Three-dimensional relaxation effect on quasi-3D flow in a blade row with spanwise loading distribution

This paper presents a quasi-three-dimensional flow calculation method including the three-dimensional flow relaxation effect in turbomachinery. A meridional flow solution is obtained by a streamline curvature method with a equilibrium equation formulated by exactly averaging the equation of continuity, momentum and energy equation in the circumferential direction. Blade-to-blade flows are solved by a singularity method considering the effects of stream surface inclination and axial velocity variation. A series of formulation for estimating the effects of the three-dimensional relaxation caused by the spanwise distribution of blade loading is performed using a secondary flow theory. In order to verify the validity of the method, it is applied to the flow analysis of a diagonal flow fan designed under a vortex type of constant circumferential velocity. The comparison of the calculated results with the experimental data shows a good agreement except the region where the flow field is affected by the tip leakage flow.