WO2023180315A2

WO2023180315A2 - Nozzle assembly with a central fuel supply and at least one air channel

Info

Publication number: WO2023180315A2
Application number: PCT/EP2023/057208
Authority: WO
Inventors: Gregor Christoffer GEBEL; Ruud Eggels; Carsten Clemen; André Fischer
Original assignee: Rolls-Royce Deutschland Ltd & Co Kg
Priority date: 2022-03-24
Filing date: 2023-03-21
Publication date: 2023-09-28
Also published as: DE102022202937A1; WO2023180315A3

Abstract

The invention relates to a nozzle assembly for a combustor (103) of an engine (T), comprising at least one nozzle (D) for injecting fuel into a combustion chamber (1030) of the combustor (103), wherein the nozzle (D) comprises a nozzle main body (DR) extending along a nozzle longitudinal axis (L) and having a nozzle head (DK), and a nozzle holder (DH) connected to the nozzle main body (DR) and having at least one fuel supply line (1). The nozzle main body (DR) comprises a central fuel pipe (3) extending along the nozzle longitudinal axis (L) and at least two radially spaced-apart air guide channels (4, 5) on the nozzle head with a respective at least one air outlet opening.

Description

Nozzle assembly with central fuel supply and at least one air duct

Description

The invention relates to a nozzle assembly for a combustion chamber of an engine with at least one nozzle for injecting gaseous fuel, in particular hydrogen, into a combustion chamber of the combustion chamber comprises a nozzle holder having a fuel supply line.

Nozzle assemblies for combustion chambers for engines are widely known in various forms. The focus of previously common nozzles of such nozzle assemblies is the injection of fuels, in which, especially in the case of gaseous fuels, the fuel is mixed with air within the nozzle in order to produce a combustible fuel-air mixture immediately downstream of the nozzle end. However, in applications that run on liquid fuels be, e.g. B. Kerosene or diesel, the air flow through the nozzle is often used to atomize (or at least support) the fuels into sprays within the nozzle or directly downstream of it. Typically, in both approaches mentioned, the air to be mixed in is already wired within the nozzle, so that a swirling fuel-air flow with turbulence and recirculation is created downstream of the nozzle end, which is classified as advantageous for combustion.

Such different nozzle assemblies are in the publications US 4 842 509 A, DE 10 62 873 A, GB 2 593 123 A, US 5 117 637 A, US 4 483 138 A, DE 103 14 941 A1, US 9 488 108 B2 and also in US 5 636 511 A shown in various embodiments. For example, in the latter, a coaxial ignition unit with a ceramic body is arranged in a central tube, onto which a hardened platinum wire is wound in the form of a coil. A mixture of fuel and air takes place in the central tube, with openings for supplying air being introduced in the wall of the central tube around the ignition unit, which is supplied via an annular channel formed by an outer coaxial tube.

Recently, concepts for aircraft engines have been increasingly developed in which the engine is partially or completely operated with hydrogen or other fuels to be injected in gaseous form, as is the case, for example. B. in US 4,713,938 A1 is intended for a gas turbine for generating electricity. But if an engine is to be built with the same design as possible, e.g. B. operated with hydrogen instead of kerosene or diesel, a different injection is necessary because the fuel is introduced into the combustion chamber in gaseous form and in the case of e.g. B. Hydrogen also has significantly shorter ignition delay times and higher flame speeds. Against this background, the nozzle assembly of claim 1 is proposed, which in particular comprises a nozzle for injecting hydrogen into a combustion chamber of an engine-side combustion chamber, but which is also suitable for injecting other fuels, in particular gaseous fuels.

A proposed nozzle assembly includes a nozzle with a nozzle main body, which includes a central fuel pipe extending along the longitudinal axis of the nozzle. At least two radially spaced air ducts, each with at least one air outlet opening, are also provided on the nozzle head, so that a central fuel outlet opening of the fuel pipe is formed at the nozzle end and the at least two air outlet openings of the two air ducts are formed radially further out.

Air intended for mixing with the fuel discharged from the fuel outlet opening can be introduced into the combustion chamber via air guide channels. At least two air guide channels located radially further outward with respect to the inner or central fuel pipe are therefore provided on the nozzle head.

The fuel pipe can protrude axially with its fuel outlet opening relative to the air outlet openings of the air guide channels, based on the longitudinal axis of the nozzle. The fuel outlet opening is therefore in a flow direction defined by the fuel pipe, along which the fuel is guided within the nozzle main body, at least as far or further downstream as the air outlet openings of the air ducts. In particular, in this context it can be provided that the fuel outlet opening is arranged furthest downstream, i.e. each air outlet opening is arranged axially set back from the fuel outlet opening of the fuel pipe with respect to the nozzle longitudinal axis. This means that the fuel can be injected further downstream into the combustion chamber than air via the radially outer air guide channels. This supports the heat release As a result of combustion of the mixture of fuel and air occurring downstream of the nozzle, the nozzle is not thermally stressed in a critical manner.

Furthermore, the air flowing in via the at least two air guide channels ensures an air-rich zone in a front area of the combustion chamber around the nozzle end (a so-called outer recirculation zone). As a result, the nozzle and a combustion chamber wall of the combustion chamber surrounding the nozzle can be thermally protected from the combustion zone. Air outlet openings of the different air guide channels can each be designed as an annular gap, in particular as an annular gap.

In principle, the at least two radially spaced air guide channels of the nozzle head can provide air flows with different air quantities, different swirls and in particular also different flow speeds. For this purpose, an outer air outlet opening of a radially outermost air duct of the at least two air ducts can have a larger cross-sectional area than an inner air outlet opening of an inner air duct of the at least two air ducts, which runs on the nozzle head between the radially outermost air duct and a section of the fuel pipe. For example, it is provided that an outer air outlet opening of a radially outermost air duct of the at least two air ducts has a cross-sectional area that is at least a factor of 2, 4 or 6 larger (through which air flows during operation of the combustion chamber or the engine) than an inner air outlet opening of an inner air duct of the at least two air ducts.

The inner air duct is provided on the nozzle head between the radially outermost air duct and a section of the fuel pipe. For example, an air flow with a comparatively high axial momentum is provided via the radially inner air duct and with less swirl than the outer air duct or no swirl. In this context it is therefore envisaged that the Radial inner air duct is set up and provided to provide a non-swirling air flow into the combustion chamber. Alternatively, the radially inner air duct can be set up and provided to provide a swirling air flow into the combustion chamber, but the swirl of the air flow from the inner air duct is set to be less than the swirl of the air flow which (during operation of the combustion chamber) via the radially outer or outermost air duct flows into the combustion chamber. An air flow with an imposed swirl does not have to be able to be generated via the radially inner air guide channel, but it can also be possible. Swirl imprinting can be advantageous, for example, with regard to the stability behavior of the burner, the flame shape and/or flame position, the pollutant formation rate and the thermal load on the nozzle. In particular, the air ducts can then be designed in such a way that the air flow from the inner air duct has a swirl that is increased by a defined amount, e.g. B. by more than 50% or more than 60%, is less than a swirl of the air flow from the outer air duct. In this way, the air flow from the radially inner air duct, for example, continues to occur primarily tangentially to the inflow of fuel from the fuel pipe and at least with a larger axial component than an air flow from the outer air duct. The air flow from the radially inner inner air guide channel adjacent to the fuel pipe thus supports a displacement of the zones of chemical combustion reactions as far as possible into the combustion chamber.

In one embodiment variant, the radially outermost air guide duct with the larger cross-section through which flow is provided is primarily intended to provide a swirling air flow into the combustion chamber. This allows an air flow to be generated at the nozzle end, which envelops the fuel flow, draws it up radially and thus creates a recirculation zone downstream of the nozzle end, in which air and fuel mix and a swirl-stabilized, recirculating combustion zone is formed. The air from the air ducts surrounding the combustion zone also creates an air-rich zone in a front area of the combustion chamber available around the nozzle (a so-called external recirculation zone). This allows the nozzle and a combustion chamber wall of the combustion chamber to be thermally protected from the combustion zone.

