## Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 14

• Tuesday, April 25, 2017
• • ,
• No comments

Roll No. ......................
Total No. of Questions : 09]
B. Tech. (Sem. – 4th)
APPLIED THERMODYNAMICS - II
SUBJECT CODE : ME – 208 (2008 Batch)
Paper ID : [ME210]
Time : 03 Hours
Instruction to Candidates:
1) Section - A is Compulsory.
2) Attempt any Four questions from Section - B.
3) Attempt any Two questions from Section - C.
Section – A
Q1)
a) What is the function of carburetor.
b) Explain why the cooling of IC Engine is necessary.
c) Explain the term slip and power input factor as applied to centrifugal
compressor.
d) Explain the phenomenon of 'surging' in a centrifugal compressor.
e) Explain the term polytropic efficiency of compress or (2), | .
f) What advantage is gained by splitting the turbine section of a gas turbine
into two parts, namely compressor turbine and power turbine (3).
g) Compare a gas turbine with a steam turbine (2).
h) Explain the term Octane number (2).
i) Compare gas turbine and reciprocating engine.
j) What is 'Morse Test'.

Section - B
Q2) Draw the valve timing diagram for an average petrol engine. Give reasons for
early opening of exhaust valve and late closing of inlet valves.

Q3) The following data refers to a test on a single cylinder oil engine working on
fbur stroke cycle:
Diameter of-brake wheel = 60 cm; rope dia= 3 cm; the dead load is 25kg,
when the spring balance reading is 5 kg, and the engine is running at400 rcvl
min. The indicator diagram has area : 4 cm2,length : 6cm and spring
stiffness is 12. The fuel consumption is 0.23kglb.h.p.-hr. and the fuel used
has a calorific value 10500 kcal/kg. Taking cylinder bore 10 cm and piston
stroke l5 cm calculate the B.H.P., I.H.P., mechanical and indicated thermal
of the engine.

Q4) l)describe the function of impeller and diffuser in centrifugal compressor.

Q5)  The centrifugal compressor of a gas turbine requires 3000 H.P. when running
at  16000 rev/minute. The tip diameter of the impeller is 50 cm and the uniform
width of casing of the vortex chamber between impeller and diffuser is 49rn.
Measurements show that static pressure and temperature at a radius of 27
cm are 2.5 kg, /cm and I10"C. The atmosphere in the test house is I
kg,.icn-r2. Assuming slip factor:0.94 and neglecting friction in the vortex
chamber. calculate :
(a) The mass flow l
( b) 'fhe resultant speed at the section given
(c) The total temperature at the section given
tt may be assumed that there is no prewhirl and the conditions in the vaneless
space correspond to those of free vortex.

Q6) An axial compressor has a degree of reaction of 0.5 at the mean radius with
relative air angles of I 30" and l00u at rotor inlet and outlet respectively. The
angles are measured in the same direction from the blade velocity direction.
The overall stagnation pressure ratio is 3.5 and the stagnation isentropic
efficiency is 85% when the inlet stagnation temperature is 330 K. The blade
speed is constant at 200 m/s and the flow velocity is also constant in the
compressor. The work done factor is 0.85. Find the stagnation polytropic
efficiency and .the number of stage.

Section - C
Q7) In a gas turbine plant, air is compressed from atmospheric conditions to the
delivery pressure 4bar and temperature 480 K. In the combustion chamber,
a fuel of calorific value 45000 kJ/kg is injected and combustion takes place at
consmnt pressure. The injection of fuel is so regulated that the air fuel ratio is
60 : I . f,or a mass flow rate of l0kg/s design the turbine e nozzle for throat and
exist areas. The maximum temperature of blades is to be 873 K. Take
cp =1 .005 kJ/kg and  =1.4 both for air and gases. p
QS) Write a note on any two of the following :
(a) Ramjet
(b) Turbo prop
(c) Supercharging of IC engines
Q9) A four cylinder, four stroke engine is supplied with l5.25 kg of air/kg of octane fuel having heat value 10650 kcal/kg. Calculate (a) the compression
ratio. (b) brake specific fuel consumption, (c) bore and stroke; (d) b.m.e.p.

The following data may be assumed :- air standard efficiency:0.53, relative efficiency : 0.70, mechanical efficiency : 0.g; volumetric efficiency : 0.g; stroke equal 1.25 times the bore ; suction conditions are I kg/cm and 60"C the engine runs at 2400 rev/min and develops 96 brake power.