圆管外侧层流降膜热质耦合问题的解析解  

Analytical Solution for Coupled Heat and Mass Transfer in Falling Film Absorption on the Outside of a Circular Tube

作　　者：夏旭 黄跃武[1] XIA Xu;HUANG Yuewu(College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China)

机构地区：[1]东华大学环境科学与工程学院

出　　处：《东华大学学报（自然科学版）》2019年第5期746-751,795,共7页Journal of Donghua University(Natural Science)

基　　金：国家自然科学基金资助项目(51078068)

摘　　要：建立柱坐标系下层流降膜吸收水蒸气的传热传质模型,通过Laplace变换,由Stehfest方法导出定温边界条件下温度场与水的质量分数场。计算不同刘易斯数(Lewis number, Le )下层流降膜吸收水的质量分数梯度,分析了压力对降膜吸收水蒸气流量的影响。结果表明:与绝热边界条件相比,定温边界条件下降膜温度较低、水的质量分数较高;对于整个流动长度, Le 的增大使降膜吸收水的无量纲流量增大;随着压力的上升,吸收的水蒸气流量几乎呈线性上升。The mathematical model of laminar falling film absorption with uniform film velocity in cylindrical coordinate was established. Both the temperature and mass fraction profile can be obtained with the help of Stehfest method under the condition that the walls are othermal. The dimensionless absorbed mass flux of falling film was discussed with different Lewis numbers ( Le ), and the effects of pressures on the absorbed mass flux were also studied. The results show that when the wall is isothermal, temperature can be lower and mass fraction of water can be higher in falling film. For the entire flow length, the increase of Lewis number is responsible for the increase of the dimensionless absorbed mass flux. There is a linear correlation between the increase of absorbed flux and the increase of pressure.

关 键 词：热质耦合 吸收 柱坐标系 LAPLACE 

分 类 号：TQ051.5[化学工程]