Injector assembly for an engine and aircraft

Abstract

The invention relates to an injector arrangement (1) for a gas turbine, in particular an aircraft engine, for introducing a gaseous fuel and a liquid fuel as well as air into a combustion chamber (CC), comprising an injector shaft (2) and an injector main body (3) aligned along an injector longitudinal axis (L), wherein the injector main body (3) comprises: - a first gas channel (12) arranged centrally on the injector longitudinal axis (L) with a downstream outlet opening (14) for introducing a gas flow, - at least one air channel (31, 36, 40) arranged radially around the outside of the first gas channel (12), as a second gas channel (30), and - a liquid fuel injection (24) arranged radially around the first gas channel (12) for introducing the liquid fuel into the combustion chamber (CC).An advantageous emission characteristic can be achieved by designing the first gas channel (12) exclusively for introducing the gaseous fuel into the combustion chamber (CC) (Fig. 1).

Description

[0001] The invention relates to an injector arrangement for an engine, in particular of an aircraft, for introducing a gaseous fuel and a liquid fuel as well as air into a combustion chamber, comprising an injector shaft and an injector main body aligned along an injector longitudinal axis, wherein the injector main body comprises: a first gas channel arranged centrally on the longitudinal axis of the injector with a downstream outlet opening for introducing a gas flow, at least one air channel arranged radially around the outside of the first gas channel as a second gas channel, and a liquid fuel injection arranged radially around the first gas channel for introducing the liquid fuel into the combustion chamber.

[0002] Furthermore, the invention relates to an aircraft with an injector arrangement.

[0003] An injector arrangement, or nozzle assembly, of the type mentioned above is specified, for example, in DE 10 2022 201 182 A1. In this arrangement, a fuel injection point for gaseous fuel is arranged radially outside around a central air channel running along a nozzle longitudinal axis, and a liquid fuel injection point is arranged.

[0004] US 2024 / 0044293 A1, US 10 794 596 B3, US 2016 / 0201897 A1 and US 11 525 403 B2 each show an injector arrangement for introducing a gaseous fuel and a liquid fuel with a central air channel.

[0005] US Patent 6,123,273 discloses a fuel injector for a gas turbine for adding a liquid fuel and a gaseous fuel into a combustion chamber, wherein a gaseous fuel feed arrangement is arranged radially outside around a liquid fuel feed arrangement.

[0006] US 10 054 093 B2 shows a fuel injector for a gas turbine for adding liquid fuel into a combustion chamber.

[0007] The invention is based on the objective of providing an injector arrangement of the type mentioned above and an aircraft with advantageous emission characteristics.

[0008] The problem is solved for the injector arrangement with the features of claim 1 and for the aircraft with the features of claim 15.

[0009] Regarding the injector arrangement, the first gas channel is designed exclusively for introducing gaseous fuel, not liquid fuel or airflow, into the combustion chamber. There is no upstream air inlet opening on the first gas channel, which may be closable or sealed.

[0010] To introduce the gaseous fuel into the combustion chamber, it can be introduced directly from the first gas channel or indirectly. In the case of indirect introduction, the gaseous fuel is first introduced axially into a further channel, in particular an air channel surrounding the first gas channel, and is at least partially premixed with the (gas, especially air) flow through the further channel before being added to the combustion chamber.

[0011] A further gas fuel injection point, in addition to the first gas channel, is preferably not present on the injector arrangement.

[0012] The gaseous fuel is primarily composed of hydrogen and / or contains hydrogen. The liquid fuel is primarily composed of kerosene and / or a sustainable alternative fuel (SAF). The aircraft has appropriately equipped fuel systems.

[0013] The injector arrangement according to the invention can be operated with gaseous and liquid fuels separately or with both fuel types simultaneously, whereby a flow pattern advantageous for mixing and resulting in low-emission combustion is formed in the combustion chamber.

