露点蒸发淡化技术是一种新的海水和苦咸水淡化方法,它是基于载气增湿和去湿的原理,同时回收冷凝去湿的热量,传热效率受混合气侧的传热控制。蒸汽冷凝传热中,不凝气的存在严重恶化其传热过程。过去的研究大多只涉及极少量或微量不凝气问题,而实际应用中含有大量的不凝气。本工作是在不凝气含量很高的条件下进行的冷凝传热研究。实验工作系通过空气和蒸汽直接混合形成饱和混合气进行冷凝,考察了混合气温度、流速、冷却水温度和流速对冷凝传热过程的影响。实验混合气温度达92～68℃,流速达1.41～9.79m/s,冷却水温度50～70℃,冷却水流速0.55～1.66m/s。实验表明,适当提高混合气温度和流速,冷凝传热的混合气侧的平均传热系数可保持在较高的实用水平,即1000W/m.2℃甚至更高。同时对含不凝气的冷凝传热过程进行了分析,得出了混合气侧局部传热系数的关联式,并对其设备提出了合理设计的原则意见。Dewvaporation desalination process is a new technology for desalination of seawater and brine water.It is based on the principle of humidification and dehumidification using carrier gas with recovery of the heat from condensing and dehumidification.This article presents the research results of condensing heat transfer with a great quantity of noncondensable gas in the steam.The saturated air was produced by direct mixture of steam with air,and then condensed in a vertical column with cooling water.Effects of mixture gas temperature,mixture gas velocity,cooling water temperature and velocity on heat transfer coefficient were investigated respectively.Mixture gas temperature was up to 92~68 ℃ and its velocity to 1.41~9.79 m/s;cooling water temperature was 50~70 ℃ and its velocity cooling water was 0.55~1.66 m/s.These results show that reasonable increase of the mixture gas temperature and its velocity can improve the heat transfer coefficient around 1000 W/m2·℃ or more.At the same time,the working characteristics of condensing transfer heat process used in our experiment was also investigated;the correction equation of local heat transfer coefficient was achieved,and some fundamental suggestions for reasonable design of this equipment is put forward.国家自然科学基金与中国节能投资公司联合资助重点项目(20236030