For the formation of an effective recirculation zone, it can also be advantageous if, as explained, the air flow introduced into the combustion chamber via the outermost air duct has a swirl, while the air flow from the inner air duct is not swirling, or the air flow into the combustion chamber via the outermost air duct Air flow introduced into the combustion chamber has at least a greater swirl than the air flow from the inner air duct. For example, one or more axial twisters or radial twisters are provided for this purpose at least in a radially outermost air duct of the at least two air ducts.

In order to provide a sufficient amount of air, in particular for an outer recirculation zone explained above, via the nozzle, one or more radially inwardly pointing inlet lips can be provided at least on a radially outermost air duct of the at least two air ducts in order to feed air into the radially outermost air duct and, if necessary, also in to guide a further air guide channel located radially further inside. When the nozzle assembly is installed as intended, the one or more inlet lips also lead, for example, to air coming from a compressor stage and guided around the nozzle main body being guided radially inwards into the radially outermost air duct and possibly also into a further air duct located radially further inwards . The use of inlet lips for one or more air ducts can be particularly advantageous for a head area of the nozzle that is comparatively thick and which may therefore initially be an obstacle to allowing a sufficiently large amount of air to flow axially into the air duct(s). In one embodiment variant, a local narrowing of the inner air duct towards its air outlet opening can be provided. Sections of inner and outer walls bordering the inner air duct and opposing each other (duct) walls thus approach each other in the area of the air outlet opening. This means that the inner air duct can be z. B. narrow in the shape of a nozzle, whereby an increase in the exit speed of the inflowing air can be achieved. In addition, a deflection of the air flow radially inwards, ie in the direction of the nozzle longitudinal axis L, can also be achieved via such a narrowing.

A centrally arranged flow body can be provided within the central fuel pipe, on the outer surface of which fuel supplied to the fuel pipe can flow along in the direction of a fuel outlet opening of the fuel pipe, via which the fuel can be introduced into the combustion chamber. Such a central flow body can be provided in combination with the at least two air guide channels. In principle, however, the use of such a central flow body can also be advantageous in other designs of a nozzle head with a central fuel pipe, e.g. B. in combination with only one surrounding coaxial air duct.

Fuel can flow axially around the centrally arranged flow body and thus serve to even out the fuel flow within the fuel pipe and/or to influence the flow direction of the fuel at the fuel outlet opening. In the fuel pipe, fuel supplied to the nozzle via at least one fuel supply line in a nozzle holder can therefore be guided within the nozzle main body up to the fuel outlet opening of the fuel pipe, which is also defined by an end of the flow body. With the help of the (downstream) end of the flow body, the fuel can be injected into the combustion chamber, in particular with a flow component pointing radially outwards, and/or can positively influence a flow field in the combustion chamber. In principle, a flow body provided within the fuel pipe can extend with one end to the nozzle end, and in particular to the fuel outlet opening. For example, the flow body at the nozzle end can protrude axially relative to an edge of the fuel outlet opening that is located radially further out, that is, it can protrude at least slightly axially beyond the edge of the fuel outlet opening. In the case of an axially projecting flow body, for example, it is provided that the flow body protrudes to an extent that is 5% or 10% of the diameter of the central fuel pipe.

In combination with the flow body, an advantageous embodiment in connection with the central injection of gaseous fuel, namely hydrogen, into the combustion chamber is that a spark plug is integrated into the fuel pipe, in particular into the flow body, with its front ignition section facing the combustion chamber. In this way, by using an advantageous small spark plug that can be operated with little energy expenditure, a fine adjustment of the fuel flow introduced into the combustion chamber can be achieved in coordination with optimal ignition conditions.

In an advantageous further embodiment it is provided that the spark plug is accommodated in a central cavity of the flow body. This results in a defined, precise installation, with the cavity in the flow body z. B. through a central hole introduced into the flow body coaxially to the longitudinal axis, e.g. B. open blind hole on the front, can be formed.

It is also advantageous that a cable connection for electrically controlling the spark plug through the flow body, for example a bushing introduced on the back of the cavity, and optionally a support element, in particular a support strut, a support that holds the flow body in the fuel pipe. structure and guided through the nozzle holder. The installation of the spark plug and the cable routing are designed to be leak-tight.

For an optimized adjustment of the fuel flow into the combustion chamber and the ignition conditions, it is advantageously provided that the flow body, which is blunt towards the combustion chamber, the area of the fuel outlet opening and the area of at least one air outlet opening of at least one air guide channel, in particular arranged in the nozzle body, are designed and coordinated with one another are that the air supply and the gas supply into the combustion chamber lead to a recirculation of the gas-air mixture towards the ignition section of the spark plug.

The installation of the spark plug in the specified combination with the flow body is based on the idea that the central injection of the gaseous fuel, in particular hydrogen, causes only a small amount of gas-air mixture to be distributed outwards towards the combustion chamber wall, especially in operating conditions with little air mass flow and low air speeds, i.e. e.g. B. to start the engine. The spark plug for igniting the gas-air mixture is conventionally positioned on the combustion chamber wall. This makes ignition only possible when a suitable amount of gas-air mixture is present. This can result in a large amount of ignitable mixture already being present in the combustion chamber before ignition occurs. This can lead to a detonation-like ignition. The solution according to the invention given here results in an advantageous integration of the ignition device for optimal ignition conditions in the mentioned structure of the nozzle assembly with central injection of the gaseous fuel, in particular hydrogen.

One end of the flow body can specify a flow direction for the fuel to be injected into the combustion chamber. For example, the flow body For this purpose, have a guide element at its end, via which fuel emerging from the fuel outlet opening is directed radially outwards in relation to the longitudinal axis of the nozzle. For example, at the end of the flow body, the guide element is formed by a radial expansion of the flow body. The fuel injection into the combustion chamber with a flow portion pointing radially outwards can influence the properties, such as shape and size, of the flow field of a recirculation zone created downstream of the nozzle end, which is particularly important with gaseous fuel and in particular hydrogen with a view to flame stability and comparatively low combustion temperatures in the vicinity of the nozzle can be advantageous.

A narrowing at the end of the fuel pipe at the fuel outlet opening, which is realized with the end of the flow body facing the combustion chamber, can also be used to specifically accelerate the fuel flow into the combustion chamber.

In principle, the flow body can be conical or conical.

Alternatively or additionally, the flow body is designed symmetrically, in particular rotationally symmetrically, to the longitudinal axis of the nozzle and/or with a blunt, centrally arranged end face facing the combustion chamber. A blunt, centrally arranged end face at one end of the flow body can, for example, support the formation of an inner recirculation zone with a comparatively high fuel concentration during operation of the combustion chamber or the engine. Such an inner recirculation zone may be accompanied by low combustion temperatures in the vicinity of the nozzle and thus immediately downstream of the nozzle end. The blunt end face can in principle - depending on the desired flow conditions - be essentially flat, (slightly) convex or (slightly) concave.

In principle, the flow body can have an upstream and optionally aerodynamically shaped, convexly curved end, which is axially spaced from an end wall of the nozzle or a rear wall of the fuel tube. In principle, however, another aerodynamically favorable shape can also be provided for the upstream end. For example, the end can be hemispherical, conical (possibly with a blunt or rounded cone tip), ogive-shaped or ovoid-shaped. Particularly depending on the design of the feed reservoir, the flow body can also be connected to an end wall of the nozzle or a rear wall of the fuel pipe in embodiment variants of the proposed solution. The flow body then extends along the longitudinal axis of the nozzle away from the end wall or the rear wall and is therefore not axially spaced from the end wall or the rear wall. While with an axial spacing of the flow body the flow body has an upstream end within the fuel pipe where fuel flows axially, this is not the case with a flow body connected to the end wall or rear wall. Depending on the construction and boundary conditions, one or the other shape of the flow body can be advantageous, for example with regard to a thickness of the nozzle main body that can be achieved in a head region of the nozzle main body.

If the flow body is not connected to an end wall of the nozzle or a rear wall of the fuel pipe and runs along the longitudinal axis of the nozzle centrally within the fuel pipe up to the fuel outlet opening, the flow body typically extends over a large part of the length of the main nozzle body having the fuel pipe, e.g. B. over at least 85% of this length. In one embodiment variant, two flow bodies that are axially spaced apart from one another with respect to the nozzle longitudinal axis can also be present within the fuel pipe. In such an embodiment variant, a pipe section of the fuel pipe through which fuel can flow over the entire cross section is present centrally between the two flow bodies. For example, a first upstream flow body is cone-shaped, while a further flow body provided downstream in the area of the fuel outlet opening is conical or otherwise aerodynamically favorable - e.g. B. hemispherical, conical (possibly with a blunt or rounded cone tip), ogive-shaped or ovoid-shaped - is designed.

