An integrated structure of a low-emission combustion chamber head, heat shield and cap cone

Abstract

The present invention provides an integrated structure of a low-emission combustion chamber head, a heat shield and a cap cone, which belongs to the field of combustion chambers and solves the problems existing in the prior art such as the inability to eliminate corner vortices. The integrated structure includes an integrated combustion chamber head, a cap cone and a heat shield; the combustion chamber head includes a fuel supply pipeline, a center duty class blunt body, a multi-stage hub, and multi-stage swirl blades; an integrated venturi structure is provided at the end of each stage hub; the cap cone is connected to the tail end of the multi-stage hub, and the profile obtained by the intersection of the cap cone and the mid-section is symmetrical about the central axis of the combustion chamber head; the cap cone includes a slope section and a tapered section; the heat shield is located behind the cap cone and connected to the tail end of the multi-stage hub; the heat shield is obtained by rotating a predetermined parabola on the mid-section 360° around the central axis of the combustion chamber head; the boundary of the heat shield extends to the cap cone, and a gap is provided at the junction with the cap cone. The above-mentioned integrated structure of the present invention can be applied to application scenarios with higher structural strength requirements.

Description

Technical Field

[0001] The invention belongs to the field of gas turbine combustion chambers, and in particular relates to an integrated structure of a low-emission combustion chamber head, a heat shield and a cap cone. Background Art

[0002] Due to the structural complexity of gas turbine combustors, it is often difficult to balance structural refinement with strength. Current low-emission combustors, in order to achieve low or even ultra-low emissions, often require highly complex head structural and aerodynamic designs. Furthermore, the relative positioning of components such as the combustor head, heat shield, and flame tube significantly impacts the combustor's performance.

[0003] In recent years, there have been several applications in China for integrated combustor head structures. Patent No. 202210790806.X discloses a lean premixed integrated head structure for a gas turbine combustor. This integrated structure only includes the combustor head and fuel supply piping, but does not include a heat shield or flame tube cap cone. Therefore, the head alone cannot achieve the desired effect of eliminating corner vortices and providing shock absorption. Summary of the Invention

[0004] In view of the above problems, the present invention proposes an integrated structure of a low-emission combustion chamber head, a heat shield and a cap cone to solve at least one of the above problems existing in the prior art.

[0005] According to one aspect of the present invention, a low-emission combustion chamber head, heat shield and cap cone integrated structure is provided, comprising: a combustion chamber head, a cap cone and a heat shield; the combustion chamber head, the cap cone and the heat shield are arranged as an integrated unit; the combustion chamber head comprises a fuel supply pipeline, a center value class blunt body, a multi-stage hub, and multi-stage swirl blades; the ends of each stage of the multi-stage hub are respectively provided with an integrated venturi structure; the cap cone is connected to the tail end of the multi-stage hub, and the profile line obtained by the intersection of the cap cone and the mid-section is about the combustion chamber The central axis of the head is symmetrical; the hat cone includes a slope section and a tapered section, and the slope section is provided with a first cooling hole; the heat shield is located behind the hat cone and connected to the tail end of the multi-stage hub; the heat shield has the following outer surface shape: it is obtained by rotating the predetermined parabola on the mid-section 360° around the central axis of the combustion chamber head, and the vertex of the predetermined parabola is located on the central axis; the heat shield is provided with a second cooling hole, and the boundary of the heat shield extends to the hat cone, and a gap is provided at the connection with the hat cone.

[0006] Furthermore, the central duty class bluff body is provided with oblique radial fuel injection holes and axial fuel injection holes; the central duty class bluff body and the multi-stage hub are coaxially nested from the inside to the outside; each stage of the multi-stage hub is tapered; the multi-stage hubs nested outside the central duty class bluff body are arranged in an increasing order from the inside to the outside; the multi-stage hub includes the lowest stage hub to the highest stage hub; the multi-stage swirl blades include the lowest stage swirl blades to the highest stage swirl blades; the lowest stage swirl blades are provided between the central duty class bluff body and the lowest stage hub; swirl blades of the same level as the higher stage hubs are provided between adjacent two stages; corresponding fuel injection holes are provided upstream of each stage of the swirl blades in the multi-stage swirl blades.

