摘要
为了明确绕管式换热器壳侧降膜流动特性对传热性能的影响,建立三维壳侧计算域,采用VOF模型,在干度工况范围为0.1~0.9,热流密度为1 275~8 000 W/m^(2),质量流率为120 kg/(m^(2)·s)时,分析了乙烷在绕管式换热器壳侧降膜流动过程。结果表明:对于乙烷工质,流型依次为层状流、半环状流、液滴流。干度为0.3,热流密度为4 000 W/m^(2)时为层状流向半环状流转化点;干度为0.6和0.7,热流密度4 000 W/m^(2)时为半环状流向液滴流转化点;在层状流向半环状流及半环状流向液滴流转化点传热系数均下降。干度为0.1~0.2,传热系数与干度成正相关;干度为0.3~0.7,传热系数与干度成负相关;干度为0.8~0.9,传热系数随干度变化不明显;流型为层状流和半环状流时,热流密度与传热系数成正相关。流型为液滴流时,热流密度与传热系数成负相关。
In order to clarify the influence of the flow characteristics of the falling film on the shell side of the spiral wound heat exchanger on the heat transfer characteristics,the computation domain on the three-dimension shell side was established,and VOF model was used to analyze the falling film flow process of ethane on the shell side of spiral wound heat exchange when the range of simulation conditions for the vapor quality was 0.1~0.9,the heat flux was 1275~8000 W/m^(2) and the mass flux was 120 kg/(m^(2)·s).The results show that,for the ethane,the flow pattern is sequentially laminar flow,semi-annular flow,and droplet flow.When the vapor quality is 0.3 and the heat flux is 4000 W/m^(2),the laminar flow transforms to semi-annular flow.When the vapor quality is 0.6 to 0.7 and the heat flux density is 4000 W/m^(2),the semi-annular flow transforms to droplet flow.The heat transfer coefficient decreases at the flow pattern transition point from laminar flow to semi-annular flow and from semi-annular flow to droplet flow.When the vapor quality is 0.1~0.2,the heat transfer coefficient is positively correlated with the vapor quality.When the vapor quality is 0.3~0.7,the heat transfer coefficient is negatively correlated with the vapor quality.When the vapor quality is 0.8~0.9,and the heat transfer coefficient does not change significantly with the vapor quality;When the flow pattern is laminar flow and semi-annular flow,the heat flux is positively correlated with the heat transfer coefficient.When the flow pattern is droplet flow,the heat flux is negatively correlated with the heat transfer coefficient.
作者
何雪静
王吉
李振林
HE Xuejng;WANG Ji;LI Zhenlin(College of Mechanical and Transportation Engineering,China University of Petroleum,Beijing 102249,China)
出处
《流体机械》
CSCD
北大核心
2023年第3期69-76,共8页
Fluid Machinery
基金
国家自然科学基金项目(52006242)
中国石油大学(北京)科研基金(2462018YJRC029)
中国石油大学(北京)科研基金(ZX20200126)
中国石油大学(北京)机械与动力工程智能化技术研究平台项目(2462020XKJS01)。
关键词
绕管式换热器
降膜流动
气液两相
流型转化
相变换热
spiral-wound heat exchanger
falling film flow
two-phase flow
flow pattern transition
phase change heat transfer
