Numerical study on endwall fence with varying geometrical parameters in a highly-loaded compressor cascade

Abstract

This study investigates the secondary flow control effect of the single diminutive streamwise endwall fence with varying geometrical parameters in a highly-loaded compressor. To determine the effects of the fence parameters upon the flow field structure and aerodynamic performance, numerous fenced cases are numerically simulated at the aerodynamic design point. The results demonstrate that the optimum endwall fence obstructs the migration of the endwall boundary layer from the pressure side (PS) to the suction side (SS), which leads to a measurable reduction in the separation line of corner reverse flow. Moreover, the counter-rotating fence vortex (FV) induced by the endwall fence can suppress the passage vortex (PV) and enhance the momentum exchange between the endwall boundary layer and high momentum freestream fluid. For the negative side, the fence with a larger surface area (the thicker, taller or longer fence) is proved to bring greater additional loss to the cascade, which offsets its positive flow control effect. In this study, the fence device with a width of 0.5 mm, a height of 10% the inflow boundary layer thickness and a length of 75% blade chord provides a 1.55% reduction on the cascade total pressure loss, as well as optimizes secondary flow structure by weakening passage vortex and dissipating corner vortex (CV).