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Scheme - E
Sample Question Paper
Course Name : Mechanical Engineering Group
Course Code : ME/ MH/MI
Semester : Fourth
Subject : Thermal Engineering
Max Marks : 100 Time: 3 Hrs.
Instructions:
1. All questions are compulsory.2. Illustrate your answers with
heat sketches whenever necessary.3. Figures to the right indicate
full marks.4. Assume suitable data it necessary.5. Preferably write
the answers in sequential order.
Q.1 A) Answer any SIX of the following: 12 Marks
a) Define Entropy state its unitb) State Boyles lawc) State
advantages & disadvantages of Solar energyd) State the names of
any two boiler mountings and any two boiler accessoriese) State
Dattons law of partial pressuref) Stat Stefan Boltzman lawg) Define
a Black body used in heat transferh) State zeroth law of
thermodynamics
Q.1 B) Answer any TWO of the following: 08 Marks
a) Draw a labeled sketch of bio-gas plant. State two application
of bio-gasb) State the sources of air leakage in condensersc) A
certain gas at high pressure and high temp. first expands
adiabatically. After
adiabatic expansion, it is compressed isothermally to its
original volume. After this,
the gas is heated at const. volume, so that gas is restored to
original temperature.
Represent this cycle on P-V and T-S diagram.
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Q.2 Answer any FOUR of the following: 16 Marks
a) Write steady state energy equation & apply it to
condenser & compressor.b) A heat exchanger is to be selected
for pasteurization of milk. What material & which
type of heat exchanger should be selected? Justify your
answer.
c) An automobile tyre contains certain volume of air at absolute
pressure 300 kp a and20 C. Barometer reads 750 mm of Hg. The
temperature of air in the tyre rises to 80 C
due to running of vehicle for two hours, Find new pressure in
tyre, Assume air as
ideal gas and tyre does not stretches due to heating.
d) Describe the working principle of economizer with neat
sketch.e) Classify the steam turbines according to 1.pressure of
steam. 2. No of stages.f) One kg of gas at 1.2 bar and 50 0C having
1 m3volume is heated at const. pressure till
its volume becomes 1.8m3. Calculate the workdone and change in
internal energy.
Assume Cp=1.1KJ/KgK.
Q.3 Answer any FOUR of the following: 16 Marks
a) Study the given figure 1 (Q3, I) and answer the following
questions1.Identify process BD2.State condition steam at D3.Name
critical point4.State formula to calculate enthalpy at D
b) A composite wall is formed of 2cm copper plate, 3mm layer of
abctos & 4.5 cm ofFiber glass. The wall (From surface to
surface) is subjected to temperature difference
of 500C. Considering heat flow in one direction, from surface to
surface,
Calculate heat flow per m2 area of wall.
Take conducting values as follows
K copper = 370w/mC, Kasbestos=150w/mC, K fiber glass=
74w/m.C
c) The COP of a refrigerator operating on cannot cycle is 5.4
when it maintains 50C inthe evaporator. Calculate the condenser
temperature and refrigerating effect if the
power required to drive the unit is 5KW.
d) Differentiate between iso thermal and adiabatic process.e)
Give the classification of boiler.f) What are the advantages of
regenerative feed heating?Name the different methods of
regenerative feed heating
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Q.4 Attempt any FOUR of the following: 16 Marks
a) State the advantages and limitations of wind energy.b) What
is boiler drought? Why it is necessary?c) Compare Jet & surface
condensers on the basis of construction, performance &
application.
d) Differentiate between reversible and irreversible process.e)
Describe the working principle of Hydro electric power plant with
neat sketch.f) Compare induced & forced droughts.
Q.5 Attempt any FOUR of the following: 16 Marks
a) State Kelvin-Planck and clausius statement of second law of
thermodynamics
b) Explain with neat sketch the working of throttling
calorimeter.
C) Steam at 10 bars & 0.87 dryness is available. How much
heat should be added per kg
At Constant pressure to make it dry & started steam.
d) Differentiate between natural convection and forced
convection heat transfer.
e) Draw a neat labeled sketch of surface condenser
Q.6 Attempt any TWO of the following: 16 Marks
a) Draw labeled sketch of Lamont Boiler. Show the path of water
steam and Air-fluegas. Explain T/S working.
b) What is compounding of steam turbines? Explain different
methods of compounding.Explain any one method.
c) 0.5 kg of air at 179C expends acrobatically to three times
its original volume and inthe process fall in temp is from 179 C to
18 C. The work done during expansion is 57
kj. Determine the specific heats of air at constants pressure
and constant volume.
F
E
B C
T D
A
S
Figure for Q 3 (iii)
