Ignition electrode mounting structure, combustion chamber

Abstract

The application provides a kind of ignition electrode mounting structure for fixing ignition electrode, ignition electrode penetrates combustion chamber outer casing, flame tube outer ring and the combustion chamber outer casing and the flame tube outer ring defined combustion chamber outer ring cavity, and extends to flame tube cavity.The ignition electrode mounting structure includes electrode sleeve, floating sleeve and cooling hole.Electrode sleeve is sleeved on the outside of ignition electrode, and the side close to the flame tube outer ring is flared;Floating sleeve includes base and cover, one side of the base abuts against the flame tube outer ring, the other side abuts against the flared portion, the cover is used to accommodate the flared portion, and the flared portion and the base are allowed to be relatively rotatably matched;Cooling hole is arranged on the flared portion, and the cooling hole is arranged to be directed to the tail of ignition electrode, so as to guide the cooling gas in the combustion chamber outer ring cavity to the tail of ignition electrode.The above-mentioned ignition electrode mounting structure can realize sealing and cooling of ignition electrode.The application also provides a combustion chamber.

Description

Technical Field

[0001] This invention relates to the field of combustion chambers, and more specifically to the field of ignition nozzle structures. Background Technology

[0002] Modern high-bypass turbofan aero-engines are gas turbines whose combustion chamber flame tubes are made of nickel-based or cobalt-based high-temperature alloys. As aero-engine technical requirements continue to rise, the inlet and outlet temperatures and pressures of the combustion chamber are also increasing. Traditional high-temperature alloys have revealed their insufficient temperature resistance, necessitating the use of large amounts of cooling air to lower their operating temperature. However, the introduction of large amounts of cooling air can also lead to incomplete combustion, generating excessive pollutants and failing to meet the high standards required for aero-engine products.

[0003] Ceramic matrix composites are a class of composite materials formed by introducing toughening and reinforcing materials into a brittle ceramic matrix. Among them, silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiC) are an example. f / SiC (SiC), as a novel high-temperature resistant ceramic matrix composite material, possesses advantages such as high temperature resistance, low density, low coefficient of thermal expansion, high specific strength, high modulus, oxidation resistance, ablation resistance, and relative insensitivity to cracking. Based on these advantages, ceramic matrix composites have become an ideal material choice for hot-section components of advanced aero-engines. International aero-engine companies, represented by SNECMA, GE, and Rolls-Royce, recognized the superior performance and application prospects of ceramic matrix composites early on and actively carried out research and application of ceramic matrix composites in aero-engines. With the support of ceramic matrix composite research and development projects from national government agencies in the countries where these companies are located, and in collaboration with universities and research institutions, extensive application verification of ceramic matrix composite components has been conducted using model development as a verification platform. These applications range from ground-based gas turbines to military low-bypass turbofan engines and commercial high-bypass turbofan engines, and from components with lower technical risks such as sealing plates, regulating plates, and tail nozzles to core aero-engine components such as high-pressure turbines and combustion chambers.

[0004] The ignition nozzle inside the combustion chamber is used to ignite the flame tube. To maintain the pressure difference between the outer annular cavity of the combustion chamber and the flame tube cavity, a sealing structure should be designed at the point where the ignition nozzle passes through the outer annular wall of the flame tube to prevent uncontrolled airflow. Even in the event of manufacturing errors or thermal deformation, the sealing structure must remain effective. Furthermore, the flame tube cavity temperature is high, so timely cooling of the ignition nozzle is necessary to protect it and extend its service life. For traditional flame tubes made of high-temperature alloy materials, this sealing is currently achieved by welding a floating sleeve onto the outer annular wall of the flame tube. However, for CMC flame tubes, a welded floating sleeve structure is not feasible.

[0005] Therefore, it is necessary to propose an ignition nozzle mounting structure to solve the above problems. SUMMARY

[0006] An object of the present application is to provide an igniter tip mounting structure that can meet the sealing requirement of an igniter tip and also can cool the igniter tip.

