气-固界面作用物理模型的确定性实现方法

Deterministic Implementation Algorithm of a Physical-based Gas-surface Interaction Model

针对最新发展的气-固界面作用物理模型,提出一种确定性计算方法。算法的核心是:针对离散速度空间分布函数,采用确定性算法计算出单轮气-固碰撞作用的散射核函数矩阵,并通过考虑吸引势阱作用和迭代累加多次气-固碰撞作用,物理地反映气体分子入射/反射速度分布函数在气-固界面上的变化。与现有基于Monte Carlo随机采样的实现方法对比,该确定性实现方法可以快速且准确地计算边界上气体分子入射/反射速度分布函数的映射关系。因此,该方法可为以离散速度空间为基础的稀薄气体流动模拟方法提供先进的边界条件。

A deterministic algorithm is developed to implement a physical-based gas-surface interaction model.The key of the algorithm is to calculate discretized matrix by a deterministic way,which represents the scattering kernel of single gas-surface collision and governs the gas molecular velocity distribution function.By considering the attractive potential well and successive gas-surface collisions,this algorithm describes physically the variation of gas molecular velocity distribution functions at the interface.Comparing with existing stochastic implementation algorithm based on Monte Carlo sampling,this deterministic implementation algorithm calculates accurately and efficiently the relation between incident and reflected velocity distributions of gas molecules.Therefore,it provides a better boundary condition for the deterministic simulation methods of rarefied gas flows based on discretized velocity space.