Design And Simulation Analysis On Hydrodynamic Pressure Finger Seal

The finger seal is a new innovative seal after labyrinth seal and brush seal, and apples to the gas-path seal of Gas turbine engines. The designed early finger seal is contacting seal which finger root contacts to rotor. The contacting wear between finger root and rotor is an important problem. So a non-contacting finger seal has been designed later. Compared to contacting finger seal, the finger root of non-contacting finger seal have the capability of self-lifting, so a clearance which has carrying capacity can be obtained between finger root and rotor. Thus the seal capability and especially life of finger seal is an obvious advantage.Finger root based on hydrokinetics have been designed. Fluid film wedge have been formed because the peculiar structure of finger root, and it can brings hydrodynamic pressure which can lifts finger root by the high rotate speed of rotor. So the friction between finger root and rotor has been avoided. Whether the designed root is a good design can be estimated by the self-lifting capability of finger root, gas leakage and the following capacity of finger root to the motion of the rotor.The analyse to hydrodynamic finger seal system is a typical fluid - structure coupling problem. The character of fluid-structure coupling dynamics is the interaction between fluid and structure. Structure can displace by fluid load, and the displacement affects the fluid and changes the distributing of fluid load. So the numerical model of hydrodynamic finger seal system has been established by ANSYS and CFX. The fluid - structure coupling analyse to hydrodynamic finger seal system has been accomplished. The analyse result indicates that the fluid has a good lifting capability and is capable of lifting finger root, and gas leakage is small.In addition, a spring - quality - damper dynamic model of FS system is proposed to describe the dynamic running of FS system because the rotor is jumpy, and following capacity of finger root to the motion of the rotor has been analyzed. The analyse result indicates that the designed hydrodynamic finger root has a very good following capacity tothe rotor, and doesn't contact to the rotor at all time.