A Three-Dimensional Analysis Code of Compressor Performance and Stability for Steady Inlet Distortion

Abstract

Inlet distortion has a great impact on the compressor performance and stability. Developing a model which quickly and accurately can assess the performance and stability of a compressor with inlet distortion is one of the key technologies needed to improve the fidelity of a compressor design system. Thus, a new 3-D analysis code called CSAC based on the theory of body force model has been developed and used to predict compressor performance and stability with inlet distortion. The code solves the compressible 3-D Euler equations modified to include source terms which represent the effect of the blade rows. The source terms were calculated by the velocity circulation vectors and entropy production which were extracted from the 3-D Navier-Stokes (N-S) steady-state solutions at the stations between each blade row at many operating points with clean inflow. An analysis was carried out to determine the local flow conditions for parameterizing the magnitude of the velocity circulation vectors and entropy production of individual blade rows. A NASA stage 35 flow field with clean inlet was simulated with the code. The calculation results agreed well with the N-S solutions and experimental data. The stage 35 performance and stability with inlet steady circumferential total pressure distortion was also simulated using the code. The predicted performance maps of the stage 35 with inlet distortion showed a reduced range and pressure rise. In addition, the results reflected the strong three-dimensional characteristics of the flow field with inlet distortion, and the interaction of the blade rows with the upstream flow field. This paper describes the modeling method of CSAC and presents a detailed examination of the computed results.