机械密封环的传热特性分析

HEAT-TRANSFER CHARACTER ANALYSIS OF RINGS OF MECHANICAL SEAL

研究机械密封端面摩擦热在动环、静环、端面间液膜和密封介质组成的传热系统中的传递规律。按换热面积守恒的原则将密封环简化为当量圆筒,提出动环和静环获得的摩擦热的计算方法,推导密封环的温度分布方程。结果表明,液膜摩擦热量随角频率的增加和平均膜厚的减小而增加。绝大部分摩擦热通过动环传递到介质,静环端面的温升较小。动环靠近介质侧的温度低于空气侧的温度,端面上的温度较高,且端面径向存在温度梯度。增大动环与介质的接触面积或选用热导率大的材料可降低动环上的最高温度和端面上内外径处的温差,提高机械密封的性能。

The transfer regularity of the frictional heating of the end faces of mechanical seal in the system consist of the rotating ring, the stationary ring, the fluid film in the end faces and the sealing medium is investigated. Taking the heat-transfer area as a constant, each ring can be simplified as an equivalent cylinder. The equations for calculating the frictional heat transferred by each ring are derived, and the temperature distribution in seal rings is discussed. The frictional heat increases both with the increase of the rotational speed and with the decrease of the average film thickness. Because the most frictional heat is transferred by the rotating ring into the sealing medium, the temperature change of the stationary ring is relatively small. For the rotating ring, the temperature beside the air is higher than that beside the sealing medium. The end face of the rotating ring processes the highest temperature and there exists radial temperature gradient. It is possible to reduce the highest temperature and the temperature difference between the inner diameter and the outer diameter by increasing the heat-transfer area or using the material with higher coefficient of heat conductivity in order to improve the performance of mechanical seals.