PRIME'S ELEMENTS IN POWER & INDUSTRIAL PLAN ENGINEERING : CHAPTER 4 GAS TURBINE

Brayton cycle has:

A. two isentropic and two constant volume pressure

B. two isentropic and two constant pressure processes

C. one constant pressure, one constant volume , and two adiabatic processes

D. two isothermals, one constant volume and a constant press

B. two isentropic and two constant pressure processes

Brayton cycle cannot be used in reciprocating engines even for same adiabatic compression ratio and work output because:

A. Otto cycle is highly efficient

B. Brayton cycle is less efficient

C. Brayton cycle is foe slow speed engines only

D. large volume of low pressure air cannot be efficiency handled in reciprocating engines

D. large volume of low pressure air cannot be efficiency handled in reciprocating engines

Which cycle is generally used for gas turbine?

A. Otto cycle

B. Dual cycle

C. Carnot cycle

D. Brayton cycle

D. Brayton cycle

When r is the compression ratio, the efficiency of Brayton cycle is given by:

A. 1 - 1/𝑟⁽ᵏ⁻¹⁾/ᵏ

B. 1 - 1/𝑟ᵏ⁻¹

C. 1 - 1/𝑟ᵏ

D. 1 - 1/r

A. 1 - 1/𝑟⁽ᵏ⁻¹⁾/ᵏ

A regenerator in a gas turbine:

A. reduces heat loss during exhaust

B. allows use of higher compression ratio

C. improves thermal efficiency

D. allows use of fuels of interior quality

C. improves thermal efficiency

Which of the following compressor is generally used for gas turbines?

A. lobe type

B. centrifugal type

C. axial flow type

D. reciprocating type

C. axial flow type

The constant pressure gas turbine works on the principle of:

A. carnot cycle

B. Bell - Coleman cycle

C. Rankine cycle

D. Brayton cycle

D. Brayton cycle

What type of gas turbine is used in air craft?

A. open cycle type

B. closed cycle type with reheating

C. closed type with reheating and regeneration

D. open cycle type with reheating, regeneration and intercooling

A. open cycle type

In a gas turbine combined cycle plant, a waste heat boiler is used to:

A. heat air from intercooler

B. gases from regenerator

C. recover heat from exhaust gases

D. none of the above

C. recover heat from exhaust gases

Overall efficiency of a gas turbine is:

A. equal to Carnot cycle efficiency

B. equal to Rankine cycle efficiency

C. less than Otto cycle efficiency

D. more than Otto or Diesel cycle efficiency

C. less than Otto cycle efficiency

Which of the following turbine has least weight per bhp development?

A. Simple open cycle gas turbine

B. Open cycle gas turbine with inter-cooling and reheating

C. Open cycle gas turbine with inter-cooling reheating and regenerating

D. Closed cycle gas turbine

A. Simple open cycle gas turbine

Which of the following is/are advantage of closed cycle gas turbine over open cycle gas turbine?

A. no containing of working substance with combustion gases

B. inferior quality fuel can be used

C. low maintenance costs

D. all of the above

D. all of the above

The range of compression ratio in a gas turbine is :

A. 3 to 5

B. 5 to 8

C. 8 to 12

D. 12 to 20

B. 5 to 8

A constant volume combustion gas turbine operates on:

A. Ericson cycle

B. Joule cycle

C. Brayton cycle

D. Atkinson cycle

D. Atkinson cycle

Past ME Board Question

Heat exchanger used to provide heat transfer between the exhaust gases and the air prior to its entrance to combustor.

A. Evaporator

B. Combustion chamber

C. Regenerator

D. Heater

C. Regenerator

Past ME Board Question

How does the value for work for unit mass flow of air in the compressor and turbine influenced by the addition of a regenerator?

A. Slightly increased

B. Unchanged

C. Greatly decreased

D. Greatly increased

B. Unchanged

Past ME Board Question

What is the ideal cycle for gas turbine work?

A. Brayton cycle

B. Stag combined cycle

C. Bottom cycle

D. Ericson cycle

A. Brayton cycle

Past ME Board Question

Brayton cycle cannot be used in reciprocating engines even for same adiabatic compression ratio and work output because:

A. Brayton cycle is highly efficient

B. Brayton cycle is for low speed engines only

C. Brayton cycle needs large air-fuel ratio

D. Large volume of low pressure air cannot be efficient handled in reciprocating engines

D. Large volume of low pressure air cannot be efficient handled in reciprocating engines

Past ME Board Question

In order to increase the gas velocity gas turbines generally have fixed nozzles. This is allow the:

A. Compression of gases

B. Condensation of gases

C. Expansion of gases

D. Evaporation of gases

C. Expansion of gases

Combustion turbines or gas turbines are the preferred combustion engines in application much above _________.

A. 8 Mw

B. 9 mW

C. 10 MW

D. 7 MW

C. 10 MW

Large units gas turbine regularly operate:

A. In 100 gas to 200 MW range

B. In 50 to 100 MW range

C. Over 150 MW

D. Below 150 MW

A. In 100 gas to 200 MW range

Small units gas turbine operate below

A. 20 MW

B. 12 MW

C. 30 MW

D. 24 MW

C. 30 MW

Heavy duty gas turbine typically have:

A. Double shafts

B. Single shafts

C. Triple shafts

D. Quadruple shafts

B. Single shafts

Which of the following is basically a jet engine that exhausts into a turbine generator?