[0014] Preferably, the injector shaft includes a gaseous fuel supply line for conveying the gaseous fuel and a liquid fuel supply line for conveying the liquid fuel to the injector body, wherein, in particular, at least at the transition to (or upstream within) the injector body, the gaseous fuel supply line is arranged on an airflow side and the liquid fuel supply line on an airflow outflow side of the injector shaft. The gaseous fuel supply line is thus arranged axially further away from the combustion chamber, upstream of the injector with respect to the airflow direction. In this way, the introduction of hydrogen into the central, first gas channel can be implemented relatively easily from a manufacturing perspective.

[0015] Preferably, the at least one air channel, designated as the first air channel, is arranged radially around the first gas channel, at least in sections (without the interposition of a further fluid channel), and has an upstream (air) inlet opening and a downstream outlet opening. Preferably, the first gas channel is surrounded by the first air channel along its entire length. The wall between the first gas channel and the first air channel (as the second gas channel) is preferably designed as a cylindrical pipe section.

[0016] Preferably, the upstream inlet opening is arranged centrally on (coaxial with respect to) the longitudinal axis of the injector and / or at the upstream end of the injector body, and is particularly designed to be at least substantially circular (or annular). In this way, during operation, a portion of the air flowing towards the injector assembly enters the injector body, more precisely the first air channel, upstream of the fuel injection point, forming an airflow into which the gaseous fuel can be mixed.

[0017] In various design configurations, the downstream outlet of the first gas channel can be positioned upstream of or at the same level as the downstream outlet of the first air channel. When positioned upstream of the first air channel outlet, the gaseous fuel is initially introduced into the surrounding airflow during operation and at least partially premixed with it. Downstream of the first gas channel outlet, the first air channel then forms the central gas channel running along the longitudinal axis of the injector. The air / fuel mixture is guided through this channel to the combustion chamber and injected through the combustion chamber outlet. The outlet of the first gas channel can, for example, be located in the upstream half of the injector body.

[0018] When positioned at the level of the outlet opening of the first air duct into the combustion chamber, the gaseous fuel is introduced into the combustion chamber without premixing during operation. This prevents flame flashback into the first air duct.

[0019] To impart swirl to the flow of the gaseous fuel, a swirl generator is preferably arranged within the first gas channel.

[0020] For the sake of simple manufacturing, the first gas channel can be formed by the gas fuel supply line, wherein the gas fuel supply line continues into the injector main body, in particular into the first air channel, and transitions by means of a change, for example by means of a bend positioned within the first air channel, into a symmetrical, downstream end section of the gas fuel supply line running along the longitudinal axis of the injector, which forms the first gas channel. The gas fuel supply line is preferably designed as a tube, at least within the injector main body.

[0021] To impart swirl to the airflow, a swirl generator is preferably arranged within the first air channel in an upstream half and / or in a downstream half of the injector body, wherein the swirl generator is particularly located upstream of the outlet opening of the first gas channel. This allows the fuel mixing and / or the flow within the combustion chamber to be positively influenced. Particularly when the swirl generator is arranged in the downstream half of the injector body, it can also provide mechanical support for the first gas channel. The first air channel can have a cross-sectional constriction to accelerate the flow at the level of and / or downstream of the swirl generator and / or the outlet opening of the first gas channel.

[0022] In a preferred embodiment, at least one liquid fuel channel with a downstream liquid fuel injection point is provided within the injector main body, downstream of the liquid fuel supply line. This liquid fuel channel is arranged radially around the first air channel directly (without the intermediate arrangement of a further fluid channel), and the liquid fuel injection point is associated with an atomizer arrangement having a film-laying surface. Preferably, several discrete liquid fuel channels are provided, the end sections of which can extend axially-radially inwards. At least in sections, a partially continuous, circumferential liquid fuel annular channel may also be provided.

[0023] Preferably, the liquid fuel channel opens into the first air channel via the liquid fuel injection, wherein, in particular, the film-laying surface is designed to be permeable to an airflow passing through the first air channel. The film-laying surface is, in particular, formed at least partially by a wall surrounding the first air channel. In this way, during operation, the air flowing through the first air channel (optionally premixed with the gaseous fuel) can advantageously advance the fuel film.

