Systems relating to axial positioning turbine casings and blade tip clearance in gas turbine engines

摘要

A gas turbine engine that includes: a flowpath defined through one of a compressor and a turbine; an inner casing defining an axially tilted outboard boundary of the flowpath, which, relative to the axial tilt, defines a converging direction in which the flowpath converges and a diverging direction in which the flowpath diverges; a row of rotor blades having outer tips that oppose the outboard boundary across a gap clearance defined therebetween; an outer casing concentrically arranged about the inner casing so to form an annulus therebetween; and a connection assembly that slidably connects the inner casing to the outer casing and includes a biasing means for axially preloading the inner casing in the converging direction.

主权项

1. A gas turbine engine comprising:
a flowpath defined through one of a compressor and a turbine; an inner casing defining an axially tilted outboard boundary of the flowpath, which, relative to the axial tilt, defines a converging direction in which the flowpath converges and a diverging direction in which the flowpath diverges; a row of rotor blades having outer tips that oppose the outboard boundary across a gap clearance defined therebetween; an outer casing concentrically arranged about the inner casing so to form an annulus therebetween; and a connection assembly that slidably connects the inner casing to the outer casing for axial movement; wherein the connection assembly includes mechanical biasing means for axially preloading the inner casing in the converging direction; the mechanical biasing means comprising a compression spring; wherein the annulus comprises at least one extraction passage that fluidly communicates with at least one extraction point, respectively, in the flowpath for producing a pressure in the annulus proportional to a pressure at the extraction point; and wherein the inner casing includes at least one receiving surface configured to receive the pressure in the annulus for producing a net axial loading on the inner casing in the diverging direction.