Gas turbine engine

Patent metadata

Field	Value
Publication number	US-2016177971-A1
Application number	US-201514642149-A
Country	US
Kind code	A1
Filing date	Mar 9, 2015
Priority date	Mar 31, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A fan casing for fitment around an array of radially extending fan blades of a gas turbine engine. The fan casing includes an annular casing element; and an annular fan track liner positioned radially inward of the annular casing element. The fan track liner includes an abradable layer and an abrasive layer, the abrasive layer being positioned radially inward of the abradable layer and proximal, in use, to the fan blades.

First claim

1 . A method of manufacturing a gas turbine engine, the method comprising:
providing a series of fan blades about a hub, arranging an annular fan casing having an annular fan track liner circumferentially around the fan blades, wherein the fan track liner comprises an abradable layer and an abrasive layer on a radially inner surface of the abradable layer; and rotating the fan blades such that the abrasive layer removes a section from a tip of one or more of the fan blades.

2 . The method according to claim 1 , wherein the abrasive layer is substantially removed during rotation of the fan blades.

3 . The method according to claim 1 , wherein the length of the one or more fan blades is reduced before the engine is mounted on-wing of an aircraft.

4 . The method according to claim 1 , wherein the abrasive layer is arranged so as to be substantially removed after engine pass-off and/or after running the engine at maximum speed for a predetermined number of rotation.

5 . The method according to claim 1 , wherein the abrasive layer comprises abrasive particles.

6 . The method according to claim 5 , wherein the abrasive layer comprises a resin matrix in which the abrasive particles are suspended.

7 . The method according to claim 5 , wherein the abrasive particles are sharp edged rhomboid particles.

8 . The method according to claim 7 , wherein the abrasive particles are diamond grit.

9 . A method of trueing blades of a gas turbine engine, the gas turbine engine comprising an array of blades arranged around a hub and a casing member positioned circumferentially around the blades, the casing member having an abradable layer, the method comprising:
providing an arrangement for interacting with the fan blades to adjust the length of the fan blades during initial running of the engine; and running the engine for a pre-determined time so that the arrangement interacts with one or more of the fan blades and adjusts the length thereof.

10 . The method according to claim 9 comprising providing an abrasive layer on a radially inward surface of the casing member and running the engine so as to abrade one or more of the blades and shorten the length thereof.

11 . A fan casing for fitment around an array of radially extending fan blades of a gas turbine engine, the fan casing comprising:
an annular casing element; and an annular fan track liner positioned radially inward of the annular casing element, wherein the fan track liner comprises an abradable layer and an abrasive layer, the abrasive layer being positioned radially inward of the abradable layer and proximal, in use, to the fan blades.

12 . The fan casing according to claim 11 , wherein the abrasive layer is a sacrificial abrasive layer.

13 . The fan casing according to claim 12 , wherein the abrasive layer is arranged so as to be substantially removed after engine pass-off and/or after running the engine at maximum speed for a predetermined number of rotation.

14 . The fan casing according to claim 11 , wherein the abrasive layer comprises abrasive particles.

15 . The fan casing according to claim 14 , wherein the abrasive layer comprises a resin matrix in which the abrasive particles are suspended.

16 . The fan casing according to claim 14 , wherein the abrasive particles are sharp edged rhomboid particles.

17 . The fan casing according to claim 16 , wherein the abrasive particles are diamond grit.

18 . A gas turbine engine comprising:
a fan casing; and an array of fan blades arranged around a hub; wherein the fan casing comprises an annular fan track liner positioned circumferentially around the fan blades, the fan track liner comprising an abradable layer proximal to the fan blades, and wherein the variation in length of the fan blades is equal to or less than ±0.15 mm.

Assignees

• Rolls Royce Plc

Inventors

• Bagnall Adam M

Classifications

• F04D29/325

  for axial flow fans (blade mountings F04D29/34, blades F04D29/38) · CPC title

• F04D29/38

  Blades {(for axial flow compressors F04D29/324)} · CPC title

• F04D29/083

  especially adapted for elastic fluid pumps · CPC title

• F04D29/526 Primary

  Details of the casing section radially opposing blade tips (ducts F04D29/545) · CPC title

• B24B19/14

  for grinding turbine blades, propeller blades or the like (using grinding belts B24B21/16) · CPC title