Development of an Improved Streamline Curvature Approach for Transonic Axial Compressor

In this paper, an improved streamline curvature (SLC) approach is presented to obtain the internal flow fields and evaluate the performance of transonic axial compressors. The approach includes some semi-empirical correlations established based on previous literatures, such as minimum loss incidence angle model, deviation model and total pressure loss model. Several developments have been made in this paper for the purpose of considering the influences of three-dimensional (3D) flow in high-loaded multistage compressors with high accuracy. A revised deviation model is applied to predict the cascade with large deflection range. The method for predicting the shock loss is also discussed in detail. In order to validate the reliability of the approach, two test cases including a two-stage transonic fan and a three-stage transonic compressor are conducted. The overall performance and distribution of spanwise aerodynamic parameters are illustrated in this paper. Compared with both the experimental and computational fluid dynamic (CFD) data at design and a number of different off-design condition, the SLC results give reasonable characteristic curves. The validation demonstrates that this improved approach can serve as a fast and reliable tool for flow field analysis and performance prediction in preliminary design stage of axial compressors.