Fan blade brush tip

Abstract

A fan assembly is provided. The fan assembly includes a rotor having a hub and a plurality of rotor blades extending radially outward from the hub. Each rotor blade includes a blade tip at a radially distal end of each blade. The rotor blade tips define a rotor diameter. The fan assembly also includes a first cylindrical casing substantially axially aligned with the blade tips, the first casing including a first inner diameter that is greater than the rotor diameter. The fan assembly further includes a brush seal assembly coupled to the blade tip of a least one of the plurality of rotor blades, the brush seal assembly configured to contact the casing segment during a first operational mode of the fan assembly, the brush seal assembly configured to avoid contact with the casing segment during a second operational mode of the fan assembly.

What is claimed is: 
     
         1 . A fan assembly comprising a fan casing including a longitudinal centerline axis extending from an upstream inlet opening to a downstream outlet opening, said assembly comprising:
 a rotor comprising a hub and a plurality of rotor blades extending radially outward from said hub, said plurality of rotor blades each comprising a leading edge and a trailing edge in a direction of fluid flow through said fan casing, and a blade tip at a radially distal end of said blade, said tips of said plurality of rotor blades defining a rotor diameter, said rotor configured to rotate about said centerline axis;   a first substantially cylindrical casing segment extending circumferentially about and substantially axially aligned with said blade tips, said first casing segment comprising a first inner diameter that is greater than said rotor diameter; and   a brush seal assembly coupled to the blade tip of at least one of the plurality of rotor blades, said brush seal assembly configured to contact the casing segment during a first operational mode of the fan assembly, said brush seal assembly configured to avoid contact with the casing segment during a second operational mode of the fan assembly.   
     
     
         2 . A fan assembly in accordance with  claim 1 , wherein the first mode comprises a power output mode. 
     
     
         3 . A fan assembly in accordance with  claim 1 , wherein the second mode comprises at least one of an offline mode and an idle mode. 
     
     
         4 . A fan assembly in accordance with  claim 1 , wherein said brush seal assembly comprises a plurality of bristles extending radially opposite a direction of rotation of the rotor during said first operational mode of the fan assembly. 
     
     
         5 . A fan assembly in accordance with  claim 1 , wherein said brush seal assembly comprises a shroud coupled to at least some of the plurality of blade tips. 
     
     
         6 . A fan assembly in accordance with  claim 1 , wherein said brush seal assembly comprises a shroud coupled to a portion of at least some of the plurality of blade tips. 
     
     
         7 . A fan assembly in accordance with  claim 1 , wherein the brush seal assembly is coupled to at least a portion of at least some of the plurality of blade tips adjacent the leading edge of the at least some of the plurality of blades. 
     
     
         8 . A fan assembly in accordance with  claim 1 , wherein the brush seal assembly is coupled to at least some of the plurality of blade tips extending from the leading edge to the trailing edge of the at least some of the plurality of blades. 
     
     
         9 . A fan assembly in accordance with  claim 1 , wherein said brush seal assembly may permit a radial excursion of said blade. 
     
     
         10 . A fan assembly in accordance with  claim 1 , wherein said brush seal assembly comprises a plurality of brush fibers made at least partially from Kevlar. 
     
     
         11 . A gas turbine engine, said gas turbine engine comprising:
 a cylindrical fan casing having a longitudinal centerline axis extending from an upstream inlet opening to a downstream outlet opening;   a rotor blade rotatably mounted within said fan casing, said rotor blade having a radial inner end coupled to a rotor and a radially outer distal end comprising a blade tip, said rotor blade configured to rotate about the centerline axis, said rotor blade comprising a brush seal assembly coupled to at least a portion of said blade tip.   
     
     
         12 . A gas turbine engine in accordance with  claim 11 , wherein said brush seal assembly comprises a plurality of brush tips extending radially opposite a direction of rotation of the rotor blade when said gas turbine engine is enabled to rotate the rotor blades. 
     
     
         13 . A gas turbine engine in accordance with  claim 11 , wherein the brush seal assembly is coupled to at least a portion of said blade tip adjacent the leading edge. 
     
     
         14 . A gas turbine engine in accordance with  claim 11 , wherein the brush seal assembly is coupled to said blade tip extending from the leading edge to the trailing edge. 
     
     
         15 . A gas turbine engine in accordance with  claim 11 , wherein a brush tip of said brush seal assembly is configured to contact the fan casing during a first operational mode of the gas turbine engine. 
     
     
         16 . A gas turbine engine in accordance with  claim 15 , wherein the first mode comprises a power output mode. 
     
     
         17 . A gas turbine engine in accordance with  claim 10 , wherein a brush tip of the brush seal assembly is configured to avoid contact with the fan casing during a second operational mode of the gas turbine engine. 
     
     
         18 . A gas turbine engine in accordance with  claim 17 , wherein the second mode comprises at least one of an offline mode and an idle mode. 
     
     
         19 . A method for mounting a brush seal assembly to a blade tip of a fan of a gas turbine engine, said brush seal assembly having a base and a brush tip, said brush tip extending from said base at an angle less than 90 degrees from horizontal, the method comprising:
 milling a segment of the blade tip about a leading edge of a rotor blade to create a milled tip configured to receive said brush seal assembly;   applying an adhesive to said milled tip, said adhesive configured to bond said base of said brush seal assembly to said blade tip; and   inserting said base of said brush seal assembly into said milled tip such that said brush tip extends in the direction of a trailing edge of the rotor blade at an angle less than 90 degrees from horizontal.   
     
     
         20 . A method in accordance with  claim 17 , further comprising applying a layer of cladding to the leading edge of the rotor blade wherein the layer of cladding covers both the rotor blade and the base of said brush seal assembly.