柱输运管中扩散超声速辐射波的能流  

Radiative energy flux of diffusive supersonic wave in a cylinder

作　　者：蓝可[1] 贺贤土[1] 赖东显[1] 李双贵[1] 

机构地区：[1]北京应用物理与计算数学研究所,北京100088

出　　处：《物理学报》2006年第7期3789-3795,共7页Acta Physica Sinica

摘　　要：采用于敏关于直角坐标系下两平板间粒子传输的辐射能流计算的理论模型,给出了柱输运管中与径向位置相关的谱辐射能流的计算公式.研究结果表明,由于管壁的自由程远小于传输介质的自由程,从而导致辐射能流中几何因子随径向变化,并认为这是最近关于扩散超声速辐射波实验中测得的辐射波强度随径向呈拱形分布的又一个重要原因.另外,还给出对横截面平均的谱辐射能流、以及当辐射与物质处于局部热动平衡时的辐射能流的计算公式,并将其中的几何因子与人们传统的通过几何自由程获得的几何因子进行了比较.为方便数值模拟,还给出了辐射能流公式中含有多重复杂积分的几何因子的拟合表达式.The calculation of radiative energy flux is very important in the study of diffusive supersonic wave transfer when the radiative thermal conduction approximation is used. In this paper, a formula of radial position-dependent spectral energy flux is given for the diffusive supersonic wave in a low density filled cylinder with a high density wall. A geometrical factor is defined to describe the influence of the radial size of the cylinder on the radiative energy flux. From the formula, the geometrical factor decreases with the radial position from center to edge, due to the much shorter mean free path in the wall than in the fill. This is another important reason in causing a significant curvature in the radiation front, which was observed in recent diffusive supersonic wave experiments. In addition, expressions for calculating the averaged spectral energy flux over the cylinder cross-section and the energy flux in local thermal equalibfium are given. The geometrical factor in the expression of the averaged spectral energy flux is compared with the conventional geometrical factor obtained via geometrical free path which people usually used in their simulation. Finally, to make the simulation easy, approximate expressions are given for the geometrical factors.

关 键 词：柱管中扩散超声速辐射波传输 辐射能流 几何因子 

分 类 号：O53[理学—等离子体物理]