Analysis on Thermal-Fluid-Solid Interaction of Straight Pad Finger Seal Performance

Abstract

Aimed at the structure and working condition analysis of the straight pad finger seal, an analysis model of the straight pad finger seal which contains three complete fingers is presented. And then the influence of heat effect to the seal structure body and fluid flow state is considered in the model. By using the thermal-fluid-solid interaction numerical calculation method, the working performance of the non-contacting finger seal and its change law with working condition is studied in the paper. The straight pad finger seal's leakage rate, gas film lift capacity and gas film flow field characteristics in different working conditions are analyzed. The results show that the gas film between finger foot and rotor has radial lift capacity, which can meet the requirement of reducing wear. And since the deformation of whole finger foot is relatively uniform, it is hard to have the appearance of circumferential warp. It is advantageous to adapt to the rotor radial runout and deflection. The performance of straight pad finger seal is influenced much more by the high-to low-pressure differential and the gas temperature of high pressure chamber. The work presented here provides helpful reference and theoretical basis to design the non-contacting finger seal with high performance.