The flow body can comprise several (at least two) protruding sections on its outer lateral surface, which flows axially around the combustion chamber during operation. On the one hand, these protruding sections can serve to intensify heat transfer between the material of the flow body, which typically consists of metal, and the cooler fuel - particularly during operation of the combustion chamber. If the flow body extends to the fuel outlet opening, it is exposed to comparatively high temperatures at least on one side facing the combustion chamber, so that the injected fuel in the area of the flow body can also be used for cooling, especially if this is hydrogen to be injected. The sections protruding from the outer lateral surface can also serve specifically to influence the flow of the fuel flow within the fuel pipe. For example, the protruding sections are formed by ribs, webs, pins, tenons or fins. The protruding sections can be provided evenly distributed on the outer lateral surface around which the flow flows axially. In particular, the protruding sections can be provided distributed over the entire outer lateral surface, or only in a limited area of the lateral surface (e.g. in the area of the fuel outlet opening). In a possible further development, the protruding sections are arranged on the outer surface in such a way that any swirl that has already been specifically imposed on the fuel flow is not counteracted or such a swirl is even supported if necessary. In particular, the protruding sections can be designed and provided to locally influence and, if necessary, increase the swirl. For example, the sections protruding from the lateral surface are designed at an angle and/or helically.

Alternatively or additionally, the flow body can comprise several depressions on its axially flow-around outer lateral surface, for example in the form of bores and/or dents. Such structures that change the surface of the flow body can also serve to intensify the heat transfer from the flow body to the fuel.

In principle, one end of the fuel pipe in the area of the fuel outlet opening can be designed in various ways. Since when using fuel with very fast reaction kinetics, such as B. in the case of hydrogen, it is to be expected that a flame in the combustion chamber will be anchored comparatively close to the nozzle, there is fundamentally the possibility that at certain operating points of the engine an anchor point of the combustion zone is located directly on a trailing edge of the fuel pipe . The end of the fuel pipe should therefore be designed in such a way that, on the one hand, the heat release in the combustion chamber in the immediate vicinity of the end of the fuel pipe is kept low and, on the other hand, sufficient robustness against the heat input from the combustion zone is ensured. In this context, it may be advantageous, for example, to design the fuel pipe at the fuel outlet opening with an edge running around the longitudinal axis of the nozzle, which edge has a radially outwardly inclined chamfer. In a further development, the chamfer can taper to an axial end of the fuel pipe or merge into a blunt end geometry. If the chamfer tapers to a point and the edge of the fuel pipe separates the fuel flow from an air flow in the adjacent air guide duct, a tapered chamfer can have the advantage that the fuel flow and the air flow meet each other tangentially. This allows a high outflow velocity of the two flows from the nozzle to be maintained. The heat release in the area of the anchor point explained above therefore remains low. However, the disadvantage here can be that in the area of a tapered end, heat introduced during operation of the combustion chamber cannot be transported away sufficiently quickly through a heat conduction within the fuel pipe, so that the tapered end runs the risk of being thermally overloaded. Such thermal overload can e.g. B. can be counteracted by a corresponding flow influence, for example through the tangential meeting of fuel and air and the resulting effects on the combustion zone, especially the anchor point of the flame and the local heat release in the anchor point.

If the chamfer changes into a blunt final geometry of the fuel pipe, a small “dead water area” or a small (inner) recirculation zone may arise immediately downstream of the nozzle end, in which the fuel and the incoming air can mix. so that when the combustion chamber is in operation, a comparatively high amount of heat is released locally as a result of combustion. However, with a blunt end geometry, the heat introduced into the edge of the fuel pipe can be better transported away through heat conduction, making it easier to avoid the risk of thermal overload.

In principle, the central fuel pipe can be sealed against the inflow of air. In this way, the fuel can be introduced into the combustion chamber in the nozzle without mixing with air via the fuel pipe which extends centrally in the nozzle main body along the longitudinal axis of the nozzle. In the intended According to the state of the nozzle assembly installed in an engine, the nozzle-side fuel pipe is thus sealed against an inflow of air from a compressor stage of the engine, in particular at an upstream end of the nozzle main body. In the case of a nozzle of a proposed nozzle assembly, there is therefore no premixing of fuel and air within the nozzle. This is particularly advantageous with regard to fuel to be injected in gaseous form and in particular highly flammable hydrogen, since this can reduce the risk of a flame flashback or premature self-ignition of the fuel to be injected. In the case of a nozzle of a proposed nozzle assembly, the fuel to be injected is first mixed with air only downstream of the nozzle end. The fuel is not premixed with air within the nozzle, so that the fuel initially comes out unmixed at the nozzle end and is only mixed with (combustion or mixed) air downstream of the nozzle end.

In one embodiment variant, the nozzle comprises a supply line reservoir connected to the fuel supply line, to which fuel can be supplied from the fuel supply line and from which fuel can be supplied to the fuel pipe. The supply line reservoir is therefore fluidly connected to both the fuel supply line and the fuel pipe, so that the fuel coming from the fuel supply line can flow into the fuel pipe via the supply line reservoir. The feed reservoir is designed, for example, as a cavity in the nozzle holder or the nozzle main body, for example as a cavity with an annular cross-section, in particular an annular shape or a circular cross-section with a circular cross-section. The supply line reservoir can support the most uniform possible introduction of fuel into the fuel pipe, for example by allowing the fuel to flow in from the supply line reservoir via several specifically arranged and z. B. evenly distributed through openings. For example, the feed reservoir is provided in an area of the nozzle which is bordered by an end wall located upstream in relation to a flow direction defined by the fuel pipe along which the fuel is guided within the nozzle main body to the nozzle end. When the nozzle assembly is installed as intended in an engine, such an end wall faces away from the combustion chamber of the combustion chamber. For example, such an upstream supply line reservoir is then formed in a head region of the nozzle main body connected to the nozzle holder. The fuel introduced from the supply reservoir into the fuel pipe can thus be guided in the fuel pipe to the fuel outlet opening over a comparatively large part (more than 60%) of the length of the nozzle main body measured along the nozzle longitudinal axis. In this way, the fuel can be guided to the nozzle end in a targeted manner and, for example, by evening out the fuel flow, if necessary with targeted twisting of the fuel flow.

At least one through opening, through which fuel can flow from the feed reservoir into the fuel pipe, can be set up, for example, for fuel to flow radially inwards into a first pipe section of the fuel pipe. A substantially radially inwardly directed flow into the first pipe section of the fuel pipe is thus made possible via the at least one through opening. One or more fluid connections provided by one or more through openings are therefore provided between the supply line reservoir and the fuel pipe, via which fuel can flow from the supply reservoir essentially radially inwards into the first pipe section and thus into the fuel pipe.

As an alternative to a substantially radial inflow of fuel from the feed reservoir into the fuel pipe, at least one through opening can also be set up for an inflow of fuel essentially in the axial direction into a first pipe section of the fuel pipe. This can happen For example, the at least one through opening extends through a rear wall of the fuel pipe that runs essentially or exactly perpendicular to the nozzle longitudinal axis and borders (limiting) the first pipe section (upstream) or through a partition wall separating the supply line reservoir from the first pipe section.

As already explained at the beginning, the proposed solution is particularly suitable for the injection of different types of fuels. However, especially with regard to the injection of gaseous fuel and in particular hydrogen, the central supply of fuel via a nozzle-side fuel pipe, which is protected from mixing with air, offers particular advantages.

With nozzle assemblies of the above-mentioned structure, an annular combustion chamber with at least one nozzle assembly, in particular according to one of claims 9 to 14, can advantageously be constructed in a combustion chamber ring. Advantageous embodiments consist in that a spark plug is/are integrated in at least one nozzle assembly, preferably at the highest point of the combustion chamber ring, or in several nozzle assemblies or in all nozzle assemblies in the manner mentioned.

The proposed solution also includes an engine with at least one embodiment variant of a proposed nozzle assembly. However, a proposed nozzle assembly can of course also be used in a (stationary) gas turbine.

