Burner device, heat generator, heating system and service water supply system and method for vibration adjustment of a burner device

Abstract

The invention provides a burner device 100 for providing heat energy by combustion of an air-fuel mixture G, comprising a flame body 1, which defines an interior space 11, which is connected via openings in the flame body 1 to an outer combustion surface 12 of the flame body 1, on which the combustion of an air-fuel mixture G introduced into the interior space 11 and flowing through the openings takes place in one or more burner flames, and a flow guide device 2, comprising an axial flow channel 21, located mostly or completely in the interior space 11, for guiding the air-fuel mixture G, which in particular runs parallel to a longitudinal axis LA of the flame body 1, the axial length of which is selected depending on an oscillation frequency induced by the one or more burner flames.

Description

Technical area

[0001] The present invention relates to a burner device, a heat generator with a burner device, a heating system and a domestic water supply system each with a heat generator and a method for vibration adjustment of a burner device. Background of the invention

[0002] Burner devices for use in heat generators are known from the prior art, in which a premixed air-fuel mixture is fed into a flame chamber and subsequently burned on an outer surface of the chamber that acts as the combustion surface. This concept corresponds to a so-called premix burner.

[0003] Depending on the fuel composition, the air-fuel mixture can exhibit different flame propagation velocities, which can potentially lead to undesirable flashback of the burner flame located on the combustion surface into the flame liner. This phenomenon is particularly noticeable when using hydrogen-containing fuels, as hydrogen has a higher flame propagation velocity than conventionally used fossil fuels.

[0004] In order to prevent such a flashback, or at least to limit its spread within the flame body, flame barriers are known from the prior art, including from EP 4 160 092 A1, which allow permeability for the air-fuel mixture in the direction of the combustion surface, but do not allow a burner flame flashing back from there to pass through.

[0005] In connection with premix burners, thermoacoustic problems also arise. These are caused by the fact that the acoustic waves emitted during combustion as a result of thermal expansion are reflected in the combustion chamber and can, in turn, affect the combustion itself, thus representing a vibrational self-excitation mechanism.

[0006] Depending on the system architecture and the selected operating parameters, oscillatory systems with self-excitation can exhibit unstable operating states in which oscillations with a comparatively high amplitude occur, in particular in the form of a so-called limit cycle oscillation.

[0007] If such a state of thermoacoustic instability occurs in a burner device, the vibrations induced by self-excitation can lead to incomplete combustion of the air-fuel mixture, flashbacks and increased noise emissions, all of which are undesirable operating conditions.

[0008] Previous approaches to solving this thermoacoustic problem aim at controlling the individual operating parameters of the burner device, such as the mass flow of the air-fuel mixture to be burned, in order to specifically influence the burner flame and thus the acoustic waves emitted by it and thus keep the system in a thermoacoustically stable operating state.

[0009] However, this approach reaches its limits, particularly with the increasing use of hydrogen-containing fuels, since with increasing hydrogen content it becomes difficult to specifically influence the burner flame through control due to the short ignition delay times of the hydrogen itself. Summary

[0010] The present invention is therefore based on the object of creating a possibility for combustion-based heat generation with a thermoacoustically stabilized burner device that is improved compared to the prior art, in particular for use with hydrogen-containing fuels.

[0011] To achieve this object, a burner device according to claim 1 is provided, as well as, based thereon, a heat generator according to claim 13, a heating system according to claim 14 and a domestic water supply system according to claim 15. Furthermore, the invention provides a method for vibration adjustment of a burner device according to claim 12.

[0012] The respective dependent claims relate to preferred embodiments, which can be provided individually or in combination.

[0013] According to a first aspect, a burner device for providing thermal energy by combustion of an air-fuel mixture is provided. The burner device comprises a flame body that delimits an interior space connected via openings in the flame body to an outer combustion surface of the flame body, on which the combustion of an air-fuel mixture introduced into the interior space and flowing through the openings takes place in one or more burner flames. The burner device also comprises a flow guide device that comprises an axial flow channel located largely or entirely within the interior space for conducting the air-fuel mixture, which runs in particular parallel to a longitudinal axis of the flame body, the axial length of which is selected as a function of an oscillation frequency induced by the one or more burner flames.

