# ME6604 gas Dynamics and Jet propulsion question Bank

Unit-1

Basic Concepts and Isentropic Flows

PART-A
PART A

1.     Define compressible fluid and incompressible fluid.
2.     Define nozzle and diffuser.
3.     What is meant by velocity of sound?
4.     Define mach number& Crocco Number
5.     What do you meant by stagnation pressure and stagnation temperature?
6.     Define stagnation enthalpy and stagnation density.
7.     What are the various regions of flow?
8.     Define Mach angle.
9.     What is meant by isentropic process?
10.    Define compressible fluid and incompressible fluid.
11.   What are the types of nozzles?
12.    What is meant by stagnation state?
13.      Define Mach cone and Mach wave.

PART-B

 1.     Derive an expression for the effect of mach number on compressibility. 2.     Derive the expression for an energy equation. 3.     A supersonic diffuser diffuses air in an isentropic flow from a mach number of 3 to a mach number of 1.5. The static conditions of air at inlet are 70 kpa and -7 C. If the mass flow rate of air is 125 kg/s, determine the stagnation conditions, areas at throat and exit, static conditions (pressure, temperature, velocity) of air at exit. 4.     A supersonic nozzle expands air from Po = 25 bar and T0 = 1050 K to an exit pressure of 4.35 bar: the exit are of the nozzle is 100 cm2. Determine i) throat area ii) pressure and temperature at the throat iii) temperature at exit iv) Exit velocity as fraction of the maximum attainable velocity v) mass flow rate. 5.     A conical diffuser has entry and exit area of 0.11 m2 and 0.44 m2 respectively. The pressure, temperature and velocity of air at entry are 0.18 Mpa, 37 ‘C and 267 m/s respectively.  Determine i) mass flow ratw  ii) the mach number, static temperature and static pressure of the air leaving diffuser  and iii) the net thrust acting on the diffuser 6.     Air at P1=3 bar and T1=227 C is flowing with a velocity of 200 m/s in a 0.3m diameter duct. If Cp=1050 J/KgK and ν=1.38. Determine the following (i)                Stagnation temperature and pressure (ii)             Mass flow rate of air (iii)           Mach number                 (Iv) Stagnation pressure. Assuming the flow is in compressible.