Experimental and Numerical Study on the Influence of Rubbing Force on Radial Crack Initiation in Labyrinth Seal Fins

Radial cracks appear in the labyrinth seal fins of the shrouded turbine blade of an aero-engine during service. To clarify the influence rule of rubbing force on crack initiation, a high-speed rubbing test bench and a numerical calculation model are established, and the research is carried out through experiment and numerical calculation. It is found that cracks can be initiated when the rubbing force is greater than 20 N with a high rubbing temperature at high speed. It is verified by numerical calculation and shows that pure mechanical load will not cause crack initiation, while the thermal load is the main reason for the radial crack initiation of fins. With the increase of rubbing force, the time of crack initiation increases, and the number and length of cracks decrease. At high rubbing temperatures, rubbing force will lead to radial crack initiation, which mainly affects the position of crack initiation.