Supply device, burner system, and method

Abstract

The invention relates to a supply device (1), in particular for use in a gas turbine, for supplying an oxidizing agent (38) and fuel (27) to a combustion chamber (3) without a swirling flow, comprising a supply nozzle (10) with a nozzle channel (14), in particular a cylindrical nozzle channel, which is delimited by a nozzle wall (16) and is oriented along a longitudinal axis (L) and which leads to a fuel chamber-side outlet opening (12) so as to adjoin the combustion chamber (3), and an injector element (24) for adding the fuel (27) into the nozzle channel (14) at an injection point (26). A stable operation using the supply device is achieved in that the injector element (24) is designed to supply liquid fuel (27), and a prefilming device (18), in particular a cylindrical prefilming device, which surrounds the injector element (24) is arranged radially between the injector element (24) and the nozzle wall (16), wherein an outer channel (30) is formed between the nozzle wall (16) and the radial exterior of the prefilming device (18), and an inner channel (34) is formed radially within the prefilming device (18), in particular between the radial interior of the prefilming device (18) and the injector element (24).

Description

[0001] The invention relates to a feed device, particularly for use in a gas turbine, for the swirl-free supply of oxidizer and fuel to a combustion chamber, comprising a feed nozzle with a nozzle channel, in particular cylindrical, enclosed by a nozzle wall and aligned along a longitudinal axis L, which opens into a combustion chamber-side outlet opening adjacent to the combustion chamber, and an injector element for adding the fuel into the nozzle channel. The invention further relates to a burner system with a feed device and a method for the swirl-free supply of oxidizer and fuel to a combustion chamber.

[0002] Such burner systems with at least one such feed device are also known as recirculation-stabilized jet flame burners for non-swirling high-velocity combustion, or FLOX® burner systems. One such burner system is described, for example, in EP 1 918 641 A2. In this system, the combustion zone in the combustion chamber is stabilized during operation by a large-scale, internal recirculation of exhaust gas, which is generated by the introduction of oxidizer / fuel jets with a sufficiently high axial impulse into the combustion chamber. The recirculation returns the combusted, hot exhaust gas to the jet root near the feed nozzles and mixes it with the incoming fresh gases. With a known annular arrangement of the feed nozzles, the recirculation zone typically forms essentially radially within the nozzle ring.

[0003] EP 0 769 655 A2 discloses an airblast atomizing nozzle for operating a burner fueled by liquid fuels. The nozzle has a liquid fuel tube in an air supply line, around which a partition is arranged. This partition forms two concentrically arranged air channels: an inner air channel and an outer air channel. The airflow through these air channels is atomizing air. A main combustion air supply is introduced further downstream in the channel.

[0004] US patent 4,261,517 A discloses a fuel nozzle for introducing atomized fuel.

[0005] EP 0 660 038 A2 shows a fuel supply device for introducing a liquid fuel, wherein the combustion air is swirled by means of swirl generators.

[0006] US 8 590 812 B2 shows a fuel supply nozzle for supplying liquid and gaseous fuels into a combustion chamber.

[0007] DE 10 2011 116 317 A1 shows a design of a feed device with a support burner which has a central primary fuel channel and a concentric secondary fuel channel.

[0008] DE 44 24 597 A1 discloses a combustion device for a gas turbine, which has an external air supply pipe in a fuel lance and two fuel supply channels for liquid fuel.

[0009] US 2014 / 013763 A1 shows a feed nozzle with a central through-channel through which a first airflow is supplied, as well as an inner annular through-channel for fuel and an outer annular through-channel for a second airflow.

[0010] When using liquid fuels in such burner systems, the fuel can interact with the inner wall of the nozzle, resulting in enriched fuel reaching the combustion chamber as a ligate or in the form of poorly atomized, large droplets. This has a direct negative impact on the stability, operating range, and emissions of the burner system.

[0011] The invention is based on the objective of providing a supply device of the type mentioned above for the stable operation of a burner system mentioned above, as well as a corresponding burner system and method for supplying the device.

[0012] The problem is solved for the feed device with the features of claim 1, for the burner system with the features of claim 11 and for the method with the features of claim 12.