The attached figures illustrate exemplary possible embodiment variants of the proposed solution.

Show here: 1 shows a detail and a sectional view of a first embodiment variant of a nozzle of a proposed nozzle assembly with a feed reservoir designed as an annular chamber, from which fuel can flow essentially radially inwards into a central fuel pipe of a nozzle main body equipped with a longitudinal flow body;

Figure 2 shows a schematic diagram of a modified embodiment variant of a proposed nozzle assembly, which has two axially spaced flow bodies in the fuel pipe, with an illustration of the circulation zones that can be achieved downstream of the nozzle end;

Figures 3A-3B, in a view corresponding to Figure 1, each show further developments of the embodiment variant of Figure 1;

Figures 4A-4D show schematic representations of embodiment variants of a nozzle main body connected to a nozzle holder with a flow body and an integrated spark plug;

Figure 5 schematic representation of a nozzle main body according to

Version e.g. B. Figure 3B during production in an additive manufacturing process;

Figures 6A-6B in views corresponding to Figures 1, 3A and 3B further embodiment variants of a proposed nozzle assembly, in which two axially spaced flow bodies are provided within the central fuel pipe; Figures 7A-9B show individual versions of different embodiments for a second flow body provided downstream (Figures 7A, 8A and 9A) as well as analogous designs of an end section of a single continuous flow body (Figures 7B, 8B and 9B) for the fuel pipe;

Figures 10A-10B show different views of a second flow body corresponding to the embodiment variants of Figures 6A and 6B, on the outer surface of which several depressions are formed;

Figure 11 shows an end section of a continuous flow body corresponding to Figures 1, 3A and 3B with depressions;

Figure 12 shows a sectional view of a nozzle main body with a nozzle head according to the previous figures without a flow body provided within the central fuel pipe

Figure 13 shows a further development of the embodiment variant of Figure 12 with a radial twister in the outermost air guide duct of the nozzle head;

Figure 14, in a view corresponding to Figure 12, shows the nozzle main body with the nozzle head, illustrating an axial offset between the air outlet openings and the fuel outlet opening at the nozzle end of the nozzle;

Figures 15A-15C show detail and sectional representation of different variants for the design of a final geometry of a downstream edge of the fuel pipe facing the combustion chamber; Figure 16 shows a detail of a possible further development of a nozzle of a proposed nozzle assembly with inlet lips for the two air guide channels on the nozzle head;

Figures 17A-17B show sections and individual representations of different variants for a design of an inner air duct in the area of an inner air outlet opening of the inner air duct;

Figure 18A shows an engine in which an embodiment variant of a proposed nozzle assembly is used;

Figure 18B shows a detail and on an enlarged scale of the combustion chamber of the engine of Figure 17A;

Figure 18C shows the structure of a conventional fuel nozzle with essential components.

18A illustrates schematically and in a sectional view a (turbofan) engine T, in which the individual engine components are arranged one behind the other along a rotation axis or central axis M and the engine T is designed as a turbofan engine. At an inlet or intake E of the engine T, air is moved and compressed along an inlet direction by means of a fan F. This fan F, which is arranged in a fan housing FC, is driven via a rotor shaft S1, which is rotated by a turbine TT of the engine T. The turbine TT is connected to a compressor V, which has, for example, an (optional) medium-pressure compressor 111 and a high-pressure compressor 112, and possibly also a low-pressure compressor (booster). The fan F, on the one hand, supplies air to the compressor V in a primary air flow F1 and, on the other hand, to generate thrust, in a secondary air flow F2 to a secondary flow channel or bypass channel B. The bypass channel B runs around a denser V, a combustion chamber assembly BK and the turbine TT core engine comprising a primary flow duct for the air supplied to the core engine by the fan F.

The air conveyed into the primary flow channel via the compressor V reaches the combustion chamber assembly BK of the core engine, in which thermal energy for driving the turbine TT is generated by combustion of fuel with air flowing in from the compressor V. For this purpose, the turbine TT has a high-pressure turbine 113, an (optional) medium-pressure turbine 114 and a low-pressure turbine 115. The turbine TT drives the rotor shafts S1, S2 and S3 and thus the medium and high pressure compressor as well as the fan F in order to generate thrust via the air conveyed into the bypass channel B. Both the air from the bypass duct B and the exhaust gas-air mixture from the primary flow duct of the core engine flow out via an outlet A at the end of the engine T and both contribute to the overall thrust of the engine. The outlet A usually has a thrust nozzle and a centrally arranged outlet cone C. Constructions are also common in which the air from the bypass channel and the exhaust gas-containing air from the primary flow channel are combined into a single air stream before exiting through outlet A. To achieve this combination, flower mixers are often used, which are arranged within the engine in front of a common exhaust nozzle and the outlet A (not shown).

18B shows a longitudinal section through the combustion chamber assembly BK of the engine T. In particular, a (ring) combustion chamber 103 of the engine T can be seen from this. A nozzle assembly is provided for injecting fuel or an air-fuel mixture into a combustion chamber 1030 of the combustion chamber 103. This comprises a combustion chamber ring R, on which several nozzles D are arranged on a combustion chamber head of the combustion chamber along a circular line around the central axis M. One or more burner seals BD with bearing openings are provided on the combustion chamber ring R, on which nozzle heads of the respective nozzles D are held so that fuel can be injected into the combustion chamber 103. Each nozzle D includes a flange via which a nozzle holder DH of the nozzle D is screwed to an outer housing G of the combustion chamber assembly BK.

Figure 18C shows schematically a structure of a conventional nozzle assembly installed by means of a nozzle holder DH with its essential components. There is an inner air duct IL with an inner swirler ID and an outer air duct AL with an outer swirler AD. Furthermore, an outer air duct 6, a central air duct 7, a central swirler 8 and a fuel injection 9 with a fuel supply line 1 are provided in order to supply fuel via a fuel ring reservoir 11 and a fuel distribution 12. A burner seal BR is present on a combustion chamber head 14.

Conventional nozzles D for an engine T are typically for the injection of liquid fuel, such as. B. kerosene or diesel, and for this purpose have a central first air duct and at least one further radially outer second air duct and a fuel duct which is provided between the two air ducts. Fuel emerging from a fuel outlet opening of such a fuel guide channel is then already mixed at the nozzle with air from the first central air guide channel and possibly also with the air from the air guide channel located radially further out, so that a fuel-air mixture is produced at one nozzle end of the nozzle D is provided.

Such a configuration of a nozzle D may be disadvantageous in particular for fuel, in particular hydrogen, to be injected in gaseous form into a combustion chamber 1030 of the combustion chamber 1031. A nozzle assembly with a nozzle D according to the proposed solution provides a remedy here, for which different embodiment variants are illustrated in FIGS. 1 to 17B. In each case, it is provided that a central fuel pipe 3 is provided on a nozzle main body DR of the nozzle D, extending along a nozzle longitudinal axis L and sealed against an inflow of air, via which fuel is delivered within the nozzle main body DR to a nozzle end of the nozzle D provided fuel outlet opening 33 of the fuel pipe 3 can be guided. The fuel can then be introduced from the fuel outlet opening 33 into the combustion chamber 1030 for initial mixing with air.

In a first embodiment variant according to FIG. 1, the central fuel pipe 3 of a nozzle D is supplied with fuel via a supply reservoir in the form of an annular chamber 2A. This annular chamber 2A extends in a ring shape around a first pipe section 3A of the fuel pipe 3 at a head region of the nozzle D, which is connected to the nozzle holder DH, and is supplied with fuel via a fuel supply line 1 which runs in the nozzle holder DH. Fuel from the fuel supply line 1 thus first reaches the annular chamber 2A via a supply opening in the fuel supply line 1, from which the fuel can flow further into the first pipe section 3A of the fuel pipe 3. The fuel flows from the annular chamber 2A via through openings 23 distributed around the circumference on an inner wall W of the first pipe section 3A, substantially radially inwards to the nozzle longitudinal axis L, into the first pipe section 3A.