[0014] In this way, a type of resonator for the air-fuel mixture is formed in the interior, which is adjusted to the vibration frequency and significantly changes the vibration behavior of the entire burner device compared to a design without a flow guide device. This reduces vibrations of the burner device and / or its components, thereby reducing the risk of incomplete combustion and / or flashbacks, which in turn increases the efficiency of the burner device. Furthermore, this results in lower noise emissions during operation, which is perceived by the user as a high level of comfort.

[0015] The proposed burner device thus solves the problem of thermoacoustic instability by introducing a structure in the form of a flow guide device upstream of the combustion surface, which would, for example, make a control of individual operating parameters aimed at the thermoacoustic instability basically unnecessary.

[0016] Preferably, the burner device is designed to burn an air-fuel mixture with hydrogen-containing fuel.

[0017] A hydrogen-containing fuel is a fuel that contains a certain proportion of elemental hydrogen (H 2 ). Other fuel gas components can be methane, propane, butane, or inert gases such as nitrogen and carbon dioxide. The hydrogen content is preferably between 10 and 100 vol.%, particularly preferably between 30 and 100 vol.%. The permissible components of the gases (including hydrogen content) are defined in relevant standards (e.g., EN 437), according to which the devices are approved / released.

[0018] The longitudinal axis of the flame body is understood to be a longitudinal axis running through the center of the interior space, which is enclosed by the surface of the flame body that functions as the combustion surface. In other words, said surface is understood to be the lateral surface running along the longitudinal axis. The flame body is preferably designed such that the openings connecting the combustion surface and the interior space extend at an angle, in particular at right angles, to the longitudinal axis.

[0019] In simple terms, the longitudinal axis of the flame dam preferably corresponds to a central axis perpendicular to the discharge directions of the air-fuel mixture from the openings. A radial direction of the flame dam is to be understood below as referring to said longitudinal axis.

[0020] The axial flow channel is obviously impermeable to the air-fuel mixture in the said radial direction and does not fill the entire interior space, but only a part of it, so that there are also areas in the interior space through which the air-fuel mixture flows, but which are not located in the axial flow channel.

[0021] The flame body preferably has a substantially cylindrical shape, in particular a circular cylinder, with a cylinder shell acting as the combustion surface and preferably an end face that defines the interior along the longitudinal axis. In the case of a cylindrical shape, the longitudinal axis would be understood as the central vertical axis of the cylinder.

[0022] The circular cylindrical design allows for a flow cross-section of the axial flow channel that is essentially constant across the longitudinal axis and is therefore easy to implement in terms of construction.

[0023] Throughout this application, the term "cylindrical" is to be understood as referring to a general cylinder according to the common mathematical definition. A circular cylinder is to be understood as a specific cylinder with a circular base or top surface.

[0024] The delimitation of the interior space is not to be understood as completely delimiting or enclosing the interior space in all three spatial directions. Rather, the flame dam leaves at least one opening open to the interior space through which the air-fuel mixture is introduced into it, preferably via an inlet surface that corresponds entirely or partially to an opening surface of the at least one opening to the interior space or arises from this by parallel displacement of a partial surface or the entire opening surface. The inlet surface and opening surface are usually perpendicular to the longitudinal axis of the flame dam.

[0025] The oscillation frequency, depending on which the length of the axial flow channel is set or selected, is preferably an oscillation frequency of a vibration of the burner device to be reduced during operation without a flow guide device or with an "unadapted" length of the flow guide device.

[0026] This is preferably an oscillation frequency of the burner device itself (as an assembly of solid bodies) or an oscillation frequency of the combustion, i.e. an oscillation frequency of the resulting pressure oscillation.

[0027] The oscillation frequency may be an oscillation frequency from a measured frequency spectrum of the burner device during operation, preferably an oscillation frequency with a comparatively high amplitude in the frequency spectrum, which is to be reduced by the flow guide device.

[0028] However, the vibration frequency can also be determined by simulation, for example by FE and / or CFD simulation, preferably with modal analysis, i.e. determined computer-aided.

[0029] Preferably, the length is selected such that a standing wave of the air-fuel mixture is formed in the axial flow channel, the frequency of which essentially corresponds to the induced oscillation frequency.