[0024] Preferably, the first gas channel is designed to allow high-velocity flow, between 50 m / s and 300 m / s, particularly between 50 m / s and 150 m / s, at least at the outlet opening, and / or the first air channel is designed to allow high-velocity flow, between 50 m / s and 150 m / s, at least at the outlet opening. In particular, the flow cross-section is designed accordingly, taking into account the operating conditions. In this way, the combustion zone is shifted further into the combustion chamber, and the thermal load on the injector assembly is reduced. Furthermore, the high velocity prevents flame flashback into the first air channel if the airflow is at least partially premixed with the gaseous fuel.

[0025] To optimize flow conditions in the combustion chamber, a second air channel (i.e., a third gas channel), particularly one with a swirl generator, is preferably arranged radially (directly, without the need for an intermediate fluid channel) around the outside of the liquid fuel channel. The inlet opening to this second air channel is preferably positioned in the downstream half of the injector body. The second air channel is particularly ring-shaped.

[0026] To further optimize the flow conditions, a third air channel (i.e., a fourth gas channel), preferably with a swirl generator, is arranged radially around the outside of the second air channel. The inlet opening to this third air channel is preferably positioned in the downstream half of the injector body. The third air channel is particularly ring-shaped.

[0027] A preferred configuration of the air channels is such that the second air channel and / or the third air channel has / have an end section oriented (axially) radially inward on the downstream side. In this way, an additional radial impulse is imposed on the flow inward, in the direction of the injector's longitudinal axis, before the flow expands radially outward due to the preferably present circumferential swirl, forming a recirculation zone that stabilizes combustion.

[0028] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings. The drawings show: Fig. 1 shows an injector arrangement according to the invention for introducing a gaseous fuel and a liquid fuel into a combustion chamber of an engine in a schematic representation in a longitudinal section along an injector longitudinal axis, a second embodiment of the injector arrangement in a schematic representation in a longitudinal section along the injector longitudinal axis, Fig. 3 shows a third embodiment of the injector arrangement in a schematic representation in a longitudinal section along the injector longitudinal axis, and Fig. 4 shows a fourth embodiment of the injector arrangement in a schematic representation in a longitudinal section along the injector longitudinal axis.

[0029] Fig. 1 Figure 1 shows a schematic longitudinal section of an injector assembly 1 for introducing fuel and air into a combustion chamber BK of an engine, particularly an aircraft engine. The injector assembly 1 has an injector shaft 2 and an injector body 3 arranged on the injector shaft 2. The injector body 3 is aligned along an injector longitudinal axis L which runs at an angle (in this case, essentially perpendicular) to the injector shaft 2.

[0030] The injector arrangement 1 is designed for operation with two types of fuel: a gaseous fuel and a liquid fuel. The fuels can be supplied to the combustion chamber BK via the injector arrangement 1 either simultaneously (in parallel) in a combined operation or individually, in separate operation of liquid and / or gaseous fuel.

[0031] The injector shaft 2 has both a gas fuel supply line 10 and a liquid fuel supply line 20. Fig. 1 The two fuel supply lines 10, 20 run parallel to each other as an example, although other arrangements are also possible, e.g. an arrangement of the liquid fuel supply line 20 inside the gas fuel supply line 10 (not shown here).

[0032] The gaseous fuel is primarily composed of hydrogen and / or contains hydrogen. The liquid fuel is primarily composed of kerosene and / or a sustainable alternative fuel (SAF). The aircraft has a suitably equipped fuel periphery (in Fig. 1 (not shown).

[0033] The injector arrangement 1 comprises a centrally arranged first gas channel 12 extending on the injector longitudinal axis L with a downstream outlet opening 14, which according to the invention is designed exclusively for introducing the gaseous fuel into the combustion chamber BK, not the liquid fuel or an air flow.

[0034] Preferably, the first gas channel 12 contains a Fig. 1 and Fig. 2 not shown swirl generator 18 arranged (cf. Fig. 3 and Fig. 4 ).

