Assessment of Numerical Optimization Algorithms in The Design of Low-Noise Axial-Flow Fan

초록

Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, incompressible, three-dimensional Reynolds-averaged Navier-Stokes equations are used as governing equations, and standard k-ε turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the search directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of production rate of the turbulent kinetic energy to pressure head. Two variables related to sweep angle distribution are selected as design variables. Performance of the final fan designed by the optimization was tested experimentally. The experimental result shows that spectrums of no-swept and forward-swept fans have differences especially in the broadband. And the overall noise level of forward swept fan is lower 10dB(A) than that of no-swept fan.