| 摘要 |
Labyrinth sealing apparatus to prevent rotational instability in the rotor of a steam turbine wherein such instability is of the type induced by steam whirl within the labyrinth seals. In a preferred form, the apparatus includes a plurality of fixed, spaced-apart annular teeth surrounding the shaft of a steam turbine whereby each tooth has a radially inner edge in very close proximity to the rotor surface, and further includes a fixed circumferential row of spaced-apart flow directing vanes encircling the rotor on the upstream side of the annular teeth. Each vane of the row extends radially inward to within very close proximity of a raised annular land on the shaft surface just opposite the vane row. The row of flow directing vanes and the raised land cause substantially the entire quantity of steam which enters the seal to pass through the row of flow directing vanes. Steam flow within the seal is caused to have a retrograde component counter to the direction of shaft rotation. This produces stabilizing forces on the rotor to neutralize destabilizing forces.
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