运用单元系综平均方法研究“层流”泡状流压力场  

Investigation on Pressure Field in Bubbly Flow with Cell-ensemble Averaging

作　　者：许兆峰[1] 罗锐[1] 杨献勇[1] 

机构地区：[1]清华大学热能工程系,北京100084

出　　处：《过程工程学报》2004年第4期380-384,共5页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:19572042)

摘　　要：在考虑真实流体粘度、忽略气泡尾迹区影响的前提下,通过对真实流体绕球形气泡的流场进行研究,运用单元系综平均方法推导出液相界面平均压力与液相平均压力差pli-pl的表达式,反映了液体粘度对该压力差的影响. 由于湍流泡状流相对雷诺数较大,无法忽略尾迹区对其气泡周围压力场的影响,因此该表达式只适用于“层流”泡状流.Bubbly flow is a basic two-phase flow problem and is usually analyzed using two-fluid models. The closure laws are very important and determine accuracy of two-fluid models. The previous closure laws were derived based on the potential flow assumption, such as the averaged pressure difference, pli-pl, between the interface and the liquid phase. However, the pressure difference is affected by fluid viscosity, wake of bubbles, bubble deformation, and so on. In this paper, taking fluid viscosity into consideration, the pressure difference is constituted using cell-ensemble average. The new formula can be applied for“laminar”bubbly flows where the relative Reynolds number is small and therefore the influence of bubble wakes on the pressure field is negligible. The new formula gives a larger result than the potential one, which agrees with the empirical data for“laminar”bubbly flows. The new formula can not be applied for turbulent bubbly flows, because the pressure field is considerably affected by wakes of bubbles. So it is necessary to investigate the effects of wakes of bubbles to construct a pressure difference formula for turbulent bubbly flows.

关 键 词：泡状流 双流体模型 单元系综平均 压力场 

分 类 号：TB126[理学—工程力学]