Effect of ENGINE EXHAUST PRESSURE on Performance of COMPRESSOR-ENGINE-TURBINE UNITS

REPORTED here are the results of work carried on to determine the effect of variations in engine exhaust pressure on the performance at various altitudes of compressor-engine-turbine combinations for aircraft, in which the turbine is geared to the engine crankshaft.

Measurements were made of indicated mean effective pressure, fuel consumption, and exhaust temperature on a liquid-cooled aircraft-engine cylinder at various inlet and exhaust pressures.

The author concludes that this combination unit can give high specific output and low specific fuel consumption, particularly at high altitudes. He also determines the ratio of engine exhaust pressure to engine inlet pressure required for maximum net output, as well as for lowest net fuel consumption. He found further that high exhaust pressures did not appear to impose undue mechanical or thermal stresses on the engine.