The fuel pipe 3 is sealed on the end face facing away from the combustion chamber 1030 with a continuous end wall DW of the nozzle D against air coming from the compressor V of the engine T. Fuel fed into the fuel pipe 3 from the fuel supply line 1 is also conveyed unmixed to the nozzle end of the nozzle D within the nozzle main body DR, i.e. without mixing with air. The fuel fed radially from the annular chamber 2A into the fuel pipe 3 flows from the first pipe section 3A, which defines an antechamber within the fuel pipe 3, in the axial direction into a second pipe section 3B, with a centrally arranged within the fuel pipe 3 Flow body 30. The fuel flows along this flow body 30 up to the fuel outlet opening 33 of the fuel pipe 3 at the nozzle end.

In this case, the central flow body 30 is designed in the shape of a peg and thus defines the second pipe section 3B, which is annular in cross-section (and thus an annular space that adjoins the first pipe section 3A axially), in which the fuel is guided along the nozzle longitudinal axis L to the fuel outlet opening 33. The fuel flow can be evened out across the cross section via the flow body 30. In addition, the flow body 30 has, at a downstream end 301, a guide collar 3010 which serves as a guide element and through which the nozzle outlet opening 33 is narrowed in order to accelerate the emerging fuel flow. In addition, the emerging fuel flow is directed radially outwards via the guide collar 3010.

The fuel injected in this way is only mixed with air downstream of the fuel outlet opening 33 within the combustion chamber 1030, which is introduced into the combustion chamber 1030 via two air guide channels 4 and 5 on a nozzle head DK of the nozzle D. A first air guide duct 4 is designed as a comparatively narrow annular gap radially on the outside of the central fuel pipe 3 on the nozzle head DK. Radially further out, the further air duct 5 is present as the radially outermost air duct on the nozzle head DK. Air outlet openings of the two air ducts 4, 5 are axially set back relative to the fuel outlet opening 33, so that the end of the fuel pipe 3 and thus the fuel outlet opening 33 is axially opposite the air outlet openings of the two air ducts 4 and 5, based on the flow direction of the fuel defined by the fuel pipe 3 protrudes (cf. also Figure 14, which will be explained in more detail below). Inner and outer walls 43 and 45 bordering the first air duct 4 thus end further upstream than the fuel pipe 3. The same applies to a radially further outermost wall 55 for the further, radially outermost air duct 5. In the radially outermost air duct 5, which has a channel width that is many times larger than the first air duct 4, swirl elements in the form of axial air swirlers 51 are provided in the embodiment variant of FIG. This creates an external swirling air flow. (Optionally, the inner air duct 4 can also be equipped with swirl elements, but the swirl imparted to the air here is less than that in the outer air duct 5).

Likewise, a wired fuel flow can be generated via axial fuel swirlers 31 within the second pipe section 3B of the fuel pipe 3, which flows into the combustion chamber 1030 at the fuel outlet opening 33. In the embodiment variant of FIG Flow body 30 continues to flow and then guided radially past the flow body 30 into the second pipe section of the fuel pipe 3 with the fuel swirlers 31. The fuel flow guided on the flow body 30 over a large part of the length of the nozzle main body DR measured along the nozzle longitudinal axis L remains unmixed until it exits at the fuel outlet opening 33 and only meets the air flows from the two air guide channels 4 and 4 located radially further outwards downstream of the nozzle D 5.

The central, sealed guidance of the fuel in the fuel pipe 3 with the flow body 30 is particularly advantageous for highly flammable hydrogen in order to avoid flashbacks and premature self-ignition in the vicinity of the nozzle. The air flows provided via the air guide channels 4 and 5 also ensure an advantageous recirculation zone formation downstream of the nozzle D in the combustion chamber 1030. Figure 2 illustrates the flows downstream of the nozzle end to be realized with a nozzle D of the proposed nozzle assembly. In contrast to the nozzle D of FIG. 1, no individual longitudinally extending, peg-shaped flow body 30 is provided within the fuel pipe 3. Rather, two axially spaced first and second flow bodies 30A and 30B are provided here within the fuel pipe 3. In the embodiment variants of FIG. 2, the fuel flows from the annular space of the first pipe section 3A further through a second pipe section 3B in the direction of the fuel outlet opening 33, which is designed as a flow space with a circular cross section. Only towards the end of the fuel pipe 3 does the fuel hit the further (second) downstream flow body 30B, which here is conical (with the tip of the cone pointing towards the first, upstream flow body 30A). Via the corresponding, radially widening shape of the conical flow body 30B towards its end 301, the fuel outlet opening 33 of the fuel pipe 3 is narrowed and also directed radially outwards.

In the present case, the first upstream flow body 30A is also designed in the manner of a hub pin in the area of the fuel distributor 31 on the fuel pipe side. The downstream second flow body 30B faces the combustion chamber 1030 with its blunt and essentially flat end face 301S. Such a blunt end face 301S is also provided at the downstream end 301 of the continuous flow body 30 in FIG. As a result, largely identical flow curves can then be achieved.

2, the respective flow body 30 or 30B located at the fuel outlet opening 33, in particular with its blunt end face 301S, supports the formation of a stable recirculating combustion zone VBZ downstream of the nozzle D. Immediately in a near field behind the nozzle end D and thus downstream of the blunt end face 301 S of the respective flow body 30 or 30B, an inner deer circulation zone IRZ is created. In this inner deer circulation zone IRZ there is a comparatively large fuel concentration, which means that the combustion temperatures during operation of the engine T in the near field of the nozzle D are to be kept low. This results in a kind of “dead water area” with a lower proportion of combustion or mixed air in an inner recirculation zone IRZ.

This is supported in particular by the inner and outer air guide channels 4 and 5 of the nozzle D which adjoin the nozzle head DK of the nozzle D in the radial direction on the outside. Air is injected into the combustion chamber 1030 with a comparatively large axial impulse and low swirl from the inner air outlet opening of the radially inner air guide duct 4, which is designed as a narrow annular gap. The air flow from the air outlet opening, which is also designed as an annular gap (with a larger cross-sectional area through which flows) of the radially outermost air guide duct 5, is in turn subject to strong swirling. As a result, the air flow generated in this way envelops the central fuel flow, draws it in radially and thus creates a recirculation zone downstream of the nozzle D in which air and fuel mix and which then forms the swirl-stabilized, recirculating combustion zone VBZ.

The air flow enveloping the recirculating combustion zone VBZ also creates an air-rich zone in the front area of the combustion chamber 103 around the nozzle end of the nozzle D, which is marked in FIG. 2 as the outer recirculation zone ORZ. The air flow in this outer recirculation zone ORZ thermally protects the nozzle D and a front combustion chamber wall of the combustion chamber 103 from the recirculating combustion zone VBZ.

Different designs of the fuel pipe 3, the air guide channels 4, 5 and in particular the flow body 30 or 30B within the fuel pipe 3 can be selected to influence the flow conditions without deviating from the proposed solution, for example with regard to the design. tion of the combustion chamber 103, the specification of different operating parameters of the engine T (e.g. example with regard to transient operating states, such as when accelerating and decelerating the engine T), the setting of certain flame shapes and flame positions, the reduction of pollutants formed, such as. B. of nitrogen oxides, and the reduction of thermal loads occurring on parts of the nozzle D and / or on the combustion chamber 103.

3A, for example, the central, peg-shaped flow body 30 is guided within the fuel pipe 3 upstream to a rear wall of the fuel pipe 3 or even to the end wall DW of the nozzle D. The fuel pipe 3 thus has an annular cross section throughout along the nozzle longitudinal axis L.

3A, radially extending support struts 303 are provided in the region of the upstream end 301 of the flow body 3 (as in the variant of FIG. 1) in order to stabilize the rotationally symmetrical flow body 30 in the region of the fuel outlet opening 33 and with the pipe walls of the fuel pipe 3 to connect. In the present case, the support struts 303 are positioned so that a swirl impressed or generated upstream of the air flow is not reduced or even destroyed. Incidentally, one or more support struts 303 do not necessarily have to be formed close to the outlet of the fuel pipe 3, but can also be located further upstream, so that the flow in a subsequent (last) section of the fuel pipe 3 - after the disruption caused by the support struts 303 - can homogenize again. In the further development of FIG. 3B, the support struts 303 have been omitted. Only further upstream is a radial connection between the flow body 30 and the pipe wall of the fuel pipe 3 via the fuel swirlers 31.

