Experimental Research On The Acoustics Performance Of Porous Metal Material Under High Temperatures

As a kind of multi-functional and new-type engineering material, porous metal material is widely used, and the research of sound absorption characteristics gains extensive attention. This thesis centers on the sound absorption characteristics of porous metal material under the environment of high temperature and temperature gradient, designs test systems under different circumstances, and conducts experimental research.The paper at first derives wave equation of the acoustic wave propagation, the wave-guide theory of acoustic wave in the circular pipe, makes a brief introduction of the acoustic characteristic parameter, the sound absorption performance, and the sound absorption simulation of the porous metal material,introduces the experimental principles of the two microphone transfer function method, explains the sound absorption mechanism and the influencing factors of the porous metal materials, especially analyses the influence of temperature on the porous sound absorption performance, and illustrates the transformation between heat energy and sound energy under the condition of thermoacoustic effect.Secondly, the paper designs the sound absorption performance testing system of the porous metal material adopting the method of two microphones transfer function under these different circumstances of indoor temperature, stable high temperature and the positive and negative gradient temperature field, illustrates each subsystem in detail, stimulates high temperature and the temperature gradient that the sample can bear.At last, the thesis studies the sound absorption performance of the porous metal material both theoretically and experimentally in those different temperature field, analyses the experimental results and the problems existing in the experiment, also puts forward some proposals about the improvement of the experimental method, experimental material, and experimental equipment.