Temperature and pressure calculation of porous materials

Abstract

Porous material contains a large number of pores, and once the pore space collapses, it changes into a dense material with the great increase of temperature because of the energy deposition by porosity collapsing. In the process of shock compression, the temperature is extremely increased, which influences the thermodynamic state of porous material significantly. Therefore, the calculation of temperature is important for the shock compression of porous material, yet it has not been solved well in the literature. In this paper, based on the study of Grneisen general function v(v), the Debye temperature function of solid material is extended to the region of porous material, and the equivalent Debye temperature function (v) of porous material is formulated, from which the isentropic temperature function Ts(v) of porous material is obtained. Furthermore, a computation model is established, in which the isentropic work of porous is assumed to be equal to that of compact material under the same pressure at 0 K. With this model, the isentropic pressure function ps(v) of the porous material is acquired. Hence, the reference equation for calculating temperature and pressure of porous material, i.e., Ts(v) and ps(v), is completed. To demonstrate this method, the p-v and T-v curves of the Hgoniot state of porous copperare computed, and the values of porosity are m 1.13, 1.22, 1.41, 1.56 and 1.98, respectively. The calculated results are in good agreement with the experimental data. A comparison with other calculation is also made, indicating a better reliability of the present method.