1 2 5 0 3 E N G T h e rm o d y n a m ic s – L a b . A s s ig n m e n t Assignment 2: (Laboratory Project) Due Date: Friday 25 th September 2015, 4:00 pm Please prepare MS Word document or print to pdf and submit online through learning at Griffith Weighting: 12.5% of the total marks for this course Please complete the laboratory exercises and submit a report combining labs 1 and 2. The report should be produced with a word processor such as Microsoft Word. Although laboratory work will be done in groups, each student must submit their own individual laboratory report. Laboratory 1: Internal combustion engine efficiency You are part of an engineering team that is developing a trickle irrigation system for agricultural purposes. The system consists of a 20000 L water tank on a stand which is 15 m high and a petrol or diesel powered pump to pump the water from a dam up into the elevated tank (Fig. 1). Your task is to report on the expected performance (from a thermodynamics point of view) of some available motor and pump combinations for the system. You must base your conclusions on experimental data you have collected from the laboratory. The range of choices under consideration has been narrowed to three pumps and two engines. One of the engines is a 232 cc four- stroke diesel motor and the other is a 172 cc four-stroke petrol motor. These engines are located in the mechanical engineering lab at Griffith University along with test beds and dynamometers which you will use to measure their performance and simulate the load that would be placed on the motor by the pump. Another engineer on the team has analized the piping system in Fig. 1 (you will learn how to do this when you study fluid mechanics) and has found that if the flow rate, Q (m 3 /s) is decided then the required difference in head (meters of water) between the 15 m 2 m Pump and motor 20 kL Dam Fig. 1 System in which motor is to be used 2 2 5 0 3 E N G T h e rm o d y n a m ic s – L a b . A s s ig n m e n t inlet and outlet of the pump follows the following equation (Note: multiply hpump by (ρg) to get pressure difference between pump outlet and inlet in pascals): 2 4 2.1 17 Q D h pump += (1) This equation is usually called the ‘system curve’. It is unique for each pipe system. It is different depending on the length and diameter of the pipe, the pipe fittings selected for the system and the difference in elevation between the supply water and tank. D is the inlet diameter of the pipe (in meters) and Q is the flow rate in m 3 /s. Q 2 /D 4 appears in the equation because losses in a piping system are usually proportional to the square of the water velocity inside the pipe. The engineer suggests a pipe with inside diameter D = 35 mm = 0.035 m. Fig. 2 shows the characteristic perfomance curves for three differe ...

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Assignment 2: (Laboratory Project)
Due Date: Friday 25
th
September 2015, 4:00 pm
Please prepare MS Word document or print to pdf and submit
online through learning at Griffith
Weighting: 12.5% of the total marks for this course
Please complete the laboratory exercises and submit a report
combining labs 1 and 2. The
report should be produced with a word processor such as
Microsoft Word. Although laboratory
work will be done in groups, each student must submit their
own individual laboratory report.

3. Laboratory 1: Internal combustion engine efficiency
You are part of an engineering team that is developing a trickle
irrigation system for
agricultural purposes. The system consists of a 20000 L water
tank on a stand which
is 15 m high and a petrol or diesel powered pump to pump the
water from a dam up
into the elevated tank (Fig. 1). Your task is to report on the
expected performance
(from a thermodynamics point of view) of some available motor
and pump
combinations for the system. You must base your conclusions
on experimental data
you have collected from the laboratory. The range of choices
under consideration has
been narrowed to three pumps and two engines. One of the
engines is a 232 cc four-
stroke diesel motor and the other is a 172 cc four-stroke petrol
motor. These engines
are located in the mechanical engineering lab at Griffith
University along with test
beds and dynamometers which you will use to measure their
performance and
simulate the load that would be placed on the motor by the
pump.
Another engineer on the team has analized the piping system in
Fig. 1 (you will learn
how to do this when you study fluid mechanics) and has found
that if the flow rate, Q
(m
3

4. /s) is decided then the required difference in head (meters of
water) between the
15 m
2 m
Pump and motor
20 kL
Dam
Fig. 1 System in which motor is to be used
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inlet and outlet of the pump follows the following equation
(Note: multiply hpump by (ρg)
to get pressure difference between pump outlet and inlet in
pascals):

6. 2
4
2.1
17 Q
D
h
pump
+= (1)
This equation is usually called the ‘system curve’. It is unique
for each pipe system. It
is different depending on the length and diameter of the pipe,
the pipe fittings selected
for the system and the difference in elevation between the
supply water and tank. D is
the inlet diameter of the pipe (in meters) and Q is the flow rate
in m
3
/s. Q
2
/D
4
appears
in the equation because losses in a piping system are usually
proportional to the
square of the water velocity inside the pipe. The engineer
suggests a pipe with inside

