微通道中单泡运动机理的研究  

Study on Mechanisms of the Single Bubble Motion in Microchannels

作　　者：郭天祥 莫成龙 产文强 陈柔 严微微[2] GUO Tianxiang;MO Chenglong;CHAN Wenqiang;CHEN Rou;YAN Weiwei(College of Metrology&Measurement Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China;College of Energy Environment&Safety Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China)

机构地区：[1]中国计量大学计量与测量工程学院,浙江杭州310018 [2]中国计量大学能源环境与安全工程学院,浙江杭州310018

出　　处：《力学季刊》2025年第1期181-192,共12页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(12102419),浙江省自然科学基金(LZ24A020005)。

摘　　要：气泡是微反应器效率和质量的重要影响因素.因此,了解微通道中气泡输运机理可以为微反应器的设计提供指导.而气泡运动是一种典型的气泡输运现象,本研究以计算流体力学为基础,通过系统参数化研究单泡运动特性,分析结果得到气泡的运动规律,从而揭示气泡运动机理.研究发现当气泡初始不附着壁面时,单泡运动轨迹是多样的,但气泡最终达到平衡位置(即离壁面的距离为一定值).并且,该平衡位置与气泡直径、驱动速度以及溶液的物化性质都具有相关性.雷诺数(Re)和毛细管数(Ca)被选用为表征以上特性的无量纲数.基于气泡大小和常用溶液物化性质,在0.288<Re<97.2,0.005<Ca<0.228范围内进行研究,得到Re和Ca的关系可以通过气泡平衡位置Y_(e)(最终气泡离壁面距离的无量纲数)进行分类:(1)当0<Y_(e)<0.45时,Re和Ca呈现幂律关系;(2)当0.45<Y_(e)<0.95时,Re和Ca则为线性关系;(3)当粘性效应可以忽略不计时,气泡附着在壁上(Y_(e)=0);(4)当粘性效应占主导地位时,气泡位于微通道的中心(Y_(e)=1).相应地,气泡运动机理可以从操纵力角度上来解释.操纵力包括由壁面、形变和剪切应力梯度引入的力,即气泡运动受壁面、惯性、粘性和表面张力效应的综合影响.Bubbles are one of the important factors affecting the efficiency and quality of microreactors.Understanding the mechanisms of bubble transportation in the microchannel can provide guidelines for the designation.Meanwhile,bubble motion is one of the usual bubble transportation phenomena.In this paper,systematic and parametric studies of single bubble motion characteristics are conducted using computational fluid dynamics,aiming to derive fundamental principles and uncover the underlying mechanisms.The bubble motion principle during the initial detachment from the wall is proposed:while the trajectories of a single bubble may vary,the bubble will ultimately reach an equilibrium position(with a constant distance from the wall)across all parametric cases.Furthermore,the equilibrium position of the bubble is influenced by its diameter,the driving velocity,and the properties of the surrounding solution.Reynolds number(Re)and Capillary number(Ca)are selected as two characterized parameters.Based on the bubble diameter and common solution properties,the discussion cases in the range of 0.288<Re<97.2,0.005<C a<0.228.The relationship between R e and C a can be distinguished by the bubble equilibrium position Y_(e)(the dimensionless number of the distance between the final bubbles and the wall):(1)power law when 0<Y_(e)<0.45;(2)linear when 0.45<Y_(e)<0.95;(3)the bubble is attached to the wall(Y_(e)=0)when the viscous effect is negligible;(4)the bubble is positioned in the center of the microchannel(Y_(e)=1)when the viscous effect dominates.Corresponding,the mechanism can be underlaid by the manipulation forces,including wall-induced,deformable-induced,and shear stress gradient lifting forces and viscous drag force.In conclusion,the motion of the bubble is the combined influence of the wall,inertia,viscosity and surface tension effects.

关 键 词：气泡运动 微通道 平衡位置 操纵力 

分 类 号：O359.1[理学—流体力学]