Terminology
- Afterburner
- extra combustor immediately upstream of final nozzle (also called reheat)
- Augmentor
- afterburner on low-bypass turbofan engines.
- Average stage loading
- constant × (delta temperature)/
- Bypass
- airstream that completely bypasses the core compression system, combustor and turbine system
- Bypass ratio
- bypass airflow /core compression inlet airflow
- Core
- turbomachinery handling the airstream that passes through the combustor.
- Core power
- residual shaft power from ideal turbine expansion to ambient pressure after deducting core compression power
- Core thermal efficiency
- core power/power equivalent of fuel flow
- Dry
- afterburner (if fitted) not lit
- EGT
- Exhaust Gas Temperature
- EPR
- Engine Pressure Ratio
- Fan
- turbofan LP compressor
- Fan pressure ratio
- fan outlet total pressure/intake delivery total pressure
- Flex temp
- use of artificially high apparent air temperature to reduce engine wear
- Gas generator
- engine core
- HPC
- high pressure compressor
- HP compressor
- high pressure compressor
- HPT
- high pressure turbine
- HP turbine
- high pressure turbine
- Intake ram drag
- penalty associated with jet engines picking up air from the atmosphere (conventional rocket motors do not have this drag term, because the oxidiser travels with the vehicle)
- IEPR
- Integrated engine pressure ratio
- IPC
- intermediate pressure compressor
- IP compressor
- intermediate pressure compressor
- IPT
- intermediate pressure turbine
- IP turbine
- intermediate pressure turbine
- LPC
- low pressure compressor
- LP compressor
- low pressure compressor
- LPT
- low pressure turbine
- LP turbine
- low pressure turbine
- Net thrust
- nozzle total gross thrust - intake ram drag (excluding nacelle drag, etc., this is the basic thrust acting on the airframe)
- Overall pressure ratio
- combustor inlet total pressure/intake delivery total pressure
- Overall thermal efficiency
- thermal efficiency * propulsive efficiency
- Propulsive efficiency
- propulsive power/rate of production of propulsive kinetic energy (maximum propulsive efficiency occurs when jet velocity equals flight velocity, which implies zero net thrust!)
- SFC
- Specific fuel consumption
- Specific fuel consumption
- total fuel flow/net thrust (proportional to flight velocity/overall thermal efficiency)
- Static pressure
- normal meaning of pressure. Excludes any kinetic energy effects
- Specific thrust
- net thrust/intake airflow
- Thermal efficiency
- rate of production of propulsive kinetic energy/fuel power
- Total fuel flow
- combustor (plus any afterburner) fuel flow rate (e.g., lb/s or g/s)
- Total pressure
- static pressure plus kinetic energy term
- Turbine rotor inlet temperature
- gas absolute mean temperature at principal (e.g., HP) turbine rotor entry
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