Leakage performance of labyrinth seal for oil sealing of aero-engine

Abstract

Experimental investigation has been done to evaluate the leakage performance of labyrinth seal for oil sealing on high-speed sealing test rig at different working and geometric parameters. Typical values of pressure ratio ranging from 1.0 to 2.0 were used and the rotating speed varied from 0 to 30,000 rpm. Dimensionless Taylor number was invited to response the effect of rotation. Oil was injected at the rate from 1.2 L/min to 2.8 L/min to check the sealing capacity. Leakage was measured at different seal configurations including sealing clearance, tooth tip thickness, pitch, teeth number, front inclined angle and oil-throwing angle. Different from gas sealing, the application of oil-throwing tooth in oil sealing attracted much interest as an obvious alternative to the conventional labyrinth seal. A blocking ring was captured during testing, which establishes understanding of underlying flow mechanisms in the clearance and plays an important role in oil sealing. There is a critical Taylor number at which the leakage coefficient drops drastically. After the critical Taylor number, a parabola rule appears. An optimal composition of tooth tip thickness, teeth number, oil-throwing angle and front inclined angle exists where the leakage performance behaves better.