基于分子动力学的密封副润湿特性对泄漏量影响研究  

Study on the Influence of Wetting Characteristics of Sealing Pair on Leakage Based on Molecular Dynamic

作　　者：杨丽红[1] 程强[1] YANG Lihong;CHENG Qiang(School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学机械工程学院,上海200093

出　　处：《润滑与密封》2022年第7期33-39,共7页Lubrication Engineering

摘　　要：在微纳尺度下的间隙密封中,流体流经不同润湿特性的界面时固液交界处会产生不同程度的边界滑移,进而影响其流动状态及泄漏量。为深入研究密封副润湿特性与泄漏量关系,基于分子动力学原理,建立间隙密封模型,模拟在不同润湿性的壁面上,以不同壁面运动速度剪切下表层水分子的边界滑移及其单向泄漏情况。研究结果:表明壁面上的最大剪应力随壁面运动速度的提高呈线性增加,在高速的剪切作用下,亲水性壁面上依然会产生轻微的边界滑移;随着剪切速率的增加,滑移长度与泄漏量趋于稳定;在实际生产中通常剪切速率较小,剪应力不足以引起边界滑移,水分子易吸附于壁面之上导致更大的泄漏量,因此在低剪切速率下,壁面润湿性对于单向剪切泄漏的影响很小;而在剪切速率较高时,润湿性较差的壁面上泄漏更小,因此可以通过在密封表面采用疏水涂层处理以达到更好的密封效果。In the clearance seal at the micro/nano scale,the liquid flowing through the interface with different wettability will produce different degree of boundary slip at the solid-liquid interface,which will affect the flow state and leakage.In order to deeply study the relationship between the wetting characteristics of sealing pair and the leakage,based on the principle of molecular dynamics,a clearance seal model was established to simulate the boundary slip and leakage of surface water molecules at different wall velocities with different wettability.The results show that the maximum shear stress on the wall increases linearly with the increase of the wall velocity,and a slight boundary slip still occurs on the hydrophilic wall under the high shear speed.With the increase of the shear rate,the slip length and leakage tend to be stable.In the actual production,the shear rate is small,the shear stress is not enough to produce boundary slip,and the water molecules are easy to adsorb on the wall,resulting in larger leakage.Therefore,at low shear rate,the wall wettability has little influence on the leakage.However,when the shear rate is high,the shear leakage of the wall with poor wettability is smaller,so the better sealing effect can be achieved by using hydrophobic coating on the sealing surface.

关 键 词：间隙密封 润湿性 泄漏 边界滑移 分子动力学 

分 类 号：TH136[机械工程—机械制造及自动化] TB42[一般工业技术]