Performance calculations for a double-compound turbo-jet engine of 12:1 design compressor pressure ratio

Abstract

This report describes.a theoretical investigation using conventional component-characteristics to discover that division of work between the low and high-pressure compressors of a double-compound simple-jet gas turbine of 12 : 1 design pressure ratio which is likely to result in the most desirable equilibrium operation over the normal engine speed range. Having decided in favour of a pressure ratio of 3 : 1 in the low-pressure compressor and 4 : 1 in the other, a study is then made using more realistic compressor characteristics to determine the probable performance of such an engine under all flight conditions when the design maximum temperature is 900 deg C (1173 deg K). The equilibrium running conditions of the engine are investigated with special reference to the problems introduced by the double-compound type of design.