Numerical Simulation of the Internal Flow and Flow-induced Noise in a Centrifugal Blower at an Off Design Point

Abstract

Large eddy simulation （LES） of the internal flow in a centrifugal blower was performed in order to analyze the rotating stall at a partial flow rate. The blower has 12 impeller blades and a vaneless diffuser. Numerical results were validated by comparisons with measurements in terms of static head, velocity distribution at the impeller outlet and propagating speed of a stall cell. Propagating speed of the stall cell is about 70% of impeller rotational speed in both the experiment and the numerical computation. In addition, the sound pressure level （SPL） at a sampling point that is 1 m away from the suction bell-mouth was computed by solving Lighthill’s equation, in which the source term was obtained from the incompressible LES. The computed SPL was compared with the experimental data.