Mixing pipe, combustion chamber and aero-engine of central staged combustion chamber

Abstract

The application relates to the technical field of aero-engines, and provides a main combustion stage mixing pipe of a center staged combustion chamber, the center staged combustion chamber and an aero-engine. The main combustion stage mixing pipe of the center staged combustion chamber comprises a mixing pipe body, the first end of the mixing pipe body is a closed end, a through hole is arranged in the