[0007] Furthermore, there is a first angle between the slope section of the cap cone and the central axis, and the value range of the first angle is 30° to 60°; the farthest distance between the slope section and the central axis is equal to 1.5 to 2 times the outlet radius of the combustion chamber head; a first cooling hole is provided on the slope section, and the aperture of the first cooling hole is 0.6 to 1 mm; there is a second angle between the tapered section of the cap cone and the central axis, and the value range of the second angle is 0 to 30°.

[0008] Furthermore, the fullness value of the parabolic curve used in the heat insulation screen is 0.3 to 0.8, and a plurality of circles of second cooling holes are provided thereon; and the minimum distance between the heat insulation screen and the cap cone is 4 to 10 mm.

[0009] Furthermore, two rows of slits are evenly arranged above and below the heat insulation screen, the slits have a height of 2 to 4 mm, a width of 4 to 6 mm, and a spacing between the slits of 8 to 12 mm.

[0010] Furthermore, the multi-stage hub is a two-stage hub, including a first-stage hub and a second-stage hub; the multi-stage swirl blades are two-stage swirl blades, including a first-stage swirl blade and a second-stage swirl blade; the central value class bluff body, the first-stage hub, and the second-stage hub are coaxially nested from inside to outside; the first-stage swirl blades are located between the central value class bluff body and the first-stage hub, and a first-stage fuel injection hole is provided upstream of the first-stage swirl blades; the second-stage swirl blades are located between the first-stage hub and the second-stage hub, and a second-stage fuel injection hole is provided upstream of the second-stage swirl blades; the cap cone is connected to the tail end of the second-stage hub; the heat insulation screen is located behind the cap cone and connected to the tail end of the second-stage hub.

[0011] Furthermore, the ends of the hubs of each stage are not in the same axial position, and the order from left to right along the direction of the central axis is: the end of the central value class blunt body, the end of the first-stage hub, and the end of the second-stage hub; there are 4 to 7 axial fuel injection holes on the end face of the central value class blunt body, and 4 to 6 oblique radial injection holes are evenly arranged along the circumferential direction at a distance of 5 to 8 mm from the end face, with a hole diameter of 1 mm to 1.5 mm; there is a third angle between the first-stage hub tapered section and the central axis, and there is a fourth angle between the second-stage hub tapered section and the central axis, and the value range of the third angle and the fourth angle are both 30° to 60°; the first-stage swirl blades include 6 to 8 blades, and the second-stage swirl blades include 12 to 16 blades. Each of the first-stage swirl blades and the second-stage swirl blades is arranged with 3 fuel injection holes on the windward side and the leeward side, with a hole diameter of 0.6 to 1 mm.

[0012] The present invention provides an integrated structure of a low-emission combustion chamber head, heat shield and cap cone, which designs the more complex parts of the combustion chamber into an integrated structure, which is not only convenient for installation and disassembly, but also ensures that the effect of the structure will not change during intense combustion.

[0013] In the embodiment of the present invention, an integrated structure of a low-emission combustion chamber head, a heat shield and a cap cone is adopted, so that the key parts of the combustion chamber can be disassembled, installed and maintained.

[0014] In an embodiment of the present invention, the combustion chamber head adopts a coaxial graded tower structure, which can realize graded and zoned combustion, reduce pressure loss, accelerate airflow, prevent head ablation, maximize the head air intake, and reduce pollutant emissions.

[0015] In the embodiment of the present invention, the slope section of the cap cone has a drainage function, and the heat shield adopts a parabolic spiral surface form, which can eliminate corner vortices to a certain extent and improve the outlet temperature field distribution.

[0016] In the embodiment of the present invention, the heat shield can protect the cap cone from being ablated by high temperature. The heat shield is in the form of a parabola-spun surface. Selecting a suitable curvature can play a shock-absorbing role and improve the structural strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 2. It is a structural schematic diagram of the integrated structure of the low-emission combustion chamber head, heat shield and cap cone according to an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of the installation of the low-emission combustion chamber head, heat shield and cap cone integrated structure and the flame tube according to an embodiment of the present invention;

[0019] Figure 3 yes Figure 1 Schematic diagram of the middle section AA;

[0020] Figure 4 is a schematic diagram of the parabolic shape and position of the heat shield according to an embodiment of the present invention;

