Studies On Heat Transfer And High Temperature Sound Absorption Properties Of Titanium Fiber Porous Materials

Nowadays, with the economy growing rapidly, people neglect problems of energy and pollution of environment. There are heat transfer processes such as heating and cooling in modern industry. Therefore, enhancing the heat transfer process has become an important subject in the academic field. At the same time, the noise pollution is serious in the industry, which does harm to people. Therefore, problems of sound absorption and noise reduction is urgent to be solved. Metal fiber porous material is excellent structure-function material for it has many pores besides performance of metal itself, which makes it promising prospect. In this paper, titanium fiber porous material was prepared by vacuum sintering technology using scanning electron microscope and optical microscope to study the influence of temperature on fiber sintering. This paper aimed at studying the effects of fiber diameter, thickness, porosity and other parameters on the boiling heat transfer and sound absorption performance of sintered titanium fibrous porous material. The following results had been obtained:Titanium fiber porous material was produced by vacuum sintering at 1250℃, at which sintering neck fully grew and formed complete metallurgical bond. Aperture distribution of Φ70um specimen was relatively concentrated and pore size is relatively uniform. Wire diameter of 120 um sample had large pore size and the total pore size distribution of 120 um samples was between 30 and 120 um.The results showed that when the heat flux is less than 15w/cm~2, the heat transfer performance of wire diameter for 70 um was the best, and with the increase of heat flux, the teat transfer performance of titanium fiber porous material is enhanced with the increase of wire diameter, and the fiber material with t diameter of 120 um showed the best heat transfer effect. Besides, within a certain range of porosity, the heat transfer performance of titanium fiber porous material does not depend on porosity, but there is an optimum value. When the value of porosity was 50%, the property of heat transfer reached to the maximum; The effect of thickness on the heat transfer of porous material was determined by the heat transfer surface area and the resistance of the bubble motion.The sound absorption experimental results showed that the sound absorption coefficient of titanium fiber porous materials increased with the increase of porosity, and sound absorption peak moved to high frequency; the average sound absorption coefficient increased as the thickness become larger; the sound absorption coefficient of low frequency was improved after adding a certain cavity behind the materials;which reached more than 0.85 to the maximum; when it under the high temperature condition, the sound absorption curve was consistent with one of room temperature that increasing with the increase of frequency. With rise of temperature, the sound absorption coefficient was increased at low frequency, but decreased at high frequency. This paper studies the sound absorption performance of the composite structure of double layers. The results show that the arrangement of composite structure in porosity improved the sound absorption performance.