超声波雾化强化氨水降膜吸收特性的数值研究  

Numerical study on absorption characteristics of ammonia falling film enhanced by ultrasonic atomization

作　　者：何韫玉 李舒宏[1] He Yunyu;Li Shuhong(School of Energy and Environment,Southeast University,Nanjing 210096,China)

机构地区：[1]东南大学能源与环境学院,南京210096

出　　处：《东南大学学报（自然科学版）》2022年第5期953-962,共10页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(52276002)。

摘　　要：为了提高氨水吸收式制冷系统中降膜吸收器的吸收性能,提出在吸收器降膜管外壁上安装超声波雾化器的方法.基于降膜吸收模型和离散相模型建立了新型吸收器中蒸汽侧含有雾滴的垂直管外氨水降膜吸收的数学模型,并采用对一维非线性偏微分方程进行离散化求解的方法研究了超声波雾化参数对降膜吸收特性的影响规律.计算结果表明,超声波雾化器的最佳安装位置为降膜管从上至下0.45 m处.与传统吸收器相比,安装有超声波雾化器的新型吸收器的氨吸收率提高了15.1%,吸收器出口吸收溶液氨质量分数由36.3%提高到37.5%;新型吸收器中的出口溶液温度相较于传统吸收器提高了2.6℃.雾化过程产生的热效应对吸收器内部温度升高的不利影响与其强化吸收的正面效果相比可以忽略不计.To enhance the absorption characteristics of the falling film absorber in ammonia absorption refrigeration system, a method for installing ultrasonic atomizers on the outer walls of the absorber falling film tubes is proposed. Based on the falling film absorption model and the discrete phase model, a mathematical model for ammonia-water falling film absorption outside vertical tubes with droplets contained on the vapor side in the new absorber is established. And the effects of ultrasonic atomization parameters on falling film absorption are studied by discretization of one-dimensional nonlinear partial differential equation. The results indicate that the optimal installed position of the ultrasonic atomizer is 0.45 m from top to bottom of the falling film tube. Compared with the traditional absorber, the ammonia absorbed rate of the new absorber increases by 15.1%. The ammonia mass fraction of the outlet absorbent solution increases from 36.3% to 37.5% under the design conditions. The temperature of the outlet solution in the new absorber is 2.6 ℃ higher than that in traditional absorber. The adverse effect of the thermal effect produced by the atomization process on the internal temperature rise of the absorber is negligible compared with the positive effect of absorption enhancement.

关 键 词：氨水吸收式制冷 降膜吸收 传热传质强化 超声波雾化 雾滴 

分 类 号：TB657[一般工业技术—制冷工程] TB69