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研究以太阳集热板制取的高温空气为热源,直接驱动竖管内溴化锂溶液降膜蒸发的传热性能。提出适用于竖管内溴化锂溶液降膜蒸发传热传质耦合的数学模型,根据合理的数值解法,运用MATLAB软件编程,计算出降膜区域内温度场和浓度场,入口Re数越大,换热效果相对降低,而传质效果增强,并得到量纲为1的降膜换热准则式。通过与经验公式对比发现,溴化锂溶液中传质对传热有抑制作用,且其影响不可忽略。
The paper studies the heat transfer performance of high temperature air from solar collectors, which directly drives falling film evaporation of LiBr solution in standpipe. A mathematic model is proposed for heat and mass transfer coupled with falling film evaporating in LiBr in vertical tube. According to a reasonable numerical solution, the temperature field and concentration field in falling film area are calculated by MATLAB software programming. The effect is relatively reduced, while the mass transfer effect is enhanced, and the dimension of a falling film heat transfer criterion formula. By comparing with the empirical formula, it is found that the mass transfer in lithium bromide solution has an inhibitory effect on the heat transfer, and its influence can not be neglected.