[0035] A second gas channel 30 is arranged in a ring-shaped radial configuration directly surrounding the first gas channel 12 (i.e., without the interposition of a further fluid channel and preferably separated only by, for example, a cylindrical pipe wall) within the injector main body 3. The second gas channel 30 is coaxial (with respect to the injector's longitudinal axis L) to the first gas channel 12 along its entire length. The second gas channel 30 is designed as a first air channel 31, allowing air to flow through it. It has, for example, a substantially circular upstream inlet opening 32 and a substantially circular downstream outlet opening 33. The upstream inlet opening 32 is located at the upstream end of the injector main body 3.

[0036] The first gas channel 12 is formed, in particular, by a tubular, downstream end section of the gas fuel supply line 10. The gas fuel supply line 10 is guided from the injector shaft 2 into the injector main body 3, specifically into the first air channel 31, by means of a transition, which in this case is designed as a bend 16 of the tubular gas fuel supply line 10. The downstream end section of the gas fuel supply line 10 runs symmetrically along the longitudinal axis L of the injector and opens into the outlet opening 14. The preferably circular flow cross-section of the gas fuel supply line 10 within the downstream end section can have the same or at least a smaller cross-sectional area than within the injector shaft 2 and / or be constant within the downstream end section.

[0037] It is also possible that a line section is present within a swirl generator 34 arranged in the first air duct 31, for conveying the gaseous fuel through the gas fuel supply line 10 and the swirl generator 34 into the first gas duct 12 (not shown here).

[0038] A further gas fuel injection, in addition to the first gas channel 12, is preferably not present on the injector arrangement 1.

[0039] The downstream outlet opening 14 of the gas fuel supply line 10, from which the gaseous fuel flows during operation, is located in the Fig. 1 In the illustrated embodiment, the injector is arranged upstream of the outlet opening 33 of the first air channel 31 into the combustion chamber BK. For example, the outlet opening 14 is located in the upstream half of the injector main body 3. Thus, in the section downstream of the outlet opening 14, the second gas channel 30, or the first air channel 31, forms the central channel running along the longitudinal axis of the injector. In this way, during operation, the supplied gaseous fuel is first introduced into the first air channel 31, into the airflow flowing through it, via the outlet opening 14, resulting in at least partial premixing of the gaseous fuel with this airflow. The resulting mixture then flows as a central gas flow through the section of the second gas channel 30 extending downstream of the outlet opening 14 and through the outlet opening 33 into the combustion chamber BK.

[0040] Particularly preferably, the first air channel 31 is configured to discharge the airflow at high velocity, for example between 50 m / s and 150 m / s, and / or the first gas channel 12 is configured to discharge the gaseous fuel flow at high velocity, for example between 50 m / s and 300 m / s, preferably between 50 m / s and 150 m / s. In this way, the combustion zone can be shifted downstream of the injector arrangement 1 during operation with the highly reactive gaseous fuel, thus reducing the thermal load on the injector arrangement 1.

[0041] The liquid fuel supply line 20 transitions at the injector body-side end of the injector shaft 2 or within the injector body 3 into at least one liquid fuel channel 22 for supplying the liquid fuel to a downstream liquid fuel injector 24. The at least one liquid fuel channel 22 is arranged radially, preferably directly (without the intermediate arrangement of a further fluid channel) around the first air channel 31. Preferably, several liquid fuel channels 22 are present, e.g., discrete channels extending axially and / or axially radially inwards. Alternatively or additionally, at least in sections, a single liquid fuel channel 22 is provided in the form of an at least substantially completely circumferential, continuous fuel ring channel (not shown here). Furthermore, the liquid fuel channel 22 can be provided, in particular, with swirl elements for swirling the liquid fuel (not shown here).The downstream liquid fuel injection 24 preferably has an atomizer arrangement, in particular in the form of a film laying arrangement, with a film laying surface 26.

