蒸气压力和流速对低浓度酒精-水混合蒸气微细竖直管外凝结的影响

本文在不同蒸气压力和流速状态下对低浓度的酒精-水混合蒸气在微细竖直圆管外表面Marangoni凝结传热特性进行了可视化实验研究,观测到不同工况下的凝结形态。结果表明,随着过冷度的增加,凝结传热系数急剧升高,凝结传热系数在达到峰值后开始下降,下降曲率相对较缓;随着压力的增加,凝结传热系数在大的过冷度下增幅较大。蒸气流速的影响与压力的影响类似。可视化研究表明蒸气压力和流速大小对凝结速率影响较大。

Effect of Vapor Pressure and Vapor Velocity on Condensation Heat Transfer for Low Concentration Ethanol and Water Mixture on a Micro-Minitube

In this present work,Marangoni condensation of ethanol-water vapor mixtures on a micro-vertical tube at different pressures and velocities had been studied,and observed the variation of condensation condition.The experiment results demonstrate that with the increase of subcooling, condensation heat transfer coefficient increase rapidly,heat transfer coefficient began to decrease after reaching the peak,decrease of curvature is relatively moderate,as the pressure increased,condensation heat transfer coefficient increased significantly in large subecooling.The effect of velocity was similar to the impact of pressure.Visualization experiments showed that pressure and flow rate had a great impact on the condensation rate.