非灰气体吸收系数与平均射线行程的耦合求解

根据贝尔定律、指数宽带模型和平均射线行程反演的方法得出了气体辐射特性参数与平均射线行程的三种关系,并通过耦合计算的方式求得封闭体系下非灰气体的发射率、吸收系数和对部分边界的平均射线行程,从而解除了以吸收系数作为平均射线行程反演的必要条件的限制.将本文的计算结果分别与Hottel线算图的拟合公式和平均射线行程的几何求解公式结果相比较,结果表明,本文提出的方法满足工程辐射计算的精度要求,可直接应用于辐射特性参数的求解.以三元模型模拟的连续加热炉典型模型段为对象,计算了炉气对钢坯表面和炉墙内表面的发射率及对应的平均射线行程,为炉膛的辐射传热求解提供了必要条件.

Coupling Calculation of Absoption Coefficient and Mean Beam Length of Non-gray Gas

Three kinds of relationships between characteristic parameters of gas radiation and mean beam lengths were found by using exponential wide band model,mean beam length calculation and Beer law.The emissivity,absorption coefficient and corresponding mean beam length in a non-gray gas system were obtained by coupling calculation,thus avoiding the absorption coefficient indispensable to inversely calculate a mean beam length.The results showed that compared with Hottel’s chart and formula for mean beam lengths,the method presented in this paper is accurate enough to solve the problem of radiative heat transfer in engineering.Taking a zone of ternary reheating furnace model as an example,the emissivity and mean beam length for the slab and wall surfaces are calculated,which provides necessary conditions of calculating radiative heat transfer.