Mixed-flow Compressor Blade Design By Inverse Method

Congifuration characteristics and advantages of both axial and centrifugal compressor are combined in a mixed-flow compressor,which suits the development needs of future aeroengines.Full potential of mixed-flow compressor will be explored by advanced design approaches.Inverse design method is more targeted in blade modification by giving physical relationships between aerodynamic parameters and the profile of the blades according to design parameters.It is widely used in 3D blade design nowadays for its high design efficiency,less dependency on experience of designers,relatively short of design cycle,strong optimization of pertinence during blade modification.Modification of a mixed-flow compressor was performed based on a three-dimensional inverse method which is developed from the inverse method carried out at the Von Karman Institute and self-developed CFD software NAPA is used.Several contents are included in this paper:1?Initial scheme of a mixed-flow impeller with split blade is structured by constructing the interception of Krain impeller in the research.According to the analysis of the performance parameters of the flow field and blade wall pressure distribution,reducing the high speed areas in main blades and splitter blades leading edges and smoothing the main blade surface load distribution are conducted as the optimization goal of inverse problem clearly.2?The accuracy of aerodynamic design in mixed-flow impeller and application of inverse problem method which is based on tracking streamline and permeable wall boundary condition are verified on the basis of surface pressure distribution of the initial blade in initial mixed-flow impeller.3?The improvement of local flow characteristics of main blades in initial impeller are carried out.The main improvement measures include weakening the high Mach number areas in the leading edge of the main blade's suction side and smoothing the local load fluctuation near the 60% position of the main blade flow direction due to the leading edges of the splitter blade.4?The research of load distribution mode between main and splitter blades and their influence in flow field parameters are carried out according to the comparison of a variety of ways through multiple independent improvement of main blade,independent improvement of splitter blade in weakening local high Mach number and synchronous improvement of spiltter blade which is following main blade by interception method.