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转动非平衡玻尔兹曼模型方程统一算法与全流域绕流计算应用 被引量:12
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作者 李志辉 蒋新宇 +1 位作者 吴俊林 彭傲平 《力学学报》 EI CSCD 北大核心 2014年第3期336-351,共16页
基于过去开展稀薄自由分子流到连续流气体运动论统一算法框架,采用转动惯量描述气体分子自旋运动,确立含转动非平衡效应各流域统一玻尔兹曼模型方程.基于转动能量对分布函数守恒积分,得到计及转动非平衡效应气体分子速度分布函数方程组... 基于过去开展稀薄自由分子流到连续流气体运动论统一算法框架,采用转动惯量描述气体分子自旋运动,确立含转动非平衡效应各流域统一玻尔兹曼模型方程.基于转动能量对分布函数守恒积分,得到计及转动非平衡效应气体分子速度分布函数方程组,使用离散速度坐标法对分布函数方程所依赖速度空间离散降维;应用拓展计算流体力学有限差分方法,构造直接求解分子速度分布函数的气体动理论数值格式;基于物面质量流量通量守恒与能量平衡关系,发展计及转动非平衡气体动理论边界条件数学模型及数值处理方法,提出模拟各流域转动非平衡效应玻尔兹曼模型方程统一算法.通过高、低不同马赫数1.5~25氮气激波结构与自由分子流到连续流全飞行流域不同克努森数(9×10-4~10)Ramp制动器、圆球、尖双锥飞行器、飞船返回舱外形体再入跨流域绕流模拟研究,将计算结果与有关实验数据、稀薄流DSMC模拟值等结果对比分析,验证统一算法模拟自由分子流到连续流再入过程高超声速绕流问题的可靠性与精度. 展开更多
关键词 玻尔兹曼模型方程 气体动理论 转动非平衡 离散速度坐标法 全流域绕流 统一算法
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激波结构内流动问题的气体运动论描述 被引量:4
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作者 李志辉 张涵信 《空气动力学学报》 EI CSCD 北大核心 2007年第4期411-418,436,共9页
从介观Boltzmann速度分布函数理论出发,发展计及分子粘性碰撞截面与扩散碰撞截面,可描述各流域一维气体流动问题的Boltzmann简化速度分布函数方程及其气体运动论数值计算方法。通过对不同Knudsen数下非定常激波管流动及不同马赫数定常... 从介观Boltzmann速度分布函数理论出发,发展计及分子粘性碰撞截面与扩散碰撞截面,可描述各流域一维气体流动问题的Boltzmann简化速度分布函数方程及其气体运动论数值计算方法。通过对不同Knudsen数下非定常激波管流动及不同马赫数定常正激波结构问题数值模拟,研究分析不同流区的激波突跃变化过程以及近连续流、稀薄过渡流特有的分子输运现象,揭示不同马赫数、不同分子模型的激波内流动与传热变化规律,证实基于Bo-ltzmann模型方程的气体运动论数值计算方法用于激波结构内流动研究的准确可靠性。 展开更多
关键词 激波结构 BOLTZMANN模型方程 速度分布函数 离散速度坐标法 有限差分计算
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基于气体运动论的差分算法对管道流动数值研究 被引量:1
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作者 李志辉 毕林 唐志共 《应用数学和力学》 CSCD 北大核心 2009年第7期833-846,共14页
从分析研究求解Boltzmann模型方程的气体运动论数值计算方法特点出发,设计了几种求解离散速度分布函数不同精度的差分显式与隐式气体运动论数值格式.通过对不同Knudsen数下一维非定常激波管内流动、二维槽道流问题计算研究与应用测试,... 从分析研究求解Boltzmann模型方程的气体运动论数值计算方法特点出发,设计了几种求解离散速度分布函数不同精度的差分显式与隐式气体运动论数值格式.通过对不同Knudsen数下一维非定常激波管内流动、二维槽道流问题计算研究与应用测试,分析了不同差分格式数值离散效应对计算结果的影响,研究讨论了提高气体运动论数值算法计算效率的途径和差分离散处理所适用的计算准则等问题. 展开更多
关键词 Bohzmann模型方程 气体运动论数值计算 离散速度坐标法 激波管问题 槽道流问题
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Influence of Participating Media on the Radiation Thermometry for Surface Temperature Measurement 被引量:2
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作者 Yuying LIU Xinxin ZHANG 《Journal of Thermal Science》 SCIE EI CAS CSCD 2005年第4期368-373,381,共7页
A temperature measurement model of radiation thermometry for the surface covered by participating media was developed. The model was based on the radiation heat transfer of participating media and principles of radiat... A temperature measurement model of radiation thermometry for the surface covered by participating media was developed. The model was based on the radiation heat transfer of participating media and principles of radiation pyrometers, and solved by integral formulation of discrete ordinate method on spectral waveband. The influence of water mist on the indicated temperature of Raytek MR1SB one/two color pyrometer was discussed. Mie theory was used to calculate the radiative properties of water mist. In order to verify the model, a laboratory temperature measurement experiment was executed. The result shows that temperature of radiation thermometry is sensitive to the spectral response wavelength of pyrometer, and the simulated temperature of pyrometer agrees well with the experimental measurements on a suitable wavelength. The simulated temperature was lower than the real temperature of surface for one-color pyrometer, and it could be higher or lower than the real one for two-color pyrometer with the influence of participating media. 展开更多
