Gas turbines

Question 1

2-3

Answer 1

combustion 
Heat addition 
constant pressure - isobaric
temperature increases
entropy increases

Question 2

what is the ideal working fluid in a gas turbine

Answer 2

air

Question 3

three components of a gas turbine

Answer 3

compressor
combustion chamber
turbine

Question 4

2 main applications of gas turbines

Answer 4

aircraft propulsion

electric power generation

Question 5

3-4

Answer 5

turbine
work output
isentropic
temperature decreases

Question 6

4-1

Answer 6

isobaric heat rejection
entropy decreases (brrr)
temperature decreases (duh!)
volume decrease

Question 7

1-2

Answer 7

isentropic compression
pressure increases, therefore temperature too
Work input

Question 8

what is the highest temperature in the joule or brayton cycle

Answer 8

T3

Question 9

Describe t1

Answer 9

ambient temperature thats fixed and beyond control

Question 10

Finish the sentence:

the larger the efficiency….

Answer 10

the smaller the work ratio

Question 11

t3 for aircraft turbines

Answer 11

1500K

Question 12

what is the pressure ratio

Answer 12

p2/p1 = p3/p4

Question 13

how can you improve the efficiency of a gas turbine

Answer 13

use a regenerator (heat exchanger)

as t4 is generally greater than t2 a heat exchanger can be used to PREHEAT air from the compressor before it reaches the combustion chamber

Question 14

specific heat at constant pressure value for air

Answer 14

1.005

Question 15

what is the specific heat ratio of air

Answer 15

1.4

Question 16

specific heat at constant volume value for air

Answer 16

0.718

Question 17

equation for efficiency of a brayton or joule cycle

Answer 17

1 - 1/ rp^gamma - 1 / gamma