[0030] In a preferred embodiment, the axial length is selected as a function of an oscillation frequency of the burner device that occurs when the burner device is operated without a flow guide device.

[0031] In this way, the frequency range in which a vibration to be reduced occurs can be identified particularly well.

[0032] In a preferred embodiment, the axial length is selected in additional dependence on the speed of sound of the air-fuel mixture, and preferably in additional dependence on a length of the interior space in the direction of the longitudinal axis of the flame body.

[0033] In this way, the specific properties of the actual air-fuel mixture used can be taken into account in the design. This is especially true if hydrogen-containing fuel is used, as this has a comparatively large influence on the speed of sound.

[0034] By taking the length into account, the maximum possible length of the flow channel that still fits into the interior space can be selected in order to maximize the effect of the resonator.

[0035] Alternatively, the average speed of sound in air can be used, although this provides less accurate results when choosing the appropriate length.

[0036] In a preferred embodiment, a ratio of a cross-sectional area of ​​the axial flow channel in a cross-section perpendicular to the longitudinal axis of the flame body to an inlet area via which the air-fuel mixture is introduced into the interior is greater than or equal to 15%, in particular greater than or equal to 25%.

[0037] In this way, a sufficiently large amount of air can be provided in the resonator to effectively reduce the vibrations at the desired frequency.

[0038] Preferably, the ratio of the cross-sectional area of ​​the axial flow channel in the cross-section perpendicular to the longitudinal axis of the flame body to the inlet area is less than or equal to 90%, in particular less than or equal to 80% and in particular less than or equal to 75%.

[0039] This provides sufficient space in the interior to ensure that all openings of the flame body are supplied with air-fuel mixture despite the flow guide device located in the interior.

[0040] Preferably, the interior space and the axial flow channel have a cylindrical cross-section, wherein an inner diameter of the flow channel corresponds to at least 25% of a diameter of the inlet surface, in particular 50% of the diameter of the inlet surface.

[0041] In a preferred embodiment, the axial flow channel is arranged centrally with respect to the flame body, so that in the cross section perpendicular to the longitudinal axis of the flame body, it is spaced from a circumferential inner wall of the flame body adjacent to the interior.

[0042] This results in a particularly symmetrical structure in which the resonator is located in the middle and is circumferentially surrounded by the air-fuel mixture that does not flow through the axial flow channel.

[0043] In a preferred embodiment, the flow guide device comprises further flow channels for passing the air-fuel mixture, which flow channels run in particular parallel to a longitudinal axis of the flame body and which are arranged between the axial flow channel and the circumferential inner wall of the flame body with respect to the cross section perpendicular to the longitudinal axis of the flame body.

[0044] The multiple flow channels, which are essentially arranged circumferentially relative to the central, axial flow channel, prevent the formation of vibration modes in the interior in a circumferential direction relative to the longitudinal axis of the flame body, which in turn improves the vibration characteristics of the burner device.

[0045] In a preferred embodiment, the flow guiding device is designed as a tube insert comprising a central tube element forming the axial flow channel and a plurality of fin elements arranged outwardly on an outer circumference of the central tube element, wherein two of the plurality of fin elements each delimit one of the further flow channels in a circumferential direction of the tube insert.

[0046] This represents a particularly simple and cost-effective variant of the flow guidance device.

[0047] Preferably, the fin elements extend over the entire length of the interior relative to the longitudinal axis of the flame body.

[0048] In a preferred embodiment, the flow guiding device comprises at least three further flow channels which, with respect to the cross section perpendicular to the longitudinal axis of the flame body, completely surround an outer circumference of the axial flow channel.

[0049] The inventors have discovered that the design with at least three additional flow channels suppresses vibration modes in the circumferential direction particularly well.

[0050] In a preferred embodiment, the burner device further comprises a flame arrester arranged largely or entirely in the interior, wherein the flow guide device is arranged largely or entirely within the flame arrester.

[0051] This design is particularly suitable for use with fuel with a high hydrogen content, where there is an increased risk of flashback.

[0052] The flame arrester allows the air-fuel mixture to pass through in the direction of the combustion surface, but does not allow a burner flame to pass back from there.