[0021] Figure 5 Schematic diagram of the size and position of the thermal insulation screen slits in an embodiment of the present invention;

[0022] Figure 6 is a three-dimensional view of a heat shield according to an embodiment of the present invention;

[0023] Figure 7 yes Figure 6 Right view;

[0024] Figure 8A 2. It is a front view of the integrated structure of the low emission combustion chamber head, heat shield and cap cone according to a preferred embodiment of the present invention;

[0025] Figure 8B 2. It is a rear view of the integrated structure of the low-emission combustion chamber head, heat shield and cap cone according to a preferred embodiment of the present invention;

[0026] Figure 8C 2. It is a side view of the integrated structure of the low emission combustion chamber head, heat shield and cap cone according to a preferred embodiment of the present invention;

[0027] Figure 8D 2. It is a top view of the integrated structure of the low-emission combustion chamber head, heat shield and cap cone according to a preferred embodiment of the present invention;

[0028] Figure 9A and Figure 9B It is a schematic diagram of the process of eliminating corner vortexes according to the present invention.

[0029] Figure: 1: Combustion chamber head; 1a: Fuel supply line; 1b: Center duty class bluff; 1c: First-stage hub; 1d: Second-stage hub; 1e: First-stage swirl blades; 1f: Second-stage swirl blades; 2a: Cap cone; 2b: First cooling hole on the cap cone; 3a: Heat shield; 3b: Second cooling hole on the heat shield; 3c: Slit; 4: Flame tube; 5: Mounting seat; 6: Center axis of the combustion chamber head; 7: Slope section of the cap cone; 8: Tapered section of the cap cone ; 9: parabola of the heat shield; AA: mid-section; β: angle between the tapered section of the first-stage hub and the central axis; γ: angle between the tapered section of the second-stage hub and the central axis; φ: angle between the slope section of the cap cone and the central axis; θ: angle between the tapered section of the cap cone and the central axis; R: radius of the combustion chamber head outlet; h: maximum distance between the slope section and the central axis; l: minimum distance between the heat shield and the cap cone; a: gap height; b: gap width; 10: shear layer; 11: angular vortex. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, exemplary embodiments or examples of the present invention will be described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments or examples obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed or detachable connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0032] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0033] Exemplary devices

[0034] According to an embodiment of the present invention, a low-emission combustion chamber head, heat shield and cap cone integrated structure is provided, comprising: a combustion chamber head, a cap cone and a heat shield; the combustion chamber head, the cap cone and the heat shield are arranged as an integrated unit; the combustion chamber head comprises a fuel supply pipeline, a center value class blunt body, a multi-stage hub, and a multi-stage swirl blade; the ends of each stage of the multi-stage hub are respectively provided with an integrated venturi structure; the cap cone is connected to the tail end of the multi-stage hub, and the profile line obtained by the intersection of the cap cone and the mid-section is about the combustion chamber The central axis of the head is symmetrical; the hat cone includes a slope section and a tapered section, and the slope section is provided with a first cooling hole; the heat shield is located behind the hat cone and connected to the tail end of the multi-stage hub; the heat shield has the following outer surface shape: it is obtained by rotating the predetermined parabola on the mid-section 360° around the central axis of the combustion chamber head, and the vertex of the predetermined parabola is located on the central axis; the heat shield is provided with a second cooling hole, and the boundary of the heat shield extends to the hat cone, and a gap is provided at the connection with the hat cone.

[0035] Figure 1A structural schematic diagram of the above-mentioned low-emission combustion chamber head, heat shield and cap cone integrated structure is shown.

[0036] like Figure 1 As shown, the low-emission combustion chamber head, heat shield and cap cone integrated structure includes a combustion chamber head 1, a cap cone 2a and a heat shield 3a.

[0037] Among them, the combustion chamber head 1, the cap cone 2a and the heat insulation screen 3a are integrated into one piece, which makes the joints of the overall structure smaller and simpler, and the structural strength is higher, which can be applied to some scenarios with higher structural strength requirements.

[0038] like Figure 2 As shown, the above-mentioned integrated structure is suitable for being assembled with the flame tube 4 through the mounting seat 5 , and the end of the cap cone 2 a is used for sealing connection with the front end of the flame tube 4 .

