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ENG001
UNIVERSITY OF BOLTON
SCHOOL OF ENGINEERING
BENG (HONS) IN MECHANICAL ENGINEERING
SEMESTER 1EXAMINATION 2017/2018
ADVANCED THERMOFLUIDS & CONTROL
SYSTEMS
MODULE NO: AME6005
Date: 18 January 2018 Time: 10.00 – 12.00
INSTRUCTIONS TO CANDIDATES: There are SIX questions.
Answer ANY FOUR questions.
All questions carry equal marks.
Marks for parts of questions are
shown in brackets.
This examination paper carries a total
of 100 marks.
All working must be shown. A
numerical solution of a question
obtained by programming an
electronic calculator will not be
accepted.
CANDIDATES REQUIRE: Thermodynamic properties of fluids
provided
Formula Sheet provided
Take density of water as 1000 kg/m3
Page 3 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Q1 a) Steam at 110 bar has a specific volume of 0.0196 m3/kg, using the property tables find the:
i) Temperature ii) Enthalpy iii) The internal energy
(10 marks)
b) 1 kg of steam at 7 bar and entropy of 6.5kJ/kg K is heated reversibly at constant pressure until the temperature is 250 oc. calculate the heat supplied and show on a –TS diagram the area which represents the heat flow.
(15 marks)
Total 25 marks
Q2 a) explain with the aid of diagram the simple Rankine cycle. (12 marks)
b) A collar bearing has external and internal diameters 200 mm and 160 mm respectively. The collar at the bearing surfaces are separated by an oil film 2 mm thick. Find the power lost in overcoming friction when the shaft is rotating at 250 rpm. Take the dynamic viscosity as 0.9 N s/m2.
(13 marks)
Total 25 marks
Q3 a) Water flow in a circular conduit where there are different diameters.
Diameter D1 = 2m changes into D2 = 3m. The velocity in the entrance profile was measured as 3 m/s. Determine:
i) The discharge at the outlet ii) The mean velocity at the outlet iii) The type of flow in both conduit profiles
Take the kinematic viscosity as 124 ˣ 10 6 m 2 /s
(10 marks)
Question 3 continues overleaf
Please turn the page
Page 4 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Question 3 continued
b) A prototype valve which will control the flow in a pipe system converting paraffin is to be studied in a model. The pressure drop ∆P is expected to depend upon the gate opening h, the overall depth d, the velocity v, the density ρ and viscosity μ. Perform dimensional analysis to obtain the relevant non dimensional groups.
(15 marks) Total 25 marks
Q4 A PID controller designed to control a position of a moving mechatronic
system is shown in Figure Q4. The transfer function of the plant is
)610(
1)(
sssGp
Gc(s) Gp(s) +

Input(s) Output(s)
Figure Q4
The design criteria for this system are:
Settling time < 3.5 sec Overshoot < 15% Steady state error < 5% (for a unit parabolic input = 1/s3)
a) Design a PID controller to determine the parameters Kp, Ki, and Kd and
clearly identify the design procedure. (15 marks)
Question4 continues overleaf
Please turn the page
Page 5 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Question 4 continued
b) If a velocity feedback is introduced into Figure Q4 and suppose
Gc(s) = 5, i) draw a block diagram with the velocity feedback and explain
the effects on a control system of including the velocity feedback.
(4 marks) ii) determine the velocity gain Kv for the damping ratio to be
increased as 0.8. (6 marks)
Total 25 marks
Q5 Figure Q5 shows a manufacturing system which includes a machining centre, a sensor system, and a controller.
Figure Q5 A manufacturing system
The machining centre (an analogue system) is controlled by the controller (a computer numerical control). The sensor system (an analogue system) detects the machining conditions and feedback the detected information to the controller. a) Draw a closedloop control system, with the help of a block diagram, for
the manufacturing system shown in Figure Q5. Clearly identify all the
Controller
Sensor System
Gs(s)
Machining Centre
Gp(s)
Page 6 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
components and explain how the whole closedloop control system works.
(6 marks)
Question 5 continues overleaf
Please turn the page
Question 5 continued
b) If the manufacturing control system’s resolution required is 4 mV, and the range of sensor system varies between 8 Volt to +8 Volt,
i) Design an Analogue to Digital Converter with suitable bits for the
manufacturing controller. (4 marks)
ii) What integer number represented a value of +4 Volts?
(2 marks)
iii) What voltage does the integer 800 represent? (2 marks)
c) If the manufacturing controller consists of a Digital to Analogue Converter with zero order element in series with the machining centre which has a transfer function
)3(
12)(
sssGp
Figure Q5 (c) shows the system. i) Find the sampleddata transfer function, G(z) for the computer
control system. The sampling time, T, is 0.5 seconds. (8 marks)
ii) Find the steadystate error for the computer control system, if the system subjects a step input.
(3 marks)
Page 7 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Figure Q5 (c) Total 25 marks
Please turn the page
Q6 A translational mechanical system is shown in Figure Q6.
Output
 +
Input
Page 8 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Figure Q6 A Translational Mechanical System
(a) Derive the differential equations describing the behaviour of the system. (8 marks)
(b) Select the state variables and transfer the differential equations obtained from Q6(a) above to the relevant firstorder differential equations. (2 marks)
(c) Determine the state space equations and system matrices A, B, C and D, where A, B, C, and D have their usual meaning.
