FILM CONDENSATION ALONG AN INCLINED SURFACE IN A POROUS-MEDIUM
FILM CONDENSATION ALONG AN INCLINED SURFACE IN A POROUS-MEDIUM
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DOI：
10.1016/0017-9310(81)90129-0
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发表时间：
1981-01-01
影响因子：
5.2
通讯作者：
CHENG, P
中科院分区：
文献类型：
--
作者：
CHENG, P
本文研究了多孔介质中楔形体或圆锥体外的稳态膜状凝结问题。在经典的膜状冷凝问题中，假设（a）冷凝物和蒸汽被一个明显的边界分开，其间没有两相区，并且（B）冷凝物具有恒定的性质。在边界层近似下，得到了凝结水温度场和流场的相似解。此外，一个封闭的形式的解决方案已获得的努塞尔数取决于瑞利数的平方根和无量纲膜厚度。后者被发现是一个函数的无量纲参数有关的壁过冷度。小的和大的壁过冷的渐近情况下也被认为是。在经典的膜状凝结问题中，我们发现“Nusselt”型近似（对于小壁面过冷度）高估了膜厚，而低估了Nusselt数。还得到了一个关于壁面过冷度的努塞尔数的近似表达式。
The problems of steady film condensation outside a wedge or a cone embedded in a porous medium filled with a dry saturated vapor are investigated. As in classical film condensation problems, it is assumed that (a) the condensate and the vapor are separated by a distinct boundary with no two-phase zone in between, and (b) the condensate has constant properties. Within the boundary layer approximations, similarity solutions have been obtained for the temperature and flow fields in the condensate. Moreover, a closed form solution has been obtained for the Nusselt number which depends on the square root of the Rayleigh number and the dimensionless film thickness. The latter is found to be a function of a dimensionless parameter related to the degree of wall subcooling. Asymptotic cases for small and large wall subcoolings are also considered. As in the classical film condensation problems, it is found that the ‘Nusselt’-type approximation (for small wall subcooling) overestimates the film thickness while underestimates the Nusselt number. An approximate expression for Nusselt number in terms of the degree of wall subcooling explicitly is also obtained.