Analysis Of Friction And Wear Characteristics And Performance Of Contact Mechanical Seals

As the most widely used sealing type,contact mechanical seal is widely used in chemical industry,aerospace,energy and other fields.The friction and wear mechanism of contact seal is the most critical problem to ensure the performance reliability during life-cycle.In this paper,the theoretical research,numerical simulation and experimental research methods are used to study the sealing characteristics and frictional characteristic of the contact mechanical seal.The main works are as follows:Firstly,the wear model of the mechanical seal is established to study the performance of the seal in the stable wear stage.The variation of sealing characteristics parameters in the stable wear stage was obtained in a coupled analysis where the average Reynolds equation,asperity contact model and mixed lubrication wear equation were solved simultaneously.Secondly,on the basis of the above theory,further consider mechanical and thermal deformation of the seal ring,which is defined as running-in stage.In the stage of running-in,the evolution mechanism of sealing characteristics and the influence of operating parameters on the evolution mechanism are studied.Then,the experiment of sealing performance is carried out to study the influence of operating parameters on the sealing performance and verify the correctness of the theoretical calculation model.Finally,the exploratory experiment is carried out on the friction and wear characteristics of carbon and silicon carbide matching contact seal.The influence of operating parameters on the sealing performance in the start-up and stop stage and stable wear stage is analyzed,the correlation between acoustic emission signal and sealing performance is explored,and the seal wear form and wear mechanism of the worn surface are analyzed.The conclusion are as follows: in the stable wear stage,the change of end face area ratio,roughness,medium pressure and spring force changes the sealing performance parameters by changing the contact state between the end faces.In the running-in stage,the end face gap changes from convergence gap to parallel gap,and the contact force between the two faces extends from inner diameter to outer diameter.In the performance experiment of contact mechanical seal,the end face temperature and friction torque have a linear relationship with the speed and medium pressure.In the variable pressure test,there is an obvious running-in stage;in the variable speed test,the seal will enter a short-term running in period when the speed is changed.In the friction and wear experiment,the RMS value of AE peak at 700 rpm,then decreases to a valley,and finally increases to a stable value.In the stable operation process,the AE signal has a slow increasing process,and the higher the pressure and speed,the faster the increasing rate is.In the wear process of Si C-C matching materials,the abrasive wear is the main form.The higher the peripheral velocity is,the more serious the abrasive wear are;the higher the pressure is,the easier the adhesive wear will occur.