An advantageous embodiment variant of the nozzle assembly for a defined ignition of the gas-air mixture during the central injection of the gaseous power Substance, in particular hydrogen, is shown in Figures 4A to 4D. Here, an ignition element in the form of a spark plug 20 is integrated into the flow body 30, which is designed in particular as explained above and below and is arranged in the nozzle assembly. The nozzle main body DR is connected to the nozzle holder DH, through which the fuel supply line 1 is guided, which in the present case is connected to a central gas distribution chamber for supplying fuel. The gas injection channel 16 and the flow body 30 are arranged centrally in the fuel pipe 3. The first (and in the embodiment according to FIGS. 4A, 4C, 4D the only) air channel 4, in which the axial air swirler 51 is arranged, is formed in an annular gap around the fuel pipe 3. The spark plug 20 is inserted into a coaxial cavity of the flow body 30 that is open towards the combustion chamber and is connected to a rear cable connection 25 (see FIG. 4C) with an ignition cable 19, which runs through a rear section of the flow body 30 and a support structure for fixing the flow body 30 in the fuel pipe 3, like support strut 303, is guided into a feed channel of the nozzle holder 1 for connection to an electrical supply or control device (not shown here).

4C shows, the spark plug 20 has a central electrode 21 surrounded by an insulator 29 and a ground electrode 22 and is advantageously screwed with a thread 24 into a complementary receiving thread of the flow body 30. In the cavity 27 of the flow body 30 which has the spark plug 20, the cable connection is located on the back of the spark plug 20 facing away from the combustion chamber 103. B. provided with a cable reel 26.

The spark plug 20 can be a small, compact version, e.g. B. with a candle length LK in the range between 20 mm and 40 mm, for example between 25 mm and 35 mm (typically with approx. 28 mm) with a diameter between approx. 6 mm and 12 mm, with an inner clear diameter D0 of the cavity is selected in coordination with the spark plug 20 and z. B. 8 mm and an average diameter D1 in the thread base e.g. B. 9 mm, with an outer one Diameter D2 of the nozzle head DK around the (here only one) air duct 4 outside z. B. 30 mm to 50 mm, for example about 36 mm. The flow body 30 in the area of the fuel outlet opening 33 can also be provided with differently designed gas outlet channels 28, such as. B. shown in Figure 4D in the four adjacent illustrations and further shown in connection with the above and subsequent exemplary embodiments.

The fuel is therefore introduced into the combustion chamber 1030 through the central fuel pipe 3. To optimize and fine-tune the fuel flow introduced into the combustion chamber 1030, the fuel pipe 3 can, as shown, be provided with a combination of different structures in order to form a suitable fuel flow, for example also by means of an axial fuel swirler, which applies an angular momentum to the fuel flow . The hub of the axial fuel swirler serves, for example, B. a rotationally symmetrical body, up to the area of the exit plane of the fuel pipe 3 (possibly a few mm beyond), which can be designed as an extension of the hub of the axial fuel swirler, and with additional support struts 303 at the end of the central fuel pipe 3 or also is provided without such struts, such as B. explained with reference to Figure 3A.

The spark plug 20 inserted in the central flow body 30 in the cavity 27 is sealed from the environment. Such as B. can be seen from Figures 4A and 4B, the nozzle main body DR can have one or more air channels 4, 5. These can also be provided with support elements, with or without swirl generation. One of these support elements can be used to pass through the ignition cable 19 or supply cable (if necessary additionally).

The spark plug sits axially appropriately in the flow body 30, so that an optimized interaction with the gaseous fuel and, for ignition, with the gas-air mixture is achieved. The particularly blunt flow body 30, the air supply Guidance via the at least one air duct 4, 5 and the supply of the gaseous fuel, in particular hydrogen, lead to the recirculation of the gas-air mixture towards the front ignition section or the tip of the spark plug 20. This is achieved by the design presented, also supported in an optimized manner in coordination with the installation conditions.

In the case of an annular combustion chamber with a number of fuel nozzles arranged in a combustion chamber ring R, any number of nozzles or nozzle assemblies of the structure mentioned can be equipped with a spark plug 20, for example with only one, in particular at or near the highest point of the combustion chamber 103 (since gas is lighter than air), or with several, e.g. B. evenly distributed over the circumference, or by arrangement in every second nozzle assembly or grouped in the nozzle assemblies, or integrated in all nozzle assemblies.

With a view to the production of a fuel pipe 3 with a central flow body 30, which should not have any support struts 303 in the area of its end 301 facing the combustion chamber 1030, Figure 5 illustrates a possible additive manufacturing process for the nozzle main body DR with the internal fuel pipe 3. This is how it is Here the nozzle main body DR with the flow body 30 located within the fuel pipe 3 is constructed from the nozzle end, which faces the combustion chamber 1030 when installed as intended. The nozzle main body DR is built up in layers on a construction plate P and a support structure ST provided thereon along a vertical construction direction AR, which runs parallel to the nozzle longitudinal axis L, but opposite to the later flow direction of the fuel through the fuel pipe 3. The nozzle main body DR with the flow body 30 is consequently built up additively here as an integral component along the vertical on the mounting plate P. Building on the embodiment variant of FIG. The first upstream flow body 30A, which is cone-shaped and is provided in the area of the fuel swirler 31 in the manner of a hub body, does not extend beyond half the length of the fuel pipe 3. The second flow body 30B, which is arranged further downstream, is each conical and defines the fuel outlet opening 33. The fuel pipe 3 is locally narrowed in the area of the fuel outlet opening 33 via the second flow body 30B. Here, the respective flow body 30B is conical, with the blunt end face 301S facing the combustion chamber 1030 and the tapered end lying upstream and pointing in the direction of the first flow body 30A. While in the embodiment variant of FIG. 6A the tapering end facing the first flow body 30A tapers to a point, in the embodiment variant of FIG. 6B this end is convexly curved. This can be accompanied by a desired flow influence in the direction of the fuel outlet opening 33. The end shown in FIG. 6B is merely an example of an aerodynamically optimized shape. Other aerodynamically advantageous shapes are of course also possible, such as ovoid, ogive, hemisphere or cone (with an optional blunt or rounded tip).

Regardless of the use of a single continuous flow body 30 or two axially offset flow bodies 30A, 30B within the fuel pipe 3, in the embodiment variants shown, provision is made in each case for a local narrowing of the fuel outlet opening 33 via the respective flow body 30 or 30B provided in the area of the fuel outlet opening 33 is realized in order to accelerate the fuel flow as it flows into the combustion chamber 1030. The respective flow body 30, 30B is then designed accordingly so that the diameter is expanded at the end of the fuel pipe 3, in order to direct the fuel flow radially outwards, is at least compensated or even overcompensated by an expansion of the flow body 30 or 30B towards its end. In this way, an annular gap in the fuel outlet opening 33 tapers towards the end of the nozzle.

The individual representations of Figures 7A to 9B illustrate different options for providing additional protruding sections 304 on an outer lateral surface of the respective flow body 30B or 30 (at least in the area of the end 301 near the fuel outlet opening). In the embodiment variants of FIGS. 7A and 7B, for example, protruding ribs 304 are provided, which run circumferentially around the nozzle longitudinal axis L and are axially spaced apart from one another. This can be used to improve heat transfer from the typically metallic flow body 30B or 30 to the fuel that can be used for cooling.

In addition, based on the embodiment variant of Figures 7A and 7B it can be seen that the blunt end face 301S does not necessarily have to be completely flat, but can also be concave (in the direction of the interior of the fuel pipe 3).

In the embodiment variant of Figures 8A and 8B, individual ribs 304 on an outer lateral surface of the respective flow body 30B or 30 are spaced apart from one another in the circumferential direction about the nozzle longitudinal axis L and are each designed to extend longitudinally. In addition, a convex curvature of the blunt end face 301 S is provided here as an example.

In the embodiment variant of Figures 9A and 9B, in a modification of the embodiment variants of Figures 7A to 8B, a rib structure with ribs 304 is provided on a respective outer lateral surface of a flow body 30B or 30, each of which is oblique to the nozzle longitudinal axis L and thus, for example, a section following a spiral around the nozzle longitudinal axis L (ie helically) along the lateral surface. In particular, in such an embodiment variant, not only heat transfer between the hotter metal of the respective flow body 30B or 30 and the cooler fuel can be intensified via the resulting rib pattern during operation of the engine T. Rather, a radial movement component can also be (additionally) impressed on the fuel flow via the respective rib structure. The protruding ribs 304 of Figures 9A and 9B are consequently arranged on the outer lateral surface in such a way that any swirl that has already been specifically imposed on the fuel flow is not counteracted or such a swirl may even be supported.