[0013] The feed device is designed in that the injector element is designed for adding liquid fuel and that a film laying device, in particular cylindrical, is arranged radially between the injector element and the nozzle wall, completely surrounding the injector element radially, wherein an external channel (for flow with an external stream) is formed between the nozzle wall and the radial outside of the film laying device.

[0014] The film laying device is designed in a sleeve-like form and / or in particular with open axial ends for flow through with oxidizer.

[0015] The cross-section of the nozzle wall is, for example, constant along its length. The outer channel and / or the inner channel, in particular, have an annular gap with a substantially constant gap height in a given cross-section (at a constant axial position and / or at least largely along its axial length).

[0016] "Swirl-free" refers to the supply of fuel and oxidizer to the combustion chamber. A swirl flow can occur when fuel is added to the oxidizer flow within the feed nozzle.

[0017] The fuel can be, for example, a mixture of liquid hydrocarbons, e.g., kerosene and / or (heating) oil, and / or a liquid hydrocarbon in its pure form. The feed device and / or the burner system can also be combined for operation with fuels in other states of matter, e.g., with gaseous or supercritical fuels, preferably in combination with a (separate) injector element and / or feed device designed for this purpose.

[0018] The film-laying device enables advantageous fuel atomization by utilizing the high momentum of the oxidizer flow within the feed nozzle. The combination of the film-laying device and the injector element allows the high flow momentum of the process air (oxidizer flow) available in a FLOX® burner system to be used for atomization by the film-laying device (especially at the atomization edge). Simultaneously, unwanted liquid interaction on the inner wall of the feed nozzle, which would be detrimental to the burner system, is avoided. The feed device is particularly suitable for very short installation lengths and feed nozzles and is also suitable for direct injection into the combustion chamber (atomization edge at the outlet opening).

[0019] According to the invention, an inner channel (for flow with an internal stream) is formed radially within the film laying device, in particular between the radial inner surface of the film laying device and the injector element. This design enables the division of the entire oxidizer stream flowing through the feed nozzle into an external stream and an internal stream, thereby advantageously providing degrees of freedom for design in favor of improved atomization and fuel placement.

[0020] Particularly for advantageous flow guidance, with the lowest possible pressure loss and / or while avoiding secondary flow (e.g., turbulence), the film laying device preferably has at least substantially constant external dimensions, in particular a constant inner and / or outer diameter, over a large part of its axial length (more than 50%, preferably over the entire axial length) (e.g., apart from a functionally favorable shape at the edges). In particular, the entire film laying device runs parallel to the nozzle wall.

[0021] For effective atomization, the film laying device has an atomizing edge at its downstream axial end. In particular, the wall of the film laying device tapers towards the atomizing edge to create a sharp-edged shape. Preferably, the atomizing edge is oriented axially, without a radial component or constriction, to avoid additional pressure losses or flow disturbances. For a streamlined shape, the wall of the film laying device also tapers towards an upstream edge.

[0022] The injector element is preferably elongated (i.e., with a greater axial than radial extent) and / or projects into the feed nozzle. In particular, the injector element has a cross-section that is at least substantially cylindrical and / or constant (e.g., apart from the downstream area, at the injection point), at least within the feed nozzle and / or the film laying device.

[0023] The feed nozzle, the film laying device, and the injector element are arranged coaxially with respect to the longitudinal axis. The injector element is preferably positioned centrally on the longitudinal axis. This ensures symmetrical flow during operation, resulting in advantageous combustion characteristics (stability, low emissions). Preferably, the fuel injection point on the injector device is located at the downstream end of the injector device and / or centrally on the longitudinal axis (of the feed device or the feed nozzle). At the injection point, the fuel enters the feed nozzle (within the film laying device) from the injector element, particularly through a single central outlet or through multiple outlets on the injector element. This advantageously prevents unwanted wetting of the injector device.The oxidizer flows (internal and external) and the axial directional component of the fuel (droplet) flow preferably point in the same axial direction, towards the combustion chamber. Fuel is not introduced counter-currently into the oxidizer flow.

[0024] In a preferred embodiment, the injection point of the injector device is arranged axially between the atomizing edge and an upstream edge of the film laying device. The upstream edge and the atomizing edge define the length of the film laying device, which is, for example, between one and five times the diameter of the film laying device. The inner channel between the upstream edge and the injection point is formed, in particular, as an annular channel.

