Combustion device

Abstract

A combustor ( 1 ) has a swirler ( 22 ). The swirler has mixing channels ( 40 ), the mixing channels having a height/width aspect ratio of less than ( 2 ). A secondary fuel inlet ( 32 ) is located downstream of mixing channel ( 40 ) and may be in a zone ( 65 ) of separated flow. Primary fuel admission may be through a threaded or push fit circular movable plug ( 100 ). The plug ( 100 ) may be conveniently removed for calibration purposes and may have a bell-mouthed entrance.

1 - 78 . (canceled)  
   
   
       79 . A mixing apparatus for mixing fuel and air for combustion in a gas turbine, the mixing apparatus comprising: 
 a body having a mixing channel for mixing fuel and air for combustion, the mixing channel having a main channel portion and a distinct insert channel portion, a fuel inlet being located on the insert channel portion.    
   
   
       80 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the fuel inlet is located in a portion of the insert channel portion having a curved cross section.    
   
   
       81 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the insert channel portion comprises a plug attached to one end of the main channel portion, the plug being removable from the body.    
   
   
       82 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the insert channel portion comprises a pre-calibrated insert of the mixing channel.    
   
   
       83 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the mixing channel has a curved cross section upstream portion thereof and a transition portion merging to an exit portion with a rectangular cross section, the upstream portion of the mixing channel being tilted relative to the exit portion thereof.    
   
   
       84 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the insert channel portion comprises a plug having several primary inlets spaced therearound.    
   
   
       85 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the mixing channel has a bell-mouth entrance.    
   
   
       86 . A mixing apparatus for mixing fuel and air for combustion in a gas turbine, the mixing apparatus comprising: 
 a body having a mixing channel for mixing air and fuel, the mixing channel in one portion thereof having an at least partly curved cross section.    
   
   
       87 . A mixing apparatus as claimed in  claim 86 , wherein: 
 the one portion of the mixing channel has an elliptic cross section.    
   
   
       88 . A mixing apparatus for mixing fuel and air for combustion in a gas turbine, the mixing apparatus comprising: 
 a body having a mixing channel for mixing air and fuel, the mixing channel having a fuel inlet section which has a plurality of fuel inlets spaced around a periphery thereof.    
   
   
       89 . A mixing apparatus as claimed in  claim 79 , wherein: 
 the mixing channel has a height/width aspect ratio≦2.    
   
   
       90 . An apparatus as claimed  claim 86 , wherein: 
 the body includes a plurality of said mixing channels, the mixing channels being regularly spaced about a dominant axis of the body.    
   
   
       91 . An apparatus as claimed  claim 86 , wherein: 
 each mixing channel comprises a bore formed in the body of the apparatus.    
   
   
       92 . An apparatus as claimed in  claim 86 , wherein: 
 a plurality of primary fuel inlets are provided.    
   
   
       93 . An apparatus as claimed in  claim 86 , wherein: 
 a plurality of secondary fuel inlets are provided.    
   
   
       94 . An apparatus as claimed in  claim 93 , wherein: 
 the secondary fuel inlets have a shield for providing shielded pilot fuel injection.    
   
   
       95 . An apparatus as claimed in  claim 94 , wherein: 
 a configuration of the shield conforms to an outflow direction of a mixing channel.    
   
   
       96 . An apparatus as claimed in  claim 94 , wherein: 
 the shield comprises a circular plate for providing shielded flow in a radially inward direction from under the side plate.    
   
   
       97 . An apparatus as claimed in  claim 96 , wherein: 
 the plate includes at least one hole therethrough enabling pilot fuel to flow in an axial direction through said plate.    
   
   
       98 . An apparatus as claimed in  claim 86 , wherein: 
 the body has a back plate and each mixing channel is formed in a portion of the body upstanding from the back plate on a fuel side thereof.    
   
   
       99 . An apparatus as claimed in  claim 93 , wherein: 
 the secondary fuel inlets are adapted to admit fuel at a location outside the mixing channel part.    
   
   
       100 . An apparatus as claimed in  claim 93 , wherein: 
 the secondary fuel inlets are adapted to admit fuel into a zone of separated flow on the body.    
   
   
       101 . A radial flow swirler for mixing air and fuel for combustion, the swirler comprising: 
 a body having a primary fuel inlet and a secondary fuel inlet, the secondary fuel inlet being configured for direct injection of pilot fuel.    
   
   
       102 . A swirler for mixing air and fuel for combustion, the swirler comprising: 
 a body having a series of mixing channels, the mixing channels having a bell-mouthed entrance, the mixing channels being generally co-planar with one another and radially inwardly angled in order to induce swirl.    
   
   
       103 . A swirler as claimed in  claim 102 , further including: 
 a backplate adjacent the mixing channels.    
   
   
       104 . A swirler as claimed in  claim 102 , wherein: 
 each channel is an elliptical bore.    
   
   
       105 . A combustor for burning fuel and air in a gas turbine engine, the combustor incorporating the mixing apparatus as claimed in  claim 79 .  
   
   
       106 . A combustor as claimed in  claim 105 , wherein: 
 the combustor has a cylindrical outer casing wall with an end plate, the mixing apparatus being located centrally on the end plate.    
   
   
       107 . A method of calibrating a fuel mixer for mixing fuel and air in a gas turbine, the method comprising: 
 providing a fuel/air mixing channel having a fuel inlet device formed with a fuel inlet;    calibrating the fuel inlet device; and    then installing the fuel inlet device on to the mixer.    
   
   
       108 . A method as claimed in  claim 107 , wherein: 
 calibrating the fuel inlet device includes calibrating the device with respect to fuel flow characteristics thereof.    
   
   
       109 . An apparatus as claimed in  claim 86 , wherein: 
 one or more secondary fuel inlets are provided shielded by an annular ring coaxial with a central axis of the apparatus discharging pilot fuel in a radially inward direction onto a back wall of the apparatus.    
   
   
       110 . A swirler as claimed in  claim 102 , wherein: 
 the mixing channel leads to a toroidal chamber.    
   
   
       111 . A swirler for mixing fuel and air for combusting, the swirler comprising: 
 a body having at least one mixing channel, wherein the mixing channel leads to a toroidal chamber.    
   
   
       112 . A swirler as claimed in  claim 111 , wherein: 
 the toroidal chamber has a same height as a height of the mixing channel.