一种直接测量W-J参数的实验方法

本文探索了一种直接测量W-J参数的方法. 实验选用NaCl作为试样, 在快速压缩过程中原位测量样品的温度和压力的变化值. 通过温度修正使测量值在原理上更符合等熵压缩过程的结果, 并采用大幅度增压结合中值定理得出中点压力处温度随压力的变化率, 进而根据R=(P/T) (∂T/∂P)_S关系式求出W-J参数, 整个过程没有引入其他参数. 此外, 作为对比, 我们还从相关的物态方程、经验公式和已知参数出发计算了NaCl的W-J参数及其随压力变化的关系. 结果表明: 实验测得的NaCl的W-J参数随压力增加而增加; 实验结果与计算值符合得很好. 这说明快速增压直接测量物质的W-J参数是一种可行且可靠的方法. 关键词： NaCl W-J参数 快速增压 高压

An experimental method to measure W-J parameters

The W-J equation of state proposed by Wu qiang and Jing fu-qian is a volume equation with pressure and temperature as the independent variables, which is mutually complementary to the Grüneisen equation of state, and is extending and perfecting in theory of the equation of state. It is significant to determine the W-J parameters for the study and application of the equation. The W-J parameters can be educed from the Grüneisen parameters and adiabatic bulk modulus, but it is difficult to take into account the uncertainty of these parameters. In this paper we explore a method of direct measurement of the W-J parameters. Temperature and pressure were recorded in situ during the rapid compression process, in which the rate of change in temperature was obtained, with pressure at midpoint pressure during the isentropic compression process, through correcting temperature and increasing substantially pressure combined with mean value theorem, and finally the W-J parameters were obtained according to equation R=(P/T) (∂ T/∂ P)_S. No additional parameter was introduced in the whole process. In addition, as a comparison, the W-J parameters and their relationship with the pressure of sodium chloride were also calculated by using the equation of state, the empirical formula and known parameters. The results showed that the experimentally measured W-J parameters are increased with increasing pressure, and all the W-J parameters obtained by experiments are in good agreement with those by calculation. This suggests that the experimental method in rapid compression process is feasible and reliable for the direct measurement of the W-J parameters.