Cross-coupled aerodynamic forces on a whirling rotor of labyrinth seals. Straight-type labyrinth seals.

This paper shows an experimental test apparatus for measuring the dynamic force of a labyrinth seal. The apparatus is made so that the seal can spin and whirl in order to measure the dynamic force. The test is performed on a multi-stage labyrinth seal, which is used in a balance piston or a center seal in a compressor. After ascertaining the data accuracy, the leakage flow and pressure distribution in the static flow are measured, and the dynamic force is also measured by changing seal eccentricity, rotating speed, swirl velocity ratio and entrance pressure. These results are discussed. The dynamic force is separated into the tangential force and radial force or direct and cross-coupled components of the spring and damping forces, then the characteristics are discussed.