Module 15.1 Fundamentals

Question 1

What is the name of the thermodynamic cycle that engine uses to produce thrust?

Answer 1

Brayton cycle

Question 2

What are the 4 stages of the Brayton cycle?

Answer 2

Intake - Suck
Compression - Squeeze
Expansion - Bang
Exhaust - Blow

Question 3

What are the 4 changes of state in Gas Turbine Engines (GTE)?

Answer 3

• Isobaric
• Isochoric
• Isothermal
• Isentropic

Question 4

What is the main purpose of the compressor?

Answer 4

Increase static pressure

Question 5

What are the 4 types of gas turbine engine?

Answer 5

• Turbojet
• Turbofan
• Turboprop
• Turboshaft

Question 6

What are the equations for:
PE?
KE?

Answer 6

PE - mgh
KE - 1/2 mv^2

Question 7

What are the advantages of turbojet?

Answer 7

• Simple design
• Limited space
• Very high speeds

Question 8

What are the disadvantages of turbojet?

Answer 8

• Very loud
• High fuel consumption
• Poor performance at low speed
  -Limited in range and endurance

Question 9

What type of engine is a GTE?

Answer 9

Heat engine

Question 10

What is isobaric heating?

Answer 10

Volume increase, pressure constant. In the combustion chamber

On diagram of the Brayton cycle it is between 2 and 3

Question 11

What part of the engine has the highest static pressure?

Answer 11

Combustion chamber inlet, exit guide vanes

Question 12

What is the hottest part of the engine?

Answer 12

Combustion chamber outlet/ 1st nozzle guide vane

Question 13

What is isentropic compression?

Answer 13

Pressure increase and volume decrease

On diagram of the Brayton cycle it is between 0 and 2

Question 14

What is the working fluid in a GTE?

Answer 14

Air

Question 15

What is the equation for power?

Answer 15

Power = Work/ Time (watts)

Question 16

What is the equation for work?

Answer 16

Work = Force x Distance (J)

Question 17

What is the difference between speed and velocity?

Answer 17

Velocity has a direction

Question 18

What is the difference between turboprop and turbojet?

Answer 18

Prop has:
- More turbines
- Power shaft
- Reduction gearbox to drive propeller

Question 19

What is the difference between turbojet and turbofan?

Answer 19

Turbofan - Set of or a large fan driven by turbine

Question 20

What is a spool?

Answer 20

Turbine driving a compressor two or three spool in a turbofan

Question 21

What does exhaust gas drive in a turboshaft engine?

Answer 21

Free turbine which is connected to a power shaft

Question 22

What does the cold section of an engine refer to?

Answer 22

Parts of the engine from the inlet up through the compressor and/or diffusers

Question 23

What drives the compressor?

Answer 23

The turbine

Question 24

What type of construction are GTE?

Answer 24

Modular

Question 25

In a turbofan engine what produces most of the thrust?

Answer 25

The fan (80%)

Question 26

What speed range are turbojets best suited to?

Answer 26

Supersonic Very inefficient at low speeds

Question 27

What happens to piston engines with altitude?

Answer 27

Performance drops

Question 28

What is newtons first law about?

Answer 28

Inertia An object at rest will stay at rest ....

Question 29

What is potential energy?

Answer 29

The energy that an object has as a virtue of its position

Question 30

What is the hot section of an engine?

Answer 30

Areas from the combustion chamber and through the exhaust

Question 31

What drives the low pressure compressor?

Answer 31

Low pressure turbine

Question 32

The number of compressors is dependant on what?

Answer 32

The number of spools

Question 33

how are spools connected?

Answer 33

Aerodynamically

Question 34

Turboprop engines are specifically designed to produce what?

Answer 34

Shaft horsepower

Question 35

What is inside the gas generator?

Answer 35

Compressor, combustion and turbine