7/25/2019 Hydraulics Lab Manual

1/12

1

CE

Hydraulics

Laboratory Manual

7/25/2019 Hydraulics Lab Manual

2/12

2

CE Hydraulics

Experimental Lab No.1

FLOWS IN PIPE NETWORKS

Purpose: To study and compare head losses in various pipe systems.

Apparatus: Fluid Circuit System

Procedure:1. Remove air from manometers

2. Arrange the circuit to run test on pipes 1, 2, and 3 in series (do not use the smallest pipe).Take comparative measurements for each of the three, 66 inch lengths of pipe at 3 flow

rates.

3. Repeat (2) rearranging the pipes into a parallel configuration.

Report:

1. Present data in both tabular and graph forms, that is plot headloss versus discharge for

each pipe system.

2. What conclusions can you draw about head losses in the various pipes of each system?

3. What is the effect of putting the pipes in parallel as compared to series?

7/25/2019 Hydraulics Lab Manual

3/12

3

7/25/2019 Hydraulics Lab Manual

4/12

4

CE Hydraulics

Experimental laboratory #2

CENTRIFUGAL PUMP

Purpose: Develop the characteristic curve for a centrifugal pump.

Theory: A centrifugal pump imparts energy to a fluid by developing a centrifugal force

through the action of vanes on the fluid. The discharge from a centrifugal pump, run at constant

speed (rpm), depends on the head looses of the system against which it is pumping. A plot of thehead difference (in head) across the pump vs. the discharge at that head difference is the pump

characteristic curve.

Apparatus: To perform this experiment, the following materials are required: a centrifugalpump, a water tank, a pressure gage, a tachometer, a stopwatch, a graduated cylinder, and a scale

or ruler.

Procedure:

1. With the storage tank filled to a level above the pump inlet, open all valves fully andbring the pump to full speed (approx. 1750 rpm). The speed is read on the tachometer (in

rpm x 10).

2. Measure the flow using a stopwatch and graduated cylinder or bucket as required.

3. Observe the pressure difference across the pump and the elevations of the pump inlet and

outlet.

4. Repeat steps 2 and 3 at least four more times (once with the valve completely closed),

closing the gate valve slightly each time causing a pressure difference to increase. Allowthe system to reach a new equilibrium before each measurement.

5. Repeat steps 2 through 5 for pump speeds of 1500 and 1200 rpm.

Report:

1. Plot the pump characteristic curve for each pump speed and discuss the relationshipbetween head and discharge.

2. Compute the water horsepower at each flow rate and head difference.

3. Discuss the accuracy of the method used to determine the flow rate and head difference

across the pump. Estimate the magnitude of any suspected error.

4. Discuss how you would develop an experiment to evaluate the efficiency of the pump.

7/25/2019 Hydraulics Lab Manual

5/12

5

7/25/2019 Hydraulics Lab Manual

6/12

6

CE HydraulicsExperimental laboratory #3

HYDRAULIC JUMP

Objective: To observe and understand the characteristics of the hydraulic jump and the sluicegate used in the flume to create conditions allowing the jump to occur.

Apparatus: Flume and sluice gate.

Theory: The hydraulic jump occurs when flow transitions from supercritical to subcritical

flow in an open channel. It is a case of rapidly varied, steady flow. In a horizontal, rectangular

channel, the sequent (downstream) depth is related to the initial (upstream) depth by the equation:

where y2 is the initial depth, y3 is the sequent depth, b is the width of flume and Q is the flow rate.

In the laboratory flume, the initial depth is produced using a sluice gate which controls the flow

under the gate (the initial depth in the hydraulic jump) based on the depth of flow upstream ofthe gate, y1, as shown below. The sluice gate is analyzed using the energy equation.

Procedure: For each of three flow rates (160, 220 and 275 gpm) and associated sluice gateopenings (1", 1" and 2") observe y1, y2 and y3.

Analysis and Report:

a. For the measured depths, y1, y2 and y3, determine if the flow is subcritical or

supercritical.

b. For each of the measured values of y2, calculate the theoretical value of y3 and

compare to the observed value.

c. For each flow rate, plot the specific energy curve and identify the depths of

interest. (y1, y2, y3, yc)

d. Compute and plot the energy losses in the jump for each sluice gate opening and

plot as a function of flow rate.

e. For each sluice gate opening, compute the losses occurring in flow under thesluice gate and plot as a function of flow rate.

7/25/2019 Hydraulics Lab Manual

7/12

7

7/25/2019 Hydraulics Lab Manual

8/12

8

CE HydraulicsComputational Lab No. 1

SOLUTION OF NONLINEAR EQUATIONS IN THE ANALYSIS OF PRESSURIZED

PIPEFLOW

Objective: Determining either the flow-rate or pipe diameter for a pressurized pipe systemrequires the solution of a nonlinear equation. Depending on the resistance equation and

whether there are significant minor losses, the resulting nonlinear equation may have to

be solved repeatedly as part of the solution process. The objective of this lab is to use anonlinear equation solver of your choice to solve a pressurized pipe flow problem, to

compare the process and results of using two different resistance equations and to

evaluate the effects of some modifications in the piping system.

