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and Time |
Semester/year |
Course/Course Code |
Max Marks |
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Ex: I
test/6 th weak
of sem 10-11 Am |
I/II
SEM |
BASIC THERMAL ENGG. |
20 |
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Year: |
Course
code:15ME42T |
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Name
of Course coordinator : Units: CO’s: |
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MARKS |
CL |
CO |
PO |
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2 |
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3 |
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Note:
Internal choice may be given in each CO at the same cognitive level (CL).
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Test/Date
and Time |
Semester/year |
Course/Course Code |
Max Marks |
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Ex:
I test/6 th weak of sem 10-11 Am |
IVSEM |
BASIC THERMAL ENGG. |
20 |
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Year: 2016-17 |
Course
code:15ME42T |
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Name
of Course coordinator : Units:1,2 Co:
1,2
Note:
Answer all questions |
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Question no |
Question |
MARKS |
CL |
CO |
PO |
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1 |
Differentiate between intensive and extensive
properties of a system. Give three examples for each. |
04 |
U |
1 |
1,2, 3,6, 10 |
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2 |
A volume of 0.5 m3 of gas at a pressure of 10 bar and 200oC
is expanded in a cylinder to 1.2 m3 at constant pressure. Determine the amount of
work done by the gas and the increase in internal energy. Assume Cp = 1.005
kJ/kg K and Cv
= 0.712 kJ/kg K. OR A closed system undergoes
a change in process in which 5 kJ of heat energy is supplied to the system.
Determine the change in internal energy under the following conditions. i)
1 kJ of work is done on the system. ii)
1.25 kJ of work is done by the system. |
06 |
A |
1 |
1,2, 3,4, 6,10 |
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3 |
Derive an expression for work done during
polytrophic process. |
04 |
U |
2 |
1,2, 3,4, 6,10 |
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4 |
One kg of gas expands
reversibly and adiabatically. Its temperature during the process falls from
515K to 390K, while the volume is doubled. The gas does 92 kJ of work in this
process Calculate: The value Cp and Cv OR
A gas has a molecular mass
of 26.7. The gas is compressed through a ratio of 12 according to the law PV1.25 = C,
from initial conditions of 0.9 bar and 333 K. Assuming specific heat at
constant volume Cv = 0.79 kJ/kg K. Calculate per kg of mass, work done and heat
flow across the cylinder walls. Gas constant and ratio of specific heat. |
06 |
A |
2 |
1,2, 3,4, 6,10 |
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MODEL
QUESTION PAPER
IV- Semester Diploma
Examination
Course Title: BASIC THERMAL ENGINEERING
Time: 3 Hours] [Max Marks: 100
Note: Answer any SIX from PartA and any SEVEN from Part B
PART-A 6x5=30 marks
1.
Define the terms: (i) system (ii) boundary and (iii) surroundings.
2.
A closed system received a heat transfer of 120 kJ and delivers a work transfer of 150 kJ. Determine the change of internal energy.
3.
Derive expression for work done in constant temperature process with PV diagram.
4.
A volume of 0.5 m3 of gas at a pressure of 10 bar and 200oC is expanded
in a cylinder to 1.2 m3 at constant pressure. Determine the amount of work done by the gas and the increase in internal
energy. Assume Cp
= 1.005 kJ/kg K and Cv = 0.712 kJ/kg
K.
5.
List the assumptions made in thermodynamic air standard cycle.
6 Define IC engine and give the
classification of IC engines.
7.
Explain following terms:
a)
Volumetric efficiency b) Mechanical
efficiency
8.
State and derive Fourier’s law of heat
conduction.
9.
State the applications and limitations of gas turbine.
PART-B
1.
a. Differentiate between intensive and extensive properties of a
system. Give three examples for each. 04
b. A cold storage is to be maintained at -5o
while surroundings are at 35oC. The leakage from the surroundings
into the cold storage is estimated to be 29 kW. The actual C.O.P. of the
refrigeration plant is one - third of an ideal plant working between the same
temperatures. Determine the power required to drive the plant. 06
2.
a) Prove that Cp-Cv=R 04
a) A piston - cylinder
containing air expands at a constant pressure of 150 KPa from a temperature of
285 K to a temperature of 550 K. The mass of air is 0.05 kg. Determine the heat transfer, work transfer and change in internal energy during the process Cp =
1.01 kJ/kg K and Cv = 0.72 kJ/kg K. 06
3.
a) List the thermodynamic processes on gases. 04
b)A piston cylinder containing air expands at a
constant pressure of 150 kpa from a temperature of 285 K to a temperature of
550 K. The mass of air is 0.05 kg. Determine the heat transfer, work transfer
and the change in internal energy during the process. Take Cp = 1 kJ/kg K,
R = 0.287 kJ/kg K. 06
4.
a. Derive an expression for work done during polytrophic process. 04
b. A gas of mass 0.56 kg is
expanded adiabatically from a pressure at 8 bar to 1 bar adiabatically. Initial
temperature of the gas is 200oC. Determine the work done and change
in internal energy. Take Cp = 1 kJ/kg K and Cv = 0.714 kJ/kg
K. 06
5.
Explain with the help of P-V and T-S diagrams working
of Otto cycle and derive an expression for the air standard efficiency of it. 10
6.
A certain quantity of air at a pressure of 1 bar and temperature 70oC
is compressed reversibly and adiabatically until the pressure is 7 bar in an
Otto cycle engine. 460 kJ of heat per kg of air is now added at constant
volume.
Determine:
i) Compression
ratio of the engine. ii)Temperature at
the end of compression. iii)Temperature
at the end of heat addition.Take for air, CP = 1 kJ/kg K and
Cv = 0.707
kJ/kg . 10
7.
a) Compare petrol and diesel engines. 04
b) A heat engine has a piston diameter of 150 mm,
length of stroke 400 mm and mean effective pressure 5.5 bar. The engine makes
120 explosions per minute. Determine the mechanical efficiency of the engine,
if the engine BP is 5 kW. 06
8.
The following data refers to a four stroke diesel engine, speed 300 rpm
cylinder diameter 200 mm, stroke 300 mm, effective brake load 500 kg, circumference
of the brake drum 400 mm, mean effective pressure 6 bar. Diesel oil
consumption 0.1 litres/min, specific gravity of diesel 0.78, calorific value of
oil = 43900 kJ/kg.
Determine : i) Brake power ii)
Indicated power iii) Frictional power 10
9.
a) Define : (i) Conduction (ii)
Radiation. 03
b)
Heat is conducted through a wall of room made of composite plate with a
conduction of 134 W/mK and 60 W/mK and thickness 36 mm and 42 mm respectively.
The temperature at the outer face is 96 0C and 8 0C. Determine the temperature
at the interface of the two materials. 07
10.
a) Explain closed cycle gas turbine with schematic diagram. 06
b)
State the applications and limitations of gas turbine 04