thermal engineering II

1.The critical pressure ratio for initially dry saturated steam is.......

• A.0.528

• A.0.546

• C.0.577

• D.0.582

2.Nozzle efficiency is described as.......

• A. Isentropic heat drop/useful heat drop

• B. useful heat drop/isentropic heat drop

• C. saturation temperature/super saturation temperature

• D. super saturation temperature/saturation temperature

3.The steam leaves the nozzle at a.........

• A.High pressure and low velocity

• B.High-pressure and high velocity

• C.Low pressure and low velocity

• D.Low pressure and high velocity

4.The flow of steam in a nozzle is subsonic at......

• A.Throat

• B.Divergent portion

• C.Convergent portion

• E.Convergent divergent portion

5. In convergent nozzle velocity velocity attained is.......

• A.Velocity of sound

• B.Supersonic velocity

• C.Around 500 m/sec

• D.1000 meter/sec

6. The effect of friction in nozzle is to .......

• A.Keep dryness fraction constant

• B.Increase dryness fraction

• C.Decrease dryness fraction

• D.First increase dryness fraction upto certain limit and then decrese it

7. Under thermal equilibrium, flow of steam is.......

• A.Isentropic

• B.Adiabatic

• C.Hyperbolic

• D.Polytropic

8.The critical pressure ratio for initially superheated steam is.......as compared to initially dry saturated steam

•    A. More

•    B.Less

•    C.Same

• D.None of the above

9.For critical pressure ratio, the discharge through a nozzle is.......

•    A.Maximum

•    B.Minimum

•    C.Zero

• D.Some value between maximum and minimum

10.. For a convergent divergent nozzle,critical pressure ratio occurs when .......

• A.Velocity at exit becomes sonic

• B.Shock wave of occurs

•    C. Nozzle efficiency is maximum

•    D.Increase in exit and inlet pressure ratio does not increase steam flow rate