Figures 10A and 10B show different views of an alternative surface treatment of the lateral surface of the second conical flow body 30B. Here, a plurality of depressions 305, for example in the form of bores or dents, are provided on the lateral surface around which the flow flows. This also positively influences the flow along the lateral surface of the flow body 30B with a view to improved heat transfer.

Figure 11 shows a design analogous to the variant in Figures 10A and 10B of a continuous flow body 30 with a plurality of equally distributed depressions 305 on its outer surface.

Figures 12 and 13 show examples of two different configurations of the nozzle main body DR with the nozzle head DK without a flow body arranged within the fuel pipe 3. In contrast to the embodiment variant of FIG. 12, no axial twister 51 is provided in the radially outermost air guide duct 5 of the embodiment variant of FIG. 13. Rather, one or more radial twisters 52 are arranged here within the radially outermost air guide duct 5. Regardless of the use of axial twisters 51 or radial twisters 52 and also regardless of the use of one or more flow bodies 30 or 30A/30B, there is an axial offset at the nozzle end of a proposed nozzle D between the individual air outlet openings of the first and second air guide channels 4 and 5 as well as the Power outlet opening 33 of the fuel pipe 3. Here, for example, an (outflow) edge of the fuel pipe 3 projects axially furthest along the nozzle longitudinal axis L, so that its fuel outlet opening lies in the area of a first virtual (exit) plane E3, which runs perpendicular to the nozzle longitudinal axis L and lies further downstream than further virtual levels E1 and E2, in which the air outlet openings of the radially outermost air duct 5 and the inner air duct 4 are located. The level E3 of the central fuel pipe 3 therefore projects deepest into the combustion chamber 1030. The exit plane E2 of the inner air guide duct 4, which adjoins radially further out, is aligned with this or is - as shown in Figure 14 - axially set back and therefore penetrates slightly less into the combustion chamber 1030. In the present case, the air outlet opening of the radially outermost air guide duct 5 with the air swirler 51 (or 52) is set back the furthest axially. In principle, e3 > e2 > e1 can apply to penetration depths e3, e2, e1 of the respective outlet openings or channels and pipes. The (exit) level E3 of the fuel pipe res 3 is therefore the furthest in the combustion chamber 1030 and therefore penetrates the furthest into the combustion chamber 1030. The (exit) level E2 of the inner air duct 4 is on the same level as this level E3 or penetrates slightly less into the combustion chamber 1030, while the (exit) level 1 of the outermost air duct 5, which serves for (stronger) air swirl, with the inner one Air duct 4 ends at the same level or penetrates slightly less into the combustion chamber 1030.

The axial offset of the air outlet and fuel outlet openings can, for example, make it possible to reduce thermal stress on the components of the nozzle D at the nozzle end. This creates zones in which fuel and air come into contact with one another and heat can be released as a result of a chemical combustion reaction, further downstream from the nozzle D. The interaction of the individual flow paths with one another, in particular the influence of any swirl that may be imposed, can be adjusted more precisely via the set axial offset. This can be particularly advantageous for any adjustment of the stability behavior of the burner, the flame shape and flame position, the pollutant formation rate (in the case of hydrogen with regard to nitrogen oxides) and a thermal load on the nozzle D and the combustion chamber 103.

In principle, the combustion chamber end of the central fuel pipe 3 in the area of the fuel outlet opening 33 can be designed differently geometrically. But especially with a view to a fuel to be injected in gaseous form with fast reaction kinetics, such as. B. hydrogen, it must be taken into account that a flame can anchor itself very close to the nozzle end of the nozzle D. In particular, at certain operating points of the engine T, a corresponding anchor point of the recirculating combustion zone VBZ can be located directly on the trailing edge of the fuel pipe 3. Against this background, Figures 15A, 15B and 15C illustrate exemplary different design options for an edge of the fuel pipe 3 that faces the combustion chamber 1030 and borders the fuel outlet opening 33.

In the embodiment variant of Figure 15A, the fuel pipe 3 has a radially outwardly inclined chamfer 330 on the edge surrounding the nozzle longitudinal axis L, which tapers to a point towards the axial end of the fuel pipe 3. Such a tapered chamfer 330 has the advantage that the fuel and air flows meet each other tangentially. As a result, a comparatively high outflow velocity of the flows from the nozzle D is maintained and the heat release in the area of the anchor point mentioned above remains low. However, the tapered chamfer 330 can be disadvantageous in view of the fact that heat introduced in the area of the tip cannot be dissipated sufficiently quickly via the pipe wall of the fuel pipe 3. This can pose a danger This means that the tip will be thermally overloaded during operation of the engine T if no further measures are taken.

Figures 15B and 15C show an alternative design of a final geometry of the fuel pipe 3. Here, the radially outwardly inclined chamfer 330 merges into a blunt final geometry. While in the embodiment variant of Figure 15B a transition into a curve is provided, the final geometry of the embodiment variant of Figure 15C opens into a blunt final plane. In both variants of Figures 15B and 15C, fuel and air flows no longer meet one another in such an (ideal) tangential manner as in the variant of Figure 15A. Rather, the blunt end geometry creates a small “dead water area” downstream of the end geometry, in which fuel and air can mix and in which a locally high level of heat release can occur as a result of combustion. However, the heat introduced into the final geometry can be better transported away by heat conduction in the pipe wall of the fuel pipe than in the case of a tapered chamfer 330 according to FIG. 15A.

In order to support the supply of air into the air channels 4 and 5 on the nozzle head DK of the nozzle D, a possible development according to FIG. 16 provides that inlet lips 450 and 550 are formed on the outer wall 45 and the outermost wall 55 upstream. Via these inlet lips 450 and 550, air from the compressor V, which flows past the nozzle main body DR, is directed radially inwards into the air guide channels 4 and 5. In this way, in particular, any adverse flow into the air ducts 4 and 5 can be effectively counteracted by a comparatively thick head region of the nozzle main body DR, so that a sufficiently large amount of air still reaches the air ducts 4 and 5.

The detailed view in Figures 17A and 17B illustrate possible designs of an end region of the radially inner air guide duct 4. In both versions, 17A and 17B, a local narrowing of the inner air duct 4 towards its air outlet opening is provided. Sections of the inner and outer walls 43 and 45 are thus brought closer to one another in the area of the air outlet opening. The inner air duct 4 thus narrows in the shape of a nozzle in order to further increase the exit speed of the inflowing air. Figure 17B also shows a slight radial deflection of the air flow in the direction of the nozzle longitudinal axis L.

It is understood that the proposed solution is not limited to the embodiments described above and various modifications and improvements can be made without departing from the concepts described herein. Any of the features may be used separately or in combination with any other features unless they are mutually exclusive, and the disclosure extends to and includes all combinations and subcombinations of one or more features described herein.

Reference symbol list

1 fuel supply line

103 combustion chamber

1030 combustion chamber

11 Fuel ring reservoir

111 low pressure compressor

112 high pressure compressors

113 high pressure turbine

114 medium pressure turbine

115 low pressure turbine

12 fuel distribution line

14 combustion chamber head

15 central gas distribution chamber

16 gas injection channel (designed as a fuel pipe)

19 ignition cables

20 spark plug

21 central electrode

22 ground electrode

23 passage opening

24 threads

25 cable connection

26 cable roll

27 Spark plug cavity

28 gas channels

29 insulator

2A annular chamber (supply reservoir)

3 fuel pipe 3A, 3B pipe section

30, 30A, 30B flow bodies

300, 301 end

3010 guide collar (guide element)

301 S front side

303 support strut

304 rib

305 deepening

31 fuel swirler (swirl element)

