Gas Power Cycles

Question 1

State the 4 air-standard assumptions

Answer 1

1) The working fluid is air, which continuously circulates in a closed
loop and always behaves as an ideal gas
2) All the processes that make up the cycle are internally reversible
3) The combustion process is replaced by a heat-addition process
from an external source
4) The exhaust process is replaced by a heat-rejection process that
restores the working fluid to its initial state

Question 2

State the cold-air-standard assumptions

Answer 2

When the working fluid is considered to be air with constant specific heats at room temperature

Question 3

Define the air-standard cycle

Answer 3

A cycle for which the air-standard assumptions are applicable

Question 4

______ cycle is the ideal cycle for gas-turbine engines

Answer 4

Brayton

Question 5

For Brayton cycle, the combustion process is replaced by

Answer 5

a constant-pressure heat-addition process from an external source

Question 6

For Brayton cycle, the exhaust process is replaced by a

Answer 6

constant-pressure heat-rejection process to the ambient air

Question 7

State two major application areas of gas-turbine engines

Answer 7

1) Aircraft propulsion

2) Electric power generation

Question 8

List the reasons why deviation of actual gas-turbine cycles from idealized ones occurs

Answer 8

• Irreversibilities in turbine and compressors
• Pressure drops
• Heat losses