Abstract: Based on the horizontal tube falling film evaporation platform with heat-transfer area of 2.375m2，this paper studied the heat-transfer performance of the evaporator in low temperature multi-effect distillation （LT-MED），with 5052 aluminum alloy tubes as heat-transfer tubes and actual seawater as raw material. The effects of sprinkling density，evaporation boiling point，evaporation temperature difference，salinity and non-condensable gas concentration on the total heat-transfer coefficients of desalination process were investigated. The results showed that the following：within the testing scope，the total heat-transfer coefficient increased with the increase of sprinkling density and evaporation boiling point；the total heat-transfer coefficient decreased with the increase of evaporation temperature difference；the total heat-transfer coefficient decreased sharply when there was non-condensable gas mixed in the steam inside the heat-transfer tube；salinity had little effectd on the heat-transfer coefficient；the heat-transfer coefficients were more than 3500 W/(m2?℃) when controlling the concentration of non-condensable gas，These results provided an experimental basis for the engineering design and production optimization of desalination.

Key words: seawater desalination, horizontal tube, falling film, evaporation, heat transfer

摘要： 在换热面积为2.375m2的水平管降膜蒸发试验平台上，采用5052铝合金管作为换热管，以实际海水为原料，进行了低温多效海水淡化中水平管降膜蒸发器传热性能研究试验。研究了料液喷淋密度、管外蒸发温度、总传热温差、海水盐度以及管内蒸汽中不凝气含量等因素对海水淡化过程降膜蒸发器总传热系数的影响。结果表明，在试验条件范围内，总传热系数随着料液喷淋密度和管外蒸发温度的升高而增加，随着传热温差的增大而降低；冷凝侧有不凝气存在时，总传热系数下降幅度较大；海水浓度对传热系数影响较小；在控制不凝气含量的条件下，传热系数在3500W/(m2?℃)以上。试验结果为海水淡化的工程设计和生产优化提供了依据。

关键词: 海水淡化, 水平管, 降膜, 蒸发, 传热