7. diameter D = 35 mm = 0.035 m.
Fig. 2 shows the characteristic perfomance curves for three
different pumps being
considered: Pump A, Pump B and Pump C supplied by the
manufacturer. The curves
show the difference in head supplied by the pump for any given
flow rate. Efficiencies
listed in Fig. 2 are mechanical efficiencies for the pump. If you
plot Eq. (1) on the
graph shown in Fig. 2, the points where Eq. (1) intercepts the
characteristic curves for
pumps A, B and C will show the required operating conditions
for your motor.
Flow rate
P
u
m
p
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Pump B
Pump C
Efficiency

8. Centrifugal Pump Characteristic Curves at 2700 rpm
Pump A
Fig. 2 Pump characteristic curves
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Using Fig. 2, Eq. 1 and the equipment available for testing the
internal combustion
engines in the lab, you are required to supply the following
information:
1. The noise in dB made by each of the motors (measured in the
laboratory). Note also
the location where the noise measurement was made.
2. The duty points for pumps A, B and C (i.e flow rate, head
and pump efficiency

10. corresponding to where Eq. (1) intersects the characteristic
curves shown in Fig. 2).
3. The power (and torque) required to turn the shaft of the pump
at each of the three duty
points.
4. Whether or not the engines in the lab are capable of
delivering enough power to run
the pumps at each of the duty points.
5. The thermal efficiency of the engines at each of the three
duty points at the specified
rpm (measured in the laboratory)
6. Time needed to fill the 20000 L water tank for each
pump/motor combination.
7. No. of litres of fuel (and approximate cost) required to fill
the 20000 L tank for each
pump/motor combination?
8. The increase in potential energy of 20000 L of water as
moves from the dam to the
tank.
9. The energy used by the motor in filling the water tank for
each pump/motor
combination.

11. 10. The overall thermal efficiency of the system (use lower
heating value for the fuel).
11. The air/fuel ratio at the conditions tested.
12. The number of kg of carbon dioxide released to the
atmosphere by filling the tank for
each pump/motor combination.
13. A recommendation as to the best pump/motor combination
for this purpose and an
explanation of why you are making this recommendation.
14. Any suggestions of how the efficiency of the system may be
improved.
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13. Report Format
It is expected your report will be typed using a word processor
such as Microsoft Word
(apart from raw data and any hand written calculations that you
may include in the
appendix) and will contain the following sections:
Title:
Name & Date:
Summary: Briefly describe (approximately half a page) the
purpose of the report and the main
findings of your investigation.
Equipment: Include photograph(s) of the apparatus used
Results and Discussion: You should summarize your results in a
table such as is shown
below: Table 1: Results. You should explain briefly how your
calculations were done
including any assumptions you have made. You should also
include a graph of the
experimental results from the lab showing the efficiencies of the
engines for different loads
(i.e. thermal efficiency of the engine (vertical axis) against
power output (horizontal axis)).
Conclusions and Recommendations: Here you should give a
recommendation as to the
best pump/motor combination for this purpose and an
explanation of why you are making this
recommendation. You should also include any suggestions of
how the efficiency of the system

14. may be improved.
Appendix 1: Raw Data This section should contain the raw data
you collected in the lab
Appendix 2: Sample Calculations This section should contain
one of the following:
• hand written sample calculations
• or a printout from a spreadsheet that you used to do your
calculations
• or a printout of a computer program code (e.g. Matlab) that
you made to do your
calculations.
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Table 1: Results
Engine: Diesel Petrol

16. Noise (dB):
Pump: A B C A B C
Flow rate (kg/s)*:
(water)
Pump Head (m)*:
Pump Efficiency*:
RPM*:
Power Required
from motor (kW)*:
Torque Required
from motor (N.m)*:
Can engine deliver
required power?
Thermal efficiency
of engine (%)

17. Time needed to
pump 20000 L of
water
No. of litres of fuel
required to pump
20000 L of water
(L)
Cost of fuel
required to pump
20000 L ($)
Increase in
potential energy of
20000 L of water
(kJ)
Energy used by
motor to fill the
tank (kJ)
Overall thermal
efficiency of the
system
Air/Fuel Ratio:

18. Mass of CO2
produced by
pumping 20000 L
of water (kg):
Recommended
pump/motor
combination:
*These correspond to the duty points and should be determined
before doing the lab.