[0025] Advantageous wetting of the inner surface of the film-laying device for film formation is achieved when the injector element for adding a fuel cone is designed with an opening angle α (in the axial-radial direction) between 40° and 120°, particularly between 60° and 100°. The fuel is preferably introduced into the feed nozzle with a swirl, causing the fuel cone to form from the injection point. The distance between the injection point and the atomization edge is preferably designed such that (at least) a portion of the fuel impacts the inner surface of the film-laying device, forming a fuel film (another portion of the fuel, preferably atomized at the injection point, follows, for example, the internal flow directly into the feed nozzle). For a compact design, the shortest possible axial extent of the fuel film is desirable.The distance between the injection point and the atomization edge is therefore designed, in particular taking into account the opening angle α of the fuel cone for film formation.

[0026] For a particularly compact design and uniform fuel distribution across the circumference of the film-laying device (uniform film formation), the injector element is preferably designed as a pressure-swirl injector, wherein a swirl generator for imparting swirl during fuel injection is arranged within the injector element. The relative fuel pressure (pressure difference between the injector element and the combustion chamber) upon introduction into the injector element is, for example, between 1 bar and 100 bar. The swirl generator particularly comprises a swirl chamber into which fuel is introduced through several openings, e.g., three, arranged symmetrically to each other and tangentially to the swirl chamber wall. This imparts an axial and a tangential velocity component to the fuel flow in the swirl chamber. The fuel flow, maintaining this velocity component, then flows through the outlet opening of the injector element.The injection point is located at the outlet of the injector element. Downstream of the injection point, the swirl flow causes the radial directional component of the fuel flow to introduce the fuel in a conical shape into the feed nozzle within the film laying device.

[0027] Preferably, the (especially circular) flow cross-section tapers towards the outlet opening, initially conically to a narrowest cross-section, and then widens continuously downstream of this narrowest cross-section, particularly in a trumpet-like manner, to a larger cross-section (e.g., with a diameter 1.2 to 3 times larger) at the transition to the feed nozzle (outlet edge). This trumpet-like widening allows the defined opening angle of the fuel cone to be maintained even at comparatively low mass flow rates through the Coanda effect.

[0028] In a preferred embodiment, a circumferential, sharp exit edge is formed at the outlet opening of the injector element at the transition to the feed nozzle. In particular, the angle between the wall surfaces converging at the exit edge is less than 90°. In this way, (initial) atomization of the fuel for uniform film formation and a defined, complete fuel injection can be achieved without wetting the outside of the injector device.

[0029] The distance between the injection point and the film-laying atomizing edge is designed such that at least a portion of the fuel strikes the inside of the film-laying device during operation, forming an (atomizable) fuel film. The distance between the injection point and the atomizing edge depends primarily on the desired fuel film formation. The fuel film length should, for example, be at least 1-2 mm. At the sharp atomizing edge, the shear layer utilizes the high momentum of the oxidizer flow to atomize the fuel film into fine droplets, which are then carried downstream by the oxidizer flow towards the outlet.

[0030] According to the invention, the outer channel and the inner channel are designed to be coordinated such that, during operation, the entire oxidizer flow through the nozzle channel splits into an outer flow and an inner flow, the velocity of the outer flow being greater than the velocity of the inner flow, e.g., by a factor between 1.3 and 7, preferably between 2 and 5. The outer and inner flows preferably flow in parallel. The outer flow serves for atomization at the downstream end of the film laying device and protects the nozzle wall from fuel wetting. Atomization into fuel droplets at the atomization edge is achieved in particular by high shear velocities of the outer flow. The inner flow interacts with the fuel downstream of the injection point. Downstream of the atomization edge, the fuel droplets follow the oxidizer flow.

[0031] To determine an advantageous velocity ratio (or a range of advantageous velocity ratios, e.g., depending on the operating point), three design factors are considered in particular: first, for advantageous atomization at the atomizing edge, shearing between the outer and inner streams should be achieved; second, wetting of the nozzle wall with fuel downstream of the atomizing edge by a high external pulse via the outer stream should be avoided; and third, a sufficiently high velocity of the inner stream should be provided to advance the fuel film within the film laying device to the atomizing edge. The design is carried out in particular using computer-aided flow simulation (CFD) and / or experimentally, whereby, for example, the ratio of the flow cross-sections of the outer channel and the inner channel can be varied.

