A Novel Quasi-3D Design Method for Centrifugal Compressor Impeller on the Blade-to-Blade Plane
In this research, a novel quasi-3D design method is developed for the centrifugal compressor impeller on the blade-to-blade plane. In this method, an iterative inverse design method called Ball-Spine Algorithm (BSA) is incorporated into the quasi-3D analysis code solving the Euler equations on the blade-to-blade and meridional planes at each shape modification step. In design procedure, the difference between the target and current pressure distribution along the suction or pressure sides of the impeller causes the blade-to-blade profile to be changed and the target pressure distribution to be satisfied. In order to validate the quasi-3D analysis code, the centrifugal compressor of a gas turbine is investigated numerically using a full 3D Navier-Stokes analysis code. The meridional and blade-to-blade planes pressure distributions obtained from quasi-3D and 3D analysis codes are compared showing good agreement between them. Furthermore, the pressure ratio and efficiency of the centrifugal compressor is obtained by some experiments in which the flow parameters at the compressor inlet and outlet are measured. Comparison of 3D analysis results with the experimental results shows good agreements. Finally, the current pressure distribution along the pressure side at 50% span is smoothed and considered as the target pressure distribution. The quasi-3D design procedure converges to a new profile after 400 modification steps. The designed impeller is numerically analyzed showing the flow pattern of the impeller is improved and the total to static efficiency of impeller increases by 0.64 percent and the total pressure ratio increased by 3.38 percent.