摘要
采用计算流体力学(CFD)的方法,研究了圆管中泰勒流的液侧传质特性,分析了泰勒气泡上局部传质特性,并研究了气泡上升速度、液膜长度和液栓长度对液膜处和气泡半球帽处平均传质系数的影响。结果表明,泰勒气泡表面局部传质系数存在3个峰值,液膜处的平均传质系数随气泡上升速度增大显著增大,随液膜长度增大而减小,而半球帽处的平均传质系数随气泡速度和液膜长度的增大变化较小,即膜接触时间增加时,液膜处的传质系数降低,而半球帽处传质系数变化较小。另外,引入场协同原则对单元胞内速度场和浓度场进行分析,解释了局部传质特性及强化机理。最后,给出了分别预测短和长膜接触时间下泰勒流液侧体积传质系数的关联式,该式在较宽的管径尺度范围(0.25～3mm)内的预测误差在±20%以内。
The characteristics of liquid side mass transfer under Taylor flow in capillaries were studied by performing computational fluid dynamics（CFD） simulations.The local mass transfer coefficients on bubble surface were evaluated,and the effects of bubble rise velocity,length of liquid film and slug length on the mean mass transfer coefficients of liquid film and the two caps were investigated.Three peak values of local mass transfer coefficient were found on bubble surface.The average mass transfer coefficient of liquid film increases with the increase of bubble rise velocity and decrease of liquid film length,whereas the average mass transfer coefficient of the two caps varies less.Mass transfer coefficient in liquid film decreases as the film contact time increases,while that in the caps changes less.Moreover,the principle of field synergy was used to explain the characteristics and enhancement of local mass transfer.The coordination between the velocity and concentration fields was better near the liquid film and two bubble caps.The results show that short film contact time for the same contact area could enhance the gas-liquid mass transfer under Taylor flow.Finally,empirical correlations were proposed to predict the liquid side volumetric mass transfer coefficients for short and long film contact time separately,and the predicted values in capillaries with diameters of 0.25—3 mm have a relative error within ±20%.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2012年第1期42-50,共9页
CIESC Journal
基金
国家重点基础研究发展计划项目(2006CB202503)
国家自然科学基金创新研究群(20821004)~~
关键词
泰勒流
气液传质
传质强化
场协同
计算流体力学
Taylor flow
gas-liquid mass transfer
mass transfer intensification
field synergy
CFD