[0039] The combustion chamber head 1 includes a fuel supply pipeline 1a, a central bluff body 1b, a multi-stage hub, and multi-stage swirl blades.

[0040] In an embodiment of the present invention, the ends of each stage of the multi-stage hub are respectively provided with an integrated venturi structure, so that the angular vortex can be eliminated at the outlet of each stage of the cyclone through the venturi structure.

[0041] The cap cone 2a is connected to the tail end of the multi-stage hub, and the profile obtained by the intersection of the cap cone 2a and the mid-section is symmetrical about the central axis 6 of the combustion chamber head 1; the cap cone 2a includes a slope section 7 and a tapered section 8, and the slope section 7 is provided with a first cooling hole 2b.

[0042] In the prior art, neither the heat shield nor the hat cone has a slope. However, in an embodiment of the present invention, the slope of the slope section 7 of the hat cone 2a is kept consistent with the parabolic curvature of the heat shield 3a as much as possible, or its slope is set so as to match the parabolic curvature of the heat shield 3a, thereby further eliminating corner vortices.

[0043] The heat shield 3a is located behind the cap cone 2a and connected to the tail end of the multi-stage hub; the heat shield 3a has the following outer surface shape: the predetermined parabola 9 on the mid-section is rotated 360 degrees around the central axis 6 of the combustion chamber head 1, and the vertex of the predetermined parabola 9 is located on the central axis 6; the heat shield 3a is provided with a second cooling hole 3b, and the boundary of the heat shield 3a extends to the cap cone 2a, and a gap 3c is provided at the connection with the cap cone 2a, as shown in FIG. Figure 1 shown.

[0044] Figure 4 is a schematic diagram of the parabolic shape and position of the heat shield according to an embodiment of the present invention, Figure 5 yes Figure 4 The left lower view shows the size and location of the thermal insulation screen seams. Figure 4As shown in the figure, assuming that the horizontal coordinate (the direction of the central axis 6) corresponding to the predetermined parabola 9 is (x0, +∞), the predetermined parabola 9 is symmetrical about the x-axis (central axis 6), and the surface obtained by rotating the portion of the predetermined parabola 9 in the range [x1, x2] around the central axis 6 is the outer surface shape of the heat shield. <x1<x2。

[0045] like Figure 1 As shown, one end of the heat shield 3a (the left side shown in the figure) is connected to the tail end of the multi-stage hub (i.e., the rightmost end of the multi-stage hub), and a cap cone 2a is also provided between the heat shield 3a and the multi-stage hub, and one end of the cap cone 2a (the left side shown in the figure) is also connected to the tail end of the multi-stage hub. The cap cone 2a is divided into two sections, one section is a slope section 7, and the other section is a tapered section 8. The slope section 7 is also a gradually increasing section. One end of the tapered section 8 is connected to the tail end of the multi-stage hub, and the other end extends in a direction away from the combustion chamber head 1 (i.e., the right side shown in the figure) to connect to the flame tube 4, as shown in FIG. Figure 2 See Figure 1 The heat shield 3a is connected to the tail end of the multi-stage wheel after the cap cone 2a (that is, on the right side), and the other end also extends in the direction away from the combustion chamber head 1. Since the heat shield 3a is an outward-expanding structure, and the cap cone 2a is on the outside of the heat shield 3a, and the front section of the cap cone 2a (the left section as shown in the figure) is an expansion section, and the rear section (the right section as shown in the figure) is a tapered section, as the heat shield 3a continues to expand, it will meet the tapered section of the cap cone 2a that is reduced on the outside, and the place where the two meet is the connection point. At this connection point, there are two rows of gaps, such as Figures 1-4 As shown, the slit is provided with a plurality of rectangular holes at the connection position, with a fixed spacing between the holes. Alternatively, the slit can also be a zigzag slit, etc.

[0046] As an example, oblique radial fuel injection holes and axial fuel injection holes are provided on the center duty class bluff body 1b; the center duty class bluff body 1b and the multi-stage hub are coaxially nested from the inside to the outside; each level of the multi-stage hub is tapered; the multi-stage hubs nested outside the center duty class bluff body 1b are arranged in increasing order from the inside to the outside; the multi-stage hubs include the lowest level hub to the highest level hub; the multi-stage swirl blades include the lowest level swirl blades to the highest level swirl blades; the lowest level swirl blades are provided between the center duty class bluff body 1b and the lowest level hub; swirl blades of the same level as the higher level hub are provided between adjacent two levels; corresponding fuel injection holes are provided upstream of the swirl blades of each level in the multi-stage swirl blades.

