摘要
针对高湿度工业废气冷凝脱湿进行模型研究和数值模拟,引入分配系数α表征雾状冷凝和膜状冷凝并存的权重.恒壁温冷凝管外混合气体在环形空间湍流冷却冷凝的温度分布、湿度分布及其梯度(传热传质推动力)分布的模拟结果显示,雾状冷凝的控制机理是冷壁面附近温度梯度与湿度梯度协同作用下传热传质产生的局部过饱和;膜状冷凝从冷壁面移出大量冷凝潜热,促使气相主体传热传质过程更迅速,脱湿效果更好.实际过程介于二者之间.DAP尾气冷却冷凝现场实验传热传质数据,在水汽冷凝减量34%～57%的范围内,与α＝0.2的数值模拟结果相当吻合,验证了本文的模型与数值模拟.
Modeling and simulation of the processes of condensation dehumidifying of high humidity industrial exhaust gases were made. An allocation factor, α, was introduced in the model to quantitatively express the effect of condensation on dehumidification with two existing mechanisms of fogging and film condensation. The profiles of temperature and steam fraction as well as their gradients （the driving forces for heat and mass transfer） were obtained numerically for turbulent flow of exhaust gases in the annular space outside a cooling tube with constant wall temperature. Dehumidification by fogging was mainly controlled by the mechanism of steam supersaturation produced from the cross interaction of heat and mass transfer driven by the temperature and humidity gradients near the cooling wall. While a much rapid heat and mass transfer would be seen in the bulk flow field when film condensation took place. It could be concluded that the actual dehumidification process should reach an inter mediate status between fogging and film condensation. From the pilot experiment of DAP tail gas cooling and dehumidification in the region of 34%--57% reduction of steam fraction, the experimental results obtained were considerably consistent with the simulation results for the allocation factor α=0. 2.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2005年第8期1389-1396,共8页
CIESC Journal
基金
国家高技术研究发展计划项目(2002AA647020
2003AA647040)
四川大学青年科学基金项目(2003045)~~
关键词
工业废气
冷凝
脱湿
模型
数值模拟
industrial exhaust gas
condensation
dehumidifying
modeling
simulation