Approach: Develop a general equation for determining the flow rate in the pressurized

piping system shown in Figure 1 given data on the system configuration (pipe material,

diameter, length, layout, minor loss coefficients, pressure requirements, etc.) for twocases: where the head loss is computed by the Darcy-Weisbach and the Hazen- Williams

equations. Given the resulting nonlinear equation, select an approach for solution (e.g.

Solver in Excel, MATLAB program). Test the approach on an appropriate exampleproblem in the text. Once you are sure your process provides the correct solution, apply it

to the system presented in Figure 1.

Report: Describe the development of the equation for Q and define all of the variables

(but present only the original equation(s) and the resulting equation that you develop).

Provide a detailed description (e.g. a flow diagram) of the procedure used to solve theproblem. Reference the values you used to describe the piping system including selection

of minor loss coefficients, resistance coefficients, etc. In the report you should present the

flow rate as a function of valve opening in graphical form for both resistance equations

and for all three pipe configurations (3 graphs, properly labelled). In the discussioncomment on the effect of the resistance equation and the effect of changing the pipe

diameter and material on the flow rate computed for the system.

7/25/2019 Hydraulics Lab Manual

9/12

9

Solve this problem:The piping system in a typical dwelling in an older home is shown below. The exit diameter of

the faucet is -inch. All of the piping is galvanized iron and the fittings are threaded. Pressure inthe main is 40 psi (gage).

1. Determine the flow rate, using both the Darcy-Weisbach and the Hazen-Williamsequation, when the faucet valve is fully open, open, open and open.

2. Using only the Hazen-Williams equation, determine the effect on the flowrate of

replacing the section of pipe with a 1 pipe.

3. Using the Hazen-Williams equation, determine the impact on the flowrate of replacing

the4. galvanized pipe in the original problem with copper tubing of the same diameter.

Data for the globe valve (from White, 5th edition, 2003)

Fractional opening K/K open1.00 1.03

0.70 1.38

0.50 1.75

0.30 3.75

1.00 1.03

0.70 1.38

0.50 1.75

0.30 3.75

Figure 1: Portion of a household plumbing system for which you want to compute the flowrate.

(Note: drawing not to scale

7/25/2019 Hydraulics Lab Manual

10/12

10

CE Hydraulics

Computational Lab No. 2

PIPE NETWORK FLOW ANALYSIS

Objective: Apply a pipe network analysis program to determine the flow and pressure in

a pipe network given inflows, demands (outflows), the lengths and diameters

of pipes and the characteristics of a pump.

Apparatus: Haestad methods WaterCad program.

Theory: Hardy Cross Pipe Network Analysis as presented in lecture.

Report:

1. For the network shown, set up the problem in WaterCad.

2. Solve for the distribution of flow and pressure in the system assuming all

pipes are new cast iron.

3. Repeat the solution assuming that the pipes are now old cast iron.

4. Describe the effects of aging on the performance of the pipe network - flowdistribution and pressure.

5. A minimum pressure of 40psi is required in the system. If this criterion isnot met,describehow can the system be redesigned to achieve it?

Data for the pipe network are as follows. Schematic is on the following page.

All pipes are 6 cast iron.

Reservoirs Pump Characteristics

Flow (cfs) Head (ft)

R-1 180 ft. 1.0 40R-2 200 ft 1.5 35

2.0 26

Pipes JunctionsLength Demand (cfs)

P-1 500 J-1 0

P-2 800 J-2 0

P-3 1000 J-3 1P-4 800 J-4 2

P-5 1200 J-5 2

P-6 1000P-7 500

P-8 500

P-9 500`

7/25/2019 Hydraulics Lab Manual

11/12

11

7/25/2019 Hydraulics Lab Manual

12/12

12

CE Hydraulics

Computational lab No. 3GRADUALLY VARIED FLOW CALCULATIONS

Objective: Develop a computer-based solution (e.g. spreadsheet) to calculate the water surface

profile for a gradually varied flow situation.

Theory: Gradually varied flow in open channels results when disturbances cause the depth of

flow to deviate from the normal depth. Depending on whether the flow is sub orsupercritical, the effects of these disturbances are propagated upstream or

downstream, affecting the depth of flow. Calculations of flow depth in graduallyvaried flow are based on the energy equation. Manning's equation is used to

compute losses due to frictional resistance. One method for the computation of thedepth of flow at various points along the channel (called the flow profile) is thedirect step method, applicable to prismatic channels. Using this approach, the

distance between specified depths are calculated.

Procedure: Use the direct step method to compute the flow profile in the rectangular, concrete

lined channel shown below. The channel has a bed slope of 0.0002 and the width is25 ft.

where the weir coefficient, C, is 3.95. Compute the profile to the point where the depth of

flow is within 5% of the normal depth.

As part of the computational scheme, compute the normal and critical depth for the channel

to verify whether the flow is sub or super critical. Plot the resulting flow profile.

Analyses and Report:

Perform the computation for a flow rate of 310 cfs, an appropriate roughness

coefficient and the specified slope. Repeat these calculations, increasing and thendecreasing the flow rate, the slope and the roughness by 10% (one at a time). (This

procedure is called a sensitivity analysis). Provide a graphical display of the results.Discuss the sensitivity of the distance required to approach the normal depth on

variations in the flow rate, the channel slope and the roughness coefficient. Discusssome reasons why this sort of analysis (sensitivity analysis) may be of interest.