Server Aerodynamic Noise Numerical Simulation Method Of Noise Reduction Design

The noise of server, as one of the three industrial-civilization pollutions, has attracted increasing attention with the more and more applications. Taking 2U pack-mounted server as the research object, the flow and acoustic field was simulated, and the optimization design for reducing the noise was studied with FLUENT software. The works carried out in the paper can be summarized as follows:1. It is pointed that air unsteady flow and pressure pulsation in interior of server cause the aeroacoustic noise, through research of the principle of aeroacoustic noise, the analysis of sound source, and noise characteristics. The sever noise includes rotation noise, vortex noise, leakage noise, etc.2. Based on finite volume method, the discrete methods of control equation are studied. All kinds of discretization scheme and turbulence model are analyzed respectively, and one order upwind scheme and RNG k ?εmodel are chosen. The SIMPLE arithmetic of unstructured grid is to solve the problem of numerical solution.3. Geometric model is built with Pro/E and GAMBIT software. The simplified modeling method is researched, and the regulations for predigesting the fluid model are presented. The unstructured tetrahedral meshes are selected to mesh generation by studying the meshing method. The settings of boundary conditions are analyzed, and different treatments of boundary conditions for axial flow fans are comparative studied, which prepare for CFD numerical analysis.4. Architecture of the simulation technology and methodology involved in Multi-field coupling system (MFCS) was proposed for servers, by Multi-field coupling analysis. The flow field and sound field are simulated with FLUENT, and FLOTHERM is used to simulate the thermal analysis for server performance. The mass flow rate of input/output, the velocity and pressure profile on center section of y axis, air path line and each receiver's noise frequency spectrum are analyzed respectively, then the simulation results are comparative analysis to validate its reliability and prepare for the optimization design for reducing the noise. 5. The dominant factors to affecting the aeroacoustic noise of server are concluded and summarized, which are composed of fan rotation speed, fan distribution location, exit geometry, exit distribution location, different exit size specifications and chips location. Then each factor is analyzed detailedly by numerical simulation. The 3D charts for each simulation result are plotted, and their influence rules are well summarized, which can reference for other electronic products'simulation analysis and design.