Compressors for Ultra-High Pressure Ratio Aero-Engines

conference proceedings

en

A highly efficient, robust compression system is a key part of any high performance core engine that is to be developed for meeting future low emission requirements, i.e. for significant reductions in CO2, NOx and other gaseous emissions. Not only does the compression system have to deliver the increased OPR demanded by the thermal cycle. It has to do so more efficiently to avoid excessive increases in cycle temperatures and weight to avoid reducing the benefit from the new cycle. This challenge is made harder as OPR is increased up to 70:1 as core engine size will reduce introducing greater threats to efficiency and compressor stability margin through: • Lower Reynolds numbers that will result in higher blade losses • Tip and shroud/seal clearances increasing due to physical size limitations • If manufacturing tolerances are maintained, blade and vane leading edges, maximum thickness and fillets radii will be relatively larger • The threat of inclement weather, deterioration and foreign object damage (FOD), will be greater as compressors get smaller • High Aspect Ratio blade design will be applied to limit the relative weight and length increase due to required pressure ratio increase of the compression system • Higher OPR compression systems will require more stability improvement features such as VSVs, bleeds and rotor tip treatments This paper gives an overview of the above issues and how the FP7 integrated project LEMCOTEC is addressing them through CFD simulations, low and high speed rig tests and innovative designs.

A highly efficient, robust compression system is a key part of any high performance core engine that is to be developed for meeting future low emission requirements, i.e. for significant reductions in CO2, NOx and other gaseous emissions. Not only does the compression system have to deliver the increased OPR demanded by the thermal cycle. It has to do so more efficiently to avoid excessive increases in cycle temperatures and weight to avoid reducing the benefit from the new cycle. This challenge is made harder as OPR is increased up to 70:1 as core engine size will reduce introducing greater threats to efficiency and compressor stability margin through: • Lower Reynolds numbers that will result in higher blade losses • Tip and shroud/seal clearances increasing due to physical size limitations • If manufacturing tolerances are maintained, blade and vane leading edges, maximum thickness and fillets radii will be relatively larger • The threat of inclement weather, deterioration and foreign object damage (FOD), will be greater as compressors get smaller • High Aspect Ratio blade design will be applied to limit the relative weight and length increase due to required pressure ratio increase of the compression system • Higher OPR compression systems will require more stability improvement features such as VSVs, bleeds and rotor tip treatments This paper gives an overview of the above issues and how the FP7 integrated project LEMCOTEC is addressing them through CFD simulations, low and high speed rig tests and innovative designs.

compressor, efficiency, stability

23.09.2015

DGLR

Rostock, Germany

12–13

15