Shaft seal with convergent nozzle

摘要

A turbomachine is disclosed that has a main fluid flowpath extending axially along the turbomachine with a rotating shaft partly enclosed in a casing, wherein the rotating shaft and casing are moveable relative to each other and define a clearance opening about the rotating shaft, whereby the main fluid flowpath fluidly communicates with an outside region, and an annular seal body defining a fluid passage having a primary fluid inlet configured to receive a pressurized fluid, a fluid outlet disposed proximate to the clearance opening, and a convergent chamber interposed therebetween, wherein the convergent chamber is configured to accelerate the pressurized fluid out of the fluid outlet so as to create a local reduced pressure at the clearance opening.

主权项

1. A shaft sealing device configured to form a seal between a rotating shaft and a casing of a turbomachine, comprising:
an annular seal body disposed within the casing adjacent the rotating shaft and extending thereabout, the annular seal body defining a fluid passage having a primary fluid inlet configured to receive a pressurized fluid; a fluid outlet defined by the annular seal body and communicably coupled to the fluid passage, the fluid outlet being in fluid communication with an inner-region of the casing; and a convergent chamber interposed between the primary fluid inlet and the fluid outlet, the convergent chamber being configured to accelerate the pressurized fluid out of the fluid outlet with an axial flow component so as to create a local reduced pressure within the inner-region of the casing, wherein, the rotating shaft and the casing are moveable relative to each other and define a clearance opening that provides fluid communication between the inner-region of the casing and an outside region; and the local reduced pressure entrains a flow of a secondary fluid from the outside region through the clearance opening and into the inner-region.