A Numerical Simulation Study On Of Frictional Characteristics Of Seal Faces On The Starting And Stopping Process Of A Dry Gas Seal

The operation process of dry gas seal is divided into dry friction stage,non contact unstable stage,and non contact stable stage.The movment of dry gas seal friction pair starting-stop condition belongs to the first stage,because during this movement the dry friction transforms to the lubricating film.In the transformation process,its friction pair contact directly,thus producing lots of friction heat,which can lead to damage of sealing ring,during dry gas seal at start-up condition,Its sealing face contact with each other similar to the contact seal,dry gas seal in the start-up phase belongs to contact seal.Researches on the characteristics of contact seal friction is of great significance to study the friction performance of dry gas sea l.For this reason,many scholars proposed a large number of microscopic models based on statistical parameters.All of these models have scale dependence and can not objectively reflect the microscopic contact characteristics.Deeper researches found that the rough surface has fractal behavior.Due to the superiority of fractal theory to contact seal research,Therefore,the contact model based on fractal parameters was born.The starting and stopping processes play an important role in reducing friction and abrasion of spiral groove dry gas seal.Therefore,the startup and shutoff of the seal was investigated by a numerical approach.The computational procedure based on the material properties of rotational and stationary rings,interaction of micro asperi ty,and frictional heat-flow coupling was implemented to build a three-dimensional thermo-mechanical coupling model considering sliding friction within rough-rigid body.And then,the ANSYS software was used to simulate the friction heat and the stress variation of rough-rigid body based on the characteristics of nonlinear multiphysics.Through the study found,different fractal dimensions and deformation of the various parameters under the common trend,in the first place increase rapidly,after the decline,and then volatility,and finally tend to flat,the reason for this phenomenon is due to the deformation of the asperities.D = 2.5 rough interface of the friction interface of the maximum contact temperature,Von Mises equivalent stress,contact force,friction are greater than D = 2.6 rough body,Therefore,it can be concluded that the characteristics of the dry gas seal in the start-stop phase are related to the size of the fractal dimension;The Von Mises' s equivalent stress,contact force and friction force are much larger than that of the micro-convex elastic-plastic deformation.The reason for this phenomenon is that the stress and strain of the asperities are linearly elastic,and as the sliding continues,the stress of the asperities increases gradually,and the interaction between the asperity bodies is smaller.In summary,in the dry gas seal friction starting and stoping condition during the contact friction process,the use of pure elasticity analysis would be too high for estimating the Von Mises equivalent stress,the simulation results have a greater deviation,affecting the practical application of the project effect.