Patent ID: 12215868

In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding elements.

DETAILED DESCRIPTION

FIG.1schematically illustrates a gas turbine engine20. The example gas turbine engine20is a turbofan that generally incorporates a fan section22, a compressor section24, a combustor section26, and a turbine section28. The fan section22drives air along a bypass flow path B in a bypass duct defined within a nacelle30. The turbine engine20intakes air along a core flow path C into the compressor section24for compression and communication into the combustor section26. In the combustor section26, the compressed air or other combustion gas is mixed with fuel from a fuel system32and ignited by igniter34to generate an exhaust gas flow that expands through the turbine section28and is exhausted through exhaust nozzle36. The fan section22is at the front of the engine20and the exhaust nozzle36is at the back of the engine20, such that as used herein “forward” refers to an orientation toward the front and “aft” refers to an orientation toward the back. Although depicted as a turbofan turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines. As one example, rather than having the propulsor be an enclosed fan, the propulsor may be an open propeller.

While present gas turbine engines use liquid hydrocarbon fuels (LHF), the engine20of the present disclosure is designed to use gaseous fuel, such as hydrogen, in the fuel system32. In this regard, the fuel system32may carry liquid cryogenic hydrogen or gaseous hydrogen, both of which are provided to the combustor section26as gaseous hydrogen. A challenge to using hydrogen is that because it is a gas, its handling and combustion properties differ from that of LHF. For instance, hydrogen does not require atomization like a liquid, and hydrogen has higher flammability and different flame characteristics than LHF. Accordingly, injector nozzles that are designed for hydrogen are needed. In these regards, the engine20includes one or more injectors38for introducing the hydrogen fuel into the combustor section26.

As shown inFIG.2, the injector38is arranged on a combustion chamber40of the combustor section26for introducing hydrogen and gas (e.g., air in the examples herein).FIG.3illustrates an isolated, sectioned view of an example of the injector38, andFIG.4illustrates a perspective, sectioned view of the injector38(both views are sectioned in a plane through central axis A2of the injector38). The injector38includes an annular gas nozzle42disposed along the central nozzle axis A2. The annular gas nozzle42includes a forward face44, a frustoconical interior surface46recessed from the forward face44, and gas feed conduits48that open at the frustoconical interior surface46. In the illustrated example, the gas feed conduits48include inner gas feed conduits48aand outer gas feed conduits48b.

The gas feed conduits48a/48bare obliquely sloped with respect to the central nozzle axis A2. In the illustrated example, the inner gas feed conduits48aare sloped at a first angle, and the outer gas feed conduits48bare sloped at a second, shallower angle. The annular gas nozzle42is connected to an air source, such as the compressor section24. A “conduit” as used herein is defined by one or more structures that together convey a fluid from one point to another. For example, a conduit conveying fluid from point A to point B may include one of, or a combination of: a tube, an aperture defined through a part of an engine, a filter, a pump, and so on, depending on the application and context as would be understood by a person of ordinary skill in the art reading the present disclosure.

The injector38further includes a hydrogen feed conduit50that extends along the central nozzle axis A2through the annular gas nozzle42. The hydrogen feed conduit50is connected to the fuel system32(hydrogen source) for providing hydrogen to be mixed with the air for combustion. The hydrogen feed conduit50and the frustoconical interior surface46define there between an annular mixing chamber52. The hydrogen feed conduit50has an end portion54that that is axially displaced to be forward of the forward face44of the annular air nozzle42. The end portion54includes feed holes56that open into the mixing chamber52. The gas feed conduits48a/48bprovide two stages of air to mix with the radially outwardly flowing hydrogen. For example, flow from the inner gas feed conduits48aintersects the flow from the feed holes56, to rapidly mix air and hydrogen. The flow from the outer gas feed conduits48bat the shallower angle serves to control the amount of flow from the injector38, as well as the cone angle.

There is a disc58disposed on the end portion54of the hydrogen feed conduit50. The disc58is a circular plate that has forward and aft sides that are substantially flat. It is attached on its aft side to the tip of the hydrogen feed conduit50. The disc58has a diameter D1, the hydrogen feed conduit50has a diameter D2, and the annular air nozzle42has a diameter D3. The disc58is diametrically larger than the end portion54of the hydrogen feed conduit50. This enlarged size of the disc58forms a forward boundary of the annular mixing chamber52. As an example, the disc58is diametrically larger than the end portion54by a factor of 1.2 to 2.5 (i.e. the ratio of D1/D2). With respect to the annular air nozzle42, the nozzle42is diametrically larger than the disc58by a factor of 2.0 to 4.0

