engine for research purposes).
The Engine Type field is used to enable different combustion
and emission models when either SI or Diesel are selected. The
Motored option allows for engine motoring simulation (engine
pumping only, no combustion via cancelling all injection
events).
On the Geometry tab, under the Friction
Correlation section enter the relevant data for this engine as
shown in Table 2.
These coefficients are used in the Chen-Flynn friction correlation
model. This model is used to calculate the FMEP (Friction Mean
Effective Pressure) for the engine. When data is collected in the
test cell, it can be plotted and correlated using the Chen-Flynn
model so that FMEP may be calculated at non-tested engine
speed/load conditions. The equation to calculate FMEP in WAVE
is:
FMEP = ACF + BCF(Pmax) + CCF(rpm * stroke/2) + QCF(rpm *
stroke/2)2
The use of the BCF term is to account for changes in P max, which
can be used to vary frictional losses across a range of engine
loads. The CCF and QCF terms are used to account for changes in
rpm, varying frictional losses across a range of engine
speeds.
If the simulation is only to simulate tested speed/load points, the
FMEP can be entered directly using only the ACF value (directly
entering FMEP in the appropriate pressure units) and setting the
other coefficients to 0 (zero).
When completed, the Geometry tab should appear as in Figure
1.
No. of Cylinders 1
Strokes per Cycle 4
Engine Type Spark Ignition
Compression Ratio 10.0
Table 1: Data to be entered in the Configuration fields
ACF 0.35 [bar]
Correlation fields
4.2 The Operating Parameters Tab
1). This will allow the simulated engine speed to change between
cases once we add more cases in Phase 3 of the tutorial.
Note that the background of the text entry field turns yellow. This
is to warn the user that the value is outside of the generally
acceptable range of values for the Engine Speed field. Hover
over the text {SPEED} and note the tooltip that pops up,
stating that the constant {SPEED} is undefined (Figure
2).
To define this constant, open the Constants Panel by clicking
on the Constants Panel button in the toolbar or by selecting
Simulation > Constants > Table... from the
pull-down menu. No constants have yet been defined so the Constants
Panel should be blank. Type SPEED under the Name column
and under the Case 1 column, set a value of 6000. This will
correspond to the {SPEED} value used in the Engine General
Panel for Engine Speed in rpm. When completed, the Constants
Panel should appear as in Figure 3. Click OK to close the
Constants Panel and save the setting.
Figure 2: The Operating Parameters tab
Figure 3: The Constants Panel
Once the SPEED constant has been defined, the background of the
Engine Speed text entry field should turn white to denote an
acceptable value. Also note that the simulation title at the top of
the WaveBuild canvas has updated to reflect the value of the SPEED
constant as given in the title. Hover the mouse over the Engine
Speed entry in the text field to pop up the tool tip and note that
the constant is now being evaluated correctly as in Figure 4.
The Reference Pressure and Reference Temperature fields
can be left as their default values of 1.0 [bar] and
298 [K] respectively. These values are used in the calculation
of volumetric efficiency for the engine and may or may not
correspond to the ambient conditions of the dynamometer cell when
tests are performed (different companies use different practices).
When completed, the Operating Parameters tab should appear as
in Figure 4.
Figure 4: The Operating Parameters tab with SPEED defined
4.3 The Heat Transfer Tab
Efficiency) and when the intake valves are closed (during
compression/combustion/exhaust). Adding swirl will increase the
total heat transfer due to increased charge motion in the
cylinder.
Modifications to the standard Woschni model have been added to
compensate for varying levels of IMEP. This can be selected by
changing the Woschni Model from Original (1967) to Load
Compensating (1990).
For the purpose of this tutorial, enter the relevant data for this
engine as shown in Table 3.
Woschni Model Original
Heat Transfer when Intake Valves are
Closed 1.0
Cylinder Head Surface Area Multiplier 1.6 (to make
7665
mm2)
Swirl Ratio 0.0
Table 3: Data to be entered in the Heat Transfer Tab
4.4 The Combustion Tab
Finally, click the Combustion tab to bring it to the front. This
panel separates the Primary Model choice (required) from the
Secondary Model choice (optional, layered on top of the Primary
Model) and Emissions Models. The general engine cylinder in WAVE
simplifies combustion. It does not use a predictive combustion
model but simply models the heat release caused by combustion vs.
time. Since we are modeling a spark ignition engine and selected
the Spark Ignition option on the Geometry tab, we have
two combustion models available to use -- the SI Wiebe and Profile
models.
The Profile model is used when Heat Release vs. Crank Angle data is
available directly for every speed/load point to be tested by the
model. This data can be directly entered into WAVE as a table with
a combustion start time and efficiency.
More widely used, however, the SI Wiebe model simply uses an
S-curve function that represents the cumulative heat-release in the
cylinder. The first derivative of this function is the rate of heat
release. The SI Wiebe model is very commonly used and represents
experimentally observed combustion heat release quite well for most
situations.
Select the SI Wiebe option from the Combustion
Model drop-down menu. Enter 8.0 [deg] for the Location of
50% Burn Point and 31.0 [deg] for the Combustion Duration
(10-90%). Watch the plot actively update as these values are
entered. The default value of 2.0 for the Exponent in Wiebe
Function is appropriate for most cases. Change it and watch
the shape of the burn curve change as well. For this example,
2.0 is an appropriate value and should be used. Fraction of
Charge to Burn should be left at the default value of
1.0 as well. When completed, the Combustion tab should
appear as in Figure 6.
Save your model
Click on the Save button in the toolbar to save the file.
Proceed to Step 5 - Defining the Intake and Exhaust
Valves
Show
Step 5 - Defining the Intake and Exhaust Valves
In this step we will define the intake and exhaust valves by
specifying their lift behavior and flow restriction behavior.
Chapter sections Example Input File:
5.1 Defining the Intake Valve Lift
Behavior .\examples\engine\TUT_si\tut_si1.wvm
5.2 Defining Coefficients (Flow vs. Discharge)
The connections from duct2 and duct3 to the
cyl1 junction are assumed to be valves (all engine cylinder
connections are assumed to be valves). The blue connection point to
duct2 denotes an intake valve and the red connection point to
duct3 denotes an exhaust valve. This is correct for this model
but is purely coincidental . WaveBuild places engine
cylinders on the screen with two connections by default. It
assumes that the first connection to be used is an intake
valve and the
second connection to be used is an exhaust valve. Any other valves
created (by double-clicking on the cylinder junction and editing
the Number of Valves field to be larger than 2) are
assumed to be intake valves. This intake/exhaust status
can be changed by highlighting the connection of choice and
changing the Type in the drop-down menu (see Figure 1
for example of a modified Cylinder Panel). For this tutorial, the
two valves created by default are suitable and the number of valves
should not be changed.
