A combustion chamber and combustor for suppressing combustion oscillations

Abstract

This invention relates to the field of energy and power technology, and provides a combustion chamber for suppressing combustion oscillations and a burner including the combustion chamber. The combustion chamber includes: a pre-combustion stage, a main combustion stage, a combustion chamber body, and a vibration damping ring. The pre-combustion stage includes a central body and a pre-combustion stage swirler and an interstage section disposed around the central body. The main combustion stage is disposed around the pre-combustion stage and includes a main combustion stage swirler and a main combustion stage outer ring. The combustion chamber body includes a transition section and a flame tube. The transition section connects the main combustion stage, the combustion chamber flame tube, and the vibration damping ring. The transition section is provided with cooling holes for cooling the vibration damping ring. The vibration damping ring is fixed to the transition section or integrally formed with the transition section, and the vibration damping ring forms a flame channel that gradually expands along the direction away from the main combustion stage. Compared with the combustion chambers of the prior art, this invention can be modified on existing burners and also has the advantages of thermal protection and cooling.

Description

Technical Field

[0001] This invention relates to the field of energy and power technology, and in particular to a combustion chamber and burner for suppressing combustion oscillations. Background Technology

[0002] Humanity still primarily obtains energy and power through the combustion of fossil fuels. In energy and power applications, combustion oscillation is a common technical challenge in various burners, widely present in boilers, gas water heaters, gas turbines, and other combustion devices. Especially under increasingly stringent emission requirements, to reduce emissions of pollutants, primarily nitrogen oxides (NOx), advanced combustion devices often employ lean premixed combustion modes. These devices frequently operate near flameout, making them highly sensitive to external disturbances and prone to heat release rate fluctuations. When these heat release rate fluctuations are acoustically coupled with the combustion system (which can be simply understood as satisfying the Rayleigh criterion), they can easily trigger significant heat release rate and pressure fluctuations. These fluctuations can range from affecting the stable operation of the combustion device to causing structural damage to the device or other components, and in severe cases, threatening the operational safety of the entire system. Therefore, combustion oscillation is something that modern advanced combustion devices must strive to avoid.

[0003] To address the problem of combustion oscillations, various methods have been proposed for controlling them, primarily categorized into active and passive control. Active control utilizes specialized monitors and active actuators to proactively apply appropriate external excitation (such as supplying inlet air or fuel) based on monitored signals like pressure pulsations within the combustion system, suppressing or eliminating the coupling between heat release rate pulsations and pressure oscillations (sound waves). However, this method requires additional control systems and actuators, places high demands on control algorithms, increases costs, and limits its applicability. Passive control involves adding fixed devices to the combustion system to suppress or eliminate combustion oscillations. Common examples include various acoustic components, such as Helmholtz resonators, which can suppress combustion oscillations at specific frequencies. The disadvantages are their large size, effectiveness only at specific frequencies, and the need for extensive prior experimentation and debugging.

[0004] In existing technologies, combustion oscillations are generally suppressed by machining the transition section or flame tube of the combustion chamber with a conical transition structure, or by installing a conical transition structure only on the outer ring outlet end face and / or the inner surface of the transition section. However, these solutions cannot be used for retrofitting existing burners, and they do not adequately consider the thermal protection of the conical transition structure, making it difficult to withstand the extremely high temperatures inside the combustion chamber and prone to structural ablation. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a combustion chamber for suppressing combustion oscillations, thereby solving the problems of difficulty in retrofitting existing burners and thermal protection.

[0006] The present invention also proposes a burner.

[0007] A combustion chamber for suppressing combustion oscillations according to a first aspect embodiment of the present invention includes:

[0008] A pre-combustion stage, the pre-combustion stage comprising a central body and pre-combustion stage cyclones and interstage sections disposed around the central body;

[0009] The main combustion stage is disposed around the pre-combustion stage, and the main combustion stage includes a main combustion stage cyclone separator and a main combustion stage outer ring;

[0010] The combustion chamber body includes a transition section and a flame tube. The transition section connects the outer ring of the main combustion stage and the flame tube. Cooling holes are provided on the transition section.

[0011] The vibration damping ring is fixed to the inner surface of the transition section or integrally formed with the transition section. A gap is left between the vibration damping ring and the transition section, and the vibration damping ring forms a flame channel that gradually expands along the direction away from the main combustion stage. Cooling air flowing out of the cooling holes of the transition section impacts the back of the flame channel for cooling. The inlet end of the flame channel is connected to the outlet end of the main combustion stage, and the outlet end of the flame channel is connected to the inner cavity of the combustion chamber body.

