The Procedure Of The Optimal Design Of Compressor Shell To Reduce Acoustic Noise

Topology optimization of acoustic structure has become one of the research subjects of great concern in recent years. The researches now are almost on the approaches for thickness layout optimization and for the thickness or height of the fixed ribs. And most researches are mainly about the structures that have analytical solutions, few about the layout of the ribs, and even fewer for the structures that have not analytical solutions such as compressor shell.The optimization design for reducing the structure radiation noise can reduce the radiation sound power through improving the structure's shape, positions and size of the added ribs. Because sound power computation need to integrate the vibration velocity distribution function of the structure, the computation cost for sound radiation optimization is huge. This paper integrates FMBEM with topological acoustic sensitivity analysis, reduces the computation volume of the optimization and realizes the optimal layout of added ribs.In this paper the suggested approach makes use of the FMBEM's high efficency, in which the sound power is used as the target function and stiffness of element as design variable. The topological acoustic sensitivity of the structure is obtained by global finite difference and find out the optimization regions where stiffness need heightening based on the distributions of acoustic sensitivity. The acoustic radiation topology optimization of a sphere shell under harmonic excitation is given for an example, in which the sound power of the structure is reduced by optimal positions of ribs based on sensitivity analysis.In this paper the optimiation approach is applied to the topology optimization design for a refrigerator compressor shell based on the compressor noise test experiment, in which key frequencies of radiation noise are obtained and the sound power of the key frequencies is used as the target function. The shell's stiffness is heightened, the normal velocity on the shell surface is reduced and the sound power and radiation efficiency of the compressor is reduced efficiently by optimal positions of added ribs on the compressor's shell. Finally the comparison noise test experiment before and after optimization proves the results of numerical simulation and shows the efficiency of the suggested optimization approach.As is showed in the research, solving topological acoustic sensitivity based on FMBEM heightens the computation efficiency of topological acoustic sensitivity, realizes the opimal layout of added ribs for structures sound radiation optimization to reduce radiation noise and is applicable for practical engineering.