Influence of the Mesh Size on the Aerodynamic and Aeroacoustics of a Centrifugal Fan using the Lattice-Boltzmann Method

摘要

The present paper deals with the direct and coupled simulation of the aerodynamics and aeroacoustics of a centrifugal fan connected to a suction-side test bench using the commercial Lattice-Boltzmann Code PowerFLOW of the Exa Corporation. The focus is on the variation of the mesh size in the finest grid resolution, which influence the time step immensely. The aim is to determine the smallest grid size in such a way that both the flow and acoustics of the centrifugal fan can be accurately predicted with an acceptable total computing time. In this study, three different mesh sizes for two different geometries of the finest resolution area will be investigated and compared. The results of the Lattice-Boltzmann simulation are compared and validated with measurement results obtained according to an ISO standard procedure at the Institute of Fluid Mechanics and Fluid Machinery at the University of Kaiserslautern. Flow information in term of the pressure increase of the centrifugal fan is well captured by the simulation. In addition, the noise is well predicted with respect to blade passing frequency and the general level of the spectrum at the considered microphone positions.