[0042] The liquid fuel injector 24 is arranged at the downstream end of the first air duct 31 for injecting the liquid fuel into the airflow flowing through the first air duct 31. The film laying surface 26 is arranged at least partially circumferentially around a downstream section of the first air duct 31 and is exposed to air (or a mixture of air and the gaseous fuel) flowing through the first air duct 31 during operation.

[0043] Radially surrounding the liquid fuel injection point 24, preferably two outer air channels, a second air channel 36 and a third air channel 40, are arranged in a downstream end section of the injector main body 3. Thus, the injector arrangement 1 shown has a total of three air channels. The air channels 36 and 40 are separated from each other by an air guide element. Preferably, a swirl generator 38 is arranged in the second air channel 36 and a swirl generator 42 is arranged in the third air channel 40 to impart a swirl to the airflow during operation.

[0044] The second air channel 36 and the third air channel 40 have axially-radially inwardly oriented end sections downstream in order to impart a radial flow impulse inwards to the air flowing through them during operation. In this way, the airflow is initially directed inwards upon entering the combustion chamber BK, before the swirl imprint causes the air to flow radially outwards and stabilize the combustion zone by means of a recirculation zone.

[0045] The swirl generator 34 is preferably arranged upstream of the outlet opening 14 of the first gas channel 12 within the first air duct 31.

[0046] Fig. 2 Figure 1 shows a second embodiment of the injector arrangement 1, wherein the outlet opening 14 of the gas fuel supply line 10 or of the first gas channel 12 is arranged at the level of the outlet opening 33 of the first air channel 31. In this way, the gaseous fuel is fed directly into the combustion chamber BK without being premixed with the air.

[0047] The remaining design of injector arrangement 1 corresponds to that in Fig. 1 training shown.

[0048] Fig. 3 Figure 1 shows a third embodiment of the injector arrangement 1, wherein the swirl generator 18, preferably arranged within the first gas channel 12, is depicted. The outlet opening 14 is, by way of example, located in the downstream half of the injector main body 3, but preferably upstream of the film laying surface 26. In the Fig. 3 The training variant shown includes the injector shaft 2 with the existing liquid fuel supply line 20 and the gas fuel supply line 10 and their transition into the injector main body 3 (see figure). Fig. 1 and Fig. 2 ) not shown.

[0049] Fig. 4 shows a fourth design variant of the injector arrangement 1, based on the one in Fig. 3 The illustrated design variant (without depiction of the existing injector shaft 2 with the liquid fuel supply line 20, the gas fuel supply line 10 and their transition into the injector main body 3, cf. Fig. 1 , and Fig. 2 Unlike Fig. 3 The swirl generator 34, located within the first air channel 31, is positioned in the downstream half of the injector main body 3, but upstream of the outlet opening 14. In this way, the swirl generator 34 also provides mechanical stabilization of the first gas channel 12.

[0050] The central flow contributes to an extremely favorable emission characteristic, with low nitrogen oxide (NOx) emissions. Bezugszeichenliste

[0051] 1 Injector assembly 2 Injector shaft 3 Injector main body 10 Gas fuel supply line 12 First gas channel 14 Outlet opening 16 Curve 18 Swirl generator 20 Liquid fuel supply line 22 Liquid fuel channel 24 Liquid fuel injection 26 Film laying surface 30 Second gas channel 31 First air channel 32 Inlet opening 33 Outlet opening 34 Swirl generator 36 Second air channel 38 Swirl generator 40 Third air channel 42 Swirl generator BK Combustion chamber L Injector longitudinal axis

Claims

1. Injector arrangement (1) for an engine, in particular of an aircraft, for introducing a gaseous fuel and a liquid fuel as well as air into a combustion chamber (CC), comprising an injector shaft (2) and an injector main body (3) aligned along an injector longitudinal axis (L), wherein the injector main body (3) comprises: - a first gas channel (12) arranged centrally on the injector longitudinal axis (L) with a downstream outlet opening (14) for introducing a gas flow, - at least one air channel (31, 36, 40) arranged radially around the outside of the first gas channel (12), as a second gas channel (30), and - a liquid fuel injector (24) arranged radially around the outside of the first gas channel (12) for introducing the liquid fuel into the combustion chamber (CC). characterized by that the first gas channel (12) is designed exclusively for introducing the gaseous fuel into the combustion chamber (CC).

