管内两层介质入口段扩散混合的耦合换热研究

对圆管内辐射物性不同的两层介质层流入口段,采用SIMPLEC算法与蒙特卡罗法数值模拟了二维稳态流动与扩散混合时的辐射-对流耦合换热。通过计算,分析了介质层几何参数、介质物性与流动参数对组份分布与耦合换热的影响。结果表明,介质组分的扩散混合对耦合换热存在明显的影响区域,且该影响区大于组分的扩散混合区;外层介质的吸收系数、入口截面的相对厚度对耦合换热的影响基本一致;质扩散系数对耦合换热的影响很小,入口雷诺数的增加会抑制质扩散。

COUPLED HEAT TRANSFER IN DIFFUSION AND MIXING OF TWO-LAYER MEDIA DEVELOPING FLOW IN TUBES

The coupled heat transfer of radiation and convection in the diffusion and mixing of two-layer media in tubes is investigated numerically. The component diffusion and convection heat transfer of laminar developing flow is solved by the SIMPLEC algorithm, and the radiative heat transfer is calculated by the Monte Carlo method. The effects of the medium layer parameter, the medium properties and the flowing parameter are analyzed. The results show that, the influence of component diffusion and mixing on the coupled heat transfer is obvious in a domain, which is larger than that of the diffusion and mixing. The effect of absorptive coefficient of the outer layer medium on the coupled heat transfer is similar to that of the radius ratio of two layers in the inlet cross section. The influence of mass diffusion coefficient on the coupled heat transfer is small, and the increase of Reynolds number can restrain the component diffusion.