Labyrinth Seal Rotordynamic Forces Using a Three-Dimensional Navier-Stokes Code

A finite difference method for determining rotordynamic forces on an eccentric whirling labyrinth cavity has been developed. A coordinate-transformation was applied to the Reynolds time-averaged Navier-Stokes equations in order to use the modified bipolar coordinate system. The SIMPLER algorithm with QUICK differencing and the high Reynolds number k–ε turbulence model are used to compute the complex turbulent flowfield. A circular whirl orbit about the geometric center of the housing was specified for simplicity. The new model was tested against the rotordynamic force measurements, and close agreement was found. For the cases considered, the radial and tangential force components become rotor dynamically less desirable with increasing inlet swirl. Also, circumferential pressure variations are included for enhanced insight into the flowfield.