Valves are defined globally, for use anywhere in the model.
Anywhere a valve is present (on an engine cylinder, in a
valve-specific junction, etc.) the user must tell WAVE which
globally defined valve to use. This, for example, allows the user
to define an intake valve once and then use it for all engine
cylinders.
Figure 1: Adding Valve Connections via the Cylinder Panel
The first entry field under the Valve Parameters section of the
panel is the Reference Diameter . This value is typically the
inner-seat diameter (see Figure 2, right), but if the port-
coefficient data has been provided in non- dimensionalized format,
whatever diameter was used to non-dimensionalize the data should be
entered here. For this tutorial, type in a Reference Diameter of
35 [mm]. The Heat Transfer Diameter is only required if the
valve is an engine valve and the engine conduction sub- model is
activated – for this tutorial, it need not be
entered.
Figure 2: Valve Measurements typically used
Click on the Edit Lift Profile button to open the Valve Lift
Profile Editor.
In the Valve Lift Profile Editor, data must be entered for the
behavior of the valve. This behavior is described as the lift of
the valve vs. time (time is entered as cam or crank angle degrees).
There are numerous options for entering this data including:
Manually entering data into the array
Copying and Pasting an array from MS Excel (on PC
platform)
Reading in a pre-formatted external file
Using a tag to alias a pre-formatted external file
INTAKE VALVE
For this tutorial the data has already been provided in a
pre-formatted external file that is aliased in the
default active.tags file. To select this file, click on
the
tag button and select the SI1INT item. Notice that the array
fills automatically by reading the contents of the
file aliased in the active.tags file and a lift vs.
crank
angle curve is now plotted on the screen.
Some suppliers may provide data for the lift curve in camshaft
degrees (the camshaft rotates once for every two crankshaft
rotations in a 4-stroke engine) so there is a Angle
Type pull-down menu to adjust the units on which the data is
based. Lash, if not already incorporated into the lift array data,
should be entered as hot lash. The lash in the system tends to
change when the engine is running hot and is reduced from the cold
lash. Rocker Ratio (if necessary) may be entered as
well.
The fields of primary importance are the Anchors and the
Multipliers, located at the bottom of the Valve Lift Profile Editor
window. The Anchors allow arbitrary alignment of the valve
profile within the engine cycle. The Profile
Anchor denotes a point specified in the array of angle
data. The Cycle Anchor denotes another point in the
engine cycle in crank angle degrees. These two points align to
locate the valve lift array within the engine cycle. These anchors
can be parameterized (set as constants) to allow variable valve
events between cases (cam phasing).
The Multipliers are used to multiply every point in the valve array
in either lift magnitude or angle duration. These can be
parameterized (set as constants) to allow variable valve lift and
duration between cases. The lift multiplier can also be
conveniently used to adjust the units of the text file to the
appropriate units for use in the model (multiply/divide to go from
inches to mm, etc.).
For this tutorial, enter the following information for valve #1,
the intake valve as shown below in Table 1. This aligns the
0 degree point in the array data (in Crank Angle degrees) with
the330 degree point in the engine cycle, shifting the valve
event over the labeled intake stroke in the plot. It also
multiplies all of the lift values by 1.414. When finished, the
Valve Lift Profile Editor for valve #1 should appear as in Figure
3, below.
Table 1: Intake Valve Data
Figure 3: Valve Profile for the Intake Valve
Click the OK button to save these setting and close the Valve
Lift Profile Editor.
5.2 Defining Coefficients (Flow vs. Discharge)
Coefficient Profiles button to open the Flow Coefficient Profiles
Editor.
Similar to the Valve Lift Profile Editor, data must be entered for
the coefficients. This behavior is described as values for both the
forward and reverse flowing direction (forward implies into the
cylinder, reverse implies out of the cylinder) vs. the lift of the
valve (non-dimensionalized by dividing the lift by the reference
diameter). Again, there are numerous options for entering this data
including:
Manually entering data into the array
Copying and Pasting an array from MS Excel (on PC
platform)
Reading in a pre-formatted external file
Using a tag to alias a pre-formatted external file
For this tutorial the data has been provided already in a
pre-formatted external file that is aliased in
the default active.tags file. To select this file, click on
the tag button and select
the CFTYP option. Notice that the array fills automatically by
reading the contents of the file aliased
in the active.tags file and a coefficient profile appears in
the plot on the right-hand side of the
panel, see Figure 4.
This file contains information for flow coefficients as
we can tell by the fact that at zero lift (zero L/D value) the
coefficient has a value of 0 (zero). Flow coefficients must be
entered with the first row in the array being an L/D value of 0
(zero) and forward and reverse coefficient values of 0
(zero).
WAVE can also accept discharge coefficients as input.
Discharge coefficients are distinguishable by
the fact that the coefficient value at zero lift (zero L/D value)
are non-zero. If the first row of the array is an L/D value of zero
and the forward and reverse coefficients are non-zero, then WAVE
assumes
that the array is entered as discharge coefficients. Click on the
tag button and select CDTYP to display a typical discharge
coefficient profile, seeFigure 5. These two profiles are derived
from the
same data so either will work and is appropriate for this
tutorial.
Click the OK button to save these setting and close the
Profile Editor.
Click the OK button on the Lift-Valve Editor panel to save the
settings for valve #1 and return to the Valve List panel.
Figure 4: Typical Flow Coefficient Profile
Figure 5: Typical Discharge Coefficient Profile
5.3 Defining the Exhaust Valve
Click the Add button again to create a second valve that will be
used to model the exhaust valve.
Figure 6: The Valves List
Follow the same steps as above but use the following information
for the lift profile (the coefficients can be the same as the
Intake Valve). When finished, the Valve Lift Profile Editor for
valve #2 (the exhaust valve) should appear as in Figure 7,
below.
With both the intake valve (valve #1) and exhaust valve (valve #2)
defined, the Valves List should appear as in Figure 6. Click the
OK button to save these setting
and close the Valves List panel.
By default, the engine cylinder junction has picked the intake
valve connection to use Valve #1 and the exhaust valve connection
to use Valve #2. This is, again, coincidental . On a
multi-valve engine it may be necessary to edit the engine cylinder
junction and correctly specify the valve number to use for each
connection.
EXHAUST VALVE
Figure 7: Profile Editor for Valve #2 (the exhaust valve)
Save your model
Click on the Save button in the toolbar to save the file.
