Thermal Engineering 29

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Objective Questions and Answer: Thermal Engineering 29

Subject: Thermal Engineering 29

Part 29: Objective questions and answers of Thermal Engineering

 

Q1. Air-fuel ratio in a jet engine will be of the order of

a) 10:01

b) 15:01

c) 20:01

d) 60:01:00

 

Q2. In which case the air-fuel ratio is likely to be maximum

a) 2-stroke engine

b) 4-stroke petrol engine

c) 4-stroke diesel engine

d) Gas turbine.

 

Q3. In jet engines the compression ratio

a) Varies as square root of the speed

b) Varies linearly to the speed

c) Varies as square of the speed

d) Varies as cube of the speed

 

Q4. The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turbine and fixed higher and lower temperature) with increase in pressure ratio will

a) Increase first at fast rate and then slow

b) Increase first at slow rate and then fast

c) Decrease continuously

d) First increase, reach maximum and then decrease

 

Q5. The working fluid in ai turbine is

a) In two phases

b) In three phases

c) In a single phase

d) In the form of air and water mixture

 

Q6. Gas turbine cycle with regenerator

a) Increases thermal efficiency

b) Allows high compression ratio

c) Decreases heat loss is exhaust

d) Allows operation at very high altitudes

 

Q7. The compression ratio in a gas turbine is of the order of

a) 3.5 : 1

b) 5:01

c) 8:01

d) 12:01

 

Q8. Reheating in multistage expansion gas turbine results in

a) High thermal efficiency

b) Reduction in compressor work

c) Decrease of heat loss in exhaust

d) Maximum work output

 

Q9. The main purpose of reheating in gas turbine is to

a) Increase temperature

b) Reduce turbine size

c) Increase power output

d) Increase speed

 

Q10. Reheating in gas turbine results in

a) Increase of work ratio

b) Decrease of thermal efficiency

c) Decrease of work ratio

d) Both (a) and (b) above

 

Q11. Work ratio of a gas turbine plant is ratio of

a) Net work output and work done by turbine

b) Net work output and heat supplied

c) Work done by turbine and heat supplied

d) Work done by turbine and net work output

 

Q12. Work ratio of a gas turbine may be improved by f

a) Decreasing the compression work

b) Increasing the compression work

c) Increasing the turbine work

d) (a) and (c) above.

 

Q13. Maximum temperature in a gas turbine is of the order of

a) 2500°C

b) 2000°C

c) 1500°C

d) 700°C.

 

Q14. In the aircraft propellers

a) The propulsive matter is caused to flow around the propelled body

b) Propulsive matter is ejected from within the propelled body

c) Its functioning does not depend on presence of air

d) All of the above

 

Q15. In air breathing jet engine, the jet is formed by expanding

a) Gases

b) Solids

c) Liquid

d) Highly heated atmospheric air.

 

Q16. Ram-jet engine

a) Is self-operating at zero flight speed

b) Is not self-operating at zero flight speed

c) Requires no air for its operation

d) Produces a jet consisting of plasma

 

Q17. For speed above 3000 km/hour, it is more advantageous to use

a) Turbo-jet engine

b) Ram-jet engine

c) Propellers

d) Rockets

 

Q18. A simple turbo-jet engine is basically

a) A propeller system

b) Gas-turbine engine equipped with a propulsive nozzle and diffuse

c) Chemical rocket regine

d) Ram-jet engine

 

Q19. Which of the following plants is smallest and lightest for genrating a given amount of power?

a) Steam power plant

b) Petrol engine

c) Diesel engine'

d) Gas turbine plant.

 

Q20. In turbo fan engine, the jet velocity as compared to turbo-jet engine is

a) Less

b) More

c) Same

d) May be less or more depending upon speed

 

Part 29: Objective questions and answers of Thermal Engineering

 

Q1. Answer:

Q2. Answer: d

Q3. Answer: c

Q4. Answer: d

Q5. Answer: c

Q6. Answer: a

Q7. Answer:

Q8. Answer: d

Q9. Answer: c

Q10. Answer: d

Q11. Answer: a

Q12. Answer: d

Q13. Answer: d

Q14. Answer: d

Q15. Answer: d

Q16. Answer: b

Q17. Answer: b

Q18. Answer: b

Q19. Answer: d

Q20. Answer: a

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