Jawaharlal Nehru Technological University Kakinada 2009-1st Sem B.Tech Aeronautical Engineering Code No: V3152/R07 I II Regular s, AEROSPACE PROPULSION-I - exam paper

Code No: V3152/R07
I II B.Tech I Semester Regular Examinations, November 2009
AEROSPACE PROPULSION-I
(Aeronautical Engineering)
Time: three hours
Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
1. Consider an air standard Brayton cycle, where the air enters the compressor at
0.12 Mpa, 18oC. It leaves the compressor at 0.65 Mpa. TIT is 950o C. Determine
pressure and temperature at every point in the cycle. Work out the efficiency of its
compressor, turbine and the overall engine.
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2. discuss with a lay out sketch the arrangement of a turbo-prop engine and its
thermodynamic cycle of operation. define the role of every component in an
integrated manner.
[16]

3. Consider Ear kind air intakes for a subsonic airplane as that for Gnat/Ajit ghter
plane. Show the internal layout for the swallowed air to reach the engine. discuss
its aerodynamics and thermodynamics in details when the airplane is in its flight
at its maximum level speed.
[16]

4. discuss the aerodynamics and thermodynamics of an external compression super-
sonic air inlet. give 1 example of such supersonic inlet. [16]
5. What do you understand by 'flame stabilization'? elaborate the different methods
used for ame stabilization in a combustion chamber? discuss the swirl vane
mechanism with the help of a sketch.
[16]
6. (a) Differentiate ranging from the following:
i. Over-expanded and Under-expanded nozzles
ii. Convergent and Divergent nozzles
(b) describe and discuss the term 'nozzle efficiency'.
[16]
7. (a) elaborate the functions of impeller and difuser in a centrifugal compressor?
Sketch the variation of velocity and pressure across the impeller.
(b) A centrifugal compressor operates with pre-whirl and is run with a rotor tip
speed of 500m/s. If slip factor is 0.95 and isentropic effciency of the compres-
sor is 0.85, compute the subsequent for operation in standard sea level:
i. Pressure ratio.
ii. The work needed per kg of air.
iii. The power needed for a ow of 30kg/s.
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8. An axial ow compressor takes in 1000 m3 /min of free air at 0.7kgf/cm2 and
50C.The blades are of airfoil kind having chord area and blade length of 19.25cm2
and 6.75cm respectively. Blade ring mean diameter is 60cm and rotational speed
is 6000rpm. On every blade ring there are 50 blades and the blades occupy 10 % of
the axial area of the ow. The values of CL and CD are 0.6 and 0.05 respectively
at zero angle of incidence. Assuming isentropic compression, compute the pressure
rise per blade ring and the theoretical horsepower per stage. presume axial inlet.
[16]

Earning:   Approval pending.