33 Fuel outlet opening

330 bevel

4 First air duct / annular gap

43 Inner wall

45 Outer wall

450 inlet lip

5 Second air duct

51 Axial air swirler (swirl element)

52 Radial air swirler (swirl element)

55 Outermost wall

550 inlet lip

6 external air duct

7 middle air duct

8 medium twisters

9 fuel injection

A outlet

AR construction direction

AL external air duct

AD outer twister

B bypass channel

BK combustion chamber assembly BR burner gasket

C outlet cone

D nozzle

DO inner diameter

D1 medium diameter

D2 outer diameter

DH nozzle holder

DK nozzle head

DR nozzle main body

DW front wall

E Inlet / Intake

E1, E2, E3 (exit) level

F fan

F1, F2 fluid flow

FC fan housing

G outer casing

ID inner twister

IL inner air duct

IRZ inner recirculation zone

L nozzle longitudinal axis

LK candle length

M central axis / rotation axis

ORZ Outer recirculation zone

P assembly plate

R combustion chamber ring

S rotor shaft

ST support structure

T (turbofan) engine

TT turbine

V compressor VBZ Recirculating combustion zone

W interior wall

Claims

Expectations

1. Nozzle assembly for a combustion chamber (103) of an engine (T), with at least one nozzle (D) for injecting fuel into a combustion chamber (1030) of the combustion chamber (103), the nozzle (D) extending along a nozzle longitudinal axis ( L) extending nozzle main body (DR) with nozzle head (DK) and a nozzle holder (DH) connected to the nozzle main body (DR) and having at least one fuel supply line (1), characterized in that the nozzle main body (DR) has a central, located along the Fuel pipe (3) extending along the nozzle longitudinal axis (L) and at least two radially spaced air guide channels (4, 5) each with at least one air outlet opening are provided on the nozzle head (DK).

2. Nozzle assembly according to claim 1, characterized in that the fuel pipe (3) with its fuel outlet opening (33) projects axially relative to the air outlet openings, based on the nozzle longitudinal axis (L).

3. Nozzle assembly according to claim 1 or 2, characterized in that an outer air outlet opening of a radially outermost air duct (5) of the at least two air ducts (4, 5) has a larger cross-sectional area than an inner air outlet opening of an inner air duct (4) of the at least two air ducts (4, 5), which is on the nozzle head (DK) between the radially outermost air duct (5) and a section of the fuel pipe (3).

4. Nozzle assembly according to claim 3, characterized in that the outer air outlet opening has a cross-sectional area that is at least a factor of 2 larger than the inner air outlet opening.

5. Nozzle assembly according to one of the preceding claims, characterized in that a radially inner air duct (4) of the two air ducts (4, 5) is set up and provided to provide a non-swirl air flow into the combustion chamber (1030) or the radially inner air duct ( 4) is set up and provided to provide an air flow into the combustion chamber (1030) which has at least a lower swirl than an air flow which flows into the combustion chamber (1030) via a radially outermost air duct (5) of the two air ducts (4, 5). provided.

6. Nozzle assembly according to one of the preceding claims, characterized in that at least in a radially outermost air duct (5) of the at least two air ducts (4, 5) one or more axial or radial swirlers (51, 52) for in the combustion chamber (1030) Air to flow in are provided.

7. Nozzle assembly according to one of the preceding claims, characterized in that one or more radially inwardly pointing inlet lips (450, 550) are provided at least on a radially outermost air duct (5) of the at least two air ducts (4, 5) in order to draw air in the radially outermost air duct (5) and/or a radially inner air duct (4) of the two air ducts (4, 5). Nozzle assembly according to one of the preceding claims, characterized in that a radially inner air duct (4) of the two air ducts (4, 5) narrows towards its air outlet opening. Nozzle assembly for a combustion chamber (103) of an engine (T), in particular according to one of the preceding claims, with at least one nozzle (D) for injecting fuel into a combustion chamber (1030) of the combustion chamber (103), the nozzle (D) being one A nozzle main body (DR) with a nozzle head (DK) extending along a nozzle longitudinal axis (L) and a nozzle holder (DH) connected to the nozzle main body (DR) and having at least one fuel supply line (1), characterized in that the nozzle main body (DR). central fuel pipe (3) extending along the nozzle longitudinal axis (L), in which at least one centrally arranged flow body (30; 30A, 30B) is provided, on the outer surface of which fuel is supplied along the fuel pipe (3) in the direction of a fuel outlet opening ( 33) of the fuel pipe (3) can flow, via which the fuel can be introduced into the combustion chamber (1030). Nozzle assembly according to claim 9, characterized in that the flow body (30; 30B) extends with one end (301) up to a nozzle end of the nozzle (D). Nozzle assembly according to claim 9 or 10, characterized in that a spark plug (20) is integrated into the fuel pipe (3), in particular into the flow body (30, 30B), with its front ignition section facing the combustion chamber (103).

12. Nozzle assembly according to claim 11, characterized in that the spark plug (20) is accommodated in a central cavity (27) of the flow body (30, 30B).

13. Nozzle assembly according to claim 11 or 12, characterized in that a cable connection for electrically controlling the spark plug (20) through the flow body (30, 30B) and optionally a support element, in particular a support strut (303), which holds it in the fuel pipe (3). Supporting structure and through the nozzle holder (DH).

14. Nozzle assembly according to claim 11 or 12, characterized in that the flow body (30, 30B) which is blunt towards the combustion chamber (103), the area of the fuel outlet opening (33) and the area of at least one air outlet opening, in particular in the nozzle body ( DR) arranged air guide duct (4, 5) are designed and coordinated with one another in such a way that the air supply and the gas supply into the combustion chamber (103) lead to a recirculation of the gas-air mixture towards the ignition section of the spark plug (20).

15. Nozzle assembly according to one of claims to 14, characterized in that the flow body (30; 30B) has an end (301) facing the combustion chamber (1030) with a guide element (3010) via which the fuel Fuel emerging from the outlet opening (33) is directed radially outwards in relation to the nozzle longitudinal axis (L).

16. Nozzle assembly according to one of claims 9 or 15, characterized in that the flow body (30; 30B) has an end face (301S) which is at least partially blunt and faces the combustion chamber (1030).

17. Nozzle assembly according to claim 16, characterized in that the end face (301 S) is designed to be essentially planar, convex or concave, at least in some areas.

18. Nozzle assembly according to one of claims 9 to 17, characterized in that the fuel outlet opening (33) at the nozzle end is designed as an annular gap and / or locally narrowed via the flow body (30; 30B).

19. Nozzle assembly according to one of claims 9 to 18, characterized in that the flow body (30; 30A, 30B) is conical or conical.

20. Nozzle assembly according to one of claims 9 to 19, characterized in that the flow body (30; 30A, 30B) is designed symmetrically to the nozzle longitudinal axis (L), in particular rotationally symmetrical to the nozzle longitudinal axis (L).

21. Nozzle assembly according to one of claims 9 to 20, characterized in that the flow body (30; 30A) is connected to an end wall (DW) of the nozzle (D) or a rear wall of the fuel pipe (3).

22. Nozzle assembly according to one of claims 9 to 21, characterized in that within the fuel pipe (3) there are two flow bodies (30A, 30B) which are axially spaced apart from one another with respect to the nozzle longitudinal axis (L).

23. Nozzle assembly according to one of claims 9 to 22, characterized in that the flow body (30; 30A, 30B) comprises a plurality of projecting sections (304) on its outer surface.

24. Nozzle assembly according to one of claims 9 to 23, characterized in that the flow body (30; 30A, 30B) comprises a plurality of depressions (305) on its outer surface.

25. Nozzle assembly according to one of the preceding claims, characterized in that the fuel pipe (3) at the fuel outlet opening (33) has an edge running around the nozzle longitudinal axis (L) with a radially outwardly inclined chamfer (330).

26. Nozzle assembly according to claim 25, characterized in that the chamfer (330) tapers to an axial end of the fuel pipe (3) or merges into a blunt end geometry. 27. Nozzle assembly according to one of the preceding claims, characterized in that the fuel pipe (3) is sealed against an inflow of air.

28. Nozzle assembly according to one of the preceding claims, characterized in that the nozzle (D) is set up and provided for injecting gaseous fuel, in particular hydrogen.

29. Annular combustion chamber with at least one nozzle assembly of the structure according to one of the preceding claims, in particular according to one of claims 1 to 14, in a combustion chamber ring (R).

30. Annular combustion chamber according to claim 29, characterized in that a spark plug (20) is/are integrated in at least one nozzle assembly, in particular at the highest point of the combustion chamber ring (K), in several nozzle assemblies or in all nozzle assemblies.

31. Engine with at least one nozzle assembly according to one of the preceding claims.

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