Wear Characteristics Of Gas Lubricated Inclined-Ellipse-Dimpled Seal Faces

The inclined dimple has good hydrodynamic effect,which is beneficial to make the two seal faces non-contact with long life under the condition of gas lubrication.However,under the stage of start or stop of the seal and the conditions of low speed,strong vibration,and so on,the seal faces is easy to be wore because of the contact of two seal faces.In order to understand the wear characteristics of dimpled end face further,the wear characteristics of gas lubricated inclined elliptical dimpled seal face was studied.Firstly,the mathematical model of inclined elliptical dimpled gas face seals with outward leakage was built based on the theory of gas lubrication,and the finite element method was used to solve that,calculating and analyzing the influences of operation parameters and geometric parameters of seal on the sealing performance.The geometric parameters of the dimple were determined,and the transformation rule of lubrication state was analyzed further.The results show that with the change of operation parameters and geometric parameters,the inclined elliptical dimpled seal face with outward leakage has the same change rules as the seal with the inward flow.The lubrication state of the seal face is greatly influenced by the closing force and the speed.The change of the lubrication state from mixed lubrication to full film lubrication can be realized by increasing the speed and reducing the closing force in the experiment,which provides the theoretical support for the further wear experiment.Secondly,the wear experiment of inclined elliptical dimpled face seal with gas lubrication focusing on the influence of speed and working temperature on the wear performance of seal face was carried out.The results show that with the change of operating conditions,seal performance show the opposite wear properties.Under the low speed,the dimpled surface show the worst wear and higher temperature.On the contrary,the dimpled surface show the well wear resistance and the lower temperature in high speed,the reduction of wear rates can be reduced about 50.8%,the temperature can be reduced by about 11.5oC.Meanwhile,sealing surface wear rates is increased rapidly with the increase of working temperature.Finally,the surface roughness is taken as the main characterization parameter,and the evolution of the geometric morphology of the seal faces was studied.The results show that the surface roughness of the smooth static ring(graphite ring)face was increased after wear and the trend of changing the radial and tangential roughness Ra of the static ring surface(graphite ring)is that decreasing firstly,increasing secondly;while the radial roughness of the rotating ring(stainless steel ring)is decreasing continuously,and the tangential surface roughness is increasing first and then decreasing.And after the working temperature was over the 60 oC,the surface roughness of the graphite ring decreases obviously.In this paper,taking gas seal with inclined-ellipse-dimple for research,and the function rule of dimpled surface on wear under the condition of gas lubrication was analyzed and given through theory and experiment.It can provide guidance for the design and practical application of gas face seal.