LABYRINTH SEAL DEVICE FOR AXIAL-FLOW TURBINE AND EXHAUST GAS TURBOCHARGER EQUIPPED WITH SAME

摘要

In this labyrinth seal device (15) for an axial-flow turbine (5), a labyrinth member (22) forming a gas labyrinth seal (GL) with a turbine disk (6) is fixed to a bearing stand (2) so as to adjoin an exhaust gas outlet casing (12) with a gap-like seal gas discharge passage (26) therebetween, said exhaust gas outlet casing (12) forming an exhaust gas passage (13). The outer circumferential surface (22a) of the labyrinth member (22) is exposed to the inside of the exhaust gas passage (13) in a manner that is level with the inner circumferential surface (13a) of the exhaust gas passage (13). The cross sectional shape of an end part of the seal gas discharge passage (26) is configured so that a seal gas (or seal air) supplied to the labyrinth seal (GL) merges with exhaust gas in an oblique manner relative to the flow direction of the exhaust gas flowing in the exhaust gas passage (13).