CFD Simulation Analysis And Bionic Noise Reduction For Busaxial Flow Fan

Bus is one of the major public transport means in modern life. More and more peoplefocus on it’s passenger capacity, dynamic performance, fuel economy etc. As one of themost important part of cooling system, the axial flow fan contribute a lot to both insideand outside noise of automobile. The glowing cooling requirement and reducing noiselimit promotes research institutions around the world to work successively on noisereduction for fan. It is significant to design new kind of fan with high flow and lownoise.This Thesis is based on a noise reduction project for bus axial flow fan. Firstly, thebasic theories of the axial flow fan is described, including the computational fluiddynamics (CFD) and the computational aero-acoustics. The3D geometry model is builtin UG and the finite element model is built in Hypermesh based on the bus axial flowfan. Combined with the CFD simulation analysis methods, the flow field simulation isperformed based on the N-S equation and RNG k turbulence model, and theaerodynamic noise calculation is performed based on large eddy simulation (LES)model. The reliability of the established simulation model is verified through comparingthe simulation results with the experiment one. Then intensive studies are done to sixgeometric parameters and three bionic parameters including the number of blades,arrangement of the blades, edge sawteeth etc. Use the single factor analysis method toget the rule of each factor’s effect on the fan performance. According to the theoreticalresearch and analysis results, two kinds of bionic models are designed to satisfydifferent requirements. At last, the simulation result shows the noise of these bionicmodels is reduced significantly.