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A fuel nozzle configured to channel fluid towards a combustion chamber is provided. The fuel nozzle includes a stem having a central passageway and at least one fuel tube disposed within the passageway. The fuel tube includes an outlet end portion having inner and outer walls separated by a cavity d

A fuel nozzle configured to channel fluid towards a combustion chamber is provided. The fuel nozzle includes a stem having a central passageway and at least one fuel tube disposed within the passageway. The fuel tube includes an outlet end portion having inner and outer walls separated by a cavity defined by a fixed aft face. The inner wall defines a central bore for delivering fuel to the combustion chamber. Further, the fuel nozzle includes an outer heat shield tube concentrically aligned with the outlet end portion of the fuel tube. The heat shield tube includes a circumferential outer wall having an aft face that stops upstream of the fixed aft face of the fuel tube. Thus, during operation, the heat shield tube is configured to thermally expand by sliding against the outer wall of the fuel tube.

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1. A fuel nozzle for channeling fluid towards a combustion chamber defined within a gas turbine engine, the fuel nozzle comprising: a stem comprising a central passageway;at least one fuel tube disposed within the central passageway, the fuel tube comprising an outlet end portion having an inner wal

1. A fuel nozzle for channeling fluid towards a combustion chamber defined within a gas turbine engine, the fuel nozzle comprising: a stem comprising a central passageway;at least one fuel tube disposed within the central passageway, the fuel tube comprising an outlet end portion having an inner wall that extends to an outlet of the fuel tube and curves up to form an aft face at the outlet that extends substantially perpendicular to the inner wall and back to form an outer wall generally parallel to the inner wall, the outer wall separated from the inner wall by an open cavity defined by the aft face, the inner wall defining a central bore for delivering fuel to the combustion chamber;an outer heat shield tube concentrically aligned with the outlet end portion of the fuel tube and external to the inner and outer walls and the open cavity of the fuel tube, the heat shield tube comprising a circumferential outer wall having an aft edge that stops upstream of the aft face of the fuel tube; anda fitting arranged between the aft edge of the heat shield tube and the combustion chamber and spaced apart from the aft edge of the heat shield by a gap;wherein, during operation, the circumferential outer wall of the heat shield tube is configured to thermally expand by sliding against an outer surface of the outer wall of the fuel tube forward of the fitting and the combustion chamber and within the gap. 2. The fuel nozzle of claim 1, wherein the fitting comprises a ferrule. 3. The fuel nozzle of claim 1, wherein the cavity comprises a vented air cavity defined by the inner and outer walls of the fuel tube, the aft face of the fuel tube, and the circumferential outer wall of the heat shield tube. 4. The fuel nozzle of claim 1, wherein the aft face of the fuel tube is substantially perpendicular to the inner and outer walls of the fuel tube. 5. The fuel nozzle of claim 4, wherein the inner and outer walls and the aft face of the fuel tube define a substantially U-shaped cross-section. 6. The fuel nozzle of claim 1, further comprising an insulator configured with the outer wall of the fuel tube within the cavity so as to provide insulation between hot air outside of the fuel nozzle and fuel within the fuel tube, wherein the insulator provides an extended thermal conduction path for the hot air. 7. The fuel nozzle of claim 6, wherein the insulator is constructed, at least in part, of yttria-stabilized zirconia. 8. A combustor assembly for use with a gas turbine engine, the combustor assembly comprising: a combustion chamber;a fuel nozzle configured to channel fluid towards the combustion chamber defined within the gas turbine engine, the fuel nozzle comprising: a stem comprising a central passageway;at least one fuel tube disposed within the central passageway, the fuel tube comprising an outlet end portion having an inner wall that extends to an outlet of the fuel tube and curves up to form an aft face at the outlet that extends substantially perpendicular to the inner wall and back to form an outer wall separated by an open cavity defined by the aft face, the inner wall defining a central bore for delivering fuel to the combustion chamber;an outer heat shield tube concentrically aligned with the outlet end portion of the fuel tube and external to the inner and outer walls and the open cavity of the at least one fuel tube, the heat shield tube comprising a circumferential outer wall having an aft edge that stops upstream of the aft face of the fuel tube anda fitting arranged between the aft edge of the heat shield tube and the combustion chamber and spaced apart from the aft edge of the heat shield by a gap;wherein, during operation, the circumferential outer wall of the heat shield tube is configured to thermally expand by sliding against an outer surface of the outer wall of the fuel tube forward of the fitting and the combustion chamber and within the gap. 9. The combustor assembly of claim 8, wherein the fitting comprises a ferrule. 10. The combustor assembly of claim 8, wherein the cavity comprises a vented air cavity defined by the inner and outer walls of the fuel tube, the aft face of the fuel tube, and the circumferential outer wall of the heat shield tube. 11. The combustor assembly of claim 8, wherein the inner and outer walls and the aft face of the fuel tube define a substantially U-shaped cross-section. 12. The combustor assembly of claim 8, further comprising an insulator configured with the outer wall of the fuel tube within the cavity so as to provide insulation between hot air outside of the fuel nozzle and fuel within the fuel tube, wherein the insulator fills at least a portion of the cavity and provides an extended thermal conduction path for the hot air. 13. The combustor assembly of claim 12, wherein the insulator is constructed, at least in part, of yttria-stabilized zirconia.