[0012] According to one embodiment of the present invention, the outlet end of the vibration damping ring is provided with a flow guiding end face.

[0013] According to one embodiment of the present invention, the inlet end of the vibration damping ring has a smooth transition with the outer ring of the main combustion stage or there is a step gap.

[0014] According to one embodiment of the present invention, a cooling purging hole is provided between the inlet end of the anti-vibration ring and the outer ring outlet end face of the main combustion stage outer ring.

[0015] According to one embodiment of the present invention, the flame channel of the anti-vibration ring is a conical surface with the same expansion angle, or a conical surface with varying expansion angle.

[0016] According to one embodiment of the present invention, the cross-section of the flame channel inlet end and the cross-section of the outlet end of the vibration damping ring are both circular, or the cross-section of the flame channel inlet end and the cross-section of the outlet end of the vibration damping ring are both elliptical; the interstage section includes an interstage section outlet end face, the main combustion stage cyclone includes a main combustion stage cyclone outlet end face, and the interstage section outlet end face is offset from the outer ring outlet end face of the main combustion stage outer ring.

[0017] According to one embodiment of the present invention, the pre-combustion stage further includes a pre-combustion stage fuel nozzle disposed in the central body, and the main combustion stage further includes a main combustion stage fuel nozzle disposed in the main combustion stage cyclone separator or the interstage section.

[0018] According to one embodiment of the present invention, the flame tube structure is a single fan shape, a rectangle, or a cylinder.

[0019] According to one embodiment of the present invention, the combustion chambers for suppressing combustion oscillations are multiple and are arranged in a ring, a horizontal and vertical arrangement, or a radial distribution from the center to the periphery.

[0020] According to a second aspect of the present invention, a burner includes a combustion chamber for suppressing combustion oscillations as described in any of the above embodiments, wherein the burner is a swirl cup structure burner, a multi-swirl burner, or a center-stage burner.

[0021] This invention provides a combustion chamber for suppressing combustion oscillations. The combustion chamber body includes a transition section and a flame tube, and cooling air flowing from cooling holes impacts the back of the flame channel for cooling. This combustion chamber for suppressing combustion oscillations is optimized for practical engineering considerations, allowing for the retrofitting of existing burners. It offers advantages such as low retrofitting costs and wide applicability, while also addressing the needs for combustion chamber thermal protection and cooling.

[0022] The burner according to an embodiment of the present invention, since it includes the above-described combustion chamber, has all the technical effects of the above-described combustion chamber, which will not be repeated here.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of a combustion chamber structure for suppressing combustion oscillations provided in an embodiment of the present invention;

[0026] Figure 2 This is a partial structural schematic diagram of an anti-vibration ring provided in an embodiment of the present invention;

[0027] Figure 3 This is a three-dimensional schematic diagram of a combustion chamber structure for suppressing combustion oscillations provided in an embodiment of the present invention;

[0028] Figure 4 This is a partial structural schematic diagram of a vibration damping ring with a flow guiding end face provided in an embodiment of the present invention;

[0029] Figure 5 This is a partial structural schematic diagram of a vibration damping ring with a flow guiding end face provided in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of an annular combustion chamber provided in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of a transition section of an annular combustion chamber provided in an embodiment of the present invention;

[0032] Figure 8 This is a partial longitudinal cross-sectional schematic diagram of an annular combustion chamber provided in an embodiment of the present invention;

[0033] Figure label:

[0034] 1. Central body; 2. Pre-combustion stage cyclone separator; 3. Interstage section; 4. Main combustion stage cyclone separator; 5. Main combustion stage outer ring; 51. Outer ring outlet end face; 6. Transition section; 61. Cooling hole; 7. Vibration damping ring; 71. Flame channel; 72. Guide end face; 73. Spacer step; 74. Cooling purge hole; 8. Flame tube. Detailed Implementation