[0032] Advantageously, the maximum flow impulse can be used for atomization at the atomization edge if the feed nozzle at and / or downstream of the film laying device, in particular at and / or downstream of the atomization edge, does not have a reduction in the flow cross-section.

[0033] An advantageous mounting of the film laying device and / or the injector element is achieved if the film laying device is attached to the nozzle wall by means of several, in particular three, fastening elements, which center the injector element, especially on the radial inner side of the film laying device. The fastening elements are preferably designed to be aerodynamically efficient, e.g., wing-like, and / or arranged symmetrically to each other around the longitudinal axis and / or in the same axial position. To minimize the influence on the flow at and / or downstream of the injection point(s), the fastening elements are preferably arranged upstream of the injection point (as far as possible, but while maintaining mechanical stability).Another type of fastening is also conceivable, provided that it has the least possible impact on the flow and / or ensures an axially symmetrical alignment of the film laying device and the longitudinal axis of the injector element.

[0034] Preferably, the feed nozzle for adding oxidizer and liquid fuel to the combustion chamber is designed with a high axial impulse, with a mean flow velocity at the outlet opening between 40 m / s and 160 m / s, particularly between 80 m / s and 140 m / s. The main flow direction is, in particular, at least largely, or exclusively, axial. In this way, a large-scale, internal recirculation flow is induced within the combustion chamber during operation to stabilize the combustion. The design relates, for example, to one or more design points.

[0035] A compact burner system design is achievable if the feed device is designed for operation at a thermal output of 1 kW to 50 kW, for example, between 10 kW and 20 kW (with respect to atmospheric pressure and / or air-fuel ratios between, for example, 0.8 and 2.1). The thermal output can be scaled accordingly with a comparable size by increasing the pressure. The injector element is specifically designed for operation with a correspondingly low fuel mass flow rate (e.g., 0.1 to 1 g / s, particularly 0.2 to 0.8 g / s). The nozzle channel diameter can be, for example, between 7 mm and 13 mm. The outer diameter of the injector element can be, for example, between 20% and 70% of the nozzle channel diameter. The outer diameter of the film laying device can be, for example, between 10% and 70% of the nozzle channel diameter. B. between 50% and 85% of the diameter of the nozzle channel, where the inner diameter for forming the inner channel is larger than the outer diameter of the injector element.

[0036] The design features described above (individually or in combination) result in highly advantageous applicability with a comparatively short flame length, even with a compact feed system, thus enabling the use of a relatively short combustion chamber. For required high power outputs, multiple feed systems are preferably used in a burner system, for example, in a matrix and / or ring arrangement. This allows the feed system to be used advantageously even in applications with high power requirements where a compact burner system design is paramount, such as in aviation.

[0037] A particularly compact design of the feed device can be achieved if the atomizing edge, for direct injection, is arranged close (e.g. a distance corresponding to a nozzle diameter or less) or at axial height of the outlet opening.

[0038] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings. The drawings show: Fig. 1 a burner system according to the invention with several feed devices and a combustion chamber in a simplified schematic representation, Fig. 2 A, feed device according to the invention for the non-twisted addition of liquid fuel into a burner system in a longitudinal section ( Fig. 2A ) and in a cross-section AA ( Fig. 2B ), and Fig. 3 A,B,C an exemplary injector element for use in the feed device according to Fig. 2 A, B in perspective view from the side ( Fig. 3A ) and in longitudinal section ( Fig. 3B, C ).

[0039] Fig. 1 Figure 1 shows an exemplary installation situation of (not shown in detail) feed devices 1 according to the invention in a burner system 4, which is particularly suitable for use in gas turbines in aviation or in power generation applications. The burner system 4 has a combustion chamber 3 and an end plate 6 arranged on the upstream side of the combustion chamber 3, through which the feed devices 1 open into the combustion chamber 3. In particular, a plurality of feed devices 1 can be present, which are arranged, for example, in a matrix-like and / or ring-like configuration on the end plate 6.

