吸收器降膜和滴状吸收过程数值模拟分析

针对以溴化锂水溶液为工质的水平管吸收器,考虑润湿比、变膜厚和横向对流作用,建立了描述管表面的降膜流动和管间滴状吸收传热传质耦合过程的数学模型,采用涡量流函数法进行数学模型求解。根据数值计算结果,分析了溶液温度、浓度和吸收速率沿管排不同位置和水平管管间的变化,以及溶液喷淋密度和进口浓度对吸收器整体传热传质性能的影响。结果表明,提高喷淋密度可以改善吸收器传热性能,提高溶液进口浓度可改善传质性能,滴状吸收过程约占总吸收量的20%。与实验数据的对比说明建立的数学模型是合理的。

Numerical simulation of falling film and droplet absorption process in absorber

A numerical simulation model of falling film and droplet absorption over and between horizontal tubes in absorber was established with consideration of wet ratio,variable film thickness and transverse convection using LiBr-water solution as working fluid.The vortex-flow function method was used to obtain the model.The solution temperature and concentration distribution and steam absorption rate along the pipes and between the tube bundle were analyzed.The effects of solution spray density and inlet concentration on the coupled heat and mass transfer characteristics were analyzed.The results show that the heat and mass transfer performance can be enhanced with the increase of spray density and inlet concentration respectively.The comparisons between the calculated and experimental results show that the numerical simulation is reasonable.