Technical Paper
Effects of Component Size and Cooling Air Flows on the Performance, Weight and Dimensions of High and Ultra-High Bypass Ratio Turbofan Engines
2013-10-07
2013-36-0511
The technical evolution of turbofan engines has been accomplished by increasing the engine thermal and propulsive efficiencies. The former is mainly a function of component efficiencies, cycle temperatures and pressures, while the latter is basically related to the engine BPR and FPR. However, several technological challenges are faced to increase those levels of efficiencies. In the thermal efficiency side, higher pressure ratios, for a given stage loading, are obtained by increasing the number of compressor stages, adding weight and size penalties to the engine, and increasing the compressor delivery temperature. Higher cycle temperatures, mainly those found in the burner exit and the stator outlet require higher cooling flows, for a given blade material technology level. Higher cooling flows lead to penalties in the engine efficiency, since the air used in the cooling is bled from the compressor.
