摘要
针对欠饱和海水在降膜蒸发器内预热、蒸发的过程,建立了分布参数模型,重点考察了预热区管内外传热由气-液两相传热转变为液-液单相传热过程对蒸发器管束传热参数空间分布的影响。结果表明:预热区域的平均管外传热系数约为蒸发区域的80.00%;受管内蒸汽未达到出口前完全凝结的影响,蒸发器出口处的海水沸点升高为入口处的38.83%,二次蒸汽流速平均值沿管长方向最大减小了14.80%,管外传热温差沿管长方向减小了6.00%;管间二次蒸汽压力增大使管外传热温差沿管列方向减小了12.20%;沿着管长方向,管内蒸汽逐渐凝结,该过程导致管外传热系数、海水盐度及BPE、二次蒸汽流速、海水饱和温度以及管外传热温差沿管排方向的梯度在管长节点数较大处具有较小的值。
For the process of preheating and evaporation of subcooled seawater in a falling film evaporator,a distribution parameter model was established.The influence of the change from gas-liquid two-phase to liquid-liquid single-phase heat transfer in the preheating zone on the spatial distribution of heat transfer parameters was investigated.The results show that the average out-tube heat transfer coefficient in the preheating area is about 80.00% of that in the evaporation area.Affected by the complete condensation of in-tube steam before reaching the outlet,the seawater boiling point elevation(BPE)at the evaporator outlet is 38.83%of that at the inlet,the average inter-tube vapor velocity decreases by up to 14.80% along the direction of the tube length,and the out-tube temperature difference decreased by 6.oo%along the direction of the tube length.With the increase of the inter-tube vapor pressure,the out-tube temperature difference decreases by 12.20% along the direction of the tube row.The in-tube steam gradually condenses along the length of the tube,which process causes the gradient of out-tube heat transfer coefficient,seawater salinity,boiling point elevation,inter-tube vapor velocity,seawater saturation temperature,out-tube temperature difference along the direction of the tube row to have a smaller value at the longer tube length.
作者
龚路远
鲍敬元
郭亚丽
金熙
周健
沈胜强
GONG Luyuan;BAO Jingyuan;GUO Yali;JIN Xi;HOU Jian;SHEN Shengqiang(National Joint Engineering Research Center for Thermal Energy Integration,School of Energy and Power Engineering,Dalian University of Technology,Dalian 116024,China;Iceberg Songyang Refrigeration(Dalian)Co.,Ltd.,Dalian 116000,China)
出处
《热科学与技术》
北大核心
2025年第5期461-469,共9页
Journal of Thermal Science and Technology
基金
国家自然科学基金资助项目(52106075)。
关键词
水平管降膜蒸发器
分布参数方法
海水淡化
传热系数
horizontal tube falling film evaporator
distributed parameter method
seawater desalination
heat transfer coefficient
