辐射超声速扩散传输产生条件的研究

 利用1维辐射扩散方程的解析理论，在外加辐射源为恒温源的条件下，对能够产生辐射超声速扩散传输的条件进行了研究，可以解析地得出在固定物质密度下能够产生超声速扩散流的参数区域。分析得出：对于一个固定的恒温外源，随着时间的增加，热波波头位置是随时间的平方根增长的，光学厚度正比于波头位置，也是随时间而逐渐增加的；而马赫数是按时间平方根倒数减少的。并推导出在不同密度下恰好产生超声速扩散时，辐射源温度和辐射热波波头位置满足的临界值条件，它们是关于介质密度的函数关系式。最后以SiO₂泡沫为算例，对这些结果的物理图像做了简要的阐述，对它们的应用进行了具体的说明和分析。

Conditions for the generation of supersonic diffusive radiation transport

Radiation transport in matter can be supersonic when the Mach number of the heat wave front is typically over 3.In this paper,the conditions under which the supersonic radiation transport was diffusive were investigated in the case of an external radiation source with constant temperature.This model was based on the analytic theory of the radiation diffusion equation in one dimension.The ranges of parameters where supersonic diffusive transport occurs were obtained for a fixed mass density in an analytical way.Furthermore,critical values for the temperature of the external radiation source and the radiation heat wave front position were also derived analytically.They are the functions of the mass density.A calculating case for SiO_2 foam is presented to show the basic physical pictures of the results above and to indicate their detailed application and analysis.