Numerical investigations on lifting and flow performance of finger seal with grooved pad

Abstract

We investigate non-contact finger seal owing to its potential to reduce the specific fuel consumption of a gas turbine engine by 2–3%. The compliance features combined with the non-contact characteristic permits the position adjustment of the finger seal to the rotor excursions without destroying the stability of the rotor-seal system. The grooved structures on the lift pad of the three-layer finger seal are proposed with a view to improve the lifting and leakage capacities. Two-way fluid-structure interaction (FSI) methods are used, and the results show that the grooved structures positively affect the sealing performance. First, an uneven clearance occurs because of the seal deformation. Next, the sealing flow field is changed owing to the grooved structure. Finally, the grooved structure is proven to improve the seal's lifting capability, and the vortices in the grooves improve the sealing performance. The vortices in the groove cavities contribute significantly to the improvement in the lifting and leakage capacities. The grooved structure changes the pressure distribution under the lift pad, and a larger force is generated on the bottom surface of the lifting pad.