GAS TURBINES MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

GAS TURBINES MULTIPLE

CHOICE QUESTIONS

(MCQ) WITH ANSWERS

Gas turbines produce huge power by

expanding gases. These gases are

produced due to burning o fuel. The

gases expand through a series of fixed

and moving blades. Compressor increases

the pressure. It is run by the turbine.

Burning fuel in the combustion chamber

increases the temperature. Volume o the

gases increases at constant pressure.

1.Types of gas turbines based on combustion process are

(a) Constant pressure type

(b) Constant volume type

© Constant pressure and volume types

(d) None

ANS: (c )

2. Gas turbine work on

(a) Brayton Cycle

(b) Atkinson Cycle

© Both Brayton & Atkinson Cycles

(d) none

ANS: (c )

3. Gas turbines are not classified on the basis of

(a) Impulse turbine

(b) Reaction turbine

© Impulse-reaction turbine

(d) None

ANS: (b)

4. Gas turbine work on

(a) Open Cycle

(b) Closed cycle

(c ) Both open & closed cycles

(d) None

ANS: (c )

5. Gas turn work on the basis of

(a) axial flow

(b) radial flow

© Both axial & radial flow

(d) None

ANS: ( C )

6. The true relation in a Joule Cycle is

(a) T₁/T₂ = (p₂/p₁)^¥/1-¥

(b) T₁/T₂ = (p₂/p₁)^¥-1/¥

(c) T₁/T₂ = (p₂/p₁)^{(¥+1  )/(1-¥)}

(d) None

ANS: (b)

7. Compressor efficiency is

(a) Isentropic work/Isothermal work

(b) Isentropic work/actual work

© Actual work/isentropic work

(d) None

ANS: (b)

8. Turbine efficiency is

(a) Isentropic work/Isothermal work

(b) Isentropic work/actual work

© Actual work/isentropic work

(d) None

ANS: (c )

9. Thermal efficiency is

(a) Heat supplied/Heat rejected

(b) Heat rejected/ heat supplied

(c ) Net work/Heat supplied

(d) None

ANS: ( C )

10. The rate of air flow per kWh output power is

(a) W_net/746

(b) 3600/746

© 3600/W_net

(d) None

ANS: (C )

11. Work ratio in a gas turbine is

(a) W _compressor/W _turbine

(b) W _Turbine/W _Compressor

(c ) W _compressor X W _turbine

(d) None

ANS:(d)

12. Work ratio in a gas turbine is

(a) W _compressor/W _turbine

(b) W _Turbine/W _net

(c ) W _Net / W _turbine

(d) None

ANS: ( c )

13. Thermal efficiency of open gas cycle is improved by

(a) Intercooling & reheating

(b) Reheating & regeneration

© Intercooling, reheating & regeneration

(d) None

ANS: ( c)

14. Thermal efficiency of a gas turbine for a certain pressure ratio increases with the

(a) Decrease of inlet temperature

(b) Increase of inlet temperature

© increase & decrease of inlet temperature

(d) None

ANS: (b)

15. Thermal efficiency of a gas turbine at a certain pressure ratio increases with the

(a) Increase of atmospheric temperature

(b) Decrease of atmospheric temperature

© Both with increase & decrease of atmospheric temperature

(d) None

ANS: (b)

16. Joule/Brayton Cycle consists of

(a) two isothermal & two isentropic processes

(b) Two isobaric & two isothermal processes

© two isobaric & two isentropic processes

(d) none

ANS: (c )

17. Atkinson Cycle consists of

(a)  Two isentropic & two isobaric processes

(b) Two isentropic, one isobaric & one isochoric processes

(c ) Two isentropic & two Isentropic processes

(d) None

ANS: (b)

18. Work ratio in a gas turbine increase with the

(a) Decrease of turbine inlet temperature

(b) Increase of turbine inlet temperature

(c ) Both with increase & decrease of turbine inlet temperature

(d) none

ANS: (b)

19. Work ratio in a gas turbine increase with the

(a) Increase of pressure ratio

(b) Decrease of pressure ratio

(c ) Both with increase & decrease of pressure ratio

(d) None

ANS: (b)

20. Optimum pressure ratio for maximum specific work output in a Joule Cycle is

(a) r_p =(T3/T1)^¥/(2(¥-1))

(b) r_p=(T3/T1)^2¥/(¥-1

(c ) r_p=(T3/T1)^(¥-1)/2¥

(d) None

ANS: (a)

21. Efficiency of a closed Cycle gas turbine

(a) η =1—1/(r_p)^¥/(¥-1)

(b) η =1—1/(r_p)^(¥–1)/¥

(c ) η =1—1/(r_p)^{(¥ +1)/(¥-1)}

(d) None

ANS: (b)

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