Calculation of Installation Effects Within Performance Computer Programs

Gasturbine engine components as compressors, burners and turbines are usually tested on rigs prior to installation into an engine. In the engine, the component behaviour is different due to a variety of reasons. The installation effects are caused by small geometrical differences due to nonrepresentative rig operating temperatures and pressures, by different gas properties and Reynolds numbers and by radial as well as circumferential temperature and pressure profiles at the inlet to the component. For highly accurate performance predictions these rig-to-engine effects have to be taken into account.

Traditionally the term "installation" is also used for describing all the differences in engine operation and behaviour between toothed and aircraft. Intake and afterbody drag, power offtake and bleed as well as intake pressure losses and inlet flow distortion have significant impact on airflow, thrust, specific fuel consumption and compressor stability. Using modem performance synthesis programs all these effects can be simulated reasonably well.