水平三维肋管管外凝结换热实验与分析(I实验研究)

本文对不同饱和蒸汽温度下R11在水平Thermoexcel-C管的管外凝结换热性能进行了实验研究。实验结果表明:随着饱和蒸汽温度的提高,C管的凝结换热系数下降。C管凝结换热强化的主要机理在于孤立三维齿结构增大了表面张力减薄凝结表面液膜厚度的作用,而C管凝液淹没区小于相同肋间距的低肋管,且在淹没区内的凝结换热大于低肋管。

MEASUREMENTS AND MODELING FOR CONDENSATION HEAT TRANSFER ON HORIZONTAL THREE-DIMENSIONAL FINNED TUBE (PART 1:EXPERIMENTAL INVESTIGATION)

The experiments were conducted for the condensation heat transfer of R11 on a horizontal Thermoexcel-C tube under various saturation vapor temperatures. Experimental results show that the condensation heat transfer coefficient of thermoexcel-C tube decreases as the saturation vapor temperature increasing. The principal mechanisms of enhanced heat transfer are that the three-dimensional structure of isolated fins makes the effect of surface tension becoming still more significant in the unflooding region on the Thermoexcel-C tube, which leads to thinner condensate film and higher condensation heat transfer coefficient, and the flooding region of Thermoexcel-C tube is smaller than that of the low-finned tube with the same fin space.