MutiLayer Micro-perforated Panel Optimal Design And Application

Based on MA Da-You's the general theory of the micro-perforated absorber in this paper calculation method of single and double micro-perforated panel's sound impedance and absorption coefficient is summarized. The calculation result of theory is validated by stationary wave tube experiment. It is indicated that both results are compatible. Then the calculation method of three and four micro-perforated panel's sound impedance is deduced including their absorption coefficient. Different structure is compared in equal condition, which is indicated that three micro-perforated panel can obtain high absorption coefficient and wider absorption belt.There are some parameters that influence the mutilayer micro-perforated panel, which is difficult to be designed. There are 12 independent parameters about three micro-perforated panel such as hole diameter, plate thickness, perforation ratio, as well as the cavity depth. The tradition method is difficult to be used to be optimized. In this paper genetic algorithm is used to optimize mutilayer micro-perforated panel. The optimization result which is showed that performance of three micro-perforated panel improves remarkably after optimization. Average absorption coefficient is reached 0.81 during the selected frequency area. Its performance can even reach to minute glass cotton. Then the experiment is carried out. The parameters of micro-perforated panel which are selected are close to the result of optimization. The result of experiment illustrated that three layer micro-perforated panel after optimization can indeed obtain satisfactory absorption curve. The result is accordant with calculation, which can be used on project.Though performance of double micro-perforated panel is also improved remarkably after optimization, there are two peak value of anti-resonance. Absorption curve of four micro-perforated panel is the best in three different structure. But its performance is close to three layer micro-perforated panel.In the end micro-perforated muffler is studied. After optimization micro-perforated panel is used on micro-perforated muffler. It is indicated that its performance is improved remarkably.