Test And Modeling Of Temperature Evolution Characteristics In Dry Gas Seal Face

In the normal operating conditions of dry gas seal,the seal face is a full-fluid-film lubrication state and no contact between the end faces.However,when the seal pair is in the process of contact and non-contact transformation in the opening and stopping phase of dry gas seal,which the rotation speed is low and the dynamic pressure effect of spiral groove is insufficient.There will be significant contact and friction between the sealing end faces.This contact and friction will cause a large amount of frictional heat to the sealed end face,resulting in deformation of the seal ring.In severe cases,the seal will lose efficacy.Therefore,further research on the frictional temperature rise caused by friction and wear has certain guiding significance for engineering applications.According to the evolution law of the friction temperature of dry gas seal und er unsteady state in this paper,the frictional temperature rise of the dry gas seal static ring surface is studied by tribological test and fractal contact theory.The main research contents and conclusions are as follows:The dry gas seal performance of the different dry gas seal static rings was tested by the HDM-2 end face friction and wear tester under suitable working conditions and the surface profile of the dry gas seal static rings was measured by three dimensional profilometer after the test.The end face friction temperature rise of dry gas seal static ring with different material composition under different speeds and loads was tested and analyzed respectively.The results show that with the increase of rotational speed and load,the end face friction temperature rise of the graphite ring and DLC film silicon carbide ring is increasing.Moreover,under the same working condition s,the end face temperature rise of the graphite ring is always greater than that of DLC film silicon carbide ring.The circular micropits texture with different diameter and surface density was firstly designed and machined on the surface of the dry gas seal static ring,and then coated DLC film on the surface of the static ring.The end face friction temperature rise of the textured DLC film dry gas seal ring under different speeds and loads was tested by HDM-2 end face friction and wear tester.By analyzing the influence of different surface density and texture circle diameter on the end face friction temperature rise,the optimal texture parameters were selected:1.d=150?m,s_p=5%;2.d=250?m,s_p=5%;3.d=150?m,s_p=15%;4.d=200?m,s_p=10%.According to the contact theory of micro convex body in friction interface of dry gas seal at start and stop stage,the calculation model of fractal dimension of friction interface was established using structure function method.The discrete data of the surface contour curve of the static ring extracted by the three-dimensional profilometer was introduced into the calculation model to calculate the fractal dimension and the characteristic scale.Then,by combining the theory of heat conduction,the calculation model of the friction interface temperature rise during the start and stop stage of dry gas seals was established.The fractal dimension and characteristic scale of different working conditions were applied to calculate the frictional temperature rise of the dry ring seal ring,and the results were compared with the experimental results.The analysis results show that the numeric al calculation results of end face friction temperature rise between graphite ring and DLC film silicon carbide ring are all close to the experimental results,and the influence of rotational speeds and loads calculated by numerical calculation on the end face friction temperature rise is also consistent with the experimental results.