Proceed to Step 6 - Adding the Fuel Injector
SI Tutorial, Phase 1 - Building a Single Cylinder
Model
Step 6 - Adding the Fuel Injector
In this step we will add a fuel injector, connect it to the intake
port, and define the required input parameters.
Chapter sections Example Input File:
6.1 Adding the Injector Element
.\examples\engine\TUT_si\tut_si1.wvm
6.2 Defining the Injector
6.1 Adding the Injector Element
The single-cylinder model is almost complete – all that
remains is to add a fuel injector. WAVE handles fuel injection in
one of two primary ways – targeting an air-fuel ratio
or injecting a specific mass of fuel. The easier of the two methods
is to target an air-fuel ratio and let WAVE inject the appropriate
amount of fuel based on the airflow. This is the approach used in
this tutorial and in a vast majority of simulations.
Injectors can be added to duct, y-junction, or cylinder elements,
but specific injectors can only attach to specific types of flow
elements. From the elements tab, drag and drop a
Proportional fuel injector above duct 2. The proportional type
injector can connect to a duct or y-junction flow element, but not
cylinder elements. A Proportional injector will always inject
enough fuel to the fluid stream to match a targeted air-fuel ratio.
This is the simplest type of injector and is very commonly
used.
To connect the injector to the flow element, click on the injector
and drag and drop a connection onto the duct2 element. This will
create a connection line between the two elements (the connection
line must start at the injector element and be dropped onto the
duct element, you cannot create a connection between the two by
starting at the duct element). When connected, the model should
appear as in Figure 1.
Figure 1: Adding an Injector
6.2 Defining the Injector
Now that the injector has been added, we can edit the properties of
the injector element. Double click on the injector element to open
the Proportional Injector Panel.
On the Operating Point tab, all that needs to be defined is
the targeted air-fuel ratio of the injector within the duct. WAVE
requires a fuel-air ratio but most frequently
air-fuel ratio information is provided. This is easily
overcome by using WAVE's capability to perform simple mathematical
operations on constants. We will define a constant named A_F and
enter air-fuel ratio data in the Constants Panel, but in the text
field for Fuel/Air Ratio, type {1/A_F}. This will automatically
convert the air-fuel ratio to a fuel-air ratio as required.
On the Position tab, we must define where, along the length of
the duct element, the injector injects fuel into the flow system
(if the injector were connected to a y-junction element, this tab
would be irrelevant as there is only one fluid cell in a
y-junction). Type 25 [mm] into the Distance from Left
End text field to move the injector to the middle of the duct
(alternatively, click and drag the injector with the middle mouse
button).
Click on the Composition tab, where the total
composition of the fuel before injection can be
specified. If the aforementioned charge cooling effect is
undesirable, then the vapor portion can be specified here. For this
tutorial, the default of 1.0 for Liquid Fuel is suitable
and can be left as is (100% of the injected fuel is in liquid
state, 20% of that vaporized when injected).
When completed, the Proportional Injector Panel should appear as in
Figures 2-5, below. Click the OK button to close the
Proportional Injector Panel and save the data (when prompted to add
the A_F constant to the Constants Panel, select No).
Figure 2: Completed Injector Editor
Figure 5: Completed Composition Tab
Click the OK button to close the Constants Panel.
The single-cylinder model is complete!
Save your model
Running the WAVE solver will process all of the information that
has been entered into the model and produce numeric results. These
results can be post-processed in WavePost to produce plots and
graphics for reports and presentations.
Phase 2 Steps Example Input File:
1 Running a WAVE Input Check
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
2 Requesting Time Plots
4 Running WAVE and Understanding the .out File
5 Introduction to Post
With these five steps, we will run the WAVE solver and create some
output data for post- processing. WavePost will be used to view
plots and cycle-averaged results for the model.
Show
SI Tutorial, Phase 2 - Running WAVE and Creating Time Plots in
WavePost
Step 2 - Requesting Time Plots
In this step we will add requests for plots of specific data to our
existing model. Time Plots are plots of results over the course of
a single engine cycle (the last engine cycle in multi-cycle
simulations). Time Plots should be requested whenever the user is
aware of specific data they are interested in analyzing.
Chapter sections Example Input File:
2.1 Duct Time Plots
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
2.2 Junction Time Plots Example Output File:
2.3 System Time Plots
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
2.4 Multiple Plots Overlaid
Suppose we are interested in observing the pressure and temperature
at the mid-point of the intake port during the engine cycle. We can
request Time Plots at the intake port (duct2) and WAVE will
automatically create these plots at the end of the simulation.
Right-click on duct2 and select the Edit Plots... option
from the pop-up menu (see Figure 1). The Duct Plot Panel will open
with no plots yet defined at this location. Click on the Create
Plot button to open the Duct Plot List.
Figure 1: Adding Plot to duct2
The list of plots available at this location is displayed (this
list is context-sensitive and generated based on the canvas item
selected). Click on the 201 Pressure plot and then, holding
the Shift button to multiple-select, click on the202
Temperature plot (most valid duct plots are in the 2xx range).
Click on the OK button to close the Duct Plot List and add
these plots to the Existing Plots list
in the Duct Plot Panel.
The location along the length of the duct from where plots should
take their data is specified under the Duct Locations region of the
panel. Locations are defined by a normalized value from zero to one
(left end of duct is 0, middle of duct is 0.5, right end of duct is
1). Default Locations can be defined for commonly-used locations to
be specified in multiple plots (Default Locations will appear
identically for all ducts when the Duct Plot Panel is opened).
Custom Locations are specific locations in the selected duct where
plots should take their data. Clicking on the Use All Locations
button will automatically create Custom Locations for every cell in
a duct. To add locations (either Default or Custom), right-click on
the column header and select Insert Column Before or Insert Column
After, as appropriate, from the context-menu.
Pressure and Temperature are scalar values and, in WAVE, are stored
at the center of a given cell (vector values, such as velocity, are
stored at cell boundaries). As there is only one cell in duct2, no
location needs to be specified. The time plots will automatically
be created at the 0.5 location (half- way along the duct).
Specifying any other location along the length of the duct will
create identical plots.
Figure 2: Duct Plot Panel with plots at duct2
Click on the OK button to close the Duct Plot Panel. Note the
plot icon now hanging off of duct2. To
edit plots at this location again, simply double-click on this icon
and the Duct Plot Panel will open.
2.2 Junction Time Plots
Suppose we desired to examine the combustion performance in the
power cylinder during the engine cycle. We may want to create a P-V
(Pressure vs. Volume) plot. Right-click on the cyl1 junction
and select the Edit Plots...option to open the Junction Plot Panel.