[0035] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0036] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0038] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0040] This invention provides a combustion chamber for suppressing combustion oscillations, such as... Figures 1 to 5As shown, the combustion chamber includes a pre-combustion stage, a main combustion stage, a combustion chamber body, and a vibration damping ring 7. The pre-combustion stage includes a central body 1 and a pre-combustion stage swirler 2 and an interstage section 3 disposed around the central body 1. The main combustion stage is disposed around the pre-combustion stage and includes a main combustion stage swirler 4 and a main combustion stage outer ring 5. The combustion chamber body includes a transition section 6 and a flame tube 8. The transition section 6 connects the main combustion stage outer ring 5 and the flame tube 8. The transition section is provided with cooling holes 61 for cooling the anti-vibration ring 7. The anti-vibration ring 7 is fixed to the inner surface of the transition section 6 or integrally formed with the transition section 6. A gap is left between the anti-vibration ring 7 and the transition section 6. The anti-vibration ring 7 forms a flame channel 71 that gradually expands along the direction away from the main combustion stage. The cooling air flowing out of the cooling holes 61 on the transition section 6 impacts the back of the flame channel 71 for cooling. The inlet end of the flame channel 71 is connected to the outlet end of the main combustion stage, and the outlet end of the flame channel 71 is connected to the inner cavity of the combustion chamber body.

[0041] The vibration damping ring 7 has a flame channel 71 that gradually expands in the direction away from the main combustion stage. During operation, based on the Coanda effect, the unburned mixture of air and fuel entering the flame channel 71 will flow along the flame channel 71, so that the flame front will flow as close as possible to the inner wall of the flame channel 71, thereby reducing the heat release rate pulsation, decoupling it from the acoustic system of the combustion system, and ultimately suppressing combustion oscillation.

[0042] This invention provides a combustion chamber for suppressing combustion oscillations. The combustion chamber body includes a transition section and a flame tube, and cooling air flowing from cooling holes impacts the back of the flame channel for cooling. This combustion chamber for suppressing combustion oscillations is optimized for practical engineering considerations, allowing for the retrofitting of existing burners. It offers advantages such as low retrofitting costs and wide applicability, while also addressing the needs for combustion chamber thermal protection and cooling.

[0043] According to one embodiment of the present invention, the vibration damping ring 7 is connected to the transition section 6 and / or the main combustion stage outer ring 5 by integral machining, welding, or fastener connection. Of course, the connection method between the vibration damping ring 7 and the transition section 6 and / or the main combustion stage outer ring 5 is not limited to the examples given herein.

[0044] According to one embodiment of the present invention, the outlet end of the anti-vibration ring 7 is provided with a guide end face 72, which may be perpendicular to or not perpendicular to the burner axial direction. The angle between the guide end face 72 and the burner axial direction can be selected according to actual needs.

[0045] According to one embodiment of the present invention, the inlet end of the anti-vibration ring 7 has a smooth transition with the outer ring 5 of the main combustion stage or there is a certain interval step 73.

[0046] According to one embodiment of the present invention, a cooling purging hole 74 is provided between the inlet end of the vibration damping ring 7 and the outer ring outlet end face 51 of the main combustion stage outer ring 5 for introducing cooling air for cooling and heat dissipation.

[0047] According to one embodiment of the present invention, the flame channel 71 of the vibration damping ring is a simple conical surface with the same expansion angle, or a complex conical surface with varying expansion angles. Its expansion angle can be selected as needed to allow the flame to form a Conrad effect, conforming as closely as possible to the flow of the vibration damping ring. Of course, the present invention is not limited to the above examples; for example, the shape of the flame channel 71 can also be: a 45° expansion angle in the first half and a 25° expansion angle in the second half; or it can present a complex curved surface.

[0048] According to another embodiment of the present invention, the cross-section of both the inlet end and the outlet end of the flame channel 71 is circular, or the cross-section of both the inlet end and the outlet end of the flame channel 71 of the vibration damping ring 7 is elliptical. This is to accommodate non-axisymmetric flame tube profiles, such as rectangular or single-fan flame tubes, while satisfying the Coanda effect. Of course, the present invention is not limited to the above examples; for example, the shape of the flame channel 71 can also be: the inlet end cross-section is circular, and the outlet end cross-section is elliptical.

[0049] According to one embodiment of the present invention, the interstage section 3 includes an interstage section outlet end face, the main combustion stage cyclone 4 includes a main combustion stage cyclone outlet end face, and the interstage section outlet end face is offset from the outer ring outlet end face 51 of the main combustion stage outer ring 5.

[0050] According to one embodiment of the present invention, the outlet end of the flame channel 71 of the vibration damping ring 7 is flush or not flush.

[0051] According to one embodiment of the present invention, the pre-combustion stage further includes a pre-combustion stage fuel nozzle disposed in the central body 1, and the main combustion stage further includes a main combustion stage fuel nozzle disposed in the main combustion stage cyclone 4 or the interstage section 3.

