内冷型溶液除湿器的热质交换分析及流型比较研究

RESEARCH ON THE HEAT AND MASS TRANSFER PERFORMANCE AND FLOW-PATTERN COMPARISON OF THE INTERNALLY-COOLED LIQUID DESICCANT DEHUMIDIFIERS

建立了分析传热传质的数学模型,并采用了文献中的实验数据进行验证,模型的计算值和文献中实验结果的偏差在±10%以内。藉此模型进行计算分析,得出内冷型除湿器的除湿量随着空气进口含湿量、溶液进口浓度、空气与溶液的传质单元数NTU_a、溶液与冷水的传热单元数/NTU_w的增加而增大,随着冷水进口温度的增加而降低。针对文献中的空气与溶液逆流、冷水与溶液叉流的流型1和空气与溶液顺流、冷水与溶液逆流的流型2进行比较分析,得出相同情况下流型1的除湿性能总优于流型2,且两种流型的除湿量的差别随NTU_a的增加而增大。

In the internally-cooled liquid desiccant dehumidifier, cooling fluid is introduced into the dehumidifier to cool the liquid desiccant and thus enhance the desiccant dehumidification ability. The theoretical model of the heat and mass transfer processes in the internally-cooled dehumidifier was set up in the paper. The predicted results by the model were validated by the experimental results available in the literature, and the differences were within ±10%. Based on the theoretical model, it is found that the moisture removal rate increases with the increase of inlet air humidity ratio, inlet solution concentration, the number of mass transfer unit between air and desiccant NTUa and the number of heat transfer unit between desiccant and cooling water NTUw, and decreases with the increase of the cooling water inlet temperature. The dehumidification performance of two different flow pattern dehumidifiers （Type Ⅰ： air-to-desiccant is counter, desic- cant-to-water is cross; Type Ⅱ： air-to-desiccant is parallel, desiccant-to-water is counter） was compared in detail. The dehumidification performance of Flow Type I is always better than that of Flow Type II at the same conditions, and the differences increase with NTUa.