Fuel injector

Abstract

A method of creating a swirling flow of fuel-lean premixed fuel and air without passage of the flow through swirler vanes is taught. A supply of fuel is mixed with a sufficient quantity of air to form a fuel-lean mixture. The mixture is passed tangentially into an annular flow passage creating a spiraling flow without bulk flow recirculation. The spiraling flow of fuel and air is passed into a combustion chamber. Reacting a fuel-rich mixture of fuel with air in the presence of a catalyst to produce heat and a reaction product may form the supply of fuel. The reaction product is mixed with air to form the fuel-lean fuel-air mixture and then the mixture is passed into an annular chamber in a direction nominally perpendicular to the chamber axis of rotation, thereby creating a flow rotating about the axis of rotation.

1 . A method of creating a swirling flow of fuel-lean premixed fuel and air without passage of the flow through swirler vanes comprising: 
 a) providing a supply of fuel;    b) providing a supply of air in sufficient quantity to form a fuel-lean mixture if mixed with the fuel;    c) passing the air tangentially into an annular flow passage creating a spiraling flow without bulk flow re-circulation and wherein the spiraling flow comprises the air mixed with the fuel in a fuel-lean ratio; and    d) passing the spiraling flow of fuel and air into a combustion chamber.    
   
   
       2 . The method of  claim 1  wherein the fuel is a partially oxidized fuel-rich fuel-air admixture.  
   
   
       3 . The method of  claim 2  wherein the fuel-rich admixure has been oxidized in the presence of a catalyst.  
   
   
       4 . The method of  claim 1  wherein the swirling flow is passed into a combustion chamber.  
   
   
       5 . The method of  claim 4  wherein multiple swirling flows rotating in the same direction are formed and passed into an annular combustor.  
   
   
       6 . The method of  claim 4  wherein the flow expands on entry into the combustor.  
   
   
       7 . The method of  claim 4  comprising the additional step of stabilizing combustion on a swirler hub.  
   
   
       8 . The method of  claim 6  wherein the swirl number is sufficiently high for vortex breakdown.  
   
   
       9 . The method of  claim 1  wherein the fuel is premixed with the air prior to passing into an annular flow passage to create a swirling flow.  
   
   
       10 . The method of  claim 1  wherein the fuel is injected into the air on passing into an annular flow passage.  
   
   
       11 . A fuel injector for a combustor comprising a fuel-air mixing chamber and an annular spiral flow chamber having a tangential flow entrance connected to the fuel-air mixing chamber.  
   
   
       12 . The fuel injector of  claim 11  comprising a catalytic reactor for partial oxidation of fuel to feed partially reacted fuel to the fuel-air mixing chamber.  
   
   
       13 . The fuel injector of  claim 12  wherein the reactor is a fuel rich reactor.  
   
   
       14 . The fuel injector of  claim 11  wherein the spiral flow chamber contains an axial hub.  
   
   
       15 . The fuel injector of  claim 14  wherein the hub is recessed within the spiral flow chamber.  
   
   
       16 . The fuel injector of  claim 14  wherein the hub has an open end.  
   
   
       17 . The fuel injector of  claim 14  wherein the hub has a closed end.  
   
   
       18 . A combustor comprising one or more fuel injectors each comprising a fuel-air mixing chamber and an annular spiral flow chamber having a tangential flow entrance connected to the fuel-air mixing chamber directing a direction of rotation.  
   
   
       19 . The combustor of  claim 18  wherein multiple fuel injectors all have the same direction of rotation.  
   
   
       20 . The method of  claim 1  further comprising: 
 e) reacting a fuel-rich mixture of fuel with air in the presence of a catalyst producing heat and a reaction product;    f) mixing the reaction product with air to form the fuel-lean fuel-air mixture; and    g) passing the mixture into an annular chamber in a direction nominally perpendicular to the chamber axis of rotation, thereby creating a flow rotating about said axis of rotation.