Engine Principles Flashcards
What is newtons 3rd law
Every force acting on a body has an equal and opposite reaction
What was the first jet propulsion engine used in 1913
Aero-Thermo Dynamic Duct (ATHODYD)
How does an ATHODYD engine work
Air forced into an air intake where its velocity drops and its pressure increases as it passes through a diverging duct. Volume is increased by inducing fuel into the air and setting it alight, propelling air out of the back
What is the difference between ram air engines and propeller engines in terms of propulsion
Ram air (ATHODYD) - large acceleration to small mass of air
Propeller - Small acceleration to a large mass of air
What are the 5 types of jet engine
Rocket
Ram (ATHODYD)
Pulse
Turbo Jet
Turbo shaft
In simple terms, how does a Rocket Jet engine work
Self contained fuel source, is ignited and fed through an exhaust providing thrust. No air intake needed
In simple terms, how does a Ram Jet (ATHODYD) engine work?
Air duct that flows through a converging or diverging tube. Fuel injected into the air and ignited, expelling it out of the rear. No rotating parts.
In simple terms, how does a Pulse Jet engine work?
Similar to the ATHODYD but uses valves and shutters to create a higher pressure momentarily before igniting and releasing the accelerated air
Who was granted the first patent for creating a gas turbine engine
Frank Whittle - Whittle engine
How does a whittle engine work
Air is directed through an intake and into a compressor which increases pressure and temperature of the air. Fuel is then inducted into the hot, compressed air and ignited. The ignited air drives a turbine, which drives the rest of the engine and expels hot air out of an exhaust providing thrust
What are the 2 rotating parts in a gas turbine engine
Compressor and Turbine
What is a single spool engine
Turbine and compressor are connected by a single shaft
What is a multi spool engine
Engines with more than 1 compressor require a separate turbine for each compressor, that run along the same shaft.
What are the 3 spool and compressor names
LP compressor
IP compressor
HP compressor
HP turbine
IP turbine
LP turbine
Why do engines use multi spool setups?
To create more power from the same air intake
What types of bypass are there and what is their purpose
High bypass - allows more than 50% of compressor air to flow around the outside of the engine
Low bypass - allows less than 50%
This assists in noise reduction and reduce fuel consumption
How can drive be transmitted by the spool
Directly coupled turbo shaft
Free power turbine
What engine is best for speeds just below 450mph?
Turbo prop
What engine is best for high speeds and high altitudes both
Pure turbojet
What is meant by thermal efficiency
The heat energy output of the engine divided by the heat energy input (fuel input)
What are the 4 stages of a working cycle
Air intake
Compression
Combustion
Exhaust
Happens constantly on a gas turbine engine
What is heating at constant pressure
The work cycle of a gas turbine engine. Constantly running whilst fuel is induced, pressure is constant where volume increases
What effects does a convergent duct have on PVT
Pressure - Decrease
Volume/Velocity- Increase
Temperature - Decrease
What effects does a divergent duct have on PVT
Pressure - Increase
Volume/Velocity - decrease
Temperature - increase
