Fuel nozzle

Abstract

A fuel nozzle for a turbine engine, comprising: a flange defining at least one flange passage; a tip spaced from the flange, the tip defining at least one tip passage; a stem having a first stem end fixedly joined to the flange and a second stem end fixedly joined to the tip, the stem having a peripheral wall extending lengthwise between the first stem end and the second stem end and peripherally around a stem chamber, the tip sealing the stem chamber at the second stem end; and at least one fuel line extending at least partially inside the stem chamber and having a first line end fluidly connected to the at least one flange passage and a second line end fluidly connected to the at least one tip passage.

1 . A fuel nozzle for a turbine engine, comprising:
 a flange defining at least one flange passage;   a tip spaced from the flange, the tip defining at least one tip passage;   a stem having a first stem end fixedly joined to the flange and a second stem end fixedly joined to the tip, the stem having a peripheral wall extending lengthwise along a linear path between the first stem end and the second stem end and peripherally around a stem chamber, the first stem end and the second stem end being coaxial, the second stem end received into a cavity defined in the tip, the tip sealing the stem chamber at the second stem end; and   at least one fuel line extending at least partially inside the stem chamber and having a first line end fluidly connected to the at least one flange passage and a second line end fluidly connected to the at least one tip passage, wherein the at least one fuel line comprises first and second fuel lines extending side-by-side through the stem chamber, the first and second fuel lines being offset from a central axis of the stem, and wherein the first and second fuel lines are exposed to the stem chamber and spaced from an inner surface of the peripheral wall of the stem and from each other by an air gap.   
     
     
         2 . The fuel nozzle of  claim 1 , wherein the first stem end and the second stem end are respectively joined to the flange and to the tip by brazing, welding or soldering. 
     
     
         3 . The fuel nozzle of  claim 1 , wherein the first line end and the second line end are respectively fixedly joined to the flange and to the tip by brazing, welding or soldering. 
     
     
         4 . The fuel nozzle of  claim 1 , wherein the first stem end and the second stem end are respectively matingly received by the flange and the tip such that the stem chamber extends from inside the flange to inside the tip. 
     
     
         5 . The fuel nozzle of  claim 1 , wherein the first stem end and the second stem end are cylindrical in shape. 
     
     
         6 . The fuel nozzle of  claim 5 , wherein the stem is provided in the form of a straight tube having a constant wall thickness throughout a length thereof. 
     
     
         7 . The fuel nozzle of  claim 1 , wherein the peripheral wall has a thickness of between 0.89 mm and 1.52 mm at a location spaced away from the flange and from the tip. 
     
     
         8 . The fuel nozzle of  claim 1 , wherein the at least one fuel line is cylindrical in shape. 
     
     
         9 . The fuel nozzle of  claim 8 , wherein an inner diameter of the peripheral wall is between 7 and 15 times an outer diameter of the at least one fuel line. 
     
     
         10 . The fuel nozzle of  claim 9 , wherein the inner diameter is between 10.2 mm and 15.2 mm. 
     
     
         11 . The fuel nozzle of  claim 1 , wherein the stem has an opening defined in the peripheral wall at an intermediate location between the tip and the flange, the opening in fluid communication between the stem chamber and outside the fuel nozzle. 
     
     
         12 . The fuel nozzle of  claim 11 , wherein the opening is located closer to the flange than to the tip. 
     
     
         13 . The fuel nozzle of  claim 11 , wherein the opening has a cross-sectional area that is less than 3 mm 2 . 
     
     
         14 . A turbine engine comprising:
 a case surrounding an air plenum;   a combustor surrounded by the air plenum, the combustor defining a combustion chamber; and   a fuel nozzle for injecting a fuel-air mixture into the combustion chamber, the fuel nozzle comprising:
 a flange attached to the case, the flange defining at least one flange passage; 
 a tip projecting into the combustion chamber, the tip defining at least one tip passage; 
 a hollow stem body structurally connecting the tip to the flange, the hollow stem body provided in the form of a straight cylindrical tube having a peripheral wall extending lengthwise from a first stem end to a second stem end, the first stem end and the second stem end being coaxial, the peripheral wall having an inner surface circumscribing a stem chamber, the flange and the tip sealing the stem chamber respectively at the first stem end and at the second stem end, the second stem end received in a cavity defined in the tip; and 
   at least one fuel line extending through the stem chamber and fluidly connecting the at least one flange passage to the at least one tip passage, wherein the at least one fuel line comprises first and second fuel lines extending side-by-side through the stem chamber, the first and second fuel lines being offset from a central axis of the hollow stem body, and wherein the first and second fuel lines are exposed to the stem chamber and spaced from the inner surface of the peripheral wall of the hollow stem body and from each other by an air gap.   
     
     
         15 . The turbine engine of  claim 14 , wherein the hollow stem body has an opening defined in the peripheral wall in fluid communication between the stem chamber and the air plenum outside of the combustor. 
     
     
         16 . The turbine engine of  claim 15 , wherein the opening has a cross-sectional area of no greater than 3 mm 2 . 
     
     
         17 . The turbine engine of  claim 14 , wherein the first stem end and the second stem end are respectively joined to the flange and to the tip by brazing, welding or soldering. 
     
     
         18 . The turbine engine of  claim 14 , wherein the at least one fuel line has a first line end and a second line end, and wherein the first line end and the second line end are respectively joined to the flange and to the tip by brazing, welding or soldering. 
     
     
         19 . The turbine engine of  claim 18 , wherein the second stem end and the second line end extend parallel to one another. 
     
     
         20 . The turbine engine of  claim 19 , wherein the hollow stem body and the at least one fuel line are provided in the form of nested tubes.