B787 TRENT 1000 Engine is an axial flow, three-shaft, counter-rotating, high-bypass turbofan engine.
- A shaft speed indicating a system of speed probes supplies N1, N2, and N3 shaft speed
- These are the components in the shaft speed system:
- Low-pressure compressor (LPC) speed probes (N1)
- Intermediate pressure compressor (IPC) speed probes (N2)
- High-pressure compressor (HPC) speed probes (N3)
- The engine uses station numbers to identify locations and rotational speeds along its axis from front to back. Internal airflow stations are based on pressure (P) and temperature (T) at that point
- Some examples of the parameters are:
- 0 – Ambient
- 20 – Inlet to the engine (also known as P2/T2 in some documents)
- 24 – Inlet to IP compressor
- 160 – Exit from fan, etc.
P20/T20 probe senses fan entry airflow (pressure and temperature) conditions in the engine air intake.
The turbine gas temperature (TGT) thermocouples sense the temperature of the airflow downstream of the combustion system. There are 12 TGT thermocouples around the turbine case. TGT thermocouples provide EGT indications.
Low pressure (LP) turbine exit temperature T50 thermocouple senses the
the temperature of the airflow downstream of the LP turbine.
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