Engine fuel nozzle and swirler
A turbine engine can utilize a combustor to combust fuel to drive the turbine, which drives the engine. A fuel nozzle assembly can supply fuel to the combustor for combustion or ignition of the fuel. The fuel nozzle assembly can include a swirler and a fuel nozzle to supply a mixture of fuel and air for combustion. Increasing efficiency and carbon-containing emission needs benefit from the use of alternative fuels, which combust at higher temperatures than traditional fuels, requiring improved fuel introduction without the occurrence of flame holding or flashback.
1. A turbine engine comprising:
a compressor section, a combustor section, and a turbine section in serial flow arrangement, with the combustor section including a fuel nozzle assembly comprising:
a fuel nozzle defining a longitudinal axis and a radial axis orthogonal thereto, the fuel nozzle comprising:
a fuel passage terminating at an outlet, the fuel nozzle including a nozzle tip coaxial with the longitudinal axis, the fuel passage configured to exhaust a flow of fuel through the outlet;
a swirler configured to feed a swirled flow of compressed air that is mixed with the flow of fuel downstream of the outlet;
nozzle cap provided within the fuel passage to receive the flow of fuel therefrom, the nozzle cap including a set of openings to supply the flow of fuel therethrough, the set of openings arranged into a plurality of rows defined circumferentially relative to and spaced from the longitudinal axis, the plurality of rows having a first portion of rows of the plurality of the rows arranged in an area within an inner fifty percent of a radial extent of the nozzle cap, and a second portion of rows of the plurality of rows arranged in an area within an outer fifty percent of the radial extent of the nozzle cap;
wherein at least one opening in each row of the set of openings has a centerline oriented at a tangential angle relative to the radial axis, wherein the tangential angle of the at least one opening in each row of the plurality of rows arranged within the outer fifty percent of the radial extent of the nozzle cap increases as a radial distance from the longitudinal axis increases; and
a nozzle lip defined between the nozzle cap and the nozzle tip, coaxial with the fuel nozzle including an axial portion and a diverging portion extending from the axial portion, the axial portion defining a constant cross-sectional area downstream of the fuel nozzle cap coaxial with the fuel nozzle, and the diverging portion defining an increasing cross-sectional area coaxial with the fuel nozzle;
wherein:
the at least one opening in each row of the plurality of rows arranged within the inner fifty percent of the radial extent of the nozzle cap imparts no swirl motion to the fuel exiting the set of openings to form a no swirl flow of fuel;
the at least one opening in said each row of the plurality of rows arranged within the outer fifty percent of the radial extent of the nozzle cap imparts a swirl motion to the fuel exiting the at least one opening in said each row of the plurality of rows arranged within the outer fifty percent of the radial extent of the nozzle cap to form a swirling flow of fuel;
the no swirl flow of fuel and the swirling flow of fuel collectively form the flow of fuel that is exhausted through the outlet such that the flow of fuel has an average swirl of greater than 0 and less than 1.5.
2. The turbine engine of claim 1 , wherein the tangential angle for an opening of the set of openings at a center of the nozzle cap is ninety degrees.
3. The turbine engine of claim 1 , wherein the nozzle tip defines a lip length and the fuel nozzle defines a nozzle diameter, and a ratio of the lip length to the nozzle diameter is between zero and five.
4. The turbine engine of claim 1 , wherein the nozzle tip defines a lip length and each opening of the set of openings defines an opening diameter, and a ratio of the lip length to the opening diameter is between zero and fifty.
5. The turbine engine of claim 1 , wherein the nozzle lip includes a diverging portion defined on an exterior surface of the fuel nozzle.
6. The turbine engine of claim 5 , wherein the nozzle lip further includes a diverging portion defined on an interior surface of the fuel nozzle.
7. The turbine engine of claim 1 wherein the nozzle cap is curved as concave or convex relative to a flow direction through the fuel passage.
8. The turbine engine of claim 1 further comprising a central passage extending within the fuel passage and extending through the nozzle cap.
9. The turbine engine of claim 1 wherein the set of openings lie in a common plane.
10. The turbine engine of claim 1 wherein said at least one opening of the plurality of rows arranged within the inner fifty percent of the radial extent of the nozzle cap has a smaller cross-sectional area than said at least one opening of the plurality of rows arranged in an area within the outer fifty percent of the radial extent of the nozzle cap.
11. The turbine engine of claim 1 , wherein the swirler is located radially outward from the fuel passage, with respect to the longitudinal axis.
12. The turbine engine of claim 11 , wherein the fuel nozzle comprises an inner supply, with the fuel passage being located radially between the inner supply and the swirler.
13. A turbine engine comprising:
a compressor section, a combustor section, and a turbine section in serial flow arrangement, with the combustor section including a fuel nozzle assembly comprising:
a fuel nozzle defining a longitudinal axis and a radial axis orthogonal thereto, the fuel nozzle comprising:
a fuel passage terminating at an outlet, the fuel nozzle including a nozzle tip coaxial with the longitudinal axis, the fuel passage configured to exhaust a flow of fuel through the outlet;
a swirler configured to feed a swirled flow of compressed air that is mixed with the flow of fuel downstream of the outlet; and
a nozzle cap provided within the fuel passage to receive the flow of fuel therefrom, the nozzle cap including a plurality of openings to supply the flow of fuel therethrough, the plurality of openings arranged into a plurality of rows defined circumferentially relative to and spaced from the longitudinal axis,
wherein:
each opening of the plurality of openings has a respective centerline;
the respective centerline of each opening of a first portion of the openings of the plurality of openings forms a respective non-zero tangential angle with respect to the radial axis such that the flow of fuel emitted from the outlet has a non-zero tangential momentum;
the respective non-zero tangential angle of a first opening provided within a first row of the plurality of rows, is smaller than the respective non-zero tangential angle of a second opening provided within a second row of the plurality of rows;
wherein the respective non-zero tangential angle of said each opening of the first portion of the openings serially increases between rows of the plurality of rows radially between the first row and the second row;
the first row is located radially inward from the second row, with respect to the longitudinal axis; and
the non-zero tangential angle of at least the first opening and the second opening is configured to produce a swirled motion of fuel, such that the flow of fuel exhausted form the outlet has an average swirl of greater than 0 and less than or equal to 1.5.
14. The turbine engine of claim 13 , wherein the respective centerline of a second portion of the openings of the plurality of openings form a respective tangential angle with respect to the radial axis that is ninety degrees.
15. The turbine engine of claim 14 , wherein: the first portion of the openings are located within a first region of the nozzle cap extending from greater than or equal to 50% to less than or equal to 100% of a radial extent of the nozzle cap, with respect to the longitudinal axis; and the second portion of the openings are located within a second region of the nozzle cap extending from greater than or equal to 0% to less than 50% of the radial extent of the nozzle cap.
16. The turbine engine of claim 13 , wherein:
the respective non-zero tangential angle of a third opening provided within a third row of the plurality of rows is larger than the respective non-zero tangential angle of the first opening, and smaller than the respective non-zero tangential angle of the second opening.
17. The turbine engine of claim 16 , wherein the third row is located radially between the first row and the second row, with respect to the longitudinal axis.
18. The turbine engine of claim 13 , wherein the first row and the second row each comprise two or more openings having the same respective tangential angle.
19. The turbine engine of claim 13 , wherein the flow of fuel contains a hydrogen fuel.