The duct plots created above will be listed in the Existing Plots
list. Click on the Create Plot button to open the Junction
Plot List.
list and add the plot to the Existing Plots list. Also note that an
asterisk appears to the right of the plot type for any plot with
the currently selected canvas item as a location.
No location within the junction needs to be specified for the plot
as there is only one calculation point in a junction. When
completed, the Junction Plot Panel should appear as in Figure 3,
below. Click the OK button to close the Junction Plot
Panel.
Figure 3: Junction Plot Panel with plot at cyl1
2.3 System Time Plots
Although there is only one cylinder in our engine, we will
eventually be creating a 4-cylinder engine. To observe the behavior
of the engine itself (system of cylinders grouped together), click
on the Simulation pull-down menu and select the Time
Plot... menu item. This will open the Time Plot Panel where
plots can be created for the engine system, as well as sensors,
actuators, and pins (to be discussed in more advanced
tutorials).
The System Location Type should be active by default when the panel
opens. Click on the Create Plot button to open the Time Plot
List for the engine system.
A few engine system specific plots are available and even
fewer are applicable to our system as modeled (system plots are
typically in the 7xx range). Click on the 701 Engine
Torque plot and click the OK button to close the
list.
Figure 4: Time Plot Panel with system plot of Engine Torque
2.4 Multiple Plots Overlaid
Perhaps we wish to examine the pressure and temperature in the
exhaust port and compare it to the conditions in the intake port.
We could create separate plots for the duct representing the
exhaust port (duct3), but it would be more useful if the data for
both ports were on the same plot. Right-click on duct3 and
select the Edit Plots... option from the pop-up menu. Note
that the only plots in the Existing Plots list are the pressure and
temperature plots from duct2. This is because these plots are
allowed at duct3 as well (a P-V plot is not sensible in a duct, nor
is engine torque).
With plot 201 highlighted, click on the Add
Location button to plot the pressure at duct3 on the same
plot as duct2.
Do the same for plot 202 to add duct3 to the plot of
temperature in duct2. Click on the Use All Locations button to
request the plots at the center of both cells in
duct3 (locations of 0.25 and 0.75).
Figure 5: Duct plot panel with duct2 and duct3 plots overlaid
Click the OK button to close the Duct Plot Panel. The model
should appear as in Figure 6 with all
time plots added.
Save your model
Click on the Save button in the toolbar to save the file.
Proceed to Step 3 - Requesting Post-Processing Datasets
Show
Step 3 - Requesting Post-Processing Datasets
In this step we will request that particular data that we may be
interested in later be output for the entire network , as
opposed to certain locations as in the case of Time Plots.
This is more convenient if the user wishes to have the data (e.g.
Pressure, Temperature, etc.) at numerous points throughout the
network or is unsure, ahead of time, at which locations this data
will be required for post-processing. It also allows the user to do
more advanced post-processing to be discussed later in
this tutorial.
3.1 Basic Datasets
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
3.2 Valve Datasets Example Output File:
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
3.1 Basic Datasets
Suppose we are not sure, beyond the behavior in the intake and
exhaust ports, which behaviors we will be interested in viewing
results for at the end of the simulation. Later analysis might
require extensive amounts of data that we didn't request plots for
ahead of time! It may also be inconvenient to return to WaveBuild
and request more plots and rerun the model, especially if the model
takes a very long time to run! We can avoid some of this by
requesting Post-Processing Datasets in advance.
Open the Postprocessing Output Panel by selecting the
Postprocessing Output... menu item from the
Simulation pull-down menu. We have yet to request any data to
be output after the simulation is
run through the WAVE solver, so the Requested Datasets list should
be blank. By default, the Basic models are listed, which are
datasets grouped together that are always available, no matter
which
junctions or physical models exist in the simulation. To
request a specific dataset that we would like written to the
simulation output file, highlight one by clicking on it and then
click on the single arrow button pointing to the right to add it to
the list of Requested Datasets (datasets can be multiple- selected
by holding down the Shift key to highlight a span of datasets or
the Ctrl key to highlight multiple, individual datasets). Clicking
on the double-arrow button will move all datasets form a Model
grouping in the the Requested Datasets list.
For this simulation, select the VELOCITY and
VOLUMETRIC_FLOW datasets. When completed, the Postprocessing
Output Panel should appear as in Figure 1.
Figure 1: Requesting Basic Datasets
3.2 Valve Datasets
At the top of the Postprocessing Output Panel, change the
Models option menu to Valve. This will make the Available
Datasets list change to those contained in the Valve subset. All
subsets besides the Basic subset are available depending upon the
junctions or physical sub-models included in the analysis.
Figure 2: Requesting Valve Datasets
Click on the OK button to save the changes and close the
panel.
Save your model
Click on the Save button in the toolbar to save the file.
Proceed to Step 4 - Running WAVE and understanding the .out
file
Show
Step 4 - Running WAVE and Understanding the .out File
In this step we will run the model file through the WAVE solver and
learn to parse the output file. In this and the following step, all
output files created during the simulation will be examined and
defined as to their purpose and use.
Chapter sections Example Input File:
4.1 Running the Solver
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
4.2 The .out File
4.1 Running the Solver
The model has been run through an input check and is all set to
create the requested data for post- processing. To run the model
through the actual WAVE solver there are two options:
Run the model in screen mode by clicking on the Run Screen
Mode button in the toolbar
Run the model in batch mode by clicking on the Run Batch
Mode button in the toolbar
Screen mode runs the model at high priority while sending standard
output to the screen. A shell will open and the simulation will
pass by, printing output in real-time for the user to examine
(output is also printed to the .out file).
Batch mode runs the model at reduced priority while sending
standard output to the .out file. On
PC, a shell will open, noting the version of the solver being used,
the window will minimize, and the simulation will run "quietly"
with no output to the screen. When the simulation is finished, the
prompt will return in the opened shell. On UNIX, the process is
detached from the current shell (similar to executing at the shell
prompt with the "&") and run in the background. No indication
of the process is given. Status of the simulation can be determined
using the "ps -ef" command.
If the model has been altered in any way and not yet saved (noted
by the asterisk next to the filename in the title bar), WaveBuild
will prompt you to first save the file before running. Run the
solver using either method and close the shell (if necessary) when
the simulation is complete.
4.2 The .out File
While the simulation is running, WAVE will create a temporary file
with the .hlt extension. The .hlt file will not be
discussed here but this file will be automatically deleted
upon successful completion of the simulation. If this file exists
when the simulation completes, it usually indicates that the
simulation failed while running in WAVE.
