Thermal Engineering 27

COEP
Lets Crack Online Exam

Objective Questions and Answer: Thermal Engineering 27

Subject: Thermal Engineering 27

Part 27: Objective questions and answers of Thermal Engineering

 

Q1. Producer gas is produced by

a) Carbonization of coal

b) Passing steam over incandescent coke

c) Passing air and a large amount of steam over waste coal at about 65°C

d) Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

 

Q2. Water gas is produced by

a) Carbonization of coal

b) Passing steam over incandescent coke

c) Passing air and a large amount of steam over waste coal at about 65°C

d) Partial combustion of coal, eke, anthracite coal or charcoal in a mixed air steam blast

 

Q3. Water is injected in gas turbine cycle to

a) Control temperature

b) Control output of turbine

c) Control fire hazards

d) Increase efficiency

 

Q4. A gas turbine used in air craft should have

a) High h.p. And low weight

b) Low weight and small frontal area

c) Small frontal area and high h.p.

d) High speed and high h.p.

 

Q5. The closed cycle in gas turbines

a) Provides greater flexibility

b) Provides lesser flexibility

c) In never used

d) Is used when gas is to be burnt

 

Q6. In the axial flow gas turbine, the work ratio is the ratio of

a) Compressor work and turbine work

b) Output and input

c) Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet

d) Actual compressor work and theoretical compressor work

 

Q7. The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the

a) Adiabatic temperature drop in the stage

b) Total temperature drop

c) Total temperature drop in the stage

d) Total adiabatic temperature drop

 

Q8. If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches

a) Isothermal

b) Isentropic

c) Adiabatic

d) Isochoric

 

Q9. Pick up the correct statement

a) Gas turbine uses low air-fuel ratio to economies on fuel

b) Gas turbine uses high air-fuel ratio to reduce outgoing temperature

c) Gas turbine uses low air-fuel ratio to develop the high thrust required

d) All of the above

 

Q10. Intercooling in gas turbine results in

a) Increase in net output but decrease in thermal efficiency

b) Increase in thermal efficiency but decrease in net output

c) Increase in both thermal efficiency and net output

d) Decrease in both thermal efficiency and net output

 

Q11. If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix i and o stand for entry and exit conditions, then in a rotary

machine whose degree of reaction is unity

a) Vi=V0

b) Vt>V0

c) U,<V0

d) V,= U0

 

Q12. Pick up the wrong statement

a) Large gas turbines employ axial flow compressors

b) Axial flow compressors are more stable than centrifugal type compressors but not as efficient

c) Axial flow compressors have high capacity and efficiency

d) Axial flow compressors have instability region of operation

 

Q13. The power available for takeoff and climb in case of turbojet engine as compared to reciprocating engine is

a) Less

b) More

c) Same

d) May be less or more depending on ambient conditions

 

Q14. Pick up the correct statement

a) Large gas turbines use radial inflow turbines

b) Gas turbines have their blades similar to steam turbine

c) Gas .turbine's blade will appear as impulse section at the hub and as a reaction section at tip

d) Gas turbines use both air and liquid cooling

 

Q15. A closed gas turbine in which fuel is burnt directly in the air is not possible because of

a) High pressure ratio

b) Increasing gas temperature

c) High specific volume

d) Paucity of 02.

 

Q16. Choose the correct statement

a) Gas turbine requires lot of cooling water

b) Gas turbine is capable of rapid start up and loading

c) Gas turbines have flat efficiency at part loads

d) Gas turbines have high standby losses and require lot of maintenance

 

Q17. Ram compression in turbojet involves

a) Reduction of speed of incoming air and conversion of part of it into pressure energy

b) Compression of inlet air

c) Increasing speed of incoming air

d) Lost work

 

Q18. In gas turbines^ high thermal efficiency is obtained in

a) Closed cycle

b) Open cycle

c) Both of the above

d) Closed/open depending on other considerations

 

Q19. In the cross compounding of the gas turbine plant

a) H.p. Compressor L connected to h.p. Turbine and l.p. Compressor ot l.p. Tur-bine

b) H.p. Compressor is connected to l.p. Turbine and l.p. Compressor is con-nected to

h.p. Turbine

c) Both the arrangements can be employed

d) All are connected in series

 

Q20. A jet engine works on the principle of conservation of

a) Mass

b) Energy

c) Flow

d) Linear momentum

 

Part 27: Objective questions and answers of Thermal Engineering

 

Q1. Answer: d

Q2. Answer: b

Q3. Answer: b

Q4. Answer: b

Q5. Answer: a

Q6. Answer: c

Q7. Answer: c

Q8. Answer: a

Q9. Answer: b

Q10. Answer: a

Q11. Answer: a

Q12. Answer: b

Q13. Answer: a

Q14. Answer: c

Q15. Answer: d

Q16. Answer: b

Q17. Answer: a

Q18. Answer: a

Q19. Answer: b

Q20. Answer: d

Be the first to comment

Leave a Reply