Analysis Of Conductivity Of Porous Material Carbon Foam

Porous material carbon foam has properties such as high conductivity, low density, resistance to high temperature and corrosion. Its unique properties K/ρ(conductivity/density) which is incomparable for normal materials predicts it will be marvelous material for heat radiation and will be more suitable for the heat radiation demand from electronic industry, aviation and aerospace industry, race car, national defense industry and communication and information sector. Currently, its manufacture method and properties is becoming the hot spot of scientific research.For the investigation of the properties of porous material, experimental method can be carried out. Based on the experimental result, empirical and semi-empirical formula can be got. Or theoretical reasoning can be processed based on the simplification of the real porous material and useful result can be got. Or by the FEM method, the properties of porous material can be analyzed. Since it costs by experimental method and it is usually hard to proliferate the usage of the formula reached, and the theoretical result gotten by reasoning based on the simplification of real porous material usually deviate from the real properties, with the development of computer technologies, causing the compute ability increasing, FEM method is used in the analysis of the properties of porous material more frequently.Based on carbon foam, the conductivity of porous material is investigated. Firstly, based on the traditional models with representative structure unit (cubic-center model and face-centered model), it is found the result got by face-centered model meets with the prediction when shape factor equals 1. Simulation method having no representative unit is proposed. Based on the even-distributed model, conclusion was made that bulk conductivity is not just influenced by solid conductivity and porosity. The distribution of pores and micro-structure of porous material will affect its overall properties. Then, on 2D surface, center randomness and radius randomness was introduced to the model in which originally, the centers of the circles was highly-ordered distributed. The influence of center randomness on overall properties such as porosity, Kbulk/Ksolid was investigated. When the center randomness and radius randomness coexist, the influence of center randomness on porosity is very slight; Kbulk/Ksolid will be lessened with the increase of center randomness. On the other hand, porosity will decrease with the increment of radius randomness; Kbulk/Ksolid will be enhanced when radius randomness increases. Finally, two dimensional Voronoi model was sent up. It is found that, Kbulk/Ksolid is not only decided by porosity neither.