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获得准确的电子输运和反应系数是采用流体模型准确仿真流注传播特性的前提.目前,电子输运系数主要有两种计算方法:一是用电子群实验数据进行插值;二是用两项近似方法解玻尔兹曼方程.方法一只能用在约化场强很小的场合,方法二的理论基础即各相同性假设是否成立和数据准确度尚无定论.针对以上问题,Ness 等人采用了多项近似法解玻尔兹曼方程计算电子输运系数.该文主要对多项近似解玻尔兹曼方程进行两点改进:一是调整速度分布函数的展开顺序,这样能把流体尺度和非流体尺度下计算过程统一起来;二是采用高斯–克龙罗德积分代替高斯-拉盖尔积分计算碰撞积分项.最后对硬球模型和Reid非弹性碰撞模型进行了计算,结果表明:采用高斯–克龙罗德积分代替高斯–拉盖尔积分计算碰撞积分项更准确;即使在只有守恒碰撞时,电子速度分布函数仍呈现各向异性特征,采用两项近似方法计算出的电子输运系数有较大误差.“,”The propagation properties of streamer could be obtained accurately by using the fluid model to simulate, provided that precise electron transport and reaction coefficients were input the model. Presently, there were two methods to calculate the transport coefficients: interpolation method based on the data of swarm experiment or two-term approximation of the Boltzmann equation. It was showed that interpolation method could be merely used in low reduced electric condition, and for the second method the reasonableness of the isotropic assumption and the accuracy of the results were a question. In view of the above problems, multi-term approximation of the Boltzmann equation to obtain electron transport coefficients was proposed by Nesset al. Here two improvements are provided: firstly, the expansion sequence is adjusted to derive the unified hierarchy in the hydrodynamic and non-hydrodynamic limit; secondly, the collision integral is evaluated based on the Gauss-Kronrod rule instead of Gauss-Laguerre rule as used in Nesss works. In the end hard sphere model and Reids ramp inelastic model are considered. It is shown that it is more accurate to evaluate the collision integral based on Gauss-Kronrod integration method than Gauss-Laguerre method. Furthermore, it is demonstrated that the electron velocity distribution is anisotropic even only undergoing conservative collision, so there is a great error if the two -term approximation is used to obtain the electron transport coefficients.