双温度氦等离子体输运性质计算

Calculation of two-temperature transport coefficients of helium plasma

获得覆盖较宽温度和压力范围内的等离子体输运性质是进行等离子体传热和流动过程数值模拟的必要条件.本文采用Saha方程计算等离子体组分,采用基于将Chapman-Enskog方法扩展到高阶近似的方法,计算获得了电子温度(T_e)不等于重粒子温度(T_h)的情形下,在300 K到40000 K的温度范围内氦等离子体的黏性、热导率和电导率.研究结果表明压力和热力学非平衡参数(θ=T_e/T_h)对氦等离子体的输运性质有较大的影响.在局域热力学平衡条件下,计算获得的氦等离子体输运性质和文献报道的数据符合良好.

The knowledge of two-temperature transport coefficients over wide temperature and pressure range is essential to model the flow and heat transfer in plasma process. In this study, the plasma composition is calculated using the Saha equation and the transport coefficients are worked out using Chapman-Enskog method expanded up to higher approximation. The electron temperature Te is assumed to be different from that of heavy species Th. The evolutions of viscosity, thermal conductivity, and electric conductivity of helium plasma are presented in elctron temperature range from 300 K to 40 000 K. It is shown that the transport coefficients strongly depend on pressure and non-equilibrium parameter （θ = Te/Th）. These values in local thermodynamic equilibrium state accord well with previously reported data.