Abstract:

The sealing rings with soft-hard pairing are extensively applied in the field of rotary dynamic sealing. However, the contact friction between the static and dynamic rings is the main cause of sealing failure. Analyzing the contact characteristics of the seal ring is important for studying the seal friction damage phenomenon and even predicting the stable operation of the seal. Traditional studies are mostly based on the assumption that the micro-surface micro-convexities of the sealing rings satisfy the single-layer characteristic of Gaussian distribution, ignoring the existence of stratification characteristics. This paper, based on the engineering background of dry gas seals, measures the two-dimensional data of the surface topography of the sealing ring, uses the discontinuous separation method to obtain layered parameters, reconstructs the sealing ring in three dimensions using the dual-Gaussian surface simulation theory, studies the contact characteristics of the sealing ring using a deterministic contact model, and analyzes the effects of related length, lower Gaussian roughness, and upper Gaussian proportion on the sealing contact characteristics in combination with surface simulation. The results show that polished finished carbon graphite sealing ring with distinctive stratified characteristic. An increase in the correlation length reduces the number of rough peaks and increases their average radius of curvature. The increase of the upper Gauss ratio leads to a slight increase in the mean curvature radius of the rough peaks. Increasing the lower Gaussian roughness will decrease the average curvature radius of rough peaks, increase the number of rough peaks, and significantly reduce the contact performance. The lower Gaussian roughness has the greatest influence on the surface morphology and contact characteristics, while the correlation length and upper Gaussian ratio have little influence on the contact characteristics.

Key words: dynamic seal, surface topography, stratified characteristic, microscale, contact

摘要：

软硬配对的密封环广泛应用于旋转式动密封领域，然而动静环间的接触摩擦是引起密封失效的主要原因。分析密封环的接触特性对研究密封摩擦损伤现象乃至预测密封稳定运行具有重要意义。传统研究大多基于密封环微观表面微凸体满足高斯分布的单层特征假设，忽略其存在的分层特征。本研究以干气密封为工程背景，通过测量密封环表面形貌二维数据，利用间断分离法获取分层参数，结合双高斯表面仿真理论对密封环三维重构，使用确定性接触模型对密封环接触特性进行研究，并结合表面仿真分析相关长度、下高斯粗糙度、上高斯占比等对密封接触特性的影响。研究结果表明：经过抛光处理的成品碳石墨密封环分层特征明显。相关长度的增加会减少粗糙峰数量并增加粗糙峰平均曲率半径。上高斯占比的增加导致粗糙峰平均曲率半径略有增加。增加下高斯粗糙度会降低粗糙峰平均曲率半径，增加粗糙峰数量，显著降低接触性能。下高斯粗糙度对表面形貌、接触特性影响最大，而相关长度、上高斯占比对接触特性影响较小。

关键词: 动密封, 表面形貌, 分层特征, 微尺度, 接触