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

Guoqing Li ^a,b,*, Qian Zhang ^c, Zhijun Lei ^a,b, Enliang Huang ^a,b, Hongwei Wu ^d, Gang Xu ^a,b

a. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
         b. University of Chinese Academy of Sciences, Beijing 100190, China
         c. Research Institute of Petroleum Exploration and Development, Beijing 100083, China
         d. School of Engineering and Technology, University of Hertfordshire, Hatfield AL109AB, United Kingdom

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.

Keywords: Labyrinth seal; Leakage; Rotating; Oil sealing; Aero-engine