Fuel injector

Abstract

A fuel injector includes: a flat tube disposed over an aperture of a wall of a combustor that extends toward a turbine in a gas turbine system. The flat tube is configured such that air compressed by a compressor of the gas turbine system flows perpendicular to a thickness direction of the flat tube before flowing through the aperture. The flat tube has a fuel hole through which gaseous fuel that flows inside the flat tube exits to a passage of the air. An entire length of a downstream edge of the flat tube with respect to a flow of the air is disposed within the aperture when viewed perpendicular to the wall.

What is claimed is: 
     
         1 . A fuel injector comprising:
 a flat tube disposed over an aperture on a wall of a combustor that extends toward a turbine in a gas turbine system, wherein   the flat tube is configured such that air compressed by a compressor of the gas turbine system flows perpendicular to a thickness direction of the flat tube before flowing through the aperture,   the flat tube has a fuel hole through which gaseous fuel that flows inside the flat tube exits to a passage of the air, and   an entire length of a downstream edge of the flat tube with respect to a flow of the air is disposed within the aperture when viewed perpendicular to the wall.   
     
     
         2 . The fuel injector according to  claim 1 , wherein the aperture is disposed on a wall of a transition piece. 
     
     
         3 . The fuel injector according to  claim 1 , further comprising:
 a co-axial tube at the downstream edge of the flat tube, wherein   the co-axial tube comprises:
 an inner tube through which liquid fuel flows; and 
 an outer tube that co-axially encloses the inner tube and through which a mixture of the liquid fuel and water flows. 
   
     
     
         4 . The fuel injector according to  claim 3 , wherein the co-axial tube further comprises:
 a fin plate that extends along a longitudinal axis of the co-axial tube, wherein   the fin plate:
 extends from an inside of the inner tube to an outside of the outer tube, and 
 divides an inside space of the inner tube into a first portion on a first side of the fin plate and a second portion on a second side of the fin plate, and 
   a portion of the fin plate disposed outside of the outer tube extends along the flow of the air.   
     
     
         5 . The fuel injector according to  claim 4 , wherein
 the inner tube has:   a first hole that connects the first portion of the inside space of the inner tube with a space inside of the outer tube and outside of the inner tube; and   a second hole that connects the second portion of the inside space of the inner tube with the space inside of the outer tube and outside of the inner tube, and   the first hole is offset from the second hole along the longitudinal axis of the co-axial tube.   
     
     
         6 . The fuel injector according to  claim 4 , wherein
 the outer tube has:   a first hole that connects a space inside of the outer tube with outside of the outer tube; and   a second hole that connects the space inside of the outer tube with outside of the outer tube and that is disposed on an opposite side of the first hole with respect to the fin plate, and   the first hole is offset from the second hole along the longitudinal axis of the co-axial tube.   
     
     
         7 . The fuel injector according to  claim 3 , wherein
 the inner tube has a hole that connects an inside space of the inner tube with a space inside of the outer tube and outside of the inner tube,   the outer tube has a hole that connects a space inside of the outer tube with outside of the outer tube, and   the hole of the inner tube is offset from the hole of the outer tube along a longitudinal axis of the co-axial tube.   
     
     
         8 . The fuel injector according to  claim 1 , further comprising:
 a hub disposed over a center of the aperture and that extends perpendicular to the wall, wherein   the flat tube has one or more bends and extends nonlinearly from the hub toward a circumference of the aperture when viewed perpendicular to the wall.   
     
     
         9 . The fuel injector according to  claim 8 , wherein the flat tube has a substantially sinusoidal shape when viewed perpendicular to the wall. 
     
     
         10 . The fuel injector according to  claim 1 , wherein a longitudinal direction of the flat tube is in a spiral shape over the aperture when viewed in a direction perpendicular to the wall. 
     
     
         11 . The fuel injector according to  claim 10 , further comprising a hood disposed over the aperture and the flat tube. 
     
     
         12 . The fuel injector according to  claim 10 , wherein a height of the flat tube measured in a direction perpendicular to the longitudinal direction and the thickness direction of the flat tube linearly decreases from an outward end of the spiral shape to an inward end of the spiral shape. 
     
     
         13 . The fuel injector according to  claim 10 , wherein a distance of the flat tube from an inner surface of the wall of the combustor linearly decreases from an outward end of the spiral shape to an inward end of the spiral shape. 
     
     
         14 . The fuel injector according to  claim 10 , wherein an outward end of the spiral shape opens toward an upstream of a flow of the air outside the combustor. 
     
     
         15 . The fuel injector according to  claim 10 , wherein
 the wall of the combustor comprises ribs extending toward an inside of the aperture, and   the flat tube fits inside the ribs.   
     
     
         16 . The fuel injector according to  claim 1 , wherein
 the aperture has an apex of an acute angle,   the apex points toward a burner of the combustor, and   the flat tube is in a loop shape.   
     
     
         17 . The fuel injector according to  claim 16 , wherein the aperture is in a wedge shape that is elongated in a direction of a gas that flows from the burner of the combustor toward the turbine. 
     
     
         18 . The fuel injector according to  claim 16 , wherein the aperture is in a diamond shape that is elongated in a direction of a gas that flows from the burner of the combustor toward the turbine. 
     
     
         19 . The fuel injector according to  claim 16 , wherein an upstream edge of the flat tube with respect to the flow of the air extends outward over a circumference of the aperture when viewed perpendicular to the wall and forms a bell mouth for the flow of the air. 
     
     
         20 . The fuel injector according to  claim 16 , further comprising:
 one or more other flat tubes that:
 are disposed over the aperture of the wall of the combustor, 
 each have a fuel hole through which gaseous fuel exits to the passage of the air, and 
 are each in a loop shape; and 
   a strut that supports the flat tube and the one or more other flat tubes, wherein   an inside of the strut communicates with an inside of the flat tube and insides of the one or more other flat tubes.