Performance Research Of Hydrodynamic Pressure Finger Seal Considering Surface Flow Effect

With the continuous improvement of the performance of aviation turbine engine,the working conditions of the seal are becoming increasingly harsh,aero engine failures occur due to the failure of seal components,the related research work of advanced sealing technology,such as hydrodynamic pressure finger seal,has been developed in this engineering background.Different from the macro scale flow system,with the continuous reduction of the leakage gap,the surface flow effect has become the main factor affecting the flow field performance of hydrodynamic pressure finger seal,the surface flow effect of gas in the leakage channel of hydrodynamic pressure finger seal is not considered in previous researches,and the effect will have an impact on the design result,therefore,the flow field model of hydrodynamic pressure finger seal is analyzed and the theoretical study of surface flow effect is taken into consideration,it has significance to design the high performance hydrodynamic pressure finger seal and its engineering application.Therefore,the structure model and flow field model of the hydrodynamic pressure finger seal are constructed in this paper,and the surface flow effect on the seal performance of the hydrodynamic pressure finger seal is considered in the gas leakage channel,the study mainly discusses the effect of wall slip effect and surface texture on the performance parameters of hydrodynamic pressure finger seal.This paper first introduces the structural feature,sealing principle and existing problems of the hydrodynamic finger seal,the design flow,the constraints of the structure and the boundary conditions of the flow field are emphatically analyzed,and the fluid solid coupling analysis is performed in the CFX module of ANSYS Workbench.By analyzing the characteristic of the gas movement in the leakage channel of the hydrodynamic pressure finger seal,and combined with the actual working condition of finger seal,the flow area of the gas in the leakage channel is determined.The tradition Navier-Stokes equation is simplified and the wall slip boundary conditions are added,by comparing the gas motions in the non slip state,the slip behaviors of the gas motion under coupled multi-factors are explored.After that,the structural model and flow field model with surface texture on the sealed rotor are designed,the calculation results show that the machined surface texture on the sealed rotor can dissipate the kinetic energy of the leakage gas more fully,and effectively block the movement of the gas in the leakage channel,so the sealing effect is increased significantly.Finally,compared with the model in the foreign literature test,the structure model of the circular arc line hydrodynamic pressure finger seal and the flow field model with surface texture on the rotor are constructed,and the leakage rate per unit time of the hydrodynamic pressure finger seal under different pressure conditions are compared,and the feasibility of the theoretical design is verified by the view of the paper.The related research work on leakage gas movement state of hydrodynamic pressure finger seal is carried out in this paper,it is proved that when considering the surface flow effect to the hydrodynamic pressure finger seal can not be neglected,it mainly manifested as the wall slip effect and surface texture on leakage gas movement.Among them,due to the existence of wall slip effect,the gas film bearing capacity in the flow field is reduced,and the leakage rate is increased.The surface texture can play the role of dissipating the leaked kinetic energy of the gas and improve the gas film capacity in the flow field,thereby reducing the seal leakage rate.The research and analysis of the hydrodynamic pressure finger seal performance considering the surface flow effect and the preliminary analysis results are of great significance to the follow up research and engineering application of the hydrodynamic pressure fingerseal.