中空纤维膜管内LiBr溶液除湿过程的数值研究

Numerical study on dehumidification using hollow fiber membrane and liquid desiccant(LiBr)

中文关键词: 直接蒸发冷却  湿空气  预除湿  溴化锂溶液  中空纤维膜

英文关键词: direct evaporative cooling  moist air  pre-dehumidify  LiBr solution  hollow fiber membrane

中文摘要:

      为研究中空纤维膜和吸湿溶液结合进行制冷预除湿过程的传质机理,建立了膜管外的水蒸气通过膜孔最后被溴化锂溶液吸收传质过程的数值模型,研究了液体进口流速、进口浓度和进口温度对管内溶液的温度分布、质量分数分布和膜孔内水蒸气质量分数分布的影响,并比较了这三种因素对传质的影响程度。在一般预除湿用疏水性膜组件的内部溶液压力条件下(小于10kpa),溶液与水蒸气的接触面在疏水性膜内壁表面。溶液流速的增大,溶液进口质量分数的增大以及溶液进口温度的降低均有利于传质进行,其中,提高溶液进口质量分数对加强传质最为有效。

英文摘要:

      A numerical model is developed to study the mass transfer mechanism of dehumidification process that combines liquid desiccant(LiBr) with hollow fiber membranes. In the vapor transfer process, the vapor in the moist air transfers through porous membrane and would be finally absorbed by the liquid desiccant. The effects of inlet solution velocity, concentration and temperature on the temperature and concentration distribution of tube side solution as well as vapor concentration distribution in membrane pores and outside the membrane have been studied. At the same time, influences made by these factors have been evaluated. Under the inside liquid pressure(less than 10kpa) of general hydrophobic membrane modules for pre-dehumidifying humid air, air-liquid interface is at the inner surface of membrane fiber. The increases of inlet solution velocity and concentration are both benefited to mass transfer process. Besides, as the inlet solution temperature drops, the vapor mass transfer would be improved. Among these three methods to strengthen dehumidification, increasing inlet solution concentration is the most effective one.