Abstract: In the case of low speed and high pressure, the wear of dry gas seal is more serious, therefore, the preparation of DLC film by static ring is proposed, and the friction characteristics of the end face of the static and dynamic ring are analyzed with the groove structure. The dry gas seal with different spiral angle was tested by friction and wear machine, and the change law of temperature rise, friction coefficient and surface wear morphology were tested. The test results show that with the increase of load and speed, the friction temperature rises, friction coefficient and grinding mark of 16° spiral angle are less than 18°. Under the same working condition, the value of average friction coefficient of 18°spiral angle is 0.02 larger than that of 16°spiral angle, and the average friction temperature is increased by 5 ℃. On the one hand, because of the different spiral angle, the interface method is different and the wear degree of the end face of 18° spiral angle is greater than 16° spiral angle. On the other hand, with the increase of load and speed, the graphitization degree of DLC films is increased, which shows DLC films and spiral groove play a key role in the friction and wear of end faces. At the same time, it is found that the wear degree of the two kinds of spiral angle inner ring is greater than the outer ring, so the spiral groove can reduce the wear degree of the end face. The test results laid a foundation for the optimization design and practical application of spiral groove dry gas seal.

Key words: Dry gas seal, DLC film, Spiral groove, Interfacial normal force, Friction property

摘要： 低转速和高压力的操作工况对干气密封端面磨损情况十分严重,因此提出静环制备类金刚石(DLC) 薄膜,结合槽型结构,分析其动静环端面的摩擦特性。利用摩擦磨损实验机对不同螺旋角下的干气密封进行实验, 测试端面温升、摩擦系数及表面磨损形貌的变化规律。实验结果表明,随着载荷和转速的增加,16°螺旋角的摩擦温升、摩擦系数、磨痕均小于18°。在同一工况下18°螺旋角平均摩擦系数比16°大0.02,平均摩擦温升高5 ℃。一方面由于螺旋角的不同引起界面法向力大小不同,使18°螺旋角的端面磨损程度大于16°。另一方面随着载荷和转速的增大,DLC薄膜石墨化程度加剧,提高润滑性;说明DLC薄膜和螺旋槽对端面摩擦磨损起到了关键作用。另外,端面内圈的磨损程度大于外圈,可以推断螺旋槽能减缓端面的磨损。实验结果为今后螺旋槽干气密封优化设计和工程实际应用奠定了一定基础。

关键词: 干气密封, DLC薄膜, 螺旋角, 界面法向力, 摩擦性能