Research on Friction Characteristic of End Faces of Mechanical Seals

Abstract

The friction of the seal faces is the most important phenomenon in working process of mechanical seals. The frictional characteristic of the end faces of mechanical seals is a key factor that can decide their operating life and sealing performance. The friction mechanism of the end faces of mechanical seals was discussed at a microscopic point of view. The operating characteristic in different friction regimes of mechanical seals, such as dry friction, fluid friction, boundary friction and mixed friction, was analyzed. The methods for judging friction regimes of the end faces of mechanical seals were introduced, such as friction factor method, duty parameter method, Mayer method and relative film thickness method. The frictional characteristic of GY70 mechanical seal was investigated. The test results indicate that the bigger the spring pressure, the bigger the friction factor. When the spring pressure is smaller, the bigger the rotational speed, the bigger the friction factor. But when the spring pressure is larger than 0.0866 MPa, the friction factor is not almost influenced by the rotational speed. When both the rotational speed and spring pressure are smaller, the medium pressure has a weaker influence on the friction factor. When the rotational speed or spring pressure is bigger, the bigger the medium pressure, the smaller the friction factor. When the spring pressure and the medium pressure are respectively equal to 0.0866 MPa and 0.45 MPa and the rotational speed is between 1116 rpm and 2940 rpm, the end faces of GY70 mechanical seal work in boundary friction regime.