Study On The Effect Of Surface Texture On The Performance Of Hydrodynamic Finger Seal

Hydrodynamic finger seal is a kind of flexible non-contact dynamic sealing device with good application potential,which is mainly used in the sealing parts of aerospace engines,gas turbines,steam turbines and other major equipment.It usually relies on a thin layer of dynamic air film effect produced when finger boot and rotor rotate,which makes the seal plate and rotor in non-contact state with low leakage and the characteristics of long life,it is suitable for high-speed dynamic sealing parts.However,in order to control the leakage level,the film is usually only 10-20 ?m.Therefore,how to control the formation of a stable film by surface texture technology is the key to the design,and the current research on this area is still very lacking.Therefore,combined with the research and application of the surface texture technology,it is of great significance to study the influence of the surface texture on the leakage flow and improve the sealing technology of the aero-engine carry out the analysis of the leakage gap flow field characteristics of the hydrodynamic finger seal,considering the influence of the surface texture on the leakage flow.In this paper,the transient structure and CFX modules of ANSYS Workbench are used to simulate the two-way fluid structure coupling of the hydrodynamic finger seal.The influence of the surface texture parameters on the performance parameters of the hydrodynamic finger seal under different rotating speed,pressure difference and other conditions is analyzed.The conclusions are as follows:1.The results show that under normal temperature,the bearing capacity of finger seal with surface texture is greater than that of finger seal with smooth surface texture,and the leakage rate is less than that of finger seal without texture.This shows that the texture of rotor surface can effecti vely improve the sealing performance of finger seal.When the pressure difference between the upstream and downstream of the seal is constant,the higher the linear speed of the rotor,the more obvious the dynamic pressure effect,the smaller the leakage rate and the better the sealing performance.When the pressure difference between the upstream and downstream of the seal is 0.1MPa,and the linear speed of the rotor is 100 m/s,compared with the non-textured surface,the air film bearing capacity is increased by 10.39%and the leakage rate is reduced by 20.75%when the textured surface of the herringbone groove with a depth of 5 ?m is machined on the rotor surface.The results show that the surface texture can effectively control the formation of a stable film,reduce the leakage rate,and improve the sealing performance.2.Under the condition that the pressure difference between the upstream and downstream of the seal is 0.4MPa and the rotor linear velocity is 100m/s,five different shapes of the surface texture of the herringbone,triangle,square,circle and rectangle are studied respectively.The dynamic pressure effect generated by the finger seal found that the effect of the texture of the herringbone groove and the triangular surface is better.Compared with the non-texture structure,the gas film bearing capacity is increased by 12.22%and 11.84%,respectively,and the leakage rate is reduced 10.46%,11.23%,and the smaller the size of the triangle texture,the denser the arrangement,the better the sealing effect.3.Under the condition that the pressure difference between upstream and downstream of the seal is 0.4MPa and the linear speed of the rotor is 100 m/s,when the depth of the herringbone groove is 5 ?m and the angle is 45°,the bearing capacity of the gas film is increased by 12.22%and the leakage rate is decreased by 10.46%compared with that of the unstructured surface,and with the increase of the depth and angle of the herringbone groove,the bearing capacity of the gas film decreases and the leakage rate increases gradually,but the sealing performance is better than that of the non-textured surface,which indicates that machining herringbone groove texture on the rotor surface can effectively improve the sealing performance of hydrodynamic finger,and the sealing performance is the best when the depth of the herringbone groove is about 5 ?m and the angle is about 45°.The research of surface texture technology provides an important reference for the structural design and leakage control of hydrodynamic finger seal.