含液多孔表面气泡驻留特性及稳定机制  

Bubble Resident Characteristics and Stabilization Mechanism on Liquid-infused Porous Surfaces

作　　者：张国涛 蔡伟杰 童宝宏[1] 涂德浴[1] 刘庆运[1] ZHANG Guotao;CAI Weijie;TONG Baohong;TU Deyu;LIU Qingyun(School of Mechanical Engineering,Anhui University of Technology,Maanshan 243002;State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084)

机构地区：[1]安徽工业大学机械工程学院,马鞍山243002 [2]清华大学高端装备界面科学与技术全国重点实验室,北京100084

出　　处：《机械工程学报》2024年第21期232-242,共11页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52005005,51975174);清华大学高端装备界面科学与技术全国重点实验室开放基金(SKLTKF22B05)资助项目。

摘　　要：含液多孔表面气泡的析出和驻留行为显著影响气液两相流场和多孔表面功能特性。以不锈钢和聚四氟乙烯(Polytetrafluoroethylene,PTFE)两种材质微孔为研究对象,建立微孔表面气液两相数值模型,分析气泡析出形态变化,研究气泡驻留行为对气液两相流场影响,揭示多孔表面气泡驻留特性及稳定驻留机制。结果表明:不锈钢孔隙内气体以凸界面析出,气泡在孔口稳定驻留和生长,直至析出体积过大,气泡颈缩并脱离孔口。PTFE孔隙内气体以凹界面析出,气泡在孔口短时驻留,此后发生横向铺展、回缩、颈缩和脱离等失稳过程。气泡析出时,其三相接触线钉扎将引起流场涡旋现象,不锈钢表面涡旋发生在气泡中心和气液界面处;PTFE表面涡旋发生在气泡中心、气液界面和液膜中;可见PTFE表面气泡对气液两相流场的扰动较为强烈,容易发生驻留失稳。多孔表面气泡的驻留行为受三相接触线状态影响,三相接触线钉扎时,气泡驻留稳定,三相接触线脱钉后,气泡失稳滑移。与疏水PTFE相比,气泡在亲水不锈钢表面更易稳定驻留,保障表面稳定发挥润滑和减阻功能。The precipitation and resident behavior of bubbles on liquid-infused porous surfaces significantly affect the gas-liquid two-phase flow field and the functional properties of porous surfaces.The subjects of the study are microporous pores of both stainless steel and polytetrafluoroethylene(PTFE)materials.A numerical model is established to analyze the changes in bubble precipitation morphology and the effect of bubble residence behavior on the gas-liquid two-phase flow field and to reveal the bubble resident characteristics and stable resident mechanism on the porous surface.The study shows gas precipitates as a convex interface in stainless steel pores.The bubbles reside and grow steadily in the orifice until the precipitation volume is too large,and the bubbles neck and detach from the orifice.PTFE pore gas precipitation in the form of a concave interface.The bubble resides at the orifice briefly and then undergoes several destabilization processes such as lateral spreading,retraction,necking,and detachment.When the bubble precipitates,its three-phase contact line pinning causes a vortex phenomenon in the flow field.The surface vortex of stainless steel occurs near the bubble center and the gas-liquid interface;the surface vortex of PTFE occurs in the bubble center,near the gas-liquid interface,and in the liquid surface film.Therefore,PTFE surface bubbles strongly perturb the gas-liquid two-phase flow field and are prone to resident instability.The resident behavior of the bubbles on the porous surface is affected by the three-phase contact line state.And the bubbles are stable when the three-phase contact line is pinned,while the bubbles no longer remain stable after the three-phase contact line is unpinned.Compared to hydrophobic PTFE,air bubbles are more likely to reside stably on hydrophilic stainless steel surfaces,to ensure stable lubrication and drag reduction on the surface.

关 键 词：含液多孔表面 气泡 驻留稳定性 润湿性 润滑和减阻 

分 类 号：TH117[机械工程—机械设计及理论]