氨-水-溴化锂工质降膜吸收数值模拟研究

Numerical Simulation Study on Falling Film Absorption of Ammonia-water-lithium BromideWorking Fluid

为了研究新型的氨-水-溴化锂三元工质的降膜吸收特性,为实际工程应用提供理论基础,本文通过数值分析方法建立三元工质降膜吸收的连续性方程、能量方程和组分平衡方程,采用MATLAB软件编程计算氨-水-溴化锂三元工质的降膜吸收结果,与实验数据相互验证,并进一步地分析了溴化锂质量分数、工质流量、冷却水温度和发生温度对降膜吸收性能的影响。研究表明:随着溴化锂质量分数从0%增加至10%,液膜出口处温度从306.7K增加至309.5K,但是当溴化锂质量分数从10%增加至15%时,液膜出口处温度下降至308.7K,说明溴化锂质量分数为10%时吸收放热量最大。当工质流量、冷却水温度、发生温度改变时,大部分的工况下溴化锂质量分数为10%时进出口溶液的浓度差较大,说明此质量分数下溶液吸收的速率最快。

To study the falling film absorption characteristics of a novel ammonia-water-lithium bromide ternary working fluid and provide theoretical basis for practical engineering applications,the continuity equations,energy equations,and component balance equations for the falling film absorption of the ternary working fluid with numerical analysis methods are established in this paper.The absorption results of the ammonia-water-lithium bromide ternary working fluid are calculated through programming in MATLAB software and verified against experimental data.Furthermore,the effects of lithium bromide mass fraction,working fluid flow rate,cooling water temperature,and operating temperature on the falling film absorption performance are analyzed.The research indicates that as the lithium bromide mass fraction increases from 0%to 10%,the temperature at the liquid film outlet increases from 306.7 K to 309.5 K.However,when the lithium bromide mass fraction increases from 10%to 15%,the temperature at the liquid film outlet decreases to 308.7 K,indicating that the maximum heat absorption occurs at a lithium bromide mass fraction of 10%.When the working fluid flow rate,cooling water temperature,and operating temperature change,in most operating conditions,there is a significant mass fraction difference between the inlet and outlet solutions when the lithium bromide mass fraction is 10%,indicating that the absorption rate is fastest at this mass fraction.