Importance of Labyrinth Seal Through-Flow Deflection for Enlarging Clearance Without Increasing Leakage

Abstract

Increased leakage resistance is important for designing labyrinth seals which are less susceptible to rubbing damage, in that larger knife-radial clearances are permissible. An enhanced understanding of the effect of labyrinth through-flow deflection on labyrinth knife throttle inlet flow skewness, and in turn, leakage resistance is obtained. Specifically, for several configurations, the effect of step height and knife radial clearance on leakage resistance and pertinent flow variables is examined. An experimentally verified Navier-Stokes computer code was utilized for detailed comparisons. Also, appropriate annular orifice measurements were analyzed for a complementary assessment of the potential for increasing leakage resistance from enhanced labyrinth throttle inlet flow skewness.