[0053] The flame arrester preferably has a geometry adapted to the flame body, also extends along the longitudinal axis of the flame body and is in particular cylindrical in shape.

[0054] There is a distance between an outer circumference of the flame arrester and the inner circumferential wall of the flame body so that the flame arrester does not lie directly there, which improves flow behavior when flowing out through the openings.

[0055] In this case, the air-fuel mixture is only introduced into the interior of the flame arrester, which, like the flame body, has at least one opening, the opening area of ​​which in this case corresponds to the inlet area for introducing the air-fuel mixture into the interior.

[0056] In a preferred embodiment with a flame arrester, the radial end sections of the fin elements are flush with a circumferential inner wall of the flame arrester, such that the further flow channels in the cross section perpendicular to the longitudinal axis of the flame body are each formed by a section of the tube element, sections of two of the plurality of fin elements and by a section of the circumferential inner wall of the flame arrester.

[0057] This ensures that the introduced air-fuel mixture flows through one of the flow channels defined by the flow guide device without overflowing into another. This results in a particularly uniform flow pattern, which in turn reduces sources of other vibrations, such as those caused by turbulence.

[0058] In an equivalent embodiment without a flame arrester, radial end sections of the fin elements are flush with a circumferential inner wall of the flame body, such that the further flow channels in the cross-section perpendicular to the longitudinal axis of the flame body are each formed by a section of the tube element, sections of two of the plurality of fin elements and by a section of the circumferential inner wall of the flame body.

[0059] According to a second aspect of the invention, a heat generator is provided for transferring thermal energy to a fluid, in particular for use in a heating system or in a domestic water supply system, wherein the heat generator comprises at least one burner device according to the first aspect or a preferred embodiment thereof and a heat exchanger coupled to the burner device, via which heat energy provided by the burner device can be transferred to the fluid.

[0060] This makes the particularly efficient and safe burner device suitable for heating any fluid, which in turn can be used in numerous other plants or systems.

[0061] The advantages already described for the burner device also apply to the heat generator comprising it, which enables efficient and vibrationally stable combustion, particularly in the case of hydrogen-containing fuel, which in the case of the heat generator is synonymous with efficient and safe heating of the said fluid.

[0062] For example, the heat exchanger can be a surface, fin or spiral coil heat exchanger.

[0063] According to a third aspect of the invention, a heating system for heating a building is provided, which comprises at least one piping system for transporting a fluid energy transport medium and a heat generator according to the second aspect of the invention, which is configured to heat the energy transport medium to be transported through the piping system.

[0064] According to a fourth aspect of the invention, a domestic water supply system for supplying domestic water is provided, which comprises at least one pipe system for transporting the domestic water and a heat generator according to the second aspect of the invention, which is designed to heat the domestic water to be transported through the pipe system.

[0065] By using the heat generator according to the invention as part of a heating system and / or a domestic water supply system of a building, the already described advantages of safe and efficient combustion, in particular of hydrogen-containing fuel, can be implemented in the area of ​​heating as well as in the area of ​​hot water supply.

[0066] According to a fifth aspect of the invention, a method for adjusting the vibration of a burner device, in particular a premix burner device, which is designed to provide thermal energy by combustion of an air-fuel mixture, is provided. The burner device comprises a flame body that defines an interior space connected via openings in the flame body to an outer combustion surface of the flame body, on which the combustion of an air-fuel mixture introduced into the interior space and flowing through the openings takes place in one or more burner flames, comprising operating the burner device with the air-fuel mixture burning on the outer combustion surface of the flame body, detecting a vibration frequency of the burner device during operation, in particular with a detection point in a combustion chamber of the burner device or in an environment of the burner device,for example, with a vibration measurement sensor, providing a flow guide device comprising an axial flow channel for conducting the air-fuel mixture, providing a flow guide device comprising an axial flow channel for conducting the air-fuel mixture, again comprising determining an axial length of the axial flow channel as a function of the detected vibration frequency; and creating the flow guide device, the axial flow channel of which has a length corresponding to the determined axial length, and inserting the provided flow guide device into the interior of the burner device.

[0067] The detection of an oscillation frequency preferably comprises detecting a frequency spectrum of the oscillations of the burner device, e.g., in the form of an FFT spectrum for amplitude and phase, or the like, and selecting an oscillation frequency from the detected oscillation spectrum.

