金属接触密封中流体压差对泄漏量的影响研究

Research on the Influence of Fluid Pressure Differential on Leakage in Metal Contact Seals

摘要: 密封是液压系统正常工作的保障，工作在高温高压环境中的液压元件常采用金属接触密封，本文通过有限元仿真从微观角度研究了流–固耦合作用对金属接触密封的泄漏过程的影响。首先基于包含粗糙度均方根与自相关长度的点云函数构建了离散化粗糙面的接触模型，然后提取变形后的接触面进行了单向流–固耦合，分析了流体压力对接触面积和泄漏通道平均高度的影响规律，并计算了在不同压差作用下的泄漏量。研究结果表明：随着压差的增大，流体对金属接触密封接触状态的影响逐渐变大，对流道入口处的形貌影响最大，最后导致密封面的分离度增加。考虑流–固耦合作用后，密封副的泄漏量明显增加，且当流体压差达到接触压力的60%时，会导致泄漏量近似呈指数激增。以上研究成果可以为金属接触密封结构的设计提供指导。

Abstract: Sealing is essential for the normal operation of hydraulic systems, and metal contact seals are commonly used in hydraulic components operating in high temperature and high pressure environments. This paper investigates the influence of fluid-solid coupling on the leakage process of metal contact seals from a microscopic perspective using finite element simulation. Firstly, a contact model of discretized rough surfaces is constructed based on a point cloud function that includes the root mean square roughness and autocorrelation length. Then, the deformed contact surfaces are subjected to one-way fluid-solid coupling, and the influence of fluid pressure on the contact area and average height of the leakage channel is analyzed. The leakage rates under different pressure differentials are also calculated. The research findings show that, as the pressure differential increases, the influence of the fluid on the contact status of the metal contact seal gradually becomes more significant, especially at the inlet of the flow channel, leading to an increase in the degree of separation of the sealing surfaces. Considering the fluid-solid coupling, the leakage rate of the sealing pair significantly increases, and when the fluid pressure differential reaches 60% of the contact pressure, the leakage rate experiences an approximate exponential increase. These research findings could provide guidance for the design of metal contact sealing structures.