Experimental Investigation on Wear Behavior of Rectangular Labyrinth Fin Against High-Speed Rotor

Abstract

The wear behaviors of the rectangular labyrinth seal fin against high-speed rotor were experimentally investigated on the incursion test rig. The material losses, worn geometries, frictional temperature distributions, and contact forces of labyrinth fin in rubbing events were measured at three incursion rates, three final incursion depths and two rotor sliding velocities. The morphologies of the worn labyrinth fin tips were magnified to reveal the wear mechanisms in rubbing events. The transient temperatures and contact forces were detailed to analyze the thermal–mechanical interactions between two contacting parts. The results show that the material loss percentage in the labyrinth fin is higher at the early stage of rubbing process, accounting for 18% mass loss of the worn region, than at final stage. The material loss is decreased with increasing the incursion rate. The incursion rate and final incursion depth have pronounced effects on the mushroom region extensions and curlings. The friction coefficient is fluctuated significantly in the high sliding velocity and low incursion rate conditions, and the averaged value of friction coefficient is about 0.1–0.125 among all experiments. The temperature at labyrinth fin tip is increased with increasing the final incursion depth, incursion rate, and sliding velocity. However, the temperature at fin tip is not increased further as it reaches about 1200 °C. The heat convection from hot fin to ambient plays an important role in worn geometries and transient temperature distributions at fin tip.