Finite Difference Analysis of Fluid Forces in the Annular Plain Seal and its Interaction Analysis with Shaft Vibration

Abstract

It is important to accurately estimate the fluid forces acting on the seal in the rotating machine and to predict the dynamic behavior of the rotor. In this paper, the fluid forces in the annular plane seal is numerically calculated by using finite-difference methods based on Navier-Stokes equations averaged in the radial direction. Then, the fluid structure interaction analysis (FSI analysis) is carried out in consideration of interaction between fluid forces and shaft vibration. In this FSI analysis, it is not necessary to assume the whirling orbit of rotor. Therefore it is possible to analyze the cases with even static eccentricity or elliptic orbit, and the behavior of the system in a wider operating condition can be predicted.