Modeling And Sound Absorption Performance Analysis Of Random Porous Metal Fiber Material

Porous metal fibers are the most commonly used sound absorbing materials.The models used to characterize and predict the acoustic performance of porous metal fibers are mainly based on the interrelated macroscopic acoustic parameters.Therefore,it has become an important research problem to construct the correlation between the macroscopic acoustic parameters and the microscopic porous structure.However,the pore distribution of the actual porous metal fiber is not inerratic,and the fiber is randomly distributed in three-dimensional space makes it more difficult to accurately characterize the sound absorption performance of the structure.In this paper,the relationship between the randomness of the microstructure of porous metal fiber and the macroscopic acoustic parameters is studied.The main research contents are as follows:1.Establishment of geometric model of random porous metal fiber material.Based on Monte Carlo method on stochastic the microstructure of porous metal fiber geometry modeling,from the angle of the fiber random distribution,considering the fiber position and radius of two random variables,the two-dimensional fiber was simulated by using normal distribution and uniform distribution methods,and the three-dimensional orientation distribution function of the fiber was established.The orientation tensor was used to describe the orientation distribution of the fiber.Established a two-dimensional and three-dimensional random fiber modeling method,the specific porosity,wire diameter,under the condition of random fiber model.2.Calculation of random porous metal fiber material’s sound absorption performance and probability distribution solution of macroscopic acoustic parameters.Monte Carlo are adopted to simulate the location of the porous metal fiber material and stochastic change of the radius to obtain fiber geometry model,the geometry information obtained imports Comsol finite element software,finite element method(bottom-up-method)to flow field in the representative volume element(low frequency limit)and the electric field(high frequency limit)analysis,through the analysis of porous metal fiber materials can be five macro acoustic parameters of the equivalent fluid model,then we use the method of mathematical statistics to deal with the calculation results,get five macro acoustic parameters of probability density distribution.3.Analysis of acoustic absorption performance of random porous metal fiber materials under high temperature environment.To eliminate sound lining structure for aeroengine bypass the object,discusses the temperature on the heat transfer coefficient under the environment of high temperature,air density,specific heat,flow resistance,prandtl constant,the influence of related parameters,For instance,extend the JCA model to high temperature environment,which established the acoustic absorption theory of porous metal fiber under high temperature environment,studying the influence of material parameters on sound absorption performance in high temperature environment.The results show that the sound absorption performance of porous metal fiber will decrease with the increase of temperature,but the overall trend is about the same as that of normal temperature.