To this point, we have been building the model and saving it along
the way into a file with a .wvm extension. It is a
simple XML format file that can be observed in any web browser
by
changing the filename extension to .xml. There should now also
exist .out, .sum , .wvd , and . wps files as
well (a .rp file will have also been created for reverse
compatibility with an older
post-processor and will not be discussed – it is
obsoleted by the . wps file).
The .out file, discussed and analyzed earlier after the input
check, now contains additional data
about the simulation. Open the .out file using any common
text-editor and examine.
First note the added requests for plots and datasets called out
when the input file is parsed.
BAS:TIME
PLOT # 1 201 Pressure
PLOT # 2 202 Temperature
PLOT # 3 111 Linear P-V Diagram
LOCATIONS: JUNC: cyl1
BAS:DATASETS
Next, note the output from the simulation during run-time.
Row (1) gives an abbreviation for what each column of data is
displaying. This information may be
Row (2) is a summary for Cylinder #1 during engine cycle 0,
the start-up cycle (WAVE simulations, by default, begin at IVC for
cylinder #1 unless otherwise specified in the General
Parameters
panel). Only Cylinder #1 will have results for engine cycle
0.
Row (3) is a summary of engine system performance for
engine cycle 0.
Rows (4+) will be a summary of every individual cylinder in
the system for each engine cycle followed by a engine
system summary for each cycle.
Starting at engine cycle 3, a line (8) denoting
auto-convergence conditions is printed to the output. When
auto-convergence conditions are satisfied (14), if the convergence
detection was activated in the General Parameters panel, WAVE will
run one more engine cycle and then finish the case. This happens
regardless of whether or not convergence conditions are satisfied
in the following engine cycle.
The column titles as labeled in row (1) relate to the lines
summarizing individual cylinder
performance. They are, in order – Cylinder Number,
Engine Cycle (cumulative from start of case), Timestep number
(cumulative from start of case), Mass Airflow (kg/hr), Volumetric
Efficiency, Exhaust Port Temperature [K], Equivalence Ratio, IMEP
[bar], PMEP [bar], Indicated Horsepower [hp], Indicated Specific
Fuel Consumption [g/kW*hr], Cylinder Pressure at IVC [bar],
Cylinder Temperature at IVC [K], and Trapped Fuel/Air Ratio at
IVC.
NC ICYC ISTEP AIR-KG/HR VOLEF TEXH PHI IMEP PMEP IHP ISFC PCYL TCYL
FTR
ENG: 1 0 1 0.00 0.000 900.0 0.000 0.000 0.000 0.00 0.0000 1.013
301.1 0.00
ENG VOLEF(TOT) = 0.0000 PHI(1) = 0.000
ENG: 1 1 723 70.68 0.858 413.2 0.883 -1.235 -1.100 -3.25 -2.1073
1.575 381.0 0.606E
ENG VOLEF(TOT) = 0.8585 PHI(1) = 0.883
ENG: 1 2 1489 79.55 0.966 1278.5 0.990 11.959 -1.202 31.50 0.2304
1.569 385.3 0.680E
ENG VOLEF(TOT) = 0.9662 PHI(1) = 0.990
I*** AUTO-CONVERGENCE: Uvariance = 0.1346E-01 Pvariance =
0.1391
ENG: 1 3 2265 79.58 0.967 1353.8 0.990 12.379 -1.213 32.61 0.2227
1.569 385.8 0.680E
ENG VOLEF(TOT) = 0.9666 PHI(1) = 0.990
I*** AUTO-CONVERGENCE: Uvariance = 0.1375E-03 Pvariance =
0.3915E-01
ENG: 1 4 3041 79.57 0.966 1356.1 0.990 12.373 -1.211 32.59 0.2227
1.568 385.9 0.680E
ENG VOLEF(TOT) = 0.9664 PHI(1) = 0.990
I*** AUTO-CONVERGENCE CONDITIONS MET: Uvariance = 0.5334E-03
Pvariance = 0.4454E-02
ENG: 1 5 3817 79.56 0.966 1356.2 0.990 12.370 -1.210 32.58 0.2228
1.569 385.9 0.680E
ENG VOLEF(TOT) = 0.9663 PHI(1) = 0.990
I*** AUTO-CONVERGENCE CONDITIONS MET: Uvariance = 0.8932E-04
Pvariance = 0.1447E-02
Next, note the information on elapsed time, number of timesteps,
and limiting elements in the system.
The number of timesteps can be used to calculate the average
timestep size in CA° over the last cycle (CA° per cycle /
#timesteps). Our engine is a 4-stroke engine so there are 720° in a
single engine cycle with 776 timesteps in the last engine cycle.
This yields an average timestep size of approximately 0.93°
– close to the default maximum timestep size of 1° set
in the General Parameters panel. Although there is no hard
and fast rule, typical, well-built WAVE models won't
have a timestep below 0.1°. If the timestep is smaller than this,
it is usually due to poor modeling practice (extremely small
element size within the model).
The limiting element information can be useful in finding an
unreasonably small Discretization Length or Overall Length (for a
duct) or Volume (for a y-junction) that may be slowing the
simulation down dramatically. Note in this simulation that duct4 is
the limiting element, with sub-volumes 1, 2, and 4 showing up in
the list
ELAPSED TIME OUTPUT: CPU TIME (IN THIS CASE) = 0.28 sec.
WALL CLOCK TIME = 0 sec.