[0007] The igniter tip mounting structure for fixing an igniter tip that penetrates a combustor outer casing, a flame tube outer ring and a combustor outer ring cavity defined by the combustor outer casing and the flame tube outer ring and extends to a flame tube cavity, comprises an igniter tip sleeve, a floating sleeve and a cooling hole. The igniter tip sleeve is sleeved on the outside of the igniter tip, and the side close to the flame tube outer ring is flared. The floating sleeve comprises a base and a cover. The base abuts against the flame tube outer ring and abuts against the flared portion. The cover is used to accommodate the flared portion and allows the flared portion to be relatively rotatable with the base. The cooling hole is arranged on the flared portion and is arranged towards the tail of the igniter tip to guide the cooling gas in the combustor outer ring cavity to the tail of the igniter tip.

[0008] In one or more embodiments, the top diameter of the cover is less than the maximum diameter of the flared portion.

[0009] In one or more embodiments, the surface of the base abutting against the flared portion is a concave spherical surface or a convex spherical surface.

[0010] In one or more embodiments, the igniter tip mounting structure further comprises a resilient member sleeved on the outside of the igniter tip and arranged to be able to transmit a radial force to the igniter tip sleeve to press the flared portion against the base to form a seal.

[0011] In one or more embodiments, the igniter tip mounting structure further comprises a clamping pad sleeved on the outside of the igniter tip and located between the resilient member and the igniter tip sleeve.

[0012] In one or more embodiments, the igniter tip mounting structure further comprises a heat shield fixedly arranged on the combustor outer casing and penetrated by the igniter tip sleeve, and the heat shield is used to isolate the resilient member from the combustor outer ring cavity.

[0013] In one or more embodiments, the flame tube outer ring comprises a plurality of inclined holes.

[0014] In one or more embodiments, the flame tube outer ring is made of ceramic matrix composite material.

[0015] Another object of the present application is to provide a combustion chamber comprising a combustion chamber outer casing, a combustion chamber inner casing, a flame tube outer ring, a flame tube inner ring and an ignition electrode, which uses the above-mentioned ignition electrode mounting structure to mount the ignition electrode.

[0016] The above-mentioned ignition electrode mounting structure achieves sealing of the ignition electrode by rotatably fitting the base of the floating sleeve with the flared portion, and can meet the sealing requirement even in the presence of manufacturing errors and thermal deformation and the like, and also achieves cooling of the ignition electrode by providing cooling holes directed towards the tail of the ignition electrode to guide cooling gas in the combustion chamber outer ring cavity to the tail of the ignition electrode, effectively prolonging the service life of the ignition electrode. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above-mentioned and other features, properties and advantages of the present application will become more apparent by reference to the following description of embodiments thereof taken in conjunction with the accompanying drawings in which:

[0018] Figure 1 is a schematic diagram of an embodiment of a high-bypass-ratio turbofan aeroengine.

[0019] Figure 2 is a schematic diagram of an embodiment of a combustion chamber.

[0020] Figure 3 is a schematic diagram of an embodiment of an ignition electrode mounting structure.

[0021] Figure 4 is a schematic diagram of an inner concave spherical surface.

[0022] Figure 5A is a schematic diagram of an embodiment of a floating sleeve and electrode sleeve when vertical.

[0023] Figure 5B is a schematic diagram of an embodiment of a floating sleeve after rotation.

[0024] Figure 6A is a schematic diagram of another embodiment of a floating sleeve and electrode sleeve when vertical.

[0025] Figure 6B is a schematic diagram of another embodiment of a floating sleeve after rotation.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 1, inlet duct

