Chapter 4 (GAS TURBINE)

Question 1

Brayton Cycle has:

Answer 1

Two isentropic and two constant pressure processes

Question 2

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

Answer 2

Large volume of low pressure air cannot be efficiently handled in reciprocating engines

Question 3

Which cycle is generally used for gas turbine?

Answer 3

Brayton cycle

Question 4

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

Answer 4

1 — 1/r^(k-1)/k

Question 5

A regenerator in a gas turbine:

Answer 5

Improves thermal efficiency

Question 6

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

Answer 6

Axial flow type

Question 7

The constant pressure gas turbine works on the principle of:

Answer 7

Brayton cycle

Question 8

What type of gas turbine is used in air craft?

Answer 8

Open cycle type

Question 9

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

Answer 9

Recover heat from exhaust gases

Question 10

Overall efficiency of a gas turbine is:

Answer 10

less than Diesel Cycle efficiency

Question 11

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

Answer 11

Simple open cycle gas turbine

Question 12

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

Answer 12

all of the above

Question 13

The range of compression ratio in a gas turbine is:

Answer 13

5 to 8

Question 14

A constant volume conbustion gas turbine operates on:

Answer 14

Atkinson cycle

Question 15

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

Answer 15

Regenerator

Question 16

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

Answer 16

Unchanged

Question 17

What is the ideal cycle for gas turbine work?

Answer 17

Brayton cycle

Question 18

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

Answer 18

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

Question 19

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

Answer 19

Expansion of gases

Question 20

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

Answer 20

10 MW

Question 21

Large units gas turbine regularly operate:

Answer 21

in 100 to 200 MW range

Question 22

Small units gas turbune operates below

Answer 22

30 MW

Question 23

Heavy duty gas turbines typically have:

Answer 23

Single shaft

Question 24

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

Answer 24

Aeroderivative gas turbine

Question 25

Most aeroderivative combustion turbine produce less than:

Answer 25

40 MW

Question 26

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

Answer 26

11 to 16

Question 27

The compression ratio based on pressures of heavy duty gas turbine is in the range of

Answer 27

14 to 15

Question 28

Aeroderivative combustion turbine have higher compression ratios typically:

Answer 28

19 to 21

Question 29

Most heavy duty conbustion turbines have how many compression stages?

Answer 29

16 to 18

Question 30

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

Answer 30

1200 C to 1290 C