[0047] As an example, there is a first angle between the slope section 7 of the cap cone 2a and the central axis 6, and the value range of the first angle is 30° to 60°; the farthest distance between the slope section 7 and the central axis 6 is equal to 1.5 to 2 times the outlet radius of the combustion chamber head 1; a first cooling hole is provided on the slope section 7, and the aperture of the first cooling hole is 0.6 to 1 mm; there is a second angle between the tapered section 8 of the cap cone 2a and the central axis 6, and the value range of the second angle is 0 to 30°.

[0048] As an example, the heat shield 3a adopts a parabola 9 with a fullness value of 0.3 to 0.8, and is provided with multiple circles of second cooling holes; the minimum distance between the heat shield 3a and the cap cone 2a is 4 to 10 mm.

[0049] As an example, two rows of slits 3c are evenly arranged above and below the heat insulation screen 3a. The height of the slits 3c is 2-4 mm, the width is 4-6 mm, and the spacing between the slits 3c is 8-12 mm.

[0050] In one example, the multi-stage hub is a two-stage hub, for example, including a first-stage hub 1c and a second-stage hub 1d; and the multi-stage swirl blades are, for example, two-stage swirl blades, for example, including first-stage swirl blades 1e and second-stage swirl blades 1f. It should be understood that the multi-stage hub and multi-stage swirl blades of the present invention are not limited to the two-stage hub and two-stage swirl blades. In other examples, they may also be three-stage hubs and three-stage swirl blades, which will not be further described here.

[0051] In this example, if Figure 3 As shown, the center value class bluff 1b, the first stage hub 1c, and the second stage hub 1d are coaxially nested from the inside to the outside; the first stage swirl blade 1e is located between the center value class bluff 1b and the first stage hub 1c, and the first stage fuel injection hole is provided upstream of the first stage swirl blade 1e; the second stage swirl blade 1f is located between the first stage hub 1c and the second stage hub 1d, and the second stage fuel injection hole is provided upstream of the second stage swirl blade 1f. Figure 1 As shown, the cap cone 2a is connected to the tail end of the second-stage hub 1d; the heat shield 3a is located behind the cap cone 2a (for example, the left side is the front and the right side is the back in the figure) and is connected to the tail end of the second-stage hub 1d.

[0052] In this example, the ends of the hubs of each stage are not in the same axial position, and the order from left to right along the center axis 6 is: the end of the center value class blunt body 1b, the end of the first-stage hub 1c, and the end of the second-stage hub 1d; there are 4 to 7 axial fuel injection holes on the end face of the center value class blunt body 1b, and 4 to 6 oblique radial injection holes are evenly arranged along the circumferential direction at a distance of 5 to 8 mm from the end face, with a hole diameter of 1 mm to 1.5 mm; there is a third angle between the tapered section of the first-stage hub 1c and the center axis 6, and there is a fourth angle between the tapered section of the second-stage hub 1d and the center axis 6. The value range of the third angle and the fourth angle are both 30° to 60°; the first-stage swirl blade 1e includes 6 to 8 blades, and the second-stage swirl blade 1f includes 12 to 16 blades. Each blade of the first-stage swirl blade 1e and the second-stage swirl blade 1f is arranged with 3 fuel injection holes on the windward side and the leeward side, with a hole diameter of 0.6 to 1 mm.

[0053] Preferred Embodiments

[0054] The following combination Figure 1-Figure 7 as well as Figures 8A-8D A preferred embodiment of the present invention will be described.

[0055] like Figure 1 As shown, in this embodiment, the low emission combustion chamber head, heat shield and cap cone integrated structure includes: combustion chamber head 1, cap cone 2a and heat shield 3a, the three parts are integrated, see Figure 2 The integrated structure can be assembled with the flame tube 4 through the mounting seat 5, and the end of the cap cone 2a is sealed and connected to the front end of the flame tube 4.

