Throughflow Moldelling And Validation Of Multistage Axial Flow Compressors

Throughflow analysis is a very important part in the aerodynamic design of multistage axial flow compressors.Advanced compressor design requires further development of throughflow analysis models.In this thesis,a set of blade force model and throughflow analysis empirical model is proposed and validated for throughflow analysis.A throughflow analysis program based on the above models is developed to analyze the multistage axial flow compressors at multiple operating conditions.The ten stage high pressure compressor NASA/GE E3,the four stage NASA/GE LSRC,and the independently designed four stage vertical low speed research compressor(SJTU LSRC)are selected to be the typical research cases in this study.The accuracy of the throughflow analysis program is verified by those typical research cases.The main research results of this thesis are as follows(1)A throughflow analysis program is developed.A blade force model that reflects the compressor design experiences is added in the numerical method,which compensates for the inability in the solving of the circumferential flow field,wake,and separation.The blade force model considers both non-viscous and viscous blade force.The non-viscous blade force is perpendicular to the stream surface generated by the deviation angle empirical model,and does not generate any loss.In this case,the flow field develops according to the flow direction specified by the deviation angle empirical model.The viscous blade force model reflects the total pressure loss of the compressor.The numerical computation result based on the viscous blade force model is in complete agreement with the prediction of the empirical model(2)A complete throughflow analysis model for off-design conditions is proposed.The datum design condition throughflow analysis model is modified to suit for the aerodynamic performance prediction of customized new blade designs.During the modification of the datum design condition throughflow analysis model,the prediction error of 2D B2B computation is investigated based on statistical analysis.The 2D B2B calculation has a high prediction error for the deviation angle.In this case,the datum design deviation angle model is revised to predict the design deviation angle of customized new blade designs.The revision method is given in the thesis.The proposed off-design throughflow analysis model is based on an implicit function of deviation angle.The model expresses the changing rate of deviation angle with incidence through analytical derivation.The model is suitable for the prediction of deviation angle at full blade height and full operating condition.The model uses the implicit function of the deviation angle to describe the dimensionless blade loading.The off-design loss is predicted based on the arbitrary-order polynomial fitting of the implicit function(3)The four stage low speed research compressor SJTU LSRC is built.The LSRC simulates the flow field of the original stage in a high pressure compressor.The throughflow analysis model for the aerodynamic design of the high pressure compressor is collected through the study of the LSRC flow field.The accuracy of the developed throughflow analysis program is validated through the detailed comparison between the test data and throughflow analysis result.The prediction model and numerical program is proved to be reliable in the further aerodynamic design of the high pressure compressor.