Phase-Field simulation of small capillary-number two-phase flow in a microtube
Phase-Field simulation of small capillary-number two-phase flow in a microtube
复制标题
DOI：
10.1016/j.fluiddyn.2008.01.002
复制
发表时间：
2008-07-01
影响因子：
1.5
通讯作者：
Kasagi, Nobuhide
中科院分区：
文献类型：
--
作者：
He, Qunwu;Kasagi, Nobuhide
表面张力的准确计算是小毛细管数气液两相流数值模拟的关键。用传统的连续介质表面力法计算表面张力时，由于计算误差的影响，会产生相当大的寄生流。在本模拟中，采用相场法捕捉局部两相界面。表面张力由化学势梯度表示。数值结果表明，表面张力的化学势公式可以将寄生流的大小减小到截断误差的水平。这是因为动能和表面能之间的交换被适当地计算。将该方法应用于600 μ m微细管内气液两相泡状流和弹状流的数值模拟。雷诺数为60-200，毛细管数为O（10（-3））。模拟得到的气泡形状和两相流流型与实验结果吻合较好。由Lockhart-Martinelli关联式表示的压降被发现大于以毫米为单位的管的压降。(c)2008日本流体力学学会和Elsevier B. V.版权所有。
Accurate calculation of surface tension force is critically important for numerical simulation of gas-liquid two-phase flows at small capillary number. It is well known that the errors in the surface tension calculation would cause considerable parasitic flow with conventional continuum surface force method. In the present simulation, Phase-Field method is employed to capture local two-phase interface. The surface tension force is represented by a chemical potential gradient. The numerical results show that the chemical potential formulation of surface tension force can reduce the magnitude of parasitic flow to the level of truncation error. This is because exchange between kinetic and surface energy is appropriately calculated. The method is applied to the simulations of air-water two-phase bubbly and slug flows in a microtube of 600 pm. The Reynolds numbers are 60-200, and the capillary number is O(10(-3)). The simulated gas bubble shape and two-phase flow patterns are in good agreement with experimental results. The pressure drop, represented by Lockhart-Martinelli correlation, is found larger than that proposed for tubes in millimeter. (c) 2008 The Japan Society of Fluid Mechanics and Elsevier B.V. All rights reserved.