Study On Tribological Characteristics Of Floating Ring Seals Based On Fractal Theory

The floating ring seal has a unique structure and good sealing performance,which is widely used in the field of aero-engines.In the operation process of the sealing device,due to the high rotational speed,there is fretting wear between the sealing structure and the shell,resulting in the change of leakage rate with the wear time in the sealing operation process,thus affecting the performance and service time of the floating ring seal.Therefore,the research on the friction characteristics of the floating ring seal can improve the sealing performance of the equipment.Firstly,the fretting wear between the seal structure and the shell is studied in the floating ring seal operation process,and its wear mechanism and end friction state are analyzed.Based on the fractal theory,the roughness of the friction surface in the contact process was characterized,and the relationship between the load and the area in the contact process was analyzed to obtain the leakage rate model based on the fractal contact theory.Based on this analysis,in the process of surface wear,the influence of its surface parameters on the leakage rate,it is concluded that the larger the fractal dimension of the end face,the smaller the scale coefficient,and the better the sealing performance.When other parameters are given,the influence of the specific load on the seal leakage rate can be ignored.In the study of sealing performance,the change of the seal leakage rate under the change of the material coefficient can be ignored.Secondly,according to the wear mechanism of the sealing surface,the wear between the floating ring and the casing is studied experimentally.The test plan is set according to the wear state of the test piece,and the actual working conditions are simulated by pairing soft and hard materials.The fretting wear test of the floating ring seal was carried out to obtain the surface topography and wear amount during the wear process,and then the parameters of the contact surface after the test were measured by a laser confocal microscope.The surface morphology parameters of the fretting wear of the floating ring seal under different working conditions were measured,and the relationship between the surface parameters of the contact surface and the wear amount with time during the operation of the floating ring seal was obtained.Finally,the relationship between the parameters of the contact surface and the wear quantity with time was fitted in the test process,and the relation equation was obtained.According to the surface characterization of the fractal theory and the similarity theory,the wear prediction model of th e contact face of floating ring seal is obtained.After the relevant wear parameters were measured in different working conditions,the contact state under corresponding working conditions was obtained through the fractal contact characterization,and the prediction equation of floating ring seal wear was obtained,and the service time of floating ring seal was estimated.In this paper,the characterization method of fractal contact theory is adopted to obtain the change rule of surface parameters in the we ar process through fretting wear test research.Combined with the similarity theory,the leakage rate in the fretting wear process of floating ring seal is analyzed,and the prediction equation of the wear quantity of floating ring seal is established.It provides a theoretical basis for improving the wear state of the floating ring seal and providing the service time and life prediction of the floating ring seal.