Core power
Encyclopedia
Core power is a parameter used in aeroengine performance engineering to enable a comparison of the power capabilities of jet engine
(e.g. turbofan
) cores.
Although the alternative core size
parameter is easier to compute, it only takes into account the basic flow size of the device, no account being taken of the impact of core supercharging or turbine rotor inlet temperature.
There are several definitions of core power in use, but the following definition is fairly popular:
The core of the engine is treated as a turbojet; so, for instance, in a simple 2-spool turbofan, the power requirements of the fan bypass section are ignored and LP turbine imagined to be only driving the inner part of the fan. Firstly, a calculation is undertaken to find the turbine exit conditions where sufficient power is being extracted from the turbine system to just drive the core compression system( i.e. the fan inner and HP compressor). Using the aforementioned turbine exit conditions as an input, an ideal (i.e. 100% efficient) turbine expansion down to atmospheric pressure is calculated. The resulting turbine shaft power is called core power.
In a turboshaft/turboprop , most of the core power is realised as shaft power, whilst in a turbojet the core power is converted into jet power. In a turbofan, some of the core power is transferred to the fan bypass section and then converted into jet power.
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
(e.g. turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
) cores.
Although the alternative core size
Core size
Core size is a parameter used in aeroengine performance engineering to enable a size comparison between jet engine cores.The alternative core power parameter is more difficult to compute, but has the advantage that it takes into account not only the basic flow size of the device, but also the...
parameter is easier to compute, it only takes into account the basic flow size of the device, no account being taken of the impact of core supercharging or turbine rotor inlet temperature.
There are several definitions of core power in use, but the following definition is fairly popular:
The core of the engine is treated as a turbojet; so, for instance, in a simple 2-spool turbofan, the power requirements of the fan bypass section are ignored and LP turbine imagined to be only driving the inner part of the fan. Firstly, a calculation is undertaken to find the turbine exit conditions where sufficient power is being extracted from the turbine system to just drive the core compression system( i.e. the fan inner and HP compressor). Using the aforementioned turbine exit conditions as an input, an ideal (i.e. 100% efficient) turbine expansion down to atmospheric pressure is calculated. The resulting turbine shaft power is called core power.
In a turboshaft/turboprop , most of the core power is realised as shaft power, whilst in a turbojet the core power is converted into jet power. In a turbofan, some of the core power is transferred to the fan bypass section and then converted into jet power.