[0068] Preferably, the oscillation frequency is selected in such a way that the oscillation frequency is selected at which the detected frequency spectrum has a peak, i.e. a comparatively high amplitude.

[0069] In this way, a critical oscillation frequency (also called problem frequency) can be identified particularly easily, since it is represented by the peak in the noise otherwise recorded and also contained in the frequency spectrum.

[0070] Preferably, the vibration frequency to be selected is in a range of 500 to 7000 Hz.

[0071] A possible variant for determining the axial length of the axial flow channel is described below with reference to exemplary equations.

[0072] In the following, f* denotes the problem frequency and c the speed of sound of the air-fuel mixture.

[0073] The axial flow channel acts as a type of resonator, the length of which is selected depending on an oscillation frequency, for example in such a way that a standing wave is formed in the air-fuel mixture in the axial direction, which acts as a type of vibration damper for the entire burner device.

[0074] For example, the axial flow channel can be assumed as a resonator with two open ends, in which frequencies of standing waves approximately satisfy the following equation 1, in which L corresponds to a length of the flow channel and n is a natural number greater than or equal to 1, which indicates the oscillation order of the standing wave (n=1 forms the fundamental oscillation). f n = n c 2 L

[0075] Will now fn = f* and equation 1 is rearranged for L, the following expression according to equation 2 results for suitable lengths of the flow channel in which standing waves with the selected frequency can form. L n = n c 2 f *

[0076] For example, for a speed of sound c=343 m / s for air and a frequency to be cancelled of 1000 Hz, the expression L n = n · 0.1715 m for suitable lengths of the axial flow channel. In the first harmonic with n=1, this would correspond to a length of 17.15 cm.

[0077] Preferably, the flow channel is selected according to the length for the first harmonic, but higher harmonics are also possible.

[0078] The design of the axial flow channel is by no means limited to the above. Other boundary conditions, such as open and closed ends, can also be selected, or other vibration orders or even modes, or modeling approaches can be used that also take into account, for example, temperature or other state variables or the flow velocity of the air-fuel mixture.

[0079] According to a further aspect, there is provided a burner device adapted according to a method according to the fifth aspect or one of its preferred embodiments.

[0080] Further aspects and their advantages as well as more specific embodiments of the aforementioned aspects and embodiments are described below with the aid of the drawings shown in the attached figures.

[0081] Fig. 1A and 1B show cross sections of a partial area of ​​a first embodiment of the burner device according to the invention.

[0082] Fig. 2A and 2B show cross sections of a partial area of ​​a second embodiment of the burner device according to the invention.

[0083] Fig. 3 shows a perspective view of a flow guide device as shown in the embodiments in Fig. 1 and Fig. 2 is used.

[0084] Fig. 4 shows a schematic flow diagram of an embodiment of the method according to the invention for vibration reduction.

[0085] It is emphasized that the present invention is in no way limited to the exemplary embodiments described below and their implementation features. The invention further encompasses modifications of the aforementioned exemplary embodiments, in particular those resulting from modifications and / or combinations of individual or multiple features of the described exemplary embodiments within the scope of the independent claims. Detailed character description

[0086] In the following figures, the flow directions of the air-fuel mixture G are indicated by the arrows, some of which are labeled G.

[0087] Fig. 1A shows a cross section of a partial area of ​​a first embodiment of the burner device 100 according to the invention along a longitudinal axis LA of a flame body 1. Fig. 1B shows a cross-section perpendicular to the longitudinal axis LA in the Fig. 1Amarked section plane AA.

[0088] The burner device 100 is designed to provide thermal energy by combustion of an air-fuel mixture G and comprises a flame body 1 and a flow guide device 2.

[0089] The flame body 1 defines an interior space 11 which is connected via openings in the flame body 1 to an outer combustion surface 12 of the flame body 1, on which the combustion of an air-fuel mixture G introduced into the interior space 11 and flowing through the openings takes place in one or more burner flames.

