液滴聚结过程中随机因素的分析  

Analysis of the Stochastic Factors in the Processes of Drop Coalescence

作　　者：唐洪涛[1,2] 王彦飞[1] 

机构地区：[1]天津科技大学机械工程学院,天津300222 [2]天津大学力学系,天津300072

出　　处：《高校化学工程学报》2012年第6期964-970,共7页Journal of Chemical Engineering of Chinese Universities

基　　金：天津市自然基金资助项目(09JCYBJC06400);国家自然科学基金资助(21106086);天津科技大学科学研究基金资助项目(20100227)

摘　　要：推导了扩散相液滴运动轨迹模型和基本流模型,并优化了计算方法,同时,将分层二相流中的界面波用于聚结机理的研究。直接数值模拟结果表明:波数对液滴在界面处的平均速度、相对速度及绝对速度的影响不明显,但对液滴所受到的不平衡剪力有显著的影响;波数的变化将使液滴的旋转运动具有倾向性,较大的波数比较小的波数对液滴的运动方式影响显著;界面波的存在使得液滴的运动方式更具有复杂性,尽管流动状态为层流,界面波的存在也会使液滴所受到的不平衡剪力与液滴直径的关系曲线发生变化,其中既包含有随机因素也包含有确定性因素;波数对阿基米德数与雷诺数的关系曲线的影响也具有一定的随机因素,但这些曲线的偏移量变化不大,这将为理论计算和工程上的简化应用提供一个良好的平台。The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates were derived with the calculation optimized. The interface waves were introduced into the mechanism of coalescence. The analytical results of direct numerical simulation indicate that the wave numbers exert indistinctive influences on mean, relative and absolute velocity, but have a great effect on the unbalanced shearing force acting on a drop and its motion. The drop motion is more easily influenced by the larger wave number than by the smaller one. The interface waves may make the drop motion to become rotated tendentiously in the clockwise or anticlockwise direction with the axis parallel to a nearby plane wall. In the meantime, it also makes the drop coalescence to become complex. Although the flowing field is in the laminar flow state, the existence of interface waves leads to the fact that in the change of the relation curves between the unbalanced shearing force and drop diameters, there are not only stochastic factors but also exists determinate factors. Under the influence of wave numbers, the relation curves between the Archimedes numbers and particle Reynolds numbers show the stochastic characters. However, the offset of the relation curves is indistinctive. It will provide a good platform for the further theoretical calculation and simplifying the engineering applications.

关 键 词：液滴 聚结 随机因素 界面波 阿基米德数 

分 类 号：TQ021.1[化学工程] TQ028.4