亲疏液复合界面下微缝隙液膜的滑移流动研究

Liquid film in micro-gap widely exists in fluid power systems, and it is one of the key factors to improve the system performance. The research of boundary slip affected by interfacial characteristics is the basic and frontier area of micro flow. Distinguished from macro flow, some new phenomena and laws generated by boundary slip provide new methods for the study and control of liquid film in micro-gap. Focusing on the new flow phenomena related to micro-gap with lyophilic and lyophobic interface, the methods to improve the control performance of liquid film in micro-gap are investigated. The project will focus on the following works. Firstly, the slip model of limiting shear stress and linearization method are introduced to establish the numerical model of slip flow of liquid film with composite interface. Secondly, based on the laser-induced fluorescence technique and PIV, the parameters and distribution of lyophilic and lyophobic interface are optimized, and the ways to reduce the effect of interface motion on the film status by the composite interface are proposed. Then, the VOF model and visualization test of film boundary are established to investigate the transient dynamic characteristics of film boundary with moving interface. Finally, the forecasting method of critical state about boundary rupture is studied, and some control ways are developed for the stability of liquid boundary in micro-gap with fast moving interface. The research with important scientific significance is helpful to reveal the flow laws of liquid film in micro-gap with lyophilic and lyophobic interface, and to provide a new method to obtain highly reliable micro-gap film at extreme operating conditions.

微缝隙液膜广泛存在于流体动力系统中，是制约系统性能提升的核心因素之一。边界滑移是微尺度流动的基础前沿问题，受到界面性质的影响，呈现出明显区别于宏观流动的现象及规律，为微缝隙液膜的研究及控制开辟了新的途径。本项目以疏液和亲液复合界面共同作用下形成的新流动现象为对象，研究提升微缝隙液膜控制性能的方法。具体内容包括：结合极限剪应力滑移模型和线性化方法，建立复合界面下液膜滑移流动的数值求解模型；在激光诱导和PIV检测实验等基础上，优化亲疏液界面参数及分布形式，提出基于复合界面降低界面运动对液膜流态影响的方法；建立VOF模型和液膜边界可视化实验，研究界面运动下液膜边界的瞬时动态特性；研究边界破裂的临界状态预测方法，发展界面高速运动下微缝隙液膜边界的稳定性维持理论。通过本项目的研究，有助于揭示亲疏液复合界面对微缝隙液膜的作用规律，并为极端工况下高可靠微缝隙液膜的获取提供新的方法，具有重要的科学意义。

微缝隙液膜广泛存在于流体动力系统中，是制约系统性能提升的核心因素之一。本项目结合边界滑移基础前沿问题，以亲疏液复合界面共同作用下形成的新流动现象为对象，研究提升微缝隙液膜控制性能的方法。本项目建立了亲疏液复合界面下微缝隙液膜滑移流动的研究模型，在对比验证模型可靠性基础上，获得了粘温特性等主要参数对液膜滑移流动的影响规律；研究了界面运动下瞬态和稳态的液膜滑移流动，基于液膜厚度、缝隙大小、压差及剪切流状态对滑移流动作用规律优选参数，得到有助于实现降低界面运动对液体流态影响的方法；研究界面运动下滑移流动、界面热质传导等因素对液膜边界的影响，结合改进的分析方法，获得了界面运动下液膜边界的瞬时动态特性；研究界面非稳态运动参数等对液膜边界的影响，结果表明在界面高速运动下液膜边界存在稳定与易受扰动的非稳定两种状态，并得到界面非线性运动下液膜边界的变化规律；基于微缝隙液膜的分析，提出了两种有助于提升柱塞泵液膜稳定性的新型设计，并申报2项发明专利。项目执行期间，发表SCI期刊论文5篇、EI期刊论文3篇。通过本项目的研究，有助于揭示亲疏液复合界面对微缝隙液膜的作用规律，为微缝隙液膜的流态控制提供一种新方法。