Numerical investigation of low-Mach number flowfield inside of vaned diffuser based on the pseudo compressibility method

Owing to the type of the flow governing equation system, and the low efficiency of standard time-marching algorithm in solving the low Math number flows, a time marching code was explored to solve the incompressible internal flow field of turbomachinery based on the pseudo compressibility method. In the full paper, we explained our exploration in some detail; in this abstract, we just added some pertinent remarks listing three topics of explanation. In the first topic, a universal N-S equation system was derived, which can govern both high subsonic and low Mach number flow by a pseudo compressibility factor developed by Chorin. In the second topic, four step Runge-Kutta time-marching method with the central difference scheme was employed to resolve the N-S equations. Also in the second topic, we pointed out how the optimal pseudo compressibility factor was determined. In the last topic, some numerical results and the analysis for a vane diffuser of a tested centrifugal compressor were presented. The analysis of these results shows preliminarily that: (1) for the low Mach number flowfield, both efficiency and accuracy of the time marching algorithm based on the pseudo compressibility method is higher than that of the traditional time-marching algorithm; (2) the pseudo compressibility method is a compensator for the time-marching algorithm, and the application of the time-marching algorithm is extended by introducing the pseudo compressibility method.