Swirl control labyrinth seal

Abstract

A labyrinth seal which reduces the inlet swirl and circumferential flow of fluid within the sealing cavity of a rotating shaft system in order to eliminate the destabilizing influence of the labyrinth seal, has a plurality of primary flow bypass passageways which extend from the high pressure face of the seal to the space between a first set and a second set of labyrinth teeth. The plurality of primary flow bypass passageways are equally spaced around the circumference of the seal and are preferably inclined such that the fluid is introduced into the seal cavity at a desired orientation. Each of the primary flow bypass passageways can be a passageway which is inclined at an acute angle to the shaft axis or a combination of an axial passageway and a radial passageway. The primary flow bypass passageways can be in the form of a plurality of generally radial passageways which intersect a common annular opening in the high pressure face of the seal. Also, multiple sets of secondary flow bypass passageways can be positioned at predetermined locations downstream from the first set of passages to function in a similar manner. Annular grooves can be provided in the outer surface of the seal to connect each adjacent set of secondary flow bypass passageways which straddle a set of labyrinth teeth.