关键词 participating media radiation thermometry surface temperature measurement discrete ordinatemethod.
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A Novel Dynamic Quadrature Scheme for Solving Boltzmann Equation with Discrete Ordinate and Lattice Boltzmann Methods 被引量:1
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作者 C.T.Hsu S.W.Chiang K.F.Sin 《Communications in Computational Physics》 SCIE 2012年第4期1397-1414,共18页
The Boltzmann equation(BE)for gas flows is a time-dependent nonlinear differential-integral equation in 6 dimensions.The current simplified practice is to linearize the collision integral in BE by the BGK model using ... The Boltzmann equation(BE)for gas flows is a time-dependent nonlinear differential-integral equation in 6 dimensions.The current simplified practice is to linearize the collision integral in BE by the BGK model using Maxwellian equilibrium distribution and to approximate the moment integrals by the discrete ordinatemethod(DOM)using a finite set of velocity quadrature points.Such simplification reduces the dimensions from 6 to 3,and leads to a set of linearized discrete BEs.The main difficulty of the currently used(conventional)numerical procedures occurs when the mean velocity and the variation of temperature are large that requires an extremely large number of quadrature points.In this paper,a novel dynamic scheme that requires only a small number of quadrature points is proposed.This is achieved by a velocity-coordinate transformation consisting of Galilean translation and thermal normalization so that the transformed velocity space is independent of mean velocity and temperature.This enables the efficient implementation of Gaussian-Hermite quadrature.The velocity quadrature points in the new velocity space are fixed while the correspondent quadrature points in the physical space change from time to time and from position to position.By this dynamic nature in the physical space,this new quadrature scheme is termed as the dynamic quadrature scheme(DQS).The DQS was implemented to the DOM and the lattice Boltzmann method(LBM).These new methods with DQS are therefore termed as the dynamic discrete ordinate method(DDOM)and the dynamic lattice Boltzmann method(DLBM),respectively.The new DDOM and DLBMhave been tested and validated with several testing problems.Of the same accuracy in numerical results,the proposed schemes are much faster than the conventional schemes.Furthermore,the new DLBM have effectively removed the incompressible and isothermal restrictions encountered by the conventional LBM. 展开更多
关键词 Dynamics quadrature dynamic discrete ordinatemethod dynamic lattice Boltzmann method thermal lattice Boltzmann method
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