TIME STEP OUTPUT: TOTAL STEPS IN LAST CYCLE = 776
-------------------------------------------------------------
DUCT/VOL: duct4/1 69.1 DUCT/VOL: duct4/2 11.3 DUCT/VOL: duct4/4
18.4
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
Duct Junction TWALL TAV PAV PMAX PMIN UMAX UMIN MACH FLOW
A
[K] [K] [bar] [bar] [bar] [m/s] [m/s] NUMBER [kg/s] [cm^
duct1 Intake 300.0 299.3 0.989 1.049 0.929 110.0 -31.1
0.3195 0.02209 12.5
duct2 orif1 310.0 294.4 0.988 1.121 0.821 114.5 -23.0 0.3423
0.02209 9.6
duct3 cyl1 400.0 1243.4 0.978 1.402 0.706 808.9 -437.8 1.0000
0.02361 0.0
duct4 orif2 400.0 1107.4 0.924 1.248 0.507 859.4 -23.5 1.3088
0.02361 6.1
-------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
NC MASS IN VOL.EFF. TRAP.RATIO IMEP PMEP IHP TEXH RES(%)
EGR(%) PHI
kg/hr bar bar K
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
NC DPMAX TH_DPMAX HTR EVO EVC IVO IVC VOL.EFF. COMBSTART
IGNDEL
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
AMB.VOL.EFF (AIR IN / AMB. REF.) = 0.966 TRAP.RAT. (FRESH
TR./ FRESH IN ) = 1.000
DEL.EFF. (FRESH IN / PLEN. REF.) = 1.020 SCAV.RAT. (GAS IN / GAS
TR. ) = 0.965
CHARG.EFF. (FRESH TR./ PLEN. REF.) = 1.020 SCAV.EFF. (FRESH TR./
GAS TR. ) = 0.965
TOT.DEL.EFF (GAS IN / PLEN. REF.) = 1.020 RESID.FR. (RESID TR./ GAS
TR. ) = 0.035
EGR FR. (RESID IN / GAS IN ) = 0.000
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
CRANK ANGLES [deg ATDC] VS. FUEL MASS BURNT:
NC %BURNT: 0% 1% 2% 5% 10% 25% 50% 75% 90% 95% 99%
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I DISPL./CYL. [l] = 0.3928 I NUMBER OF CYLINDERS = 1.000
I
I [in^3] = 23.97 I COMPRESSION RATIO = 10.00 I EFFECTIVE CR
(VC-TDC
I BORE [mm] = 78.10 I BORE/STROKE = 0.9524 I
I [in] = 3.075 I CON. ROD LENGTH[mm] = 150.0 I
I STROKE [mm] = 82.00 I WRIST PIN OFFSET[mm] = 0.000 I
----------------------------------------------------------------------------------------------------------
I INT. VALVE DIA.[mm] = 35.00 I EXH. VALVE DIA.[mm] = 28.00
I #1 EVO [deg]
I MAX. LIFT [mm] = 12.57 I MAX. LIFT [mm] = 8.640 I #1 EVC
[deg]
I I I #1 IVO [deg]
----------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I RPM = 6000. I #1 INT.PORT PR[bar] = 0.9883 I #1 IGN DELAY
[de
I AMB. PRESSURE [bar] = 1.000 I [inHg] = 29.27 I #1 COMB.
START[de
I [inHg] = 29.61 I #1 INT.PORT TEMP[K] = 291.1 I INJ.TIMING
[de
I AMB. TEMP. [K] = 298.0 I [degF] = 64.38 I
MID.INJ.PRESS.[bar
I [degF] = 76.73 I #1 EXH.PORT PR[bar] = 0.9780 I [psi
I FUEL TYPE (C:H:O) C = 7.300 I [inHg] = 28.96 I
INJ.DURATION [de
I H = 13.90 I I FUEL RATE [kg/hr
I O = 0.000 I PISTON VEL. [m/s] = 16.40 I (MULTI)
[lbm/hr
I FUEL LHV [MJ/kg] = 43.18 I [ft/min] = 3228. I #1 FUEL /
SHOT [k
I [btu/lbm] = 0.1856E+05 I I
I (A/F) STOICH = 14.56 I I 1% FUEL PWR/CYL [
I FUEL MOLEC. WEIGHT = 101.7 I I
----------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I INDIC. POWER [hp] = 32.58 I BRAKE POWER [hp] = 27.93 I
PMEP [bar
I IND.EFFICIENCY [%] = 37.43 I BRAKE EFFICIENCY[%] = 32.09 I
[psi
I IMEP(NET) [bar] = 12.37 I BMEP [bar] = 10.61 I FMEP
[bar
I [psi] = 179.4 I [psi] = 153.8 I [psi
I ISFC [kg/kW/hr] = 0.2228 I BSFC [kg/kW/hr] = 0.2598 I
IMEP(GROSS) [bar
I [lbm/hp/hr] = 0.3662 I [lbm/hp/hr] = 0.4272 I [psi
I IND. TORQUE [N*m] = 38.67 I BRAKE TORQUE [N*m] = 33.15 I
FRICT. TORQUE [N*
I [ft*lbf] = 28.52 I [ft*lbf] = 24.45 I PUMP. TORQUE
[N*
I ISAC [kg/kW/hr] = 3.275 I AUXILIARY POWER [hp] = 0.000 I
#1 EXHAUST TEMP [
I [lbm/hp/hr] = 5.383 I [kW] = 0.000 I [deg
I IND. ENERGY BALANCE:(MULTI) I FRESH AIR IN[kg/hr] = 79.56
I #1 PMAX [bar
I NET PISTON WORK [%] = 37.43 I (WET) [lbm/hr] = 175.4 I
[psi
I AVAIL.EXH.ENTH. [%] = 9999. I TRAPPING RATIO = 1.000 I #1
CA AT PMAX [de
I DEBIT INTK.ENTH.[%] = 9999. I VOL.EFF.(DELIVERED) = 0.9663
I #1 MAX DP/DTH [bar/de
I H. TRAN.(IN-CYL)[%] = 15.93 I #1 VOL.EFF.(PLENUM) = 0.9747
I [psi/de
I BLOWBY AT RING1 [%] = 9999. I A/F TRAPPED = 14.70 I #1 CA
AT MAX DP/DTH[de
I IMBALANCE [%] = 9999. I PHI TRAPPED = 0.9903 I #1 MAX
AVG.GAS T[
I PUMPING WORK [%] = -3.662 I RESIDUAL FRAC. [%] = 3.460 I
[deg
I I BRAKE POWER [kW] = 20.83 I FRIC. (%FUEL ENER.
I I I H.TRAN.(IN-CYL)[k
----------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I NOx [ppm] = 0.000 I HC EMISSIONS(C1) [ppm] = 63.96 I CO
EMISSIONS [pp
I NOx AS NO2 [g/hr] = 0.000 I [g/hr] = 2.622 I [g/hr
----------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
I I BEFORE EVC I AFTER EVC I
--------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I I BEFORE EVC I AFTER EVC I I
--------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I I NO I NO2 I CO I
----------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
I I NO I NO2 I CO I HC I
-------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------
Show
Step 5 - Introduction to Post-Processing and WavePost
In this step we will examine the files created by WAVE for
post-processing and use WavePost to examine and create Time Plots
from the simulation. We will also observe how WavePost displays
Cycle Average quantities using datasets requested in
WaveBuild.
Chapter sections Example Input File:
5.1 The .sum File
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
5.2 The .wvd File Example Output File:
5.3 The .wps File
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
5.4 Time Plots in WavePost
5.5 Cycle Average Results
5.1 The .sum File
At the end of the simulation, WAVE should have created a
.sum file. The .sum file is a simple
ASCII
text file that can be viewed using any text editor, but is intended
for use by the WavePost post- processor.
