CHAPTER 4 GAS TURBINE

Brayton cycle

two isentropic and two constant pressure processes.

Brayton cycle in reciprocating engines

cannot be used even for same adiabatic compression ratio and work output because large volume of low pressure air cannot be efficiently handled in reciprocating engines.

Cycle used for gas turbine

Brayton cycle.

1-1/r^(k-1)/k

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

improves thermal efficiency

A regenerator in a gas turbine_

Axial flow type

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

brayton cycle

The constant pressure gusturbing works on the principle of

open cycle type

What type of gas turbine is used in air craft?

decrease

For multi stage compression of an ideal Brighton cycle, the back work ratio will_

11 to 16

In most common design of gust irvine, the pressure ratio ranges from____

recover heat from exhaust gases

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

less than diesel cycle efficiency

Overall efficiency of a gas turbine is_

simple open cycle gas turbine

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

all of these

Which of the following is advantage of close cycle gas turbine over open cycle gas turbine.

5/8

The range of compression ratio in a gas turbine is___

isobaric process

In brayton cycle, The heat is transformed during which process?

heat is transferred

In Brayton cycle , the during constant pressure process .

aircraft propulsion and electric power generation

The two major application areas of gas turbine engines are

exit temperature

The use of regenerator in is recommended only when the turbine exhaust temperature is higher than the compressor

10 to 25

Aircraft gas turbines operates at higher pressure, typically between?

Atkinson cycle

A constant volume combustion gas turbine operates on

Regenerator

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

unchanged

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

Brayton Cycle

What is the ideal cycle for gas turbine work?

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

Brayton cycle cannot be used in the reciproating engines. Even for some adiabatic compression ratio and work output because

expansion of gases

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

10 MW

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

in 100 to 200 MW range

Large units gas turbine regularly operate:

30 MW

Small units gas turbine operate below

single shaft

Heavy duty gas turbines typically have

Aeroderivative gas turbine

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

​

40 MW

Most aeroderivative combustion turbine produce less than:

11 to 16

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

14 to 15

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

19 to 21

Aeroderivative combustion turbine have higher compression ratios typically

16 to 18

Most heavy duty combustion turbines have how many compression stages?

1200 to 1290 C

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

540 to 590 C

The exhaust temperature, which makes the exhaust an ideal heat source for a combined cycle is typically_

3 to 4 expander stages

Most combustion turbines have:

240 to 250 kg/s

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

Joule cycle

The Brayton gas turbine cycle is also known as:

50 to 75%

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

650 to 1000 C

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

Open combustors

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

33 to 36%

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

42%

Aeroderivative turbines commonly achieve efficiencies up to:

a cross flow heat exchanger

which of the following is an example of a regenerator

50 to 75%

Which of the following is a typical back-work ratio of the turbine

less heat added

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

compressor and turbine work

A generator in a gas turbine has no effect in:

increase thermal efficiency

In a Brayton cycle multiple stages of compression and expansion will

5

The first commercial high pass ratio engines has a bypass ratio of

decrease

A single stage expansion process of a ideal brayton cycle without regeneration is placed by a multisage expansion process with reheating between the same pressure limits as a result of modification.What will happen to thermal efficiency

all of these

Which of the following are application brayton cycle

joule cycle

The Brayton gas turbine cycle is also known as:

increase thermal efficiency

In a Brayton cycle, reheating and intercooling will

Heat added

In Brayton, cycle, reheating has no effect in:

Turbine Work

In Brayton, intercooling has no effect in

Wc/Wt

if Wt is the turbine work power and Wc is the compressor work power then the back-work ratio is?

5

The first commercial high pass engines has a bypass ratio of

increase

Reheating process in Brayton cycle, the turbine work whill

Wt-Wc

if Wt is the turbine power and Wc is compressor power, then the network is

2

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

38 to 38.5%

New combustion turbines on the cutting edge of technology (advanced turbine systems) are able to achieve

cycle pressure level

It is the ratio of the maximum pressure in the cycle to the atmospheric pressure.

air rate

The quantity of working medium entering the first stage of compression per unit of output energy.

fuel rate

The quantity of a specific fuel consume per unit of output energy.

Regenerator Effectiveness

It is the ratio of actual heat transfer in a regenerator to the theoretical possible. If the heated fluid were to reach the temperature of the entering hot gas

work ratio

It is a ratio of output power to the total installed turbine power

turbo-prop

Which of the following does not use ambient air for propulsion?