Basic Turbine Engine Theory Flashcards
What is the basic description of the function of a turbine engine?
Air is drawn or rammed via intake, into a multi-stage compressor, fuel is added and ignited in the combustor, and the air is expanded through the turbine stages before being expelled out the back of engine.
How is Newton’s second law mathematically expressed?
Force = mass x acceleration or F = Ma
What is Newton’s 3rd law?
For every action there is an equal and opposite reaction.
What is the practical application of Newton’s 3rd law?
Jet thrust
How is thrust produced in a turbojet or turbofan engine?
By accelerating a mass of air through the engine.
What is Charles’s law?
Charles’s Law states that at constant pressure, the volume of a given mass of gas is directly proportional to its absolute temperature.
What is Boyle’s law?
Boyle’s law states that at constant temperature, the pressure and the volume of gas are inversely proportional.
How does temperature, density, pressure and velocity of a gas flow vary through a convergent duct at subsonic speed?
Temperature, density and pressure reduce and velocity increases.
How does temperature, density, pressure and velocity of a gas flow vary through a divergent duct at subsonic speed?
Temperature, density and pressure increase and velocity reduces.
How does temperature, density, pressure and velocity of a gas flow through a convergent duct at supersonic speed?
Temperature, density and pressure increase and velocity reduces.
How does temperature, density, pressure and velocity of a gas flow vary through a divergent duct at supersonic speed?
Temperature, density and pressure reduce and velocity increases.
Where does subsonic flow decrease in velocity and increase in pressure?
Through a divergent duct.
Where does subsonic flow increase in velocity and decrease in pressure?
Through a convergent duct.
Where does supersonic flow decrease in velocity and increase in pressure?
Through a convergent duct.
Where does supersonic flow increase in velocity and decrease in pressure?
Through a divergent duct.
What property is exhibited by accelerating gas flow?
That the total energy is constant.
Where in a turbofan engine is the pressure highest?
In the diffuser.
Where in a turbojet engine is gas velocity highest?
Exiting the exhaust nozzle.
Where in a turbine engine is the gas temperature highest?
At the flame in the combustion chamber.
How does gas pressure vary as it passes through the combustion chamber?
It remains nearly constant, reducing very slightly due to the construction inefficiencies.
How does gas temperature and velocity cart as it passes through the combustion chamber?
Temperature and velocity both increases.
How does gas pressure, temperature and velocity vary as it passes through the turbine section?
Pressure and temperature progressively reduce, and velocity increases through the nozzle guide vanes and staters and reduces through the turbine blades.
Why is the Brayton Cycle in a turbine engine referred to as an open or continuous cycle?
Because intake, compression combustion and exhaust are all occurring at the same time.
What are the basic sections of a turbine engine? 5
The intake, the compressor, the combustion chamber, the turbine and the exhaust section.
