Unified three-dimensional simulation method for full working conditions of compression systems

Abstract

The complete operating range of the compressor includes stable and unstable conditions, and the boundary between the two is the stall and surge line. Previously, the two were modeled in isolation from each other. The unsteady flow equation of the compression system is constructed based on the idea of the body-force model. It is possible to obtain the steady characteristics and transient simulation of post-stall, realizing the unified simulation of the full working conditions of the compression system. Among them, by using and developing the elementary cascade method, the continuity of correlation method for the body-force source term in different flow regions is realized. The model was validated on four single-stage compressors as well as one two-stage compressor, and the results showed that the steady-state characteristics, stable boundary, and rotating stall characteristics obtained by the developed model were in good agreement with the experimental results. The experiments showed that when the blade solidity was increased, the compressor's work capacity increased and its stability improved, and the rotational frequency of the stall cell increased slightly. The calculated results always agreed with the trend of the experimental results. In addition, the variation of blade forces during rotating stall can be easily obtained using the concept of body force and more details of the flow field can be obtained using the model.