稀薄流中基于碰撞分子特定次序的DSMC改进方法

Modified DSMC Method Based the Specific Order of Collision Molecules

针对高超声速弹箭前方绕流流场中气体分子间碰撞导致复杂化学反应的问题,提出了一种化学反应类型取决于碰撞分子特定次序的DSMC(direct simulation Monte Carlo)改进方法。在变径硬球模型、Larsen-Borgnakke唯象论模型和Bird的化学反应概率模型的基础上,先取五组元(N2,O2,N,O,NO)混合气体间的离解、置换和复合反应为主要化学反应类型,采用Fortran语言编制了气体分子化学反应的DSMC源程序,模拟了高超声速二维圆柱绕流,并将模拟结果与有关文献中的理论数据进行了比较,在80 km,85 km,90 km处,圆柱表面处的热流系数峰值误差分别为1.1%,2.0%和1.9%,数值结果验证了该方法的可行性和合理性。

In order to solve the complex chemical reactions caused by the collision molecules in rarefield flow regime around the hypersonic projectile,a modified direct simulation Monte Carlo(DSMC)method depending on the specific sequence of the collision molecules was proposed.Based on the variable hard-spere model,the Larsen-Borgnakke phenomenological model and the chemical reaction model of Bird,the dissociation,displacement and reconbination reaction in five-species mixed gas(N 2,O 2,N,O,NO)were chosen as the main chemical reaction types,and the DSMC code was produced by using Fortran.Gas-molecular chemical reaction in hypersonic two-dimensional flow around a cylinder was simulated,and the results were compared with the theoretical data.At 80 km,85 km and 90 km,the error of the peak value of heat-flow coefficient at the surface of the cylinder is 1.1%,2.0%and 1.9%,respectively.The numerical results verify the feasibility and rationality of the proposed method.