Film riding aerodynamic seals for rotary machines

摘要

A seal assembly for a rotary machine is provided. The seal assembly includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the sealing device segments includes a stator interface element. The sealing device segment also includes a shoe plate having one or more labyrinth teeth facing the rotor and a load-bearing surface region, wherein the shoe plate allows a high pressure fluid to an upstream portion of the forwardmost labyrinth tooth and a low pressure fluid to a downstream portion of the aftmost labyrinth tooth. The sealing device segment further includes a secondary seal in contact with the stator interface element at a radially outer end and in contact with an elevated nose of the shoe plate on a radially inner end; and multiple bellow springs or flexures attached to the shoe plate and to the stator interface element.

主权项

1. A seal assembly for a rotary machine, the seal assembly comprising: a plurality of sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor, wherein each of the plurality of sealing device segments comprises: a stator interface element; a shoe plate comprising one or more labyrinth teeth facing the rotor and a load bearing surface region, wherein the shoe plate is configured to allow a high pressure fluid to an upstream portion of forwardmost labyrinth tooth and a low pressure fluid to a downstream portion of the aftmost labyrinth tooth and further configured to generate an aerodynamic force between the shoe plate and the rotor, a secondary seal configured to be in contact with the stator interface element at a radially outer end and configured to be in contact with an elevated nose of the shoe plate on a radially inner end, wherein the secondary seal comprises an outer layer section and an inner layer section such that each of the outer layer section of the secondary seal having an circumferentially overhanging portion overlaps a sealing device segment gap formed between inner layer section of adjacent secondary seal segments; and a plurality of bellow springs or flexures attached to the shoe plate and to the stator interface element, wherein the shoe plate comprises the one or more labyrinth teeth located towards a front end of the shoe plate for separating a high pressure side from a low pressure side in the rotary machine and one or more ports for allowing flow of low pressure fluid from the downstream portion of aftmost labyrinth tooth to a rear cavity formed by the plurality of bellow springs or flexures, the stator interface element and the shoe plate.