Fuel injector for fuel spray nozzle

Abstract

A fuel injector for a fuel spray nozzle of a gas turbine engine combustor includes an angular lip axially projecting into an upstream section of an annular passage to guide a fuel layer vortex to flow along a radially outer passage wall of the annular passage and to guide an air layer vortex to fill into and pass through an annular space between the fuel layer vortex and a radially-inner passage wall of the annular passage. The air layer vortex is free of mixing with the fuel layer vortex before the fuel layer vortex is discharged from the annular passage for fuel atomization.

1 . A method for spraying fuel into a combustor of a gas turbine engine, the method comprising:
 a) generating a fuel layer vortex rotating in a first rotational direction along a radially-outer passage wall of an annular passage and flowing axially through the annular passage, the fuel layer vortex being free of contacting a radially-inner passage wall of the annular passage;   b) generating an air layer vortex rotating in the first rotational direction radially between the fuel layer vortex and the radially-inner passage wall and axially flowing through the annular passage, the air layer vortex being in contact with and free of mixing with the fuel layer vortex until the fuel layer vortex and the air layer vortex are discharged from the annular passage; and   c) generating a swirling air flow to impinge on a sheet of swirling fuel formed by the fuel layer vortex discharged from the annular passage, resulting in atomized fuel spray in the combustor.   
     
     
         2 . The method as defined in claim  15  wherein the swirling air flow rotates in a second rotational direction opposite to the first rotational direction. 
     
     
         3 . The method as defined in claim  15  wherein the swirling air flow rotates in the first rotational direction. 
     
     
         4 . The method as defined in claim  15  wherein the fuel flow vortex is generated at a first velocity in the first rotational direction to result in a centrifugal force forcing the fuel layer vortex to rotate along the radially outer passage wall of the annular passage and to be discharged radially outwardly from the annular passage, and wherein the air layer vortex is generated at a second velocity in the first rotational direction, the second velocity being lower than the first velocity. 
     
     
         5 . The method as defined in claim  18  wherein the first velocity is equal to or higher than 100 feet per second.