[0090] The flow guide device 2 is arranged in the interior 11 and comprises an axial flow channel 21 located in the interior 11 for conducting the air-fuel mixture G, which in the first embodiment runs parallel to the longitudinal axis LA of the flame body 1. Furthermore, the flow guide device 2 comprises three further flow channels 22, which, with respect to a cross-section perpendicular to the longitudinal axis LA of the flame body 1, completely surround an outer circumference of the axial flow channel 21 (see Fig. 1B ).

[0091] The axial length L of the axial flow channel 21 is selected depending on an oscillation frequency induced by the one or more burner flames. With respect to the flame body 1, the axial flow channel 21 is arranged centrally, so that, in the cross-section perpendicular to the longitudinal axis LA of the flame body 1, it is spaced from a circumferential inner wall of the flame body 1 adjacent to the interior space 11.

[0092] The flow guide device 2 is designed as a tube insert comprising a central tube element 23, which forms the axial flow channel 21, and three fin elements 24, which are arranged on an outer circumference of the central tube element 23 in an outwardly directed manner, wherein two of the plurality of fin elements 24 each delimit one of the three further flow channels 22 in a circumferential direction of the tube insert.

[0093] Radial end sections of the fin elements 24 are flush with a circumferential inner wall of the flame body 1, such that the three further flow channels 22 in the cross section perpendicular to the longitudinal axis LA of the flame body 1 are each formed by a section of the tube element 23, sections of two of the three fin elements 24 and by a section of the circumferential inner wall of the flame body 1 (see Fig. 1B ).

[0094] The air-fuel mixture G is introduced via the right-hand opening of the circular-cylindrical flame body 1 to the interior 11, the opening area of ​​which in this case also corresponds to an inlet area 13 for the air-fuel mixture G.

[0095] The axial flow channel 21, which is also circularly cylindrical, has a diameter in the cross section perpendicular to the longitudinal axis LA of the flame body 1 which corresponds approximately to 50% or more of the diameter of the inlet surface 13.

[0096] The flow guide device 2 forms a type of resonator for the air-fuel mixture G in the interior space 11, which is adapted to the oscillation frequency and via which the oscillation behavior of the entire burner device 100 is significantly modified compared to a design without the flow guide device 2, in particular to reduce oscillations of the burner device 100 and / or its components, thereby reducing the risk of incomplete combustion and / or flashbacks into the interior space 11, which in turn increases the efficiency of the burner device 100. Furthermore, this results in lower noise emissions during operation, which is perceived by the user as a high level of comfort.

[0097] Fig. 2A shows a cross section of a partial area of ​​a second embodiment of the burner device 100 according to the invention along a longitudinal axis LA of a flame body 1. Fig. 2Bshows a cross-section perpendicular to the longitudinal axis LA in the Fig. 2A marked section plane AA.

[0098] The basic structure corresponds approximately to that of the first embodiment, which is why a further description is omitted here.

[0099] The essential difference between the first and the second embodiment is that the latter still has a flame arrester 3 arranged largely in the interior 11, which is particularly suitable for use with hydrogen-containing fuels.

[0100] The inlet area 13 corresponds to the opening area of ​​the right-hand opening of the flame arrester 3 from Fig. 2A, through which the air-fuel mixture G is introduced into the interior 11 or into the interior of the flame arrester 3, and is offset parallel to an opening surface 11 of the flame body 1 along the longitudinal axis LA. The interior of the flame arrester 3 is at least a partial area of ​​the interior 11.

[0101] The introduction into the flame arrester 3, which is permeable to the air-fuel mixture G, takes place, so that during operation the air-fuel mixture G flows from the partial area of ​​the interior 11 located inside the flame arrester 3 through the flame arrester 3 into one of the remaining partial areas of the interior 11 and from there exits through the openings in the flame body onto the combustion surface 12.

[0102] In contrast to the first embodiment from Fig. 1A and 1BThe tube insert is not fitted into the flame body 1, but mostly into the flame arrester 3, and is therefore only located in the part of the interior 11 delimited by the flame arrester 3.

[0103] In this way, the flow guide device 2 is arranged upstream (with respect to the flow direction of the air-fuel mixture G during operation of the burner device 100) of the flame arrester 3 and can contribute to vibration reduction there, whereby the latter is not only protected from flashback flames, but also does not impede the flow of the air-fuel mixture G in the region of the openings of the flame body 1.

