Experimental Investigation on the Rubbing Process of Labyrinth Seals Considering the Material Combination

Labyrinth seals are used to prevent and control the massflow rate between rotating components. Due to thermally and mechanically induced expansions during operation and transientflight maneuvers, a contact, the so-called rubbing process, between rotor and stator cannot be excluded. A large amountof rubbing process data concerning numerical and experimental investigations is available in public literature as well as at the Institute of Thermal Turbomachinery (ITS). The investigations were carried out for different operating conditions, material combinations, and component geometries. In combination with the experiments presented in this paper, the effects of the different variables on load due to rubbing are compared, and discussed with the focus lying on the material combination. The influence of the material on the loads can be identified as detailedas never before. For example, the contact forces in the currentexperiments are higher due to a higher temperature resistance of Young’s modulus. The analysis will also be based on the rubbing of turbine blades. Design guidelines are derived for labyrinth seals with improved properties regarding tolerance of rub events. ... mehrBased on the knowledge obtained, guidelines for designing reliable labyrinth seals for future engines are discussed.