Numerical Simulation Of Aerodynamic Noise Of Axial Fan Based On Fluid-acoustic Coupling

Axial flow fans are widely used in modern equipment with large heat generation for heat dissipation due to their advantages such as excellent performance and low power consumption.At the same time,the noise generated by the axial flow fan during operation will also endanger human health.Therefore,the noise problem of axial flow fans has been paid more and more attention by people.In this paper,the small axial fan of electronic equipment is taken as research object.Use numerical simulation and experimental verification to analyze the inside and around the flow field and the sound field.The influencing factors of the aerodynamic noise which are caused by the single unit fan and the whole unit fan respectively are researched on above basis.The main contents of this paper are as follows:(1)Establish the numerical simulation method of axial flow fan.The flow field and sound field performance of axial fan are simulated by the method of computational fluid dynamics and acoustic analogy in aeroacoustics.Determine the model simplification method,the meshing method and the setting method of the flow solution and the sound solution.And the correctness of these methods is confirmed by wind tunnel test and noise test.After that,The relationships between the flow and the sound are established by analyzing the distribution of the parameters in the flow field and the sound field.(2)Study the operating state of the axial flow fan.A Single axial fan is as the research object,changing the fan speeds and back pressures separately for numerical simulation.Through the research on the changing rules of fan flow rate,efficiency and noise under different speeds and back pressures,it is determined that the most suitable working back pressure range for the fan studied at a speed of 4000 rpm is between 40 and 80 Pa.And it also has a positive impact to improve the working life of fan because of the reasonable working condition of axial fan.(3)Research on influencing factors of aerodynamic noise of single axial fan.Take the single axial fan as the research object and change the structure of fan blades.Through the analysis of the numerical simulation results,obtain the effects of different installation angles,bending angles,sweep angles and blade thickness on the single axial fan.The corresponding rules of flow,aerodynamic noise and other parameters are summarized,which provide the basis for the design of axial fan blades.(4)Research on influencing factors of aerodynamic noise of induction cooker.Different from before,the research object is a simplified induction cooker.Through the simulation analysis,study the impact of the cooling axial fan on the flow field and the sound field inside the induction cooker.Summarize the several regularities about the flow field and the sound field in different number of heat dissipation holes and different position of the fan,which can provide reference for the structural improvement in the induction cooker.