A STUDY OF CURVED LABYRINTH SEALS FOR STEAM TURBINES

Abstract: A Study has been conducted evaluate the structural behavior of newly designed labyrinth seals. Structural analysis was performed to understand, evaluate and compare new seals with a baseline straight seal that is typical of commonly used seals in steam turbines. New configurations of labyrinth seal knives were developed for use in steam turbines. The main objective of this study is to develop a better understanding of selected various labyrinth seals that may be configured to minimize the steam leakage and reduce seal interactions with the shaft. Computational fluid dynamic modeling of the various configurations, from a related study, and preliminary structural analysis led new designs to incorporate curvature into knife geometries including a sharp flat free-edge. Two-dimensional linear elastic static structural analysis was performed on a baseline straight labyrinth seal knife and seven different new configurations incorporating flexible geometries like curved seals, using finite element analysis software ANSYS®. Structural behavior of all new seals was evaluated in comparison with the results obtained for the baseline straight seal knife.

Keywords: Curved Labyrinth Seals, Steam Turbines, knife geometries, sharp flat free-edge.