1987 年 30 巻 270 号 p. 1951-1956
The characteristics of the forced convective condesation of a binary mixture of vapors on a vertical tube were experimentally investigated using a R 113-R 114 mixture under the condition of 1 300<Re<9 300. One smooth tube and three kinds of finned tubes were used as test condenser tubes. The experimental results of the heat-transfer coefficient in the small temperature-difference region were compared with the theoretical results using an analogy between heat and mass transfer. In the small bulk-to-wall temperature-difference region, the heat-transfer coefficient, especially for a high-performance finned tube, was reduced markedly by the thermal resistance of the diffusion layer. The effect of the diffusion lsyer was significant in the low Re number region, but it decreased considerably in the high Re number region. On the other hand, in the large bulk-to-wall tempersture-difference region, the reduction of the heat-transfer coefficient decreased and was almost independent of the vapor flow velocity.