The Influence of inlet swirl distortions on the performance of a jet propulsion two-stage axial compressor

Abstract

Aeroengine intakes containing S-shaped diffusers produce different types of inlet swirl distortions and essentially a combinaion of a twin swirl and a bulk swirl. The main object of this investigation was to asess the influence of inlet swirl distortions on the performance of a transonic two-stage axial compressor installed in a turbo jet byass engine Larzac 04. A typical inlet swirl distortion was simulated by a delta-wing in front of the engine. An experimental method was investigated to measure the performance map of the installed low pressure compressor for different engine operating lines. The inluence of an inlet swirl distortion with diferent strengths on the performance map of the compressor was investigated experimentally. It is shown that the performance parameters derease and a temperature distortion is generted behind the compressor.As the basis of the theoretical investigations of the performance map including inlet swirl distortions a compuing model considering four compressors workng in parallel was established. The model is based on the idea that an inlet swirl distorion can be substituted by two fundamental types of swirl components, i.e. a bulk swirl co-rotating, and a bulk swirl counter-rotating to the revolution of the compressor. Computed performance maps of the compressor will be discussed and compared with the experimental data.