微细通道内蒸汽直接接触凝结汽液界面演变特征的实验研究

Experimental study on evolution characteristics of the vapor-liquid interface in direct contact condensation in micro channel

中文关键词: T型微细通道  可视化实验  直接接触凝结  汽液界面  脱离和断裂

英文关键词: T-type micro channel  visualization experiment  direct contact condensation  vapor-liquid interface  detachment and rupture

中文摘要:

      为探究微细尺度条件下蒸汽直接接触凝结汽液界面瞬时特征及演变行为，开展了圆形截面T型微细通道内蒸汽直接接触凝结的可视化实验研究。利用高速摄像系统获取了饱和蒸汽体积流量630μL/min、过冷水温度60℃及过冷水体积流量12650μL/min工况下直接接触凝结过程的瞬时图像信息。研究发现，汽液界面演变历程不能简单的用一种凝结流型进行表述，其过程中包含了柱状、环状和间歇凝结流型的特征。蒸汽自支管入射至主管后其长度变化曲线经历了相对较长时间（108.2ms）地振荡增长，而消失过程则相对短暂（16.2ms）。此外，水平主管内的蒸汽柱先后发生了脱离和断裂现象，且其与支管正下方的蒸汽泡的凝结机理有所不同。

英文摘要:

      In order to investigate transient characteristics and evolution behavior of the vapor-liquid interface of direct contact condensation in micro channel, the visualization experiment of steam direct contact condensation in a circular T-type micro channel was carry out. Using a high-speed camera, the two-phase interface image was obtained under the working condition of sub-cooled water temperature 60℃ and volume flow rate 12650μL/min for saturated steam with volume flow rate 630μL/min. The results show that the evolution process can not be described simply by one flow pattern because it involves characteristics of the following flow patterns: Columnar flow, annular flow and chugging. After the steam was injected into the main pipe from the branch pipe, it takes relatively a long period of time (108.2 ms) for steam growth curve with oscillation shape, while the disappearance takes only 16.2 ms. In addition, the steam plume in the horizontal main pipe undergoes detachment and subsequently rupture, furthermore, it has different condensation mechanism compared to steam bubble below the branch pipe exit.