摘要
近空间飞行器绕流环境一方面表现为连续介质黏性干扰效应严重,另一方面因稀薄间断粒子效应而表现为物面速度滑移、温度跳跃等非平衡流动特点,导致连续流Navier-Stokes方程精细化求解困难。以20°楔角平板绕流为研究对象,借助适于蒙特卡罗方法的经典现象学能量交换模型为基础,通过将全部碰撞视为非弹性,控制转、平动能量参与交换比例缓解内能松弛过快,开发一种限制碰撞能量交换且解耦碰撞分子转动双松弛的直接模拟蒙特卡罗方法计算程序。对比验证程序与统一算法、开源DS2V程序、直接模拟蒙特卡罗-信息保存3种方法在超声速圆柱绕流的计算结果,结果显示,忽略统计波动影响程序能再现精细的流场激波结构且最大误差仅为5.6%;在此基础上模拟马赫数对20°楔角平板的气动力热影响并对比分析程序与二维直接模拟蒙特卡罗方法程序计算速度,发现粒子数密度、温度以及压力在楔角位置明显累计,在考虑飞行器热防护设计时,应重点关注楔角位置;相同计算条件下该程序单位时间步长计算速度相比直接模拟蒙特卡罗方法程序快28.7%。
In the flow environment of spacecraft in near space,the viscous interference effect of the continuous medium is substantial.Additionally,surface velocity slip and temperature jump,which are non-equilibrium flow characteristics induced by the thin discontinuous particle effect,complicate the solution of the Navier-Stokes equation for continuous flow.Based on the classical phenomenological energy exchange model proposed by Borgnakke and Larsen(BL)for the direct simulation Monte Carlo(DSMC)method,this study examines the flow around a plate at a 20°wedge angle.By treating all collisions as inelastic and controlling the ratio of rotational and translational energy exchange,the excessive relaxation of internal energy is mitigated.A DSMC program is developed to limit collision energy exchange and decouple the rotational double relaxation of collision molecules.The numerical results of the proposed program are compared with those from GKUA,DS2V,and DSMC-IP for supersonic cylindrical flow,and the comparisons are verified.The results show that the proposed program accurately reproduces the shock structure of the flow field,with a maximum error of only 5.6%.On this basis,the aerodynamic thermal effect of the Mach number on a 20°wedge angle plate is simulated,and the calculation speed of the program is compared to that of the classical two-dimensional DSMC2 program.Notably,particle population density,temperature,and pressure are substantially concentrated at the wedge angle position.When considering the thermal protection design of aircraft,special attention should be given to the wedge angle position.Under the same calculation conditions,the unit time step calculation speed of this program is 28.7%faster than that of the DSMC2.
作者
胡佳志
李志辉
李凡
HU Jiazhi;LI Zhihui;LI Fan(Beijing Aerohydrodynamic Frontier Research Center,Beijing 100120,China)
出处
《哈尔滨工程大学学报》
北大核心
2025年第9期1737-1744,共8页
Journal of Harbin Engineering University
基金
国家自然科学基金项目(12332013).