[0052] According to one embodiment of the present invention, the flame tube 8 has a single-fan shape, an approximately rectangular shape, or a cylindrical shape, which can be designed accordingly based on the actual situation.

[0053] According to one embodiment of the present invention, there are multiple combustion chambers for suppressing combustion oscillations, and they are arranged in a ring, a transverse and longitudinal arrangement, or a radial distribution from the center to the periphery. Specifically, as shown in... Figures 6 to 8As shown, it is a ring-shaped combustion chamber, that is, the flame tube 8 is a large cylindrical structure with multiple combustion chamber structures and anti-vibration ring structures around it. Of course, it can also be designed as a combustion chamber of other shapes, such as a combustion chamber structure with the same horizontal and vertical spacing or a combustion chamber structure that is arranged from the center to the periphery. It can be designed according to the actual situation.

[0054] According to one embodiment of the present invention, the burner includes, but is not limited to, conventional swirl cup structure burners, multi-swirl burners, and center-stage burners.

[0055] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A combustion chamber for suppressing combustion oscillations, characterized in that, include: The pre-combustion stage includes a central body (1) and a pre-combustion stage cyclone separator (2) and an interstage section (3) disposed around the central body (1); The main combustion stage is disposed around the pre-combustion stage, and the main combustion stage includes a main combustion stage cyclone separator (4) and a main combustion stage outer ring (5); The combustion chamber body includes a transition section (6) and a flame tube (8). The transition section (6) connects the outer ring (5) of the main combustion stage and the flame tube (8). The transition section (6) is provided with cooling holes (61). The vibration damping ring (7) is fixed to the inner surface of the transition section (6) or integrally formed with the transition section (6). There is a gap between the vibration damping ring (7) and the transition section (6). The vibration damping ring (7) forms a flame channel (71) that gradually expands along the direction away from the main combustion stage. The cooling air flowing out of the cooling hole (61) of the transition section (6) impacts the back of the flame channel (71) for cooling. The inlet end of the flame channel (71) is connected to the outlet end of the main combustion stage. The outlet end of the flame channel (71) is connected to the inner cavity of the combustion chamber body. The outlet end of the anti-vibration ring (7) is provided with a flow guide end face (72), which is perpendicular to the burner axis; A cooling purging hole (74) is provided between the inlet end of the anti-vibration ring (7) and the outer ring outlet end face (51) of the main combustion stage outer ring (5).

2. The combustion chamber for suppressing combustion oscillations according to claim 1, characterized in that, The inlet end of the vibration damping ring (7) has a smooth transition with the outer ring (5) of the main combustion stage or there is a gap step (73).

3. The combustion chamber for suppressing combustion oscillations according to claim 2, characterized in that, The flame channel (71) of the vibration damping ring (7) is a conical surface with the same expansion angle, or a conical surface with a varying expansion angle.

4. The combustion chamber for suppressing combustion oscillations according to claim 1, characterized in that, The cross-section of the inlet end of the flame channel (71) of the anti-vibration ring (7) and the cross-section of the outlet end are both circular, or the cross-section of the inlet end of the flame channel (71) of the anti-vibration ring (7) and the cross-section of the outlet end are both elliptical; the interstage section (3) includes an interstage section outlet end face, the main combustion stage cyclone separator (4) includes a main combustion stage cyclone separator outlet end face, and the interstage section outlet end face is offset from the outer ring outlet end face (51) of the main combustion stage outer ring (5).

5. The combustion chamber for suppressing combustion oscillations according to claim 1, characterized in that, The pre-combustion stage also includes a pre-combustion stage fuel nozzle, which is disposed in the central body (1). The main combustion stage also includes a main combustion stage fuel nozzle, which is disposed in the main combustion stage cyclone separator (4) or the interstage section (3).

6. The combustion chamber for suppressing combustion oscillations according to claim 1, characterized in that, The flame tube (8) has a single-fan shape, a rectangular shape, or a cylindrical shape.

7. The combustion chamber for suppressing combustion oscillations according to any one of claims 1-6, characterized in that, The combustion chambers used to suppress combustion oscillations are multiple and are distributed in a ring, in a horizontal and vertical arrangement, or in a radiating pattern from the center to the periphery.

8. A burner, characterized in that, The burner includes a combustion chamber for suppressing combustion oscillations as described in any one of claims 1-7, wherein the burner is a swirl cup structure burner, a multi-swirl burner, or a centrally staged burner.

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