WE CLAIM:
1. A fuel nozzle apparatus having a centerline axis (26), and comprising:
a main fuel injector (24) including an enclosed interior volume in fluid communication with a plurality of fuel ports (58) configured to discharge fuel therefrom;
a main fuel conduit (22) disposed upstream of the main fuel injector (24) and configured to supply liquid fuel to the interior volume; and
a fluid lock (82) disposed between the main fuel conduit (22) and the main fuel injector (24), the fluid lock (82) comprising a plurality of parallel capillary channels (88).
2. The apparatus of claim 1 wherein each capillary channel has a cross-sectional flow area of 0.002 square inches or less.
3. The apparatus of claim 1 wherein a cross-sectional flow area of the main fuel conduit (22) is significantly greater than a cross-sectional flow area of one of the capillary channels (88).
4. The apparatus of claim 1 wherein:
the main fuel injector (24) is of annular form; and
a pilot fuel injector (18) is disposed coaxially within the main fuel injector (24).
5. The apparatus of claim 4 further comprising:
an annular venturi (44) surrounding the pilot fuel injector (18); and a radial array of outer swirl vanes (52) interconnecting the pilot fuel injector (18) and the venturi (44).
6. The apparatus of claim 1 further comprising an annular outer body (60)
surrounding the main fuel injector (24), and having a generally cylindrical exterior

surface (70) including an array of spray wells (74) formed therein, each spray well (74) being aligned with one of the main fuel ports (58).
7. The apparatus of claim 6 wherein some of the spray wells (74)
incorporate a scarf (76) comprising a ramped portion of the exterior surface (70)
which is oriented at an acute angle to the centerline axis (26).
8. The apparatus of claim 6 wherein the spray wells (74) are arranged as:
a first group which do not incorporate scarfs (76); and
a second group which each incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented at an acute angle to the centerline axis (26), wherein the spray wells (74) of the second group alternate with the spray wells (74) of the second group around the periphery of the outer body (60).
9. The apparatus of claim 8 wherein the spray wells (74) of the second
group are oriented at an acute angle to the centerline axis (26), in a downstream
direction.
10. The apparatus of claim 6 wherein the spray wells (74) are arranged as:
a first group which each incorporate a scarf (76) comprising a ramped
portion of the exterior surface (70) which is oriented in an upstream direction, at an acute angle to the centerline axis (26); and
a second group which each incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented in a downstream direction, at an acute angle to the centerline axis (26), wherein the spray wells (74) of the second group alternate with the spray wells (74) of the second group around the periphery of the outer body (60).
11. A fuel nozzle apparatus, comprising:
a centrally-located pilot fuel injector (18);

a pilot fuel conduit coupled to pilot fuel injector (18);
an annular main fuel injector (24) surrounding the pilot fuel injector (18), comprising an enclosed interior volume in fluid communication with plurality of fuel ports (58) configured to discharge fuel therefrom;
an annular outer body (60) surrounding the main fuel injector (24), venturi (44), and pilot fuel injector (18), and having a generally cylindrical exterior surface (70), including an array of spray wells (74) formed therein, each spray well (74) being aligned with one of the main fuel ports (58), wherein some of the spray wells (74) incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented at an acute angle to the centerline axis (26);
a main fuel conduit (22) disposed upstream of the main fuel injector (24) and configured to supply liquid fuel to the interior volume; and
a blocking device (90) disposed between the main fuel conduit (22) and the main fuel injector (24).
12. The apparatus of claim 11 wherein the blocking device comprises a fluid lock (82) having a plurality of parallel capillary channels (88).
13. The apparatus of claim 11 further comprising
a fuel system (12) operable to supply a flow of liquid fuel;
a pilot valve (14) which is coupled to the fuel system (12) and to the pilot fuel conduit; and
a main valve (20) which is coupled to the fuel system (12) and to the main fuel conduit (22).
14. The apparatus of claim 13 wherein the spray wells (74) are arranged
as:
a first group which do not incorporate scarfs (76); and a second group which each incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented at an acute angle to the

centerline axis (26), wherein the spray wells (74) of the second group alternate with the spray wells (74) of the second group around the periphery of the outer body (60).
15. The apparatus of claim 14 wherein the spray wells (74) of the second group are oriented at an acute angle to the centerline axis (26), in a downstream direction.
16. The apparatus of claim 13 wherein the spray wells (74) are arranged as:
a first group which each incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented in an upstream direction, at an acute angle to the centerline axis (26); and
a second group which each incorporate a scarf (76) comprising a ramped portion of the exterior surface (70) which is oriented in a downstream direction, at an acute angle to the centerline axis (26), wherein the spray wells (74) of the second group alternate with the spray wells (74) of the second group around the periphery of the outer body (60).