Pulse Jet
uses shutters and springs to pack air into combustion chamber and ignite the engine.
Ram Jet
Simplest of Jet Engines, No moving parts
Rocket Engine
In their simplest forms are a tube with gun powder, thrust is made from the reaction
Reaction Turbine
- Changes speed and direction of gases
- As gas passes between turbine blades cross-sectional area gets smaller
- Increased velocity = decrease pressure
- Turbine absorbs the energy to change gas velocity
- Since engine efficiency goes up w/ higher combustion temps special cooling must be provided to the turbine.
Impulse Turbine
- Pressure and speed of gases remain the same
- Only change is in direction of flow
- Turbine absorbs the energy required to change the direction of the high speed gas
Compressor Stall
- Inlet velocity and rotational velocity imbalance
- AoA exceeds critical AoA
Convergent Duct
Velocity- Increasing
Pressure - decreasing
Temp- decreasing
Divergent Duct
Velo- decreasing
Pressure- increasing
Temp- Increasing
Gas Turbine Engine Construction
- Inlets
- Fans and compressors
- Combustion Section
- Exhaust and nozzles
- Thrust reversers
ADVANTAGES OF GAS TURBINE ENGINES OVER RECIPROCATING ENGINES
- Development time is reduced
- Production is simpler and quicker
- An existing turbine engine can be scaled up or down in size
- Power is produced continuously rather than intermittently therefor the working pressures are low and engine is lighter
- Engine vibration is eliminated
- Higher operating speeds can be attained and frontal area is reduced
- Power to weight ratio is increased.
- Operates more efficiently at a higher altitude (needs no supercharging)
- The higher the RPM, the more efficient the turbine engine functions.
Brayton Cycle
Constant pressure cycle, used to define the events that take place in a gas turbine engine
Turboshaft Engine
A gas turbine engine that delivers power through a shaft to drive something other than a propeller
Used for helicopters and apu’s
Turboprop Engine
Drives a conventional propeller through reduction gears
-prop and engine accelerate air
Turbofan Engine
Essentially a ducted multi bladed propeller driven by a gas turbine
-cross between turbojet and turboprop
Turbojet Engine
Produces thrust through the hot gases exiting the exhaust section of the engine
Major sections of a Turbojet Engine
- Compressor
- Combustion
- Turbine Section
- Nozzle Section
Principles of Gas Turbine Engines
- Air is brought to front and compressed
- Fuel is mixed w/ the compressed air
- The compressed fuel air mix is burned
- Heated exhaust gases rush out of the engine
1791
John Barber first patent of a gas turbine engine
1808
John Bumble gas turbine w/ rotating blades
1850
W.F. Fernihough developed steam and gas turbine engine
1930
Frank Whittlle patented first turbojet a/c
1936
Power Jets Founded and first German patented engine for jet propulsion
1939
First jet propulsion flight
1937
First successful test stand of pure reaction turbojet