[0028] 2, fan

[0029] 3, planetary gearbox

[0030] 4, low-pressure compressor

[0031] 5, high-pressure compressor

[0032] 6. combustion chamber

[0033] 7. high pressure turbine

[0034] 8. low pressure turbine

[0035] 9. low speed shaft

[0036] 10. high speed shaft

[0037] 61. combustion chamber outer casing

[0038] 62. diffuser

[0039] 63. combustion chamber inner casing

[0040] 64. fuel nozzle

[0041] 65. outer cap

[0042] 66. head adapter section

[0043] 67. inner cap

[0044] 68. flame tube outer ring

[0045] 69. flame tube inner ring

[0046] 70. igniter

[0047] 79. floating sleeve

[0048] 101. ambient atmosphere

[0049] 102. outer bypass airflow

[0050] 103. inner bypass airflow

[0051] 201. combustion chamber outer annulus

[0052] 202. flame tube annulus

[0053] 701. gasket

[0054] 703. connector

[0055] 704. spring

[0056] 705. retainer

[0057] 707. igniter sleeve

[0058] 707a. flared end

[0059] 708. cover

[0060] 708a. cover end

[0061] 709. base

[0062] 710, local face DETAILED DESCRIPTION

[0063] The application will be further described with reference to the specific examples and drawings, in which more details are set forth in order to provide a thorough understanding of the application, but it will be apparent that the application can be carried out in a variety of ways other than those specifically set forth herein without departing from the scope of the application. Therefore, the present application should not be limited to the specific examples described herein, but should be given the full scope permitted by the appended claims, along with an equivalent of each and every feature described or referenced.

[0064] It is to be noted that these and other subsequent figures are merely examples and are not drawn to scale, and should not be used to limit the scope of the protection actually claimed for the present application.

[0065] A gas turbine engine is an internal combustion engine that uses a continuous flow of gas as the working fluid to convert heat energy produced by burning fuel into useful work. One of them is a high-bypass turbofan aero engine. The combustor is one of the core components of the gas turbine engine, which mainly consists of a combustor case, fuel nozzles and flame tubes. The flame tube allows fuel injection into its cavity, and the fuel mixes with air and burns to produce high-temperature gas. The flame tube includes a head end wall cooperating with the fuel nozzle and an inner and outer ring of the flame tube.

[0066] In combination Figure 1 It is understood that the gas turbine engine includes an inlet duct 1, a fan 2, a planetary gearbox 3, a low-pressure compressor 4, a high-pressure compressor 5, a combustor 6, a high-pressure turbine 7, a low-pressure turbine 8, a low-speed shaft 9 and a high-speed shaft 10. After entering the gas turbine engine, the outside atmosphere 101 is divided into an outer bypass airflow 102 and an inner bypass airflow 103.

[0067] The combustor 6, as shown in Figure 2 includes a combustor outer case 61, a diffuser 62, a combustor inner case 63, a fuel nozzle 64, an outer cap 65, a head adapter 66, an inner cap 67, a flame tube outer ring 68, a flame tube inner ring 69, and an ignition electrode 70. The flame tube outer ring 68 and the flame tube inner ring 69 are made of ceramic matrix composites prepared by the prepreg tape-lay-up-infiltration process technology.

[0068] Compared with traditional high-temperature alloy materials, application of ceramic matrix composites to hot-end components such as the inner and outer rings of the combustion chamber liner of an aero-engine can reduce the weight of a single aero-engine component by more than 30%, greatly reduce the amount of cooling air, and have the potential to increase the working temperature before the turbine of the aero-engine by about 200-300°C, further improve the thermal efficiency of the aero-engine, greatly reduce the oil consumption of the aero-engine, reduce the emissions of NOx and COx, and significantly improve the fatigue service life of the components, greatly reduce the amount of cooling air of the combustion chamber liner, increase the temperature before the turbine of the aero-engine, effectively reduce the oil consumption of the aero-engine, and improve the thermal efficiency of the aero-engine.

[0069] High-voltage electricity passes through surface discharge between electrodes of the ignition electrode 70 to generate an electric spark, thereby igniting the fuel and air mixture in the combustion chamber 6. The ignition electrode 70 extends into the combustion chamber liner cavity 202 from outside the combustion chamber case, through the combustion chamber outer case 61, the combustion chamber outer ring cavity 201, and the combustion chamber liner outer ring 68.

[0070] Considering the manufacturing and installation process, an opening is generally provided on the combustion chamber liner outer ring 68 for the ignition electrode 70 to pass through. In addition, there is a certain pressure difference between the combustion chamber outer ring cavity 201 and the combustion chamber liner cavity 202, and there is a risk of arbitrary flow of air. If the combustion chamber liner outer ring 68 is made of ceramic matrix composites, the traditional welding fixation method is not applicable.

[0071] The ignition electrode installation structure described in the present disclosure can achieve sealing between the ignition electrode 70 and the combustion chamber liner outer ring 68, meet the sealing requirements under complex conditions such as manufacturing errors and thermal deformation, and cool the ignition electrode.

