Quasi-three-dimensional compressor performance simulation using streamline curvature and multi-parallel compressor theory

Engine inlet distortion can severely affect compressor performance by causing the non-dimensional speed lines and surge line to shift. This paper discusses a highly integrated method for modelling engine inlet total pressure distortion and predicting compressor performance under these conditions. This study utilizes a three dimensional (3D), computational fluid dynamics (CFD) tool, based on vortex lattice theory, to simulate the development of distorted flow within the intake and to establish the boundary conditions at the compressor's inlet face. The derived 3D pressure distributions at the intake outlet are subsequently decomposed into circumferential and radial pressure profiles. Circumferential and radial distortions are examined separately. The influence of the first profile type on compressor performance is assessed with the support of a multi-parallel compressor calculation procedure. The impact of the radial distortion profile is assessed by using a two-dimensional (2D) streamline curvature (SLC) software. Concerning the radial distortion, several distributions are examined along with various profile types. The circumferential total pressure distortion patterns addressed, are varied with respect to the spoiled sector extend and the absolute value in total pressure difference. More precisely, three spoiled sector angles of 60, 120 and 180 degrees are examined. This work demonstrates the applicability of the method by using a generic intake model fitted in front of a single stage compressor, as a case study. All the individual simulation tools, namely the intake flow simulation code, the SLC code and the multiparallel compressor code, are briefly presented in this paper with more focus on the SLC software, which has not been published before. All simulation tools, used by this study, have been validated individually in the past against experimental data. Their combined operation however, as a unified simulation package, has not been validated yet and hence, numerical results presented in this study should be taken qualitative.