[0056] In this embodiment, the combustion chamber head 1 includes a fuel supply pipeline 1a, a center value class bluff body 1b, a first-stage hub 1c, a second-stage hub 1d, a first-stage swirl blade 1e, and a second-stage swirl blade 1f.

[0057] Figures 8A-8D The front view, rear view, side view and top view of the above-mentioned low-emission combustion chamber head, heat shield and cap cone integrated structure are respectively shown.

[0058] There are 4 to 7 axial fuel injection holes on the end face of the center value class blunt body 1b, and 4 to 6 oblique radial injection holes are evenly arranged along the circumference at a distance of 5 to 8 mm from the end face, with a hole diameter of 1 mm to 1.5 mm; the center value class blunt body 1b, the first-stage hub 1c, and the second-stage hub 1d are coaxially nested from the inside to the outside, and the ends of the hubs at each level are not in the same axial position. The order from left to right along the central axis 6 of the combustion chamber head is: the end of the center value class blunt body 1b, the end of the first-stage hub 1c, and the end of the second-stage hub 1d; the first-stage hub 1c and the second-stage hub 1d are both tapered, and the ends are provided with an integrated venturi structure; the first The angle between the tapered section of the first-stage hub 1c and the central axis 6 is β, and the angle between the tapered section of the second-stage hub 1d and the central axis 6 is γ, and the value range of β and γ is 30°~60°; the first-stage swirl blade 1e is located between the central value class blunt body 1b and the first-stage hub 1c, and a fuel injection hole is provided upstream of the blade; the second-stage swirl blade 1f is located between the first-stage hub 1c and the second-stage hub 1d, and a fuel injection hole is provided upstream of the blade; the number of first-stage swirl blades 1e is 6~8, and the number of second-stage swirl blades 1f is 12~16, and 3 fuel injection holes are arranged on the windward side and leeward side of each blade, with a hole diameter of 0.6~1mm.

[0059] In this embodiment, the cap cone 2a is connected to the tail end of the second-stage hub 1d, and the profile of the cap cone 2a on the mid-section AA is symmetrical about the central axis 6 of the combustion chamber head, and consists of a slope section 7 and a tapered section 8; the angle between the slope section 7 and the central axis 6 is φ, and the value of φ is 30°~60°. The farthest distance h from the central axis 6 is 1.5 to 2 times the outlet radius R of the combustion chamber head 1, and 3 to 4 cooling holes are provided on it, with a hole diameter of 0.6 to 1 mm; the angle between the tapered section 8 and the central axis 6 is θ, and the value of θ is 0 to 30°; the uniform wall thickness of the cap cone 2a is 1.5 to 3 mm.

[0060] The heat shield 3a is located behind the cap cone 2a, with a minimum distance l of 4 to 10 mm from the cap cone 2a, and is connected to the tail end of the second-stage hub 1d; the shape is obtained by rotating the parabola 9 on the middle section AA 360° around the central axis 6 of the combustion chamber head, the vertex of the parabola 9 is located on the central axis 6, the curve fullness value Rho is 0.3 to 0.8, and 3 to 4 circles of cooling holes 3b are provided on it, with an aperture of 0.6 to 1 mm; the boundary of the heat shield 3a extends to the cap cone 2a, and two rows of slits 3c are evenly arranged at the upper and lower junctions with the cap cone 2a, as shown in FIG. Figure 5 As shown, the height a of the slit 3c is, for example, 2 to 4 mm, the width b is, for example, 4 to 6 mm, and the spacing between the slits 3c is, for example, 8 to 12 mm; the uniform wall thickness of the heat insulation screen 3a is 1.5 to 3 mm. Figure 6 is a three-dimensional view of a heat shield according to an embodiment of the present invention; Figure 7 yes Figure 6 Right view of .

[0061] Figure 9A and Figure 9B The process of eliminating corner vortex of the present invention is shown.