[0072] In combination with Figure 3 It is understood that the ignition electrode 70 extends through the combustion chamber outer case 61, the combustion chamber liner outer ring 68, and the combustion chamber outer ring cavity 201 defined by the combustion chamber outer case 61 and the combustion chamber liner outer ring 68, and the tail end of the ignition electrode 70 extends into the combustion chamber liner cavity 202 to achieve the ignition function.

[0073] The ignition electrode installation structure includes an electrode sleeve 707, a floating sleeve 79, and a cooling hole 711. The electrode sleeve 707 is sleeved outside the ignition electrode 70, and the side close to the combustion chamber liner outer ring is flared 707a, also known as a trumpet mouth. The floating sleeve 79 includes a base 709 and a cover 708. One side of the base 709 abuts against the combustion chamber liner outer ring 68, i.e. Figure 3 The lower side of the base 709 shown in the figure is in contact with the combustion chamber liner outer ring 68, and the other side is in abutment with the flared portion 707a, i.e. Figure 3The upper side shown abuts against the flared opening 707a, forming a one-line sealing structure. The cover 708 is used to accommodate the flared opening 707a and allows for a rotatable fit between the flared opening 707a and the base 709. A cooling hole 711 is provided on the flared opening 707a, and the cooling hole 711 is arranged towards the tail of the ignition nozzle 70 to guide the cooling gas in the outer annular cavity 201 of the combustion chamber to the tail of the ignition nozzle 70.

[0074] Specifically, the ignition nozzle 70 is fixed to the outer casing 61 of the combustion chamber via a nozzle mounting base 702. The nozzle mounting base 702 is fixedly connected to the outer casing 61 of the combustion chamber via a connector 703 such as a bolt. A sealing gasket 701 is also provided between the nozzle mounting base 702 and the ignition nozzle 70 for sealing the radially outer side of the ignition nozzle 70. The ignition nozzle 70 extends radially inward, passes through the outer annular cavity 201 of the combustion chamber, and extends into the flame tube cavity 202.

[0075] The ignition nozzle sleeve 707 is fitted outside the ignition nozzle 70 and located inside the outer annular cavity 201 of the combustion chamber. One side of the ignition nozzle sleeve 707 has a flared opening 707a, which is used to cooperate with the partial surface 710 on the base 709 of the floating sleeve 79 to form a seal.

[0076] When the outer ring 68 of the flame tube is tilted due to manufacturing errors or during engine operation, the outer ring 68 of the flame tube and the ignition nozzle 70 will not be perpendicular. At this time, the floating sleeve 79 will rotate under the influence of the outer ring 68 of the flame tube. Figure 4 As shown in the rotation directions A and A', the base 709 of the floating sleeve 79 will no longer be perpendicular to the electric nozzle sleeve 707, but will instead be at an angle. The floating sleeve 79 rotates together with the flame tube, and the flare 707a and the local surface 710 on the base 709 always maintain an annular line seal structure, as... Figure 4 As shown by line C, the sealing structure of this line is not affected by the rotation of the flame tube or manufacturing errors.

[0077] It should be noted that, Figure 4 This is only a schematic diagram of the principle and only shows a portion of the structure of the floating sleeve 79 and the electric nozzle sleeve 707. It should not be used to limit the scope of protection of this embodiment.

[0078] By making contact between the flared structure of the electric nozzle sleeve 707 and the local surface 710 on the floating sleeve 79, and setting it to allow relative rotation within a certain range, the sealing performance can still be guaranteed even under complex conditions such as manufacturing errors and thermal deformation.

[0079] In one embodiment, the surface of the base 709 that abuts against the flare 707a, i.e., the partial surface 710, is a convex spherical surface or a concave spherical surface, so as to allow for rotational engagement between the flare structure of the electric nozzle sleeve 707 and the base 709.

[0080] Specifically, the inner concave spherical surface is combined Figure 4 、 Figure 5A and Figure 5B It is understood that the position of the electrode nozzle sleeve 707 is unchanged, but the floating sleeve 79 will rotate in the direction A or A' under the influence of the flame tube outer ring 68, but the inner concave spherical surface still maintains linear contact with the electrode nozzle sleeve 707, ensuring the sealing effect.

[0081] The outer convex spherical surface is combined Figure 6A and Figure 6B It is understood that when the floating sleeve 79 rotates in the direction A or A' under the influence of the flame tube outer ring 68, the outer convex spherical surface can also ensure sealing, so that the linear contact does not affect the sealing due to the rotation of the floating sleeve and the movement of the flame tube.