(9 marks)
Question Q6 continues overleaf
Please turn the page
Question 6 continued
d) Briefly explain the following three approaches for the analysis and design of closed loop control systems:
C1
C2
M2
M1
K2
Y2
Y1
F
Page 9 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
i) The Laplace transfer function
ii) The frequency responses technique iii) The state space technique
(6 marks)
Total 25 marks
END OF QUESTIONS
Page 10 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
FORMULA SHEETS
W = P (v2 – v1)
V
V PV = W
1
2ln
Q = Cd A √2gh
12 21
g
ghgCV m
.ΔMΔt
ΔMF
F = ρ QV
Re = V L ρ/
dQ = du + dw
du = cu dT
dw = pdv
pv = mRT
h = hf + xhfg
s = sf + xsfg
v = x Vg
hm w  Q...
1 n
V P  V P =W 2211
Page 11 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
3
2
2
R
RL
LF
n
T
dQds
1
2n12 L
T
TCSS pL
f
fg
pLgT
hTCS
273L n
f
pu
f
gf
pLT
TC
T
hfTCS nn L
273L
1
2n
1
2np12
P
PMRL
T
TL MCSS
sCDFD
2u 2
1
suFL
2
LC 2
1
)( gZPds
dS p
L
pDQ
128
4
gD
L
Rh f
2
v64 2
Re
16f
g2d
fLv4h
2
f
Page 12 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
g
Khm
2
v2
g
VVkhm
2
2
21
H
L
T
T1
T
QSSSgen )12
geno STSSTUUW 02121 )(
)( 12 VVPWW ou
)()()( 21021021 VVPSSTUUWrev
)()()( 00 oVVPoSSTUU
genToSI
Page 13 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
1000
gQHp
RRt60
NT
R
RL
uL2F
t
V
rV
4
2
4
1
2
1
2n
G(s) = )()(1
)(
sHsGo
sGo
(for a negative feedback)
G(s) = )()(1
)(
sHsGo
sGo
(for a positive feedback)
SteadyState Errors
)]())(1([lim0
ssGse iOs
ss
(for an openloop system)
)]()(1
1[lim
0s
sGse i
os
ss
(for the closedloop system with a unity feedback)
)](
]1)()[(1
)(1
1[lim
1
10
s
sHsG
sGse i
sss
(if the feedback H(s) ≠ 1)
])1)((1
)([lim
12
2
0d
sss
sGG
sGse
(if the system subjects to a disturbance input)
Laplace Transforms A unit impulse function 1
Page 14 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
A unit step function s
1
A unit ramp function 2
1
s
First order Systems
)1( / t
ssO eG (for a unit step input)
)1( / t
ssO eAG (for a step input with size A)
(for an impulse input) Secondorder systems
dtr = 1/2 dtp =
P.O. = exp %100))1(
(2
ts = n
4 d = n(12)
PID Controller GPID = Kp + Ki/s + Kds
)/()1
()(
t
sso eGt
inoono
no b
dt
d
dt
d
22
2
2
2
22
2
2)(
)()(
nn
no
i
o
ss
b
s
ssG
Page 15 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Page 16 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Page 17 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
Page 18 of 18
School of Engineering BEng (Hons) Mechanical Engineering Semester 1 Examination 2017/2018 Advanced Thermofluids & Control Systems Module No: AME6005
DIMENSIONS FOR CERTAIN PHYSICAL QUANTITIES
Quantity Symbol Dimensions
Quantity Symbol Dimensions
Mass m M Mass /Unit
Area m/A 2 ML 2
Length l L Mass moment ml ML
Time t T Moment of
Inertia I ML 2
Temperature T θ   
Velocity u LT 1 Pressure /Stress
p /σ ML 1T 2
Acceleration a LT 2 Strain τ M 0L 0T 0
Momentum/Impulse mv MLT 1 Elastic
Modulus E ML 1T 2
Force F MLT 2 Flexural Rigidity
EI ML 3T 2
Energy  Work W ML 2T 2 Shear
Modulus G ML 1T 2
Power P ML 2T 3 Torsional
rigidity GJ ML 3T 2
Moment of Force M ML 2T 2 Stiffness k MT 2
Angular momentum  ML 2T 1 Angular stiffness
T/η ML 2T 2
Angle η M 0L 0T 0 Flexibiity 1/k M 1T 2
Angular Velocity ω T 1 Vorticity  T 1
Angular acceleration
α T 2 Circulation  L 2T 1
Area A L 2 Viscosity μ ML 1T 1
Volume V L 3 Kinematic Viscosity
τ L 2T 1
First Moment of Area
Ar L 3 Diffusivity  L 2T 1
Second Moment of Area
I L 4 Friction
coefficient f /μ M 0L 0T 0
Density ρ ML 3 Restitution coefficient
M 0L 0T 0
Specific heat Constant Pressure
C p L 2 T 2 θ 1
Specific heat Constant volume
C v L 2 T 2 θ 1
Note: a is identified as the local sonic velocity, with dimensions L .T 1