[0040] The feed devices 1 serve to introduce liquid fuel 27 and oxidizer 38 from a distributor side 2 (not shown in detail here) into the combustion chamber 3 via the end plate 6. The combustion chamber 3 extends axially along a central longitudinal axis M of the burner system 4 and, for example, radially rotationally symmetric about the same. The feed devices 1 extend along longitudinal axes L that are aligned parallel to the central longitudinal axis M of the burner system 4.

[0041] Fuel 27 can be, for example, a mixture of liquid hydrocarbons, such as kerosene and / or (heating) oil, and / or a pure liquid hydrocarbon. Burner system 4 is specifically designed for operation with air-fuel ratios between 0.8 and 2.1.

[0042] The burner system 4 is designed as a recirculation-stabilized jet flame burner for swirl-free, high-velocity combustion. In this type of burner system, unburned fuel 27 and oxidizer 38 are introduced into the combustion chamber 3 without swirl and with such a high axial impulse that a large-scale recirculation zone 5 forms in the combustion chamber 3 to stabilize the combustion zone. The average flow velocity at the outlet opening(s) 12 is, for example, between 40 m / s and 160 m / s.

[0043] Fig. 2A und Fig. 2B show the internal structure of the feed device 1 in a sectional view ( Fig. 2A : Longitudinal section, Fig. 2B : Cross-section AA). How Fig. 2A As shown, the feed device 1 has a feed nozzle 10 with a nozzle channel 14, in particular cylindrical, with an exemplary constant cross-section, enclosed by a nozzle wall 16 and aligned along the longitudinal axis L. The nozzle channel 14 opens into a circular outlet opening 12 on the combustion chamber side, which, in the assembled state, adjoins the combustion chamber 3.

[0044] For adding the fuel 27 into the nozzle channel 14, the supply device 1 comprises an injector element 24. The injector element 24 is arranged coaxially to the supply nozzle 10 on the longitudinal axis L in the nozzle channel 14. An injection point 26, at which the fuel 27 enters the nozzle channel 14 during operation, is located centrally on the longitudinal axis L at the downstream end of the injector element 24 to ensure the most symmetrical possible introduction of fuel 27.

[0045] The injector element 24 is exemplified as a pressure-swirl injector, wherein the liquid fuel 27 is introduced into the injector element 24 at a high relative fuel pressure, e.g., up to 100 bar, and swirled by means of a swirl generator 46 located within the injector element 24 before being introduced into the nozzle channel 14. Other configurations of the injector element 24 for introducing liquid fuel 27 are possible, provided, in particular, that advantageous, uniform film formation can be achieved at the film laying device 18, for example, using a "jet-in crossflow" configuration.

[0046] Fig. 3A, Fig. 3B und Fig. 3C The injector element 24 is shown in an exemplary design in a perspective view from the side ( Fig. 3A ) and in longitudinal section ( Fig. 3B und Fig. 3C ), whereby in Fig. 3C An outlet opening 48 is shown in detail C.

[0047] How Fig. 3A As shown, the injector element 24 has an essentially cylindrical outer circumference.

[0048] How Fig. 3B As shown, within the injector element 24, the swirl generator 46 is arranged with a cylindrical swirl chamber 47 and, by way of example, three mutually symmetrically arranged inlet openings 45 to the swirl chamber 47. Downstream of the swirl generator 46, the injector element 24 has the outlet opening 48 with a circumferentially sharp outlet edge 52 adjacent to the supply nozzle 10.

[0049] The swirl generator 46 is held in place by a retaining element 44. Upstream of the retaining element 44, a compression spring 42 is arranged to decouple the swirl generator 46 from vibration.

[0050] How Fig. 3C As shown more precisely, downstream of the swirl generator 46, the flow cross-section, which is primarily circular, narrows conically towards the outlet opening 48, initially to a narrowest cross-section 50, and then widens continuously downstream of this narrowest cross-section 50, particularly in a trumpet-like manner, to a larger cross-section (e.g., 1.2 to 4 times larger) at the outlet plate 52. This trumpet-like widening allows the defined opening angle of the fuel cone to be maintained even at comparatively low mass flow rates.

[0051] The sharp exit edge 52 is obtained in particular by ensuring that the angle between the converging wall surfaces at the exit edge 52 is less than 90°. In this way, initial atomization of the fuel can be achieved at the exit edge 52.