[0062] like Figure 9A As shown in the figure, the direction of the streamline arrows indicates the direction of gas flow. Near the outlet of the combustion chamber head 1 (i.e., the swirler outlet), the gas velocity, temperature, and pressure are significantly higher than those in other areas of the combustion chamber. This high-temperature, high-pressure gas forms a shear layer 10. Furthermore, the air pressure and temperature inside the heat shield 3 are higher than outside. After a portion of the mainstream air enters the combustion chamber through the cooling holes 3a on the heat shield 3, it forms an air film inside the heat shield 3. This air film adheres closely to the heat shield 3, isolating the high-temperature environment inside the heat shield 3 from the outside, providing excellent thermal insulation for the combustion chamber and protecting the combustion chamber head. Another portion of the mainstream air, after entering the combustion chamber through the mainstream air inlet, encounters the shear layer 10, changing its flow direction and forming a corner vortex 11 at the corner formed by the shear layer 10 and the cap cone 2. This corner vortex can cause fuel to accumulate, resulting in excessive temperatures and wall ablation. Therefore, the relative position and shape of the cap cone 2 and the heat shield 3 must be controlled to eliminate the corner vortex 11.

[0063] like Figure 9B As shown, by adjusting the angle φ of the sloped section 7 of the cap cone 2 and the curvature of the heat shield 3 until they are substantially aligned with the slope of the shear layer 10, and adjusting the relative position between the heat shield 3 and the sloped section 2a of the cap cone 2, a structure is achieved that eliminates corner vortices 11. After entering the combustion chamber, mainstream air is blocked by the shear layer 10 and can only flow along the air film. Furthermore, because the distance between the heat shield 3 and the sloped section 7 is sufficiently small, corner vortices cannot form in the space between them. The result is a near-complete elimination of corner vortices, which significantly benefits combustion and increases the lifespan of the equipment.

[0064] In summary, this embodiment provides an integrated structure of a low-emission combustion chamber head, a heat shield and a cap cone, including: a combustion chamber head, a cap cone, and a heat shield. The three components are an integrated structure, and the cap cone part at the end is sealed and connected to the front end of the flame tube; the combustion chamber head includes a fuel supply pipeline, a central duty class blunt body, a first-stage hub, a second-stage hub, a first-stage swirl blade, and a second-stage swirl blade. The duty class central blunt body, the first-stage hub, and the second-stage hub are coaxially nested from the inside to the outside. The first and second-stage hubs are both tapered, and an integrated venturi structure is provided at the end. The swirl blades are located in the flow channel between the hubs; the cap cone is connected to the tail end of the second-stage hub, and the cap cone consists of a slope section and a tapered section; the heat shield is located behind the cap cone, and its shape is obtained by rotating the parabola on the mid-section 360° around the central axis. The appropriate curvature can play a shock-absorbing role and improve the structural strength. The vertex of the parabola is located on the central axis. The boundary of the heat shield extends to the cap cone, and a gap is provided at the connection with the cap cone. The present invention is easy to disassemble, install and maintain, can realize graded and zoned combustion, prevent head ablation, reduce pollutant emissions, eliminate corner vortices to a certain extent, and improve the outlet temperature field.

[0065] Although the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of the foregoing description, will appreciate that other embodiments are contemplated within the scope of the invention thus described. This disclosure is intended to be illustrative rather than restrictive of the scope of the invention, which is defined by the appended claims.

Claims

1. A low-emission combustion chamber head, heat shield and cap cone integrated structure, characterized in that: include: Combustion chamber head (1), cap cone (2a) and heat shield (3a); The combustion chamber head (1), cap cone (2a) and heat shield (3a) are integrally arranged; The combustion chamber head (1) comprises a fuel supply pipeline (1a), a central duty class blunt body (1b), a multi-stage hub, and multi-stage swirl blades; the ends of each stage of the multi-stage hub are respectively provided with an integrated venturi structure; The cap cone (2a) is connected to the tail end of the multi-stage hub, and the profile line obtained by the intersection of the cap cone (2a) and the mid-section is symmetrical about the central axis (6) of the combustion chamber head (1); the cap cone (2a) includes a slope section (7) and a tapered section (8), and the slope section (7) is provided with a first cooling hole (2b); The heat shield (3a) is located behind the cap cone (2a) and connected to the tail end of the multi-stage hub; the heat shield (3a) has the following outer surface shape: it is obtained by rotating the predetermined parabola (9) on the mid-section 360 degrees around the central axis (6) of the combustion chamber head (1), and the vertex of the predetermined parabola (9) is located on the central axis (6); the heat shield (3a) is provided with a second cooling hole (3b), and the boundary of the heat shield (3a) extends to the cap cone (2a), and a gap (3c) is provided at the connection with the cap cone (2a); There is a first angle between the slope section (7) of the cap cone (2a) and the central axis (6), and the first angle has a value range of 30° to 60°; there is a second angle between the tapered section (8) of the cap cone (2a) and the central axis (6), and the second angle has a value range of 0° to 30°; The predetermined parabola (9) curve fullness value adopted by the heat insulation screen (3a) is 0.3-0.8, and a plurality of circles of second cooling holes are provided on the heat insulation screen; The heat insulation screen (3a) has two rows of slits (3c) evenly arranged above and below. The relative position between the heat shield (3a) and the slope section (7) of the cap cone (2a) is designed to weaken or eliminate the corner vortex (11).

2. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 1 is characterized in that: The central duty class bluff body (1b) is provided with an oblique radial fuel injection hole and an axial fuel injection hole; the central duty class bluff body (1b) and the multi-stage hub are coaxially nested from the inside to the outside; each stage of the multi-stage hub is of a tapered type; The multi-stage hubs nested outside the central duty class bluff body (1b) are arranged in order of increasing levels from the inside to the outside; the multi-stage hubs include the lowest-level hub to the highest-level hub; the multi-stage swirl blades include the lowest-level swirl blades to the highest-level swirl blades; A lowest-level swirl blade is provided between the central duty class bluff body (1b) and the lowest-level hub; Between two adjacent stages, there are swirl blades of the same level as the higher-level hub; Corresponding fuel injection holes are provided upstream of each stage of the multi-stage swirl blades.

3. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 1 or 2, characterized in that: The maximum distance between the slope section (7) and the central axis (6) is equal to 1.5 to 2 times the outlet radius of the combustion chamber head (1); a first cooling hole is provided on the slope section (7), and the aperture of the first cooling hole is 0.6 to 1 mm.

4. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 1 or 2, characterized in that: The minimum distance between the heat insulation screen (3a) and the cap cone (2a) is 4 to 10 mm.

5. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 1 or 2, characterized in that: The height of the slits (3c) is 2-4 mm, the width is 4-6 mm, and the spacing between the slits (3c) is 8-12 mm.

6. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 2, characterized in that: The multi-stage hub is a two-stage hub, comprising a first-stage hub (1c) and a second-stage hub (1d); The multi-stage swirl blade is a two-stage swirl blade, comprising a first-stage swirl blade (1e) and a second-stage swirl blade (1f); The central value class bluff body (1b), the first-stage hub (1c), and the second-stage hub (1d) are coaxially nested from the inside to the outside; the first-stage swirl blade (1e) is located between the central value class bluff body (1b) and the first-stage hub (1c), and a first-stage fuel injection hole is provided upstream of the first-stage swirl blade (1e); the second-stage swirl blade (1f) is located between the first-stage hub (1c) and the second-stage hub (1d), and a second-stage fuel injection hole is provided upstream of the second-stage swirl blade (1f); The cap cone (2a) is connected to the rear end of the second-stage hub (1d); The heat shield (3a) is located behind the cap cone (2a) and is connected to the tail end of the second-stage hub (1d).

7. The low-emission combustion chamber head, heat shield and cap cone integrated structure according to claim 6, characterized in that: The ends of the hubs of each stage are not in the same axial position, and the order from left to right along the central axis (6) is: the end of the central value class blunt body (1b), the end of the first stage hub (1c), and the end of the second stage hub (1d); The end face of the central value class blunt body (1b) is provided with 4 to 7 axial fuel injection holes, and 4 to 6 oblique radial fuel injection holes are evenly arranged along the circumference at a distance of 5 to 8 mm from the end face, with a hole diameter of 1 mm to 1.5 mm; a third angle is formed between the tapered section of the first-stage hub (1c) and the central axis (6), and a fourth angle is formed between the tapered section of the second-stage hub (1d) and the central axis (6), and the value range of the third angle and the fourth angle are both 30° to 60°; The first-stage swirl blade (1e) includes 6 to 8 blades, and the second-stage swirl blade (1f) includes 12 to 16 blades. Three fuel injection holes are arranged on the windward side and the leeward side of each blade of the first-stage swirl blade (1e) and the second-stage swirl blade (1f), and the hole diameter is 0.6 to 1 mm.

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