Analysis on Hysteresis Charcteristics of Finger Seal

Abstract

The hysteresis phenomena of finger seal is studied by using the finite element method. It is concluded that there is no hysteresis for the finger seal working in static conditions. But the hysteresis of the finger seal working in dynamic situations is an inevitable phenomenon when the radial force on the finger changes in a cycle, which influences the leakage obviously. The hysteresis characteristics are analyzed from the viewpoint of energy. It is found that the hysteresis is caused by the different friction work at a cycle of force applied to the finger which generates the hysteresis energy. Under a certain condition, the characteristic of hysteresis depends on whether there is hysteresis energy or not, and the hysteresis degree is determined by the value of hysteresis energy. It is presented that the lower hysteresis finger seal can be obtained through the reasonable structure design of finger seal to increase the finger seal’s stiffness or decrease the pressure on the upside seal. It is a good way to reduce the hysteresis energy so as to weaken the hysteresis by decreasing the friction coefficient of finger and aft plate. The basis for the further reasonable design of finger seal with low hysteresis and high performance is also established.