Numerical Study of Vortex Structure in the Shear Layer between Swirling Backflow and Axial Main Flow

Abstract

The present paper treats the backflow vortex structure observed at the turbomachinery inlet at reduced flow rate. It is caused by the roll-up of the shear layer between swirling backflow and axial main flow. In order to verify this, a simple model test was carried out in which the effect of impeller was represented by an axisymmetric swirling backflow. In the present paper, the flow field of a simplified model test is simulated by using LES calculations to investigate detailed flow structure. The computed results are compared with experimental results.