ME 2351 GAS DYNAMICS AND JET PROPULSION – ASSIGNMENT -1
PART – A
1.
State the difference between compressible fluid and incompressible fluid?
2.
Differentiate nozzle and diffuser?
3.
Compare the isentropic and the adiabatic processes.
4.
Define Zone of action and Zone of silence.
5.
What do you understand by adiabatic energy equations? Give the equations.
6.
Explain Mach cone and Mach angle?
7.
Derive the maximum fluid velocity.
8.
Define the critical velocity of sound and prove that c* = {2 Cp (To – T*)}
9.
What are the applications of gas dynamics?
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10. Why is it more convenient to use M instead of M?
11. What is chocked flow through a nozzle?
12. Distinguish between Mach wave and normal shock?
13. When does the maximum mass flow occur for an isentropic flow with variable area?
14. State the expression for dA/A as a function of Mach number?
15. What are the different regions of compressible flow?
16. If an aeroplane goes to higher altitudes maintaining the same speed, the Mach number will remain constant. Say true
or false.
17. Define mach angle and mach wedge.
18. Find the sonic velocity in oxygen when it is at 110° C, g=1.4 and molecular weight 32.
19. How will you illustrate the role of Mach number as a measure of compressibility?
20. A plane travels at a speed of 2400 KM/h in an atmosphere of 5°C, find the mach angle.
PART – B
21. A nozzle in a wind tunnel gives a test section Mach number of 2.0. Air enters the nozzle from a large reservoir at 0.69
2
bar and 310K. The cross sectional area of the throat is 1000 cm . Determine the following quantities for the tunnel for
one dimensional isentropic flow:
(i) Pressures, temperatures and velocities at the throat and test sections.
(ii) Area of cross section of the test section
(iii) Mass flow rate
(iv) Power required to drive the compressor.
22. Explain the effect of Mach number on compressibility. Calculate the percentage deviation due to the assumption of
incompressibility when Mach number is equal to 0.5 and specific heat ratio is 1.4.
2
23. Air flows through a nozzle which has inlet area of 10cm . If the air has a velocity of 80m/s, a temperature of 301K, and a
pressure of 700kPa at the inlet section and a pressure of 25kPa at the exit, finds the mass flow rate through the nozzle
and, assuming one dimensional isentropic flow, the velocity at the exit section of the nozzle.
24. A conical diffuser has entry and exit1 diameters as 0.15m and 0.3m respectively. The pressure, temperature and
velocity of air at entry are 0.96 bar, 340 K and 185 m/s respectively. Determine: Exit pressure, Exit velocity and Force
exerted on the diffuser walls. Assume γ=1.4 and cp =1.005 kJ/kgk.
25. Derive the Bernoulli's equation for compressible and incompressible fluids