[0082] In addition, the flared portion 707a has cooling holes 711, and the inclination angle of the cooling holes 711 is arranged to face the tail of the ignition electrode nozzle 70, so that the high-pressure gas flow with relatively low temperature in the outer ring cavity 201 of the combustion chamber can be conveniently blown to the tail of the ignition electrode nozzle 70, thereby realizing real-time cooling of the ignition electrode nozzle 70 and effectively prolonging the service life of the ignition electrode nozzle. It should be noted that the diameter of the cooling hole 711 is arranged to make the gas amount sent to the tail of the ignition electrode nozzle 70 not affect the original sealing performance.

[0083] In one embodiment, the top diameter of the sleeve cover 708, that is, the diameter at the sleeve cover end 708a, is smaller than the diameter of the flared portion 707a, so as to ensure that the electrode nozzle sleeve 707 and the sleeve cover 708 on the floating sleeve 79 do not fall off. In one embodiment, the sleeve cover 708 and the base 709 can be fixedly connected by means of welding.

[0084] In one embodiment, the ignition electrode mounting structure further comprises a resilient member 704, such as a spring. The resilient member 704 is sleeved outside the ignition electrode nozzle 70 and is arranged to be able to transmit a radial force to the electrode nozzle sleeve 707, so as to press the flared portion 707a against the base 709, and then press the base 709 against the flame tube outer ring 68 to form a seal. Through the elastic force or elastic restoring force provided by the resilient member 704, the electrode nozzle sleeve 707 can be flexibly pressed, and then the flared portion 707a is tightly matched with the base 709 on the floating sleeve 79, and the floating sleeve 79 and the flame tube outer ring 68 are also pressed, so that the floating sleeve 79 is pressed against the flame tube outer ring 68 by the radial downward force, realizing sealing and preventing the gas flow from the outer ring cavity 201 of the combustion chamber to flow into the flame tube cavity 202.

[0085] On the basis of the above-mentioned embodiments, the ignition electrode mounting structure further comprises a clamping pad 705, which is sleeved outside the ignition electrode 70 and located between the elastic member 704 and the electrode sleeve 707. Considering that it will be difficult to ensure the application point of the elastic force provided for the elastic member 704 when the diameter of the electrode sleeve 707 is too small, the clamping pad 705 with a larger diameter is additionally provided to provide the application point of the elastic force for the elastic member 704, so that the elastic force is applied and transmitted radially downward.

[0086] In order to protect the elastic member 704, in an embodiment, the ignition electrode mounting structure further comprises a heat shield 706, which is fixedly arranged on the combustion chamber outer casing 61 and penetrated by the electrode sleeve 707, and the heat shield 706 is used to isolate the elastic member 704 from the combustion chamber outer annular cavity 201. The heat shield 706 is fixedly mounted on the combustion chamber outer casing 61, which can prevent the high-temperature gas from directly impacting the elastic member 104 and prolong the service life of the elastic member.

[0087] The flame tube outer ring 68 is also provided with a plurality of inclined holes, and the wall surface is provided with inclined holes for cooling the wall surface. By providing a plurality of inclined holes, the high-pressure gas with a relatively low temperature in the combustion chamber outer annular cavity 201 can enter the flame tube cavity 202 regularly and moderately through the inclined holes. In addition, since the flame tube outer ring 68 is provided with a larger aperture at the position of the ignition electrode 70, it will cause excessive gas leakage of the high-pressure gas in the combustion chamber outer annular cavity 201 to the flame tube cavity 202, which is not conducive to combustion. Therefore, the ignition electrode mounting structure of the present disclosure can realize the relative sealing of the combustion chamber outer annular cavity 201 and the flame tube cavity 202 at the position of the ignition electrode 70 through the design of the floating sleeve 79 and the electrode sleeve 707, so as to avoid the leakage of excessive gas flowing through the position of the tail end of the ignition electrode 70.

[0088] In combination with the above introduction of the ignition electrode mounting structure, it can also be understood that a combustion chamber comprises a combustion chamber outer casing 61, a combustion chamber inner casing 63, a flame tube outer ring 68, a flame tube inner ring 69 and an ignition electrode 70, the combustion chamber uses the above-mentioned ignition electrode mounting structure to mount the ignition electrode, which can meet the sealing requirement of the ignition electrode and also can cool the ignition electrode, thereby effectively prolonging the service life of the ignition electrode.

