灰体球内表面的辐射传递系数

Radiative Heat Transfer Coefficient of the Sphere Target with Gray Inner Surface

针对内表面为灰体的球形目标,分析了发射微元的辐射能量在球腔内的多次反射过程,利用角系数公式计算了各次能量交换过程中每个微元吸收、反射的能量,推导了灰体球内表面微元间的辐射传递系数理论计算公式.同时,利用蒙特卡洛方法计算了不同发射率条件下,发射微元对各球面微元间的辐射传递系数.理论推导结果表明,当灰体球内表面各微元的发射率相同时,微元间的辐射传递系数等于微元间的辐射角系数,与表面发射率无关.蒙特卡洛方法在不同发射率条件下的数值计算结果验证了理论公式的正确性.

To calculate the energy exchange by thermal radiation between one facet and any other facet of gray sphere,the multiple reflections of the radiated energy from a spherical facet（i.e.,the emitting facet）are analyzed.In this process,energy absorbed and reflected by each spherical facet for each multiple reflections is calculated by using the radiative shape factor.Theoretical formulas of radiative heat transfer coefficient between the emitting facet and any other spherical facet is derived.The radiative heat transfer coefficients are calculated at different values of surface emissivity by Monte Carlo method,and compared with that of the theoretical formulas.Formulas indicate that the value of the radiative heat transfer coefficient is equal to the shape factor for any two spherical facets of a gray sphere.Numerical result of the Monte Carlo method proves the correctness of the theoretical formulas.