The .sum file contains a group of name=value pairs that
detail the cycle-averaged results for each
case in the simulation. Cycle-averaged results are single-number
values detailing results that are calculated as an average over the
entire last cycle in the simulation. Examples include Torque,
Power, and Fuel-Consumption (a list of what each name in the
.sum file equates to can be found in
Open the .sum file and examine:
SUM:
HTR%= 15.92595 FRICT%= 5.339182 RES%= 3.459644 VOLEFD= 0.9663104
HTR= 10338.71
THEVO1= 105.0000 THEVC1= 405.0000 OVERL1= 75.00000 COMBSTART1=
-24.34658 VOLEF1= 0.9663104
AFTRP1= 14.70000 PMAXSI1= 61.92454 TH_PMAX1= 14.30476 IMEPSI1=
12.36994 EGR%1= 0.000000
HTR1= 10338.71 TRAPRT1= 1.000016 PVOLEF1= 0.9747397 DPMAX1=
2.043934 TH_DPMAX1= 0.9765625
PEXH= 0.9779931 TINT= 291.1385 TEXH= 1356.193 DELEFF= 1.020265
SCAVRA= 0.9653720
DELEFT= 1.020247 EGR= -0.1722039E-04 BHP= 27.93407 BPOWKW= 20.83043
BMEPSI= 10.60529
TORQBR= 24.45019 IHP= 32.58212 IMEPSI= 12.36994 IMEPBR= 179.4108
ITORQSI= 38.66922
NMEPBR= 179.4108 GMEPSI= 13.58031 GMEPBR= 196.9657 PMEPSI=
-1.210373 PMEPBR= -17.55498
FMEPBR= 25.59414 FTORQ= 5.516422 AUXPOWKW= 0.000000 PHITRAP=
0.9902628 PPMNO= 0.000000
PPMHC= 63.96400 GMHC= 0.7283791E-03 BSHC= 0.1258814 PPMCO= 0.000000
GMCO= 0.000000
HTRIVP1= 18.83508 HTCEVP1= 279.9336 HTREVP1= -124.5681 TH0%B1=
-24.34658 TH1%B1= -16.48995
TH10%B1= -7.087250 TH25%B1= -0.2220210 TH50%B1= 8.000735 TH75%B1=
16.41493 TH90%B1= 23.92243
TH0%_2%B1= 9.931245 TH0%_5%B1= 13.56872 TH0%_10%B1= 17.25933
TH0%_90%B1= 48.26900 TH2%_90%B1= 38.33776
DTLduct1= 299.2815 DTRduct1= 297.5500 DPLduct1= 0.9891816 DPRduct1=
0.9873856 DHduct1= -0.1634780E
DVLduct1= 20.95363 DVRduct1= 20.97836 DFLduct1= 0.2208944E-01
DFRduct1= 0.2208986E-01 DMLduct1= 0.3194962
DTRduct2= 294.3535 DPLduct2= 0.9882348 DPRduct2= 0.9882348 DHduct2=
-0.3115508E-01 DPTOTLduct2= 1.00146
DVRduct2= 20.18555 DFLduct2= 0.2208986E-01 DFRduct2= 0.2360319E-01
DMLduct2= 0.3423029 DMRduct2= 1.000000
DPLduct3= 0.9782504 DPRduct3= 0.9351169 DHduct3= 1.857011
DPTOTLduct3= 1.054536 DPTOTRduct3= 1.07270
DFLduct3= 0.2360543E-01 DFRduct3= 0.2360524E-01 DMLduct3= 1.000000
DMRduct3= 1.308751 DTLduct4= 1107.390
DPRduct4= 0.9949624 DHduct4= 2.728034 DPTOTLduct4= 1.062538
DPTOTRduct4= 1.031677 DVLduct4= 171.7042
DFRduct4= 0.2362354E-01 DMLduct4= 1.308751 DMRduct4= 0.5594955
$case= 1.000000 $subcase= 0.000000
$pi= 3.141593 A_F= 14.70000 SPEED= 6000.000
#
5.2 The .wvd File
WAVE also will create a .wvd file. The
.wvd file is a binary file (not legible in a
text-editor) written in
Ricardo SDF (Standard Data File) format and is also intended for
use by the WavePost post- processor. Data for requested time plots
and datasets are stored in the .wvd file. If necessary,
this
data can be extracted by using either the SDFBrowser or the
sdftoascii command-line program, both installed with WAVE. The
.wvd file also stores a copy of the network layout and
other key
information for post-processing. This file is vital to running the
WavePost post-processor and should not be tampered with by editing,
renaming, etc.
5.3 The .wps File
When any time plots are requested in WaveBuild, WAVE will create a
.wps file at the end of the
analysis. The . wps file is also an XML format file that
can be observed in any web browser by
changing the filename extension to.xml. It is simply a session file
(template) for the WavePost post-
processor detailing what information to extract from the
. wvd file for requested time plots that are
created during the WAVE simulation.
When WavePost is launched directly from WaveBuild, it will look in
the working directory for a . wps file with the same
prefix as the currently loaded . wvm file in
WaveBuild. If it exists, the file is
opened in WavePost and the . wvd and .sum
files from the same simulation are assumed to be the
results set for analysis.
5.4 Time Plots in WavePost
Launch WavePost from WaveBuild by clicking on the WavePost button
in the toolbar . The WavePost GUI will open and automatically load
the .wps created by WAVE (since we requested time
plots in WaveBuild). The network should appear in the main WavePost
window identical to its appearance in WaveBuild (see Figure
1).
Figure 1: WavePost GUI
The Results Frame in the lower right corner of WavePost shows all
results available in the current session file. Plots are
categorized as Time Plots, Sweep Plots, Spatial Plots, or TCMAP
Plots. The Time Plots that we requested in WaveBuild have been
automatically created and are listed in the tree under the Time
Plots folder. Double-click on the Pressure plot to see the
result (see Figure 2). Notice that this plot has a data line for
the single element in duct2 as well as both of the elements in
duct3, where we decided to "Use All Locations".
Figure 2: Time Plot of Pressure in duct2 and duct3
Each plot can be individually opened and edited. Elements of the
plot, such as the data line, the axes, the title, etc. are all
selectable and changeable. Individual data curves can be hidden
through the Curve Selector Panel (Tools > Curve Selector...).
Data can also be Cut, Copied, and Pasted between plots. A single
plot can also be Cloned (File > Clone) to create an exact copy
of a plot to use as a template for new data.
Data can be added to a plot from the existing results ( Add >
Data...) or imported from an ASCII text file, Ricardo SDF-formatted
file, or, on PC, from an MS-Excel file (File > Import >
Excel..., ASCII..., or SDF...). Data on an existing plot can
also be exported to an Excel file (on PC) or to an
ASCII text file by selecting the File >
Export... pull-down menu item.
