Through-flow Performance Prediction For Axial-radial Combined Compressor Based On The Streamline Curvature Method

Based on the streamline curvature method of quasi-orthogonal,the governing equation of pressure gradient for combined compressors is derived in this paper,and a newly through-flow method is developed.A program for through-flow performance prediction of axial flow,centrifugal and combined compressors is being developed in C++ computer language,which is effectively used for performance prediction of compressors.Firstly,based on the prediction method,the empirical models for axial-flow compressors are introduced,including reference incidence angle,deviation angle,loss and blockage models.The through-flow performance for an isolated axial-flow compressor and a three-stage subsonic axial-flow compressors are calculated respectively,and the comparison with the experimental results verifies the rationality of the method and the accuracy of the empirical models.In addition,through the comparison study of the through-flow performance prediction by different wall blockage models,it is found that the appropriate blockage model can further improve the prediction accuracy.Secondly,the empirical models of the centrifugal compressor impeller and vaneless diffuser are introduced,and the appropriate spanwise and streamwise distribution expansion studies are carried out.The through-flow performance for high/low pressure ratio centrifugal compressor are calculated respectively,and the comparison with the results of the three-dimensional CFD simulation verifies the accuracy of the empirical models and the rationality of the two-dimensional expansion studies.Finally,the program for through-flow performance prediction of combined compressor is being developed by integrated the axial flow and centrifugal compressor program.The through-flow performance for a certain axial-centrifugal combined compressor are predicted.The results show that the program have reference value for performance prediction in a certain sense.In addition,the causes of the performance characteristic prediction error are analyzed in detail,which also provides a direction for further modification and improvement of the program.The program for through-flow performance prediction designed in this paper can quickly and effectively evaluate the performance characteristics of combined compressor,which is an effective tool for performance prediction and analysis.