蒸汽在过冷液体喷雾上直接接触相变换热过程实验研究  

Experimental study on process of direct contact phase change heat transfer of steam on subcooled liquid spray

作　　者：黄安阳 罗祎青[1] 张会书 袁希钢[1] HUANG Anyang;LUO Yiqing;ZHANG Huishu;YUAN Xigang(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300354,China)

机构地区：[1]天津大学化工学院,天津300354

出　　处：《化学工业与工程》2023年第2期57-66,共10页Chemical Industry and Engineering

基　　金：天津市自然科学基金(19JCYBJC20300)。

摘　　要：以水为工质,通过实验研究了饱和水蒸汽与过冷水喷雾逆流直接接触冷凝换热过程,考察了不同入口液相温度下液膜厚度及破碎长度变化、液膜轴向及径向的温度分布;基于实验数据计算出了液膜局部传热系数及总传热系数。实验研究的结果表明,直接接触冷凝换热过程中,低入口液相温度时的液膜厚度和破碎长度更大;液膜在径向方向上存在温度梯度变化,液膜表面的温度较高,中心存在1个最低温度;随着液膜运动轴向距离的增大,液膜温度逐渐升高,喷嘴出口处液膜的温升最快,在整个喷雾的冷凝换热过程中,液膜温升占喷雾换热总温升的80%~85%,因此相比液滴,液膜起主要换热作用;喷嘴出口处的局部传热系数最大,并随着轴向距离增大逐渐减小。实验得到总传热系数的值远大于传统的膜状冷凝传热系数,体现了蒸汽-过冷液体喷雾这类直接接触换热方式的优势。The direct contact condensation heat transfer process of saturated steam and subcooled water spray countercurrent was studied experimentally using water as working fluid.The changes of liquid sheet thickness and breaking length under different inlet liquid temperature and the axial and radial temperature distribution of liquid sheet were investigated.The local heat transfer coefficient and total heat transfer coefficient of the liquid sheet were calculated based on the experimental data.The experimental results show that the liquid sheet thickness and breaking length are larger at low inlet liquid temperature during direct contact condensation heat transfer.There is a temperature gradient in the radial direction of the liquid sheet,and the temperature of the surfaces of the liquid sheet is high,and there is a minimum temperature in the center.With the increase of the axial distance of the liquid sheet movement,the temperature of the liquid sheet increases gradually,and the temperature rise of the liquid sheet at the outlet of the nozzle is the fastest.In the process of condensation heat transfer of the whole spray,the temperature rise of the liquid sheet accounts for 80%—85%of the total temperature rise of the spray heat transfer.Therefore,compared with the droplet,the liquid sheet plays a major role in heat transfer.The local heat transfer coefficient at the nozzle exit is the largest and decreases with the increase of axial distance.The experimental results show that the total heat transfer coefficient is much larger than the traditional membrane condensation heat transfer coefficient,which reflects the advantages of direct contact heat transfer such as steam-subcooled liquid spray.

关 键 词：直接接触冷凝传热 液膜 喷嘴 温度分布 传热系数 

分 类 号：TQ021.3[化学工程]