水平方形管进口区域单面冷却凝结换热  

Condensation in entrance region of rectangular horizontal channel

作　　者：杨阳[1] 彭晓峰[1] 王晓东[1] 王补宣[1] 

机构地区：[1]清华大学热能工程系,北京100084

出　　处：《热科学与技术》2005年第2期130-135,共6页Journal of Thermal Science and Technology

基　　金：国家自然科学基金青年基金资助 (5 0 40 60 0 1)

摘　　要：对方形管进口区蒸汽单侧冷却凝结进行可视化观测及参数测量,发现随蒸汽雷诺数(Re为1 669～5 5 5 3 )的提高,凝结液成膜方式、发展演化和稳定性均与低雷诺数下由液滴、液桥合并形成的稳定液膜有较大差异。液膜不同流动形态,如周期性断裂、局部失稳、小溪流,对换热的影响十分显著,进口区域存在的高换热特性正是由于液膜流动方式的不稳定性所致。高蒸汽雷诺数(Re为5 5 5 3 )时,蒸汽流动的脉动性。A visual observation was conducted on the vapor condensation pattern and the formation and evolution of the condensation liquid film in the inlet region of a horizontal channel. With the increase in Reynolds number of vapor, ranging from 1 669 to 5 553, the formation pattern, evolution, and stability of the condensation liquid film are distinct from those of the stable liquid film, which is formed by the coalescence of the liquid drops and liquid bridges at low Reynolds number. The different flow patterns of the liquid film, or periodical rupture, local instability, and rivulet, have great influence on the heat transfer and will result in a high heat transfer rate in the inlet region. The comparison of the condensation patterns and heat transfer rates at the different vapor Reynolds number indicates that the instability and rupture of the film can greatly enhance the heat transfer. At higher vapor Reynolds number of 5 553, the pulsation of the vapor flow, shear stress of the free interface, and Marangoni effect are the critical reasons resulting in the rupture of the film.

关 键 词：方形管 凝结换热 进口 MARANGONI效应 冷却 单面 水平 参数测量 低雷诺数 发展演化 流动形态 局部失稳 不稳定性 流动方式 换热特性 蒸汽流动 液膜 可视化 周期性 脉动性 切应力 断裂 成膜 液滴 

分 类 号：TQ021.4[化学工程] TG332.22[金属学及工艺—金属压力加工]