Abstract: The aerodynamic forcing exerted by the air flow through the labyrinth seal acts on the rotor and accordingly shifts the rotor dynamics. Toward the end of gaining insight into this, the labyrinth seal-rotor experimental apparatus is established. The air flow and rotor dynamics of the labyrinth seal-rotor combi-nation at the pressure ratio 1.5, 3.0, 6.0 and 7.0 is measured. The numerical simulation based on perturbation analysis is performed. The comparative investigation of the cavity averaged pressure, periphery pressure distribution and the critical rotating speed demonstrates the reduction of the critical rotating speed by the leakage flow, as well as the favorable agreement between the experimental measurement and numerical simulation.

Key words: Critical rotating speed, Labyrinth seal, Rotor dynamics