Theoretical and Experimental Investigations About Vaneless Return Channels of Multi-Stage Radial Flow Turbomachines

Abstract

Based on the Navier-Stokes-Equations, a numerical method which is a variation of the “partially-parabolic” approach used by Moore et al., was applied to calculate the three-dimensional, turbulent, viscous flow in vaneless return channels of multistage radial flow turbomachines. To avoid the high demand for computer time and storage capacity generally needed for the numerical treatment of the Navier-Stokes-Equations, the method is restricted to the calculation of flows with a predominant flow direction without separation. The procedure carries out an iteration between a marching integration of the conservation equations through the three-dimensional flow field along the mean flow direction and the solution of an elliptic pressure correction equation. So it is guaranteed that downstream influences can be considered upstream.