[0052] During operation, the high pressure generates fuel droplets at the injector element 24, which, due to the swirl, enter the nozzle channel 14 in a fuel cone 28 emanating from the injection point 26. The opening angle α of the fuel cone 28 can be, for example, between 60° and 100°.

[0053] The feed device 1 has a film laying device 18 arranged radially between the injector element 24 and the nozzle wall 16. The film laying device 18 is sleeve-like, in particular cylindrical, and / or completely surrounds the injector element 24 radially.

[0054] An outer channel 30 is formed between the nozzle wall 16 and the radial outer surface of the film laying device 18, in which an outer stream 32 of the oxidizer 38 flows during operation. Radially inside the film laying device 18, between the radial inner surface of the film laying device 18 and the injector element 24, an inner channel 34 is formed, in which an inner stream 36 of the oxidizer 38 flows during operation. The inner channel 34 extends from an upstream edge 22 to the injection point 26 of the injector element 34.

[0055] The film laying device 18 is arranged coaxially to the feed nozzle 10 and the injector element 24 for a symmetrical flow guidance (see figure). Fig. 2B The film laying device 18 is attached to the nozzle wall 16, in particular by means of several symmetrically arranged fastening elements 40, e.g., three. The fastening elements 40 are preferably arranged as far upstream as possible on the film laying device 18 in order to have as little influence as possible on the flow at and downstream of the injection point 26. Advantageously, the fastening elements 40 can project radially on the inside of the film laying device 18 such that they also center the injector element 24.

[0056] How Fig. 2A As further shown, the film laying device 18 has an atomizing edge 20 at its downstream end. The wall of the film laying device 18 tapers towards the atomizing edge 20 in order to achieve the sharpest possible edge for fine droplet atomization.

[0057] At its upstream end, the film laying device 18 has an edge 22. The edge 22 is aerodynamically shaped, in Fig. 2A exemplified by a tapered wall of the film laying device 18 in order to generate the lowest possible pressure loss and / or the lowest possible secondary flow (especially turbulence).

[0058] The film laying device 18 is arranged axially within the feed nozzle 10 such that the injection point 26 lies between the atomizing edge 20 and the upstream edge 22 of the film laying device 18. The axial length of the film laying device 18, between the atomizing edge 20 and the edge 22, depends on various parameters. Firstly, run-in effects within the internal flow 36 should have largely subsided by the time of the injection point 26. Secondly, the distance between the injection point 26 and the atomizing edge 20 is preferably designed such that at least a portion of the fuel 27 impacts the inside of the film laying device 18, forming a fuel film. The distance is therefore designed, in particular, taking into account the opening angle α of the fuel cone 28. At the same time, the distance should be kept as small as possible to allow for a compact design of the feed device 1.

[0059] The distance between the atomizing edge 20 and the outlet opening 12 of the feed nozzle 10 can be varied depending on the desired combustion pattern, between, for example, 0 mm (axial position of the atomizing edge 20 on the outlet opening 12, corresponding to "direct injection") and, for example, up to ten times the diameter of the nozzle channel 16. A particularly compact design of the feed device can be achieved by arranging it as far downstream as possible. Depending on the upstream positioning, the combustion process, e.g., the flame length, can be influenced.

[0060] The radial spacing of the nozzle wall 16, the film laying device 18, and the injector element 24 is determined by an advantageous flow design. The outer channel 30 and the inner channel 34 are designed relative to each other such that, during operation, the total oxidizer flow passing through the nozzle channel 14 is divided according to an advantageous ratio ("air split"). It has proven particularly advantageous if the velocity of the outer flow 32 is, for example, greater than the velocity of the inner flow 36 by a factor of between 1.3 and 7.Three design factors are taken into account in particular: a high shear between the outer flow 32 and the inner flow 36 for advantageous atomization at the atomizing edge 20, a high external impulse from the outer flow 32 downstream of the atomizing edge 20 to prevent wetting of the nozzle wall 16 with fuel, and a sufficiently high velocity of the inner flow 36 to advance the fuel film within the film laying device 18 to the atomizing edge 20. The design is carried out in particular using computer-aided flow simulation (CFD) and / or experimentally.