A. Aeroderivative gas turbine

B. Industrial gas turbine

C. Brayton engine

D. Joule turbine

A. Aeroderivative gas turbine

Most aeroderivative combustion turbine produce less than:

A. 20 MW

B. 30 MW

C. 40 MW

D. 50 MW

C. 40 MW

The compression ratio based on pressure in the compression stage in a gas turbine is typically:

A. 11 to 16

B. 5 to 8

C. 12 to 18

D. 8 to 14

A. 11 to 16

The compression ratio based on pressure of heavy duty gas turbine is in the range of ________.

A. 14 to 15

B. 19 to 21

C. 11 to 16

D. 16 to 18

A. 14 to 15

Aeroderivative combustion turbine have higher compression ratio typically:

A. 14 to 15

B. 19 to 21

C. 11 to 16

D. 16 to 18

B. 19 to 21

Most heavy duty combustion turbines have how many compression stages?

A. 14 to 16

B. 18 to 20

C. 10 to 12

D. 16 to 18

D. 16 to 18

The temperature of the gas entering the expander section is typically:

A. 1200 C to 1290 C

B. 1000 C to 1200 C

C. 1500 C to 1490 C

D. 1300 C to 1390 C

A. 1200 C to 1290 C

The exhaust temperature which makes the exhaust an ideal heat source for combined cycles is typically:

A. 540 C to 590 C

B. 600 C to 650 C

C. 300 C to 350 C

D. 440 Cto 490 C

A. 540 C to 590 C

Most combustion turbines have:

A. 2 to 3 expander stages

B. 3 to 4 expander stages

C. 4 to 5 expander stages

D. 1 to 2 expander stages

B. 3 to 4 expander stages

The exhaust flow rate in modern heavy duty turbines per 100 MW is approximately:

A. 240 to 250 kg/s

B. 140 to 150 kg/s

C. 340 to 350 kg/s

D. 440 to 450 kg/s

A. 240 to 250 kg/s

The Brayton gas turbine cycle is also known as:

A. Joule cycle

B. Stirling cycle

C. Ericsson cycle

D. Atkinson cycle

A. Joule cycle

Approximately how many percent of the turbine power is used to drive the high efficiency compressor?

A. 50 to 75 %

B. 60 to 85 %

C. 45 to 70 %

D. 30 to 55 %

A. 50 to 75 %

Depending on the turbine construction details, the temperature of the air entering the turbine will be between:

A. 650 C to 1000 C

B. 750 C to 1100 C

C. 550 C to 950 C

D. 850 C to 1200 C

A. 650 C to 1000 C

Which of the following engines are typically used by Turbojet and turboprop?

A. Open combustors

B. Closed combustors

C. Turbo combustors

D. High combustors

A. Open combustors

The full load thermal efficiency of existing heavy duty combustion turbines in simple cycle is approximately:

A. 34 to 36 %

B. 30 to 32 %

C. 40 to 42 %

D. 26 to 28 %

A. 34 to 36 %

New combustion turbine on the cutting edge of technology (Advanced turbine system) are able to achieve

A. 38 to 38.5 %

B. 36 to 36.5 %

C. 40 to 40.5 %

D. 34 to 34.5 %

A. 38 to 38.5 %

Aeroderivative commonly achieve efficiencies up to:

A. 42 %

B. 38 %

C. 45 %

D. 35 %

A. 42 %

Which of the following is the typically backwork ratio of gas turbine?

A. 50 to 75 %

B. 40 to 65 %

C. 30 to 55 %

D. 35 to 60 %

A. 50 to 75 %

Which of the following is an example of a generator?

A. A counter flow heat exchanger

B. A cross flow heat exchanger

C. A mixed flow heat exchanger

D. A parallel heat exchanger

B. A cross flow heat exchanger

Which of the following is an effect of having a regenerator?

A. Less heat is added

B. Compressor work is reduced

C. Turbine work is increased

D. Compressor work is increased

A. Less heat is added

A regenerator in a gas turbine has no effect in:

A. Compressor and turbine work

B. Heat added

C. Thermal efficiency

D. Combustor

A. Compressor and turbine work

In Brayton cycle multiple stages of compression and expansion will _________.

A. Increase thermal efficiency

B. Decrease thermal efficiency

C. Limit thermal efficiency

D. Control efficiency

A. Increase thermal efficiency

In Brayton cycle, reheating and intercooling will __________.

A. Increase thermal efficiency

B. Decrease thermal efficiency

C. Limit thermal efficiency

D. Control efficiency

A. Increase thermal efficiency

In a Brayton cycle, reheating has no effect in:

A. Heat added

B. Thermal efficiency

C. Backwork ratio

D. Network

A. Heat added

In a Brayton cycle, intercooling has no effect:

A. Turbine work

B. Thermal efficiency

C. Backwork ratio

D. Network

A. Turbine work

If Wₜ is the turbine power and W꜀ is the compressor power then the backwork ratio is

A. Wₜ /W꜀

B. W꜀ / Wₜ

C. Wₜ − W꜀ / Wₜ

D. Wₜ − W꜀ / W꜀

B. W꜀ / Wₜ

If Wₜ is the turbine power and W꜀ is the compressor power then network is:

A. Wₜ × W꜀

B. W꜀ / Wₜ

C. Wₜ − W꜀

D. Wₜ + W꜀

C. Wₜ − W꜀

Physical limitation usually preclude more than how many stages of intercooling and reheating?

A. 2

B. 3

C. 4

D. 5

A. 2