[0104] Fig. 3 shows a perspective view of a flow guide device 2, as shown in the embodiments in Fig. 1A, 1B and Fig. 2A , 2B is used.

[0105] The flow guide device 2 is designed as a tube insert, which is either inserted into the flame body 1 made of Fig. 1A, 1B or into the flame arrester 3 from Fig. 2A , 2B is fitted

[0106] The tube insert comprises a central tube element 23, which forms the axial flow channel 21 with the axial length L selected depending on the oscillation frequency, and three fin elements 24, which are arranged on an outer circumference of the central tube element 23 directed outwards.

[0107] The tube insert can be manufactured from a single piece. Alternatively, the finished fin elements 24 can also be integrally bonded to the tube element to form the tube insert.

[0108] At least one of the fin elements 24 has a recess on the rear side, which serves as an anti-twist device within the interior space 11 or within the flame arrester 3.

[0109] Fig. 4shows a schematic flow diagram of an embodiment of the method according to the invention for vibration reduction in a burner device.

[0110] In step S1, a burner device is operated by burning an air-fuel mixture on an outer combustion surface of the flame body.

[0111] The burner device is designed to provide heat energy by combustion of the air-fuel mixture and for this purpose comprises the flame body, which delimits an interior space which is connected via openings in the flame body to the outer combustion surface of the flame body, on which the combustion of the air-fuel mixture introduced into the interior space and flowing through the openings takes place in one or more burner flames.

[0112] In step S2, an oscillation frequency of the burner device during operation is recorded, again comprising sub-steps S2.1 and S2.2.

[0113] In step S2.1, a frequency spectrum of the vibrations of the burner device is recorded and in step S2.2, a vibration frequency is selected from the recorded vibration spectrum, in particular such that the frequency spectrum has a peak with respect to the vibration amplitude at the selected vibration frequency.

[0114] In step S3, a flow guide device is provided which comprises an axial flow channel for passing the air-fuel mixture, for which an axial length is determined in sub-step S3.1 as a function of the oscillation frequency selected in step S2 and on the basis of which the flow guide device is created in sub-step S3.2, the axial flow channel of which has a length which corresponds to the determined axial length from sub-step S3.1.

[0115] In step S4, the provided flow guide device is inserted into the interior of the burner device.

[0116] Embodiments of the present invention and their advantages have been described in detail above with reference to the accompanying figures.

[0117] It is emphasized again that the present invention is in no way limited to the above-described embodiments and their implementation features. The invention further encompasses modifications of the aforementioned embodiments, in particular those resulting from modifications and / or combinations of the features of the described embodiments within the scope of the independent claims. List of reference symbols

[0118] 1 Flame body 2 Flow guide device 3 Flame arrester 11 Interior 12 Burning surface 13 Inlet surface 21 Axial flow channel 22 Additional flow channels 23 Tube element 24 Fin element 100 Burner device GAir-fuel mixture LALongitudinal axis fuel

Claims

1. Burner device (100) for providing thermal energy by combustion of an air-fuel mixture (G), comprising: - a flame body (1) which delimits an interior space (11) which is connected via openings in the flame body (1) to an outer combustion surface (12) of the flame body (1), on which the combustion of an air-fuel mixture (G) introduced into the interior space (11) and flowing through the openings takes place in one or more burner flames, and - a flow guide device (2) which comprises an axial flow channel (21) which is located largely or completely in the interior space (11) for passing the air-fuel mixture (G), which runs in particular parallel to a longitudinal axis (LA) of the flame body (1), the axial length of which is selected as a function of an oscillation frequency induced by the one or more burner flames.

2. Burner device (100) according to claim 1, wherein the axial length is selected as a function of an oscillation frequency of the burner device (100) which occurs when the burner device (100) is operated without a flow guide device (2).

3. Burner device (100) according to claim 2, wherein the axial length is selected in additional dependence on the speed of sound of the air-fuel mixture (G).

4. Burner device (100) according to at least one of claims 1 to 3, wherein a ratio of a cross-sectional area of ​​the axial flow channel (21) in a cross-section perpendicular to the longitudinal axis (LA) of the flame body (1) to an inlet area (13) via which the air-fuel mixture is introduced into the interior (11) is greater than or equal to 15%, in particular greater than or equal to 25%.