2. Injector arrangement (1) according to claim 1, characterized by that in the injector shaft (2) a gas fuel supply line (10) for conveying the gaseous fuel and a liquid fuel supply line (20) for conveying the liquid fuel to the injector main body (3) are provided, wherein in particular at least at the transition to the injector main body (3) the gas fuel supply line (10) is arranged on an air inlet side and the liquid fuel supply line (20) is arranged on an air outlet side of the injector shaft (2).

3. Injector arrangement (1) according to claim 1 or 2, characterized by that which at least one air channel as the first air channel (31) is arranged at least sectionally radially directly around the first gas channel (12) and has an upstream inlet opening (32) and an downstream outlet opening (33).

4. Injector arrangement (1) according to claim 3, characterized by thatthe upstream inlet opening (32) is arranged centrally on the injector longitudinal axis (L) and / or at the upstream end of the injector main body (3).

5. Injector arrangement (1) according to claim 3 or 4, characterized by that the downstream outlet opening (14) of the first gas channel (12) is arranged upstream of or at the level of the downstream outlet opening (33) of the first air channel (31).

6. Injector arrangement (1) according to one of the preceding claims, characterized by that a swirl generator (18) is arranged within the first gas channel (12).

7. Injector arrangement (1) according to one of the preceding claims, characterized by thatthe first gas channel (12) is formed by the gas fuel supply line (10), wherein the gas fuel supply line (10) is continued into the injector main body (3), in particular into the first air channel (31) and transitions by means of a transition, for example by means of a bend (16) positioned within the first air channel (31), into a symmetrical and downstream end section of the gas fuel supply line (10) running on the longitudinal axis (L) of the injector, which forms the first gas channel (12).

8. Injector arrangement (1) according to one of the preceding claims, characterized by that a swirl generator (34) is arranged within the first air channel (31) in an upstream half and / or in a downstream half of the injector main body (3), wherein in particular the swirl generator (34) is arranged upstream of the outlet opening (14) of the first gas channel (12).

9. Injector arrangement (1) according to one of the preceding claims, characterized by that downstream of the liquid fuel supply line (20) within the injector main body (3) at least one liquid fuel channel (22) with a downstream liquid fuel injection (24) is provided, wherein the at least one liquid fuel channel (22) is arranged directly radially around the first air channel (31) and wherein the liquid fuel injection (24) is in particular associated with an atomizer arrangement with a film laying surface (26).

10. Injector arrangement (1) according to one of the preceding claims, characterized by that the liquid fuel channel (22) opens into the first air channel (31) by means of the liquid fuel injection (24), wherein in particular the film laying surface (26) is designed to be flowable over by an airflow passing through the first air channel (31).

11. Injector arrangement (1) according to one of the preceding claims, characterized by thatthe first gas channel (12) is designed to allow flow at high speed, between 50 m / s and 300 m / s, in particular between 50 m / s and 150 m / s, at least at the outlet opening (14) and / or the first air channel (31) is designed to allow flow at high speed, between 50 m / s and 150 m / s, at least at the outlet opening (33).

12. Injector arrangement (1) according to one of claims 9 to 11, characterized by that A second air channel (36), in particular with a swirl generator (38), is arranged radially around the outside of the liquid fuel channel (22).

13. Injector arrangement (1) according to claim 12, characterized by that A third air channel (40), in particular with a swirl generator (42), is arranged radially around the outside of the second air channel (36).

14. Injector arrangement (1) according to claim 12 or 13, characterized by thatthe second air duct (36) and / or the third air duct (40) has a radially inwardly oriented end section on the downstream side.

15. Aircraft with an injector arrangement (1) according to one of the preceding claims and with a fuel periphery designed for operating the aircraft with a gaseous fuel and with a liquid fuel.

Images