[0061] During operation, oxidizer 38 flows from distributor side 2 into feed nozzle 10. At the film laying device 18, the total oxidizer flow is split into the outer flow 32, which flows through the outer channel 30, and the inner flow 36, which flows at a lower velocity through the inner channel 34.

[0062] The fuel 27 is introduced into the injector element 24 at a high relative fuel pressure (e.g., between 1 and 100 bar). The fuel 27 flows through the inlet openings 45 into the swirl chamber 47. Through the inlet openings 45 and / or within the swirl chamber 47, the fuel is set into rotation with an axial and a tangential velocity component, e.g., by means of (optionally present) guide elements, and thus flows to the outlet opening of the injector element 24. The injection point 26 is located at the outlet opening 48 of the injector element 24. Downstream of the injection point 26, the swirl flow causes the radial directional component of the fuel flow to be introduced in a conical shape into the feed nozzle 10 within the film laying device 18.

[0063] At injection point 26, fuel 27 is atomized at the outlet edge 52 and added to the fuel cone 28 with an opening angle α between 60° and 100°, e.g., 90°. A portion of the fuel 27 strikes the inside of the film laying device 18 a few millimeters (e.g., between 2 mm and 10 mm) upstream of the atomization edge 20, forming a fuel film (film of fuel 27) on the inside of the film laying device 18. The remaining portion of the atomized fuel 27 follows the inner flow 36 without contacting the film laying device 18.

[0064] The inner flow 36 propels the fuel film to the atomization edge 20. At the atomization edge 20, the inner flow 36 and the outer flow 32 meet, forming a shear layer due to the velocity difference. At the sharp atomization edge 20, the fuel film is atomized into fine droplets by utilizing the high momentum of the oxidizer flow and the shear layer. These droplets are carried further downstream by the oxidizer flow towards the outlet opening 12.

[0065] The comparatively high impulse of the external flow 32 ensures that the fuel droplets do not wet the nozzle wall 16, but are instead carried as completely as possible into the combustion chamber 3 by the oxidizer flow. Combustion of the oxidizer-fuel mixture takes place in the combustion chamber 3.

[0066] The two-stage atomization, with the first atomization at the exit edge 52 of the injector element 24 and the second atomization at the atomization edge 20, results in a fuel 27 that is advantageously atomized upon entering the combustion chamber 3. The first atomization contributes in particular to the formation of a uniform fuel film on the inner circumference of the film laying device 18.

[0067] Investigations by the inventors at ten different mean flow velocities of the oxidizer flow at the outlet opening 12, from 70 m / s to 160 m / s, have, for example, resulted in a very small droplet diameter across the entire feed nozzle 10. Specifically, 20 droplets with Sauter diameters (D 32, characteristic droplet diameters) between just under 10 µm and just under 30 µm were measured downstream of the atomization edge over the radius of the feed nozzle 10. This allows for advantageous vaporization and emission characteristics of the burner system 4.

[0068] The inventors' investigations have shown that the advantageous operation is possible with a comparatively very compact design thanks to the above-described design of the feed device 1.

[0069] For example, a single feed unit can be designed for operation at a thermal output of, say, between 5 kW and 30 kW (scaling up or down is possible). In this way, both applications with comparatively moderate power density and / or moderate energy requirements (e.g., in decentralized energy conversion) and, for example, by using a large number of feed units 1 in a burner system 4, applications with high power requirements and / or power density (e.g., aviation applications) can be served.

[0070] In summary, by means of the above-mentioned advantageous measures (individually or in combination) for the formation of a single feed device 1, a burner system designed according to the concept of the recirculation-stabilized jet flame burner for non-twisted high-speed combustion can also be operated stably, reliably and with low emissions using liquid fuels with a comparatively short flame length, thereby providing a compact burner system.