During operation of the engine20, air is provided through the gas feed conduits48, which are obliquely sloped with respect to the central nozzle axis A2such that the gas feed conduits48point at the hydrogen feed conduit50axially aft of the feed holes56. For instance, the central axes A3of the air feed conduits48intersect the hydrogen feed conduit50aft of the feed holes56. As a result, the air jetted from the gas feed conduits48aimpinges the outer surface of the hydrogen feed conduit50, thereby causing the air to circulate in the mixing chamber52. The gas feed conduits48b, which have a different angle of incidence relative to the disc58, are pointed radially outwardly of the disc58. For instance, the central axes A3of the air feed conduits48bdo not intersect the disc58. As a result, the air jetted from the gas feed conduits48bflows across the mixing chamber52and carries mixed air and hydrogen and out of the injector38into the combustion chamber40. The aft side of the disc58provides a forward bound of the mixing chamber52, which facilitates containment of the air in the mixing chamber for enhanced flow circulation. The circulating air exits the mixing chamber52through a discharge region60radially between the disc58and the annular air nozzle42. The feed holes56are pointed toward the discharge region60such that the exiting air entrains the hydrogen that streams from the feed holes56, thereby mixing with the hydrogen and carrying it into the combustion chamber40for ignition.

FIG.5illustrates another example disc158. The disc158has the same outer diameter as the disc58except that it includes hydrogen bleed holes158athat extend through the thicker disc158. The hydrogen bleed holes158aare arranged circumferentially around the disc158at uniform intervals and are located radially intermediate the axis A2and the radially outer edge159of the disc158. The hydrogen bleed holes158amay be oriented, with respect to central holes axes, parallel to the axis A2or angled to axis A2. For example, the hydrogen bleed holes158aare radially and tangentially sloped to induce a swirling flow of bleed hydrogen. The hydrogen bleed holes158aallow small amount of hydrogen through the disc158to facilitate flame stabilization near low fuel flow and lean blow out conditions. In this regard, the number of hydrogen bleed holes158aand radial location may be varied to tailor performance.

The term “tangential slope” (or variations thereof) refers to an orientation (component) that (a) forms an oblique angle with the axis A2and (b) lies in a plane that is (i) non-intersecting with the axis A2and (ii) is substantially tangent to the circumference at the radial location from the axis A2where the hole158aopens. For instance, a tangential slope is in either a clockwise or counter-clockwise direction with respect to the axis A2(looking aft). The term “radial slope” (or variations thereof) refers to an orientation that has a radial angle component with respect to the axis A2. For instance, a radial slope is either in a radially inwardly or outwardly direction with respect to the axis A2(looking aft).

FIG.6illustrates another example disc258. The disc258is the same as the disc158except that rather than being circular, the disc258has a serrated outer edge259. In this example, the disc259is finely serrated but in another example inFIG.7, the disc358has a serrated outer edge359that is coarsely serrated. For example, the finely serrated outer edge259has more than12teeth around the circumference, and the coarsely serrated outer edge359has less than12teeth around the circumference. For the discs258and358, the diameter D1is the mean diameter of the serrated edge259/359, i.e., the mean of the maximum diameter at the tip of the serration and the minimum diameter at the valley between serrations. The serrated outer edges and inner edges259/359facilitate mixing of the hydrogen and air. Hence, the outer diameter, inner diameter and the number of serrated teeth are parameters for optimization to achieve maximum mixing and flame stability.

As also shown inFIG.7, the disc358includes a single hydrogen bleed hole358athat is co-axial with the axis A2. The hydrogen bleed hole358aserves the same purpose as the hydrogen bleed holes158adiscussed above. In this regard, in further examples of any of the foregoing examples, a hydrogen bleed hole358amay be used instead of, or in addition to, the hydrogen bleed holes158a. This disclosure may be further understood in view of the following examples. An injector38for a gas turbine engine20according to an example of the present disclosure includes an annular gas nozzle42that is disposed along a central nozzle axis A2and includes a forward face44, a frustoconical interior surface46, and gas feed conduits48that open at the frustoconical interior surface46. A hydrogen feed conduit50extends along the central nozzle axis A2through the annular gas nozzle42. The hydrogen feed conduit50and the frustoconical interior surface46define there between an annular mixing chamber52. The hydrogen feed conduit50has an end portion54that is axially displaced from the forward face44. The end portion54includes feed holes56that open into the mixing chamber52. A disc58is disposed on the end portion54of the hydrogen feed conduit50and is diametrically larger than the end portion54of the hydrogen feed conduit50.

In a further example of the foregoing example, the disc58is diametrically larger than the end portion54by a factor of 1.2 to 2.5.

In a further example of any of the foregoing examples, the annular gas nozzle42is diametrically larger than the disc58by a factor of 2.0 to 4.

In a further example of any of the foregoing examples, the gas feed conduits48are obliquely sloped with respect to the central nozzle axis A2.

In a further example of any of the foregoing examples, the gas feed conduits48are pointed at the hydrogen feed conduit50axially aft of the feed holes56.

In a further example of any of the foregoing examples, the disc58has a serrated outer edge159/259/359.

In a further example of any of the foregoing examples, the disc58has at least one hydrogen bleed hole158a.

In a further example of any of the foregoing examples, the disc58forms a forward boundary of the annular mixing chamber52.

A gas turbine engine20according to an example of the present disclosure includes a combustor section26that has a combustion chamber40, a hydrogen source32, and an injector38as in any of the foregoing examples.

Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.