Validation of the Lattice Boltzmann Method for Simulation of Aerodynamics and Aeroacoustics in a Centrifugal Fan

Abstract

Due to the fact that legal and market requirements are becoming stricter, fan noise reduction, in addition to energy efficiency, represent a challenge for fan product designers. Most experimental studies are associated with trial-and-error approaches. Therefore, numerical methods are mostly preferable. However, the quantitative prediction of the noise emitted by radial fans via numerical simulations remains challenging. The Lattice Boltzmann method (LBM) is a relatively new approach that promises a direct calculation of the aerodynamics coupled with the aeroacoustics. This article presents an LBM simulation of a centrifugal fan using the commercial Lattice Boltzmann Code SIMULIA PowerFLOW of Dassault Systèmes. The simulation model includes both the fan impeller and the spiral housing. In accordance with the experimental setup, the fan was mounted in a test bench to analyze four different operating points. The results of the LBM simulation were validated by experimental measurements. Flow information in terms of pressure rise and efficiency of the centrifugal fan as a function of the flow rate are in a good agreement. Considering the acoustic spectra and the blade passing frequency, the simulation was able to precisely predict the noise of the centrifugal fan. The simulation results are also used to visualize the flow and acoustic field inside of the fan to detect noise-generating flow features. By evaluating the filtered pressure fluctuation in the fluid volume and on the wall, four main noise sources of the centrifugal fan can be identified.

Keywords

• Lattice Boltzmann method
• centrifugal fan
• aeroacoustics
• aerodynamics