Claims

1. Supply device (1) for use in a gas turbine, for turbulence-free supply of oxidizer (38) and fuel (27) into a combustion chamber (3), the supply device comprising - a supply nozzle (10) having a nozzle channel (14) which is in particular cylindrical, is enclosed by a nozzle wall (16), is aligned along a longitudinal axis (L), and opens into a combustion chamber-side outlet opening (12) in order to adjoin the combustion chamber (3), and - an injector element (24) for adding the fuel (27) into the nozzle channel (14) at an injection point (26), the injector element (24) being designed for the addition of liquid fuel (27), a film laying device (18), which is in particular cylindrical and surrounds the injector element (24), being arranged radially between the injector element (24) and the nozzle wall (16), an outer channel (30) being formed between the nozzle wall (16) and the radial outer side of the film laying device (18), and an inner channel (34) being formed radially inside the film laying device (18), in particular between the radial inner side of the film laying device (18) and the injector element (24), the film laying device (18) having an atomizing edge (20) at its downstream axial end, the supply nozzle (10), the film laying device (18) and the injector element (24) being arranged coaxially with one another with respect to the longitudinal axis (L), and the distance between the injection point and the atomizing edge being designed such that at least part of the fuel strikes the inner side of the film laying device during operation, forming a fuel film, characterized in that the outer channel (30) and the inner channel (34) are designed to coordinate such that, during operation, an entire oxidizer flow flowing through the nozzle channel (14) is divided into an outer flow (32) and an inner flow (36), the velocity of the outer flow (32) being greater than the velocity of the inner flow (36) by a factor between 1.3 and 7, preferably between 2 and 5.

2. Supply device (1) according to claim 1, characterized in that the film laying device (18) has constant external dimensions, in particular a constant internal diameter and / or external diameter, at least over a large part of its axial length.

3. Supply device (1) according to any of the preceding claims, characterized in that the wall of the film laying device (18) tapers towards the atomizing edge (20).

4. Supply device (1) according to any of the preceding claims, characterized in that the injector element (24) is elongate and / or projects into the supply nozzle (10), the injector element (24) having, in particular at least inside the supply nozzle (10) and / or the film laying device (18), a cross section that is at least substantially cylindrical and / or constant.

5. Supply device according to any of the preceding claims, characterized in that the injection point (26) of the injector device (24) is arranged axially between the atomizing edge (20) and an upstream edge (22) of the film laying device (18).

6. Supply device (1) according to any of the preceding claims, characterized in that the injector element (24) is designed to add a fuel cone (28) having an opening angle (α) between 40° and 120°, in particular between 60° and 100°.

7. Supply device (1) according to any of the preceding claims, characterized in that the injector element (24) is designed as a pressure-turbulence injector, a turbulence generator (46) for turbulence imposition during fuel injection being arranged in the injector element (24).

8. Supply device (1) according to any of the preceding claims, characterized in that, at an outlet opening (48) of the injector element (24), a flow cross section initially tapers, in particular conically, to a narrowest cross section (50) and, downstream of the narrowest cross section (50) widens continuously, in particular in the manner of a trumpet, to a larger cross section at the transition into the supply nozzle (10), a circumferential, sharp exit edge (52) being formed in particular at the outlet opening (48) of the injector element (24) at the transition into the supply nozzle (10).

9. Supply device (1) according to any of the preceding claims, characterized in that, at and / or downstream of the film laying device (18), in particular at and / or downstream of the atomizing edge (20), the supply nozzle (10) does not exhibit a reduction in the flow cross section, and / or in that the film laying device (18) is attached to the nozzle wall (16) by means of several, for example three, fastening elements (40), which in particular center the injector element (24) on the radial inner side of the film laying device (18).

10. Supply device (1) according to any of the preceding claims, characterized in that the supply nozzle (10) for adding oxidizer and liquid fuel into the combustion chamber (3) has a high axial impulse, a mean flow velocity at the outlet opening (12) being between 60 m / s and 160 m / s, in particular between 80 m / s and 140 m / s, and / or in that the atomizing edge (20) is located near or at the axial height of the outlet opening (12).

11. Burner system (4) having a burner head (7) comprising at least one supply device (1) according to any of the preceding claims and an end plate (6) via which the at least one supply device (1) opens into a combustion chamber (3) of the burner system (4), wherein the burner system (4) is designed for operation with large-scale recirculation inside the combustion chamber, induced by the axial impulse of the incoming oxidizer / fuel jets, for stabilizing a combustion zone in the combustion chamber (3).

12. Method for turbulence-free supply of oxidizer (38) and fuel (27) into a combustion chamber (3) by means of a supply device (1) according to any of claims 1 to 10, in which method liquid fuel (27) is added to an oxidizer (38) inside a film laying device (18) arranged in a supply nozzle (10).

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