5. Burner device (100) according to at least one of claims 1 to 4, wherein the axial flow channel (21) is arranged centrally with respect to the flame body (1) so that, in the cross section perpendicular to the longitudinal axis (LA) of the flame body (1), it is spaced from a circumferential inner wall of the flame body (1) adjacent to the interior space (11).

6. Burner device (100) at least according to claim 5, characterized in that the flow guiding device (2) comprises further flow channels (22) for passing the air-fuel mixture (G), which run in particular parallel to a longitudinal axis (LA) of the flame body (1), which are arranged between the axial flow channel (21) and the circumferential inner wall of the flame body (1) with respect to the cross section perpendicular to the longitudinal axis (LA) of the flame body (1).

7. Burner device (100) at least according to claim 6, wherein the flow guide device (2) is designed as a tube insert which comprises a central tube element (23) which forms the axial flow channel (21), and a plurality of fin elements (24) which are arranged on an outer circumference of the central tube element (23) directed outwards, wherein in each case two of the plurality of fin elements (24) delimit one of the further flow channels (22) in a circumferential direction of the tube insert.

8. Burner device (100) according to at least one of claims 6 or 7, wherein the flow guide device (2) comprises at least three further flow channels (22) which, with respect to the cross section perpendicular to the longitudinal axis (LA) of the flame body (1), completely surround an outer circumference of the axial flow channel (21).

9. Burner device (100) according to at least one of claims 1 to 8, wherein the burner device (100) further comprises a flame arrester (3) arranged largely or entirely in the interior (11), wherein the flow guide device (2) is arranged largely or entirely within the flame arrester (3).

10. Burner device (100) at least according to one of claims 7 or 8 and according to claim 9, wherein radial end sections of the fin elements (24) are flush with a circumferential inner wall of the flame arrester (3), such that the further flow channels (22) in the cross section perpendicular to the longitudinal axis (LA) of the flame body (1) are each formed by a section of the tubular element (23), sections of two of the plurality of fin elements (24) and by a section of a circumferential inner wall of the flame arrester (3).

11. Burner device (100) according to one of claims 7 or 8, characterized in thatradial end sections of the fin elements (24) are flush with a circumferential inner wall of the flame body (1), such that the further flow channels (22) are each formed by a section of the tubular element (23), sections of two of the plurality of fin elements (24) and by a section of the circumferential inner wall of the flame body (1) in the cross-section perpendicular to the longitudinal axis (LA) of the flame body (1).

12. A method for adjusting the vibration of a burner device (100) which is designed to provide thermal energy by combustion of an air-fuel mixture (G), and which comprises a flame body (1) which delimits an interior space (11) which is connected via openings in the flame body (1) to an outer combustion surface (12) of the flame body (1), on which the combustion of an air-fuel mixture (G) introduced into the interior space (11) and flowing through the openings takes place in one or more burner flames, comprising the steps of: - operating the burner device (100) with a combustion of the air-fuel mixture (G) on the outer combustion surface (12) of the flame body (1); - detecting a vibration frequency of the burner device (100) during operation, in particular with a detection point in a combustion chamber of the burner device (100) or in an environment of the burner device (100);- Providing a flow guide device (2) comprising an axial flow channel (21) for conducting the air-fuel mixture (G), again comprising: - determining an axial length of the axial flow channel (21) as a function of the detected oscillation frequency; and - creating the flow guide device whose axial flow channel has a length corresponding to the determined axial length. - Inserting the provided flow guide device (2) into the interior (11) of the burner device (100).

13. A heat generator for transferring thermal energy to a fluid, in particular for use in a heating system or in a domestic water supply system, at least comprising: - a burner device (100) according to one of claims 1 to 11; - a heat exchanger coupled to the burner device (100), via which heat energy provided by the burner device (100) can be transferred to the fluid.

14. A heating system for heating a building, comprising at least: - a piping system for transporting a fluid energy transport medium; and - a heat generator according to claim 13 for heating the energy transport medium to be transported through the piping system.

15. A domestic water supply system for supplying domestic water, comprising at least: - a pipe system for transporting the domestic water; and - a heat generator according to claim 13 for heating the domestic water to be transported through the pipe system.

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