Study Of The Performance Of Mechanical Seals With Laser Textured Ring Face

Mechanical seal is one of the most important devices for fluid machinery and power machinery. The contacting faces of sealing rings are the dominant faces in the mechanical seals which are keys to determine sealing performance, as well as friction and working life. In order to improve the lubrication conditions of mechanical seal friction pairs and to improve sealing performance, people use surface modeling technology to texture a variety of geometric shapes morphology on mechanical seals ring face, to generate dynamic pressure effects and pumping effect, reducing friction wear and leakage, and to replace ordinary mechanical seals used in high-risk parameters and the poor working conditions.In this paper, the internal flow of mechanical seals is analyzed based on friction and lubrication theories and viscous hydrodynamic. Reynolds equations applied to sealed fluid hydrodynamic lubrication are derived from the continuity equation and momentum equation, and significant effect of every item to dynamic pressure was analyzed. The geometry model of mechanical seal ring face laser textured both spiral grooves and micro-cavities was established, and the inner flow between the faces was calculated applied CFD software, and the results of numerical simulation show that there is a certain scope of application conditions for mechanical seal textured with particular shaped spiral grooves. At the same time numerical simulations for mechanical seal flow field with both grooves and cavities on the ring face were taken, and the results show that micro-cavities can produce a high dynamic pressure and reduce the contacting shear force, effectively reducing the friction and wear of friction pairs, and the processing cost can be reduced when micro-cavities are radialized distributed in the weir area.The selections of operating conditions were consistent with the numerical simulation settings. Sealed medium pressure and rotational speed, the two key condition parameters effect seal performance, were both chosen different values to form different combinations for 12 different operating conditions. Mechanical seal performance tests were carried out under the 12 different operating conditions, on four different face-textured seals—none face texture, micro-cavities textured, spiral grooves textured, both spiral grooves and micro-cavities textured. The test results verified the correctness of the numerical simulation results, and showed the advantages of different face-textured mechanical seals under different operating conditions. Common mechanical face seal which has good sealing performance, but the severe friction and wear result in a very limited application in high-risk parameters and the poor operating conditions; micro-cavities face-textured mechanical seal has superior lubrication performance, but the leakage is relatively large; spiral grooves face-textured mechanical seal ensures seal performance with better lubrication performance than ordinary mechanical face seal, but certain parameters for spiral groove has a certain range of application conditions, and the ability to reduce friction and wear is worse than that of the micro-cavities face-textured mechanical seal; both micro-cavities and spiral grooves face-textured mechanical seal have obvious advantages over the above three kinds of face-textured mechanical seals, with good sealing performance while effectively reducing the friction face wear, and better adaptabilities for high parameters working conditions.A new type of face-textured mechanical seal was creatively put forward, with a circumferential groove textured on the original dam area connected to the radial end of the original spiral grooves, circumferential continuous. It can effectively reduce the friction and wear during open startup and shutdown, and can balance face pressure and heat distributions while working. The manufacturing processes of this kind of face texture are much more simple than the both spiral grooves and micro-cavities textured face.