Plots can be printed directly to a printer or to an image file by
clicking on the Print button in the toolbar.
The plots that were pre-requested in WaveBuild are already created
and listed under the Time Plots folder. But we also requested
some Basic and Valve Datasets. This data has been stored in
the .wvd file and we can now create our own time plots
using this data. We will create an overlay of
Valve Flow Coefficient (CF) and Valve Discharge Coefficient (CD)
vs. non-dimensionalized valve lift (L/D).
Diameter in the Variables option menu. The X Axis Selector
Panel should appear as in Figure 3,
below.
Figure 3: X Axis Selector Panel
Click the OK button to save the selections and close the
panel. Back in the Time Data Panel, under
the Elements option menu, highlight the Junction Cyl1 Intake
1 option and pick Valve Flow
Coefficient in the Variables option menu. When finished, the
Time Data Panel should appear as
in Figure 4.
Figure 4: Time Data Panel
Click the OK button to save the settings and close the panel.
The data curve for Flow Coefficient will appear in the Time Plot
and the plot title and axis labels will be automatically generated.
Double-click on the plot title and edit it to read " CF and CD".
Double-click on the Y-axis and edit the label to read "Valve
Coefficient" (delete the word Flow). Double-click on the X-axis and
edit the label to read "L/D". Double-click on the plot frame
(easiest to do at the top or right-edge of the plot) and click in
the Grid checkbox.
Highlight the data curve and, using the Copy and Paste toolbar
buttons, paste a second data curve on the same plot. Double-click
on the second data curve in the legend to open the Curve Panel.
Click on the Edit Databutton and then click on the Modify Data
Source button. Change the
Variable to VALVE:DISCHARGE_COEFFICIENT and click on the
OK button to save the
Figure 5: CF and CD Plot for cyl1 Intake Valve
Time plots can also be made quickly by right-clicking on an element
in the flow network diagram and selecting a variable to plot.
Right-click on duct1 to create a time plot of Velocity at
location 0.0 (Figure 6) and right-click oncyl1 to create
a time plot of Pressure (Figure 7).
Figure 6: Velocity Time Plot at duct1, Location 0.0
5.5 Cycle Average Results in WavePost
Any dataset that stores data for elements (cells/junctions)
which was requested in WaveBuild can be displayed as color contours
on the flow network diagram. In the Results Frame in the lower
right corner of WavePost, right-click on the Average folder
under the Network Displays folder. This will open the Average Panel
and will automatically redraw the model canvas to display the flow
network as a simple scaled model; the ducts and junctions are
redrawn with relative diameters displayed and color contours to
represent the selected variable. Change the name to Case #1
Velocity and select the Velocity variable, then click the
OK button to close the panel. This creates the Network Display
in the Average folder named Case #1 Velocity.
The scale at the bottom of the window automatically sets upper and
lower bounds by using the highest and lowest calculated values from
the dataset. These can be controlled in the Contour Map Panel
(accessible from the Average Panel, or by double-clicking on the
contour bar at the bottom of the canvas) using the slider bars or
by typing numerical values in the given text fields.
Figure 8: Cycle Average Velocity
Save your file
Save this WavePost session file (. wps) by selecting the Save
As... option from the File pull-down
menu. It is important to save a WavePost file under a different
name when it has been edited (plots created, changed, etc.)
since WAVE will overwrite the file every time the solver is run. If
you would like to rerun the model file and still have access to the
plots and network displays you've just created save the
. wps file to the same directory with a new name.
WavePost
Show
SI Tutorial, Phase 3 - Converting to a Multi- Case,
4-Cylinder Model and Sweep Plots in WavePost
A 4-cylinder model can be built using the single-cylinder
model as a template. The 4-cylinder model will be analyzed over a
range of operating speeds by creating a multi-case analysis.
Phase 3 Steps Optional Starting Point:
1 Copying and Pasting the Single-Cylinder Model
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
2 Joining the Cylinders Using a Simple Y-Junction
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si4.wvm
4 Changes in the .out and .sum Files
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si4.wps
With these five steps, we will create a parameterized 4-cylinder
model that runs un-throttled over a range of 1000-6000 rpm. We will
then observe the behavior of the engine over the speed range
by
creating Sweep Plots in WavePost.
Show
SI Tutorial, Phase 3 - Converting to a Multi- Case,
4-Cylinder Model and Sweep Plots in WavePost
Step 1 - Copying and Pasting the Single-Cylinder Model
Time and effort can be saved when creating our 4-cylinder model by
using the existing single-cylinder model as a template. Copy and
Paste functionality can be used to create three copies of the
single- cylinder network, including the attached ducts representing
the ports. The engine information then needs to be updated to
reflect the addition of three new cylinders.
Chapter sections Example Input File:
1.1 Detaching the Ambient Junctions
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si4.wvm
1.2 Copying and Pasting the Network
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si4.wps
The single-cylinder model currently has Ambient junctions at both
ends, named Intake and Exhaust. We don't need to include these
when replicating the engine
network. These ambient junctions can be detached and moved aside
for the time being.
Middle-click on the end of duct1 that is attached to the
Intake ambient. Holding the middle-mouse button down,
drag the end of duct1 out onto the canvas and release
the mouse button. This will detach the duct from the ambient.
Repeat for the end of duct4 attached to the
Exhaust ambient.
Using the middle mouse button, drag the Intake ambient
further to the left, to move it out of the way. Repeat for the
Exhaust ambient, moving it further to the right. When
finished, the model should appear as in Figure 1.
Figure 1: Ambients Detached from Ducts
1.2 Copying and Pasting the Network
The engine-cylinder network, with the attached ducts representing
the intake and exhaust ports, is identical for all four cylinders
in the engine. We can therefore copy and paste the existing single-
cylinder network three times to create the other cylinders in our
4-cylinder engine. Using the left mouse button, draw a box around
the ducts and engine-cylinder network to select the entire system
(be careful not to draw the box around the ambient junctions). All
of the selected items within the box will be highlighted in red.
Click on the Copy button in the toolbar . Then click on the
Paste
button in the toolbar and the mouse pointer will become a
crosshair icon. Click on the canvas
beneath the cyl1 junction and a duplicate network will be
created. Click on the Paste button and place the duplicate network
two more times to create four identical duct/junction networks to
represent all four engine-cylinders. Note that the ducts and
junctions have all been numbered sequentially.
Figure 2: Canvas Properties panel
1.3 Creating an Engine Block Icon
Adding an Engine Block icon to the canvas will provide a
clickable and selectable object, enabling direct access to the
Engine General Panel (previously accessed thr