Module 15.1 Fundamentals Flashcards
What is the name of the thermodynamic cycle that engine uses to produce thrust?
Brayton cycle
What are the 4 stages of the Brayton cycle?
Intake - Suck
Compression - Squeeze
Expansion - Bang
Exhaust - Blow
What are the 4 changes of state in Gas Turbine Engines (GTE)?
- Isobaric
- Isochoric
- Isothermal
- Isentropic
What is the main purpose of the compressor?
Increase static pressure
What are the 4 types of gas turbine engine?
- Turbojet
- Turbofan
- Turboprop
- Turboshaft
What are the equations for:
PE?
KE?
PE - mgh
KE - 1/2 mv^2
What are the advantages of turbojet?
- Simple design
- Limited space
- Very high speeds
What are the disadvantages of turbojet?
- Very loud
- High fuel consumption
- Poor performance at low speed
-Limited in range and endurance
What type of engine is a GTE?
Heat engine
What is isobaric heating?
Volume increase, pressure constant. In the combustion chamber
On diagram of the Brayton cycle it is between 2 and 3
What part of the engine has the highest static pressure?
Combustion chamber inlet, exit guide vanes
What is the hottest part of the engine?
Combustion chamber outlet/ 1st nozzle guide vane
What is isentropic compression?
Pressure increase and volume decrease
On diagram of the Brayton cycle it is between 0 and 2
What is the working fluid in a GTE?
Air
What is the equation for power?
Power = Work/ Time (watts)
With regard to s
What is the equation for work?
In Joules
Work = Force x Distance (J)
What is the difference between speed and velocity?
Velocity has a direction
What is the difference between turboprop and turbojet?
Prop has:
- More turbines
- Power shaft
- Reduction gearbox to drive propeller
What is the difference between turbojet and turbofan?
Turbofan - Set of or a large fan driven by turbine
What is a spool?
Turbine driving a compressor two or three spool in a turbofan
What does exhaust gas drive in a turboshaft engine?
Free turbine which is connected to a power shaft
What does the cold section of an engine refer to?
Parts of the engine from the inlet up through the compressor and/or diffusers
What drives the compressor?
The turbine
What type of construction are GTE?
Modular
In a turbofan engine what produces most of the thrust?
The fan (80%)
What speed range are turbojets best suited to?
Supersonic
Very inefficient at low speeds
What happens to piston engines with altitude?
Performance drops
What is newtons first law about?
Inertia
An object at rest will stay at rest ….
What is potential energy?
The energy that an object has as a virtue of its position
What is the hot section of an engine?
Areas from the combustion chamber and through the exhaust
What drives the low pressure compressor?
Low pressure turbine
The number of compressors is dependant on what?
The number of spools
how are spools connected?
Aerodynamically
Turboprop engines are specifically designed to produce what?
Shaft horsepower
What is inside the gas generator?
Compressor, combustion and turbine