[0089] The application uses specific language to describe the embodiments of the application. As used in this application, the terms "one embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, it is emphasized and should be appreciated that a described "embodiment" or "one embodiment" or "an alternative embodiment" is not necessarily a same embodiment as previously mentioned embodiments. Additionally, the various features, structures, or characteristics of one or more embodiments of this application can be combined in any suitable manner. In order to simplify the present disclosure, expressions of the foregoing description are sometimes used to generalize the description of one or more embodiments of the application. However, such a disclosure does not imply that the application requires a greater number of features than those mentioned in the claims. In fact, an embodiment of the application has fewer features than all the features disclosed in the foregoing description of a single embodiment.

[0090] Although the present application has been disclosed in connection with the preferred embodiments shown, it should be understood that certain modifications would occur to those skilled in the art and are intended to be within the scope of the application, which is to be limited only by the claims. Accordingly, any modification made by those skilled in the art are to be considered within the scope of the application. Therefore, it is manifestly intended that the application be limited only by the claims.

Claims

1. An ignition nozzle mounting structure for fixing an ignition nozzle (70), the ignition nozzle (70) penetrating through the combustion chamber outer casing (61), the flame tube outer ring (68), and the combustion chamber outer ring cavity (201) defined by the combustion chamber outer casing (61) and the flame tube outer ring (68), and extending into the flame tube cavity (202). Its features are, The ignition nozzle mounting structure includes: The ignition nozzle sleeve (707) is sleeved on the outside of the ignition nozzle (70), and the side near the outer ring of the flame tube is flared (707a); A floating sleeve (79) includes a base (709) and a cover (708). One side of the base (709) abuts against the outer ring (68) of the flame tube, and the other side abuts against the flare (707a) to form a line seal structure. The cover (708) is used to accommodate the flare (707a) and allows the flare (707a) and the base (709) to be rotatably engaged. There is a first gap between the cover (708) and the nozzle sleeve (707), and a second gap between the base (709) and the ignition nozzle (70). A cooling hole (711) is provided on the flare (707a). The cooling hole (711) is arranged toward the tail of the ignition nozzle (70) to guide the cooling gas in the outer ring cavity (201) of the combustion chamber to the tail of the ignition nozzle (70).

2. The ignition nozzle mounting structure as described in claim 1, characterized in that, The top diameter of the cover (708) is smaller than the maximum diameter of the flare (707a).

3. The ignition nozzle mounting structure as described in claim 1, characterized in that, The surface of the base (709) that abuts against the flared opening (707a) is a concave spherical surface or a convex spherical surface.

4. The ignition nozzle mounting structure as described in claim 1, characterized in that, The ignition nozzle mounting structure also includes an elastic element (704), which is sleeved on the outside of the ignition nozzle (70) and configured to transmit radial force to the nozzle sleeve (707) to press the flared end (707a) onto the base (709) to form a seal.

5. The ignition nozzle mounting structure as described in claim 4, characterized in that, The ignition nozzle mounting structure also includes a retainer (705), which is sleeved on the outside of the ignition nozzle (70) and located between the elastic member (704) and the nozzle sleeve (707).

6. The ignition nozzle mounting structure as described in claim 4, characterized in that, The ignition nozzle mounting structure also includes a heat shield (706), which is fixedly mounted on the combustion chamber outer casing (61) and penetrated by the nozzle sleeve (707). The heat shield (706) is used to isolate the elastic element (704) from the combustion chamber outer annular cavity (201).

7. The ignition nozzle mounting structure as described in claim 1, characterized in that, The outer ring (68) of the flame tube includes multiple oblique holes.

8. The ignition nozzle mounting structure as described in claim 7, characterized in that, The outer ring (68) of the flame tube is made of ceramic matrix composite material.

9. A combustion chamber, comprising an outer combustion chamber housing (61), an inner combustion chamber housing (63), an outer ring of the flame tube (68), an inner ring of the flame tube (69), and an ignition nozzle (70), characterized in that, The ignition nozzle is installed using the ignition nozzle mounting structure according to any one of claims 1-8.

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