Study On Performance Of Liquid Lubricated Laserface Mechanical Seals

There exits lots of easily volatile medium in the petrochemical industry. Vaporization of such mediums often leads to failure in mechanical seals due to their direct contact. So solution to the seal problem about volatile medium is essential to the safe production process. The LaserFace liquid lubricated mechanical seal (LF-MS), patented by John Crane Company, is a perfect solution to such problem. The newly developed technology can enhance seal face lubrication and decrease seal leakage. To improve its face design theory, explore the seal mechanism and promote the application in industry, theoretical and experimental study on LF-MS’s seal mechanism is made in this paper. The main work and results are as follows:Firstly, based on fluid lubrication theory and seal principle, considering the effects of roughness on seal faces, a mixed friction mathematical model is established. Introducing Reynolds cavitation boundary condition, the finite element method(FEM) is used to solve the mathematical models. The validation of the algorithm is verified. Secondly, the LF-MS’s seal mechanism is disclosed by analyzing the liquid film’s pressure distribution and velocity distribution between the seal faces. Comparative study is made on the seal performance among LF-MS, contacting and non-contacting mechanical seals. The results show that the LF-MS has excellent advantages on good hydrodynamic effect, large film stiffness and low friction coefficient especially in the state of "near contact". Finally, the influence of the operating parameters and geometric parameters on seal performance of LF-MS is investigated. The effect of inlet groove and "return" groove on seal performance is analyzed. The result showed that geometric parameters of seal faces are important to LF-MS’s seal performance."Return" groove with variable depth structure can improve the seal performance and lubrication. Based on the above theoretical research, laboratory tests are carried out to analyze the effect of operating parameter on seal performance.The achievement in this paper provides the basis for systematical study on LF-MS, and can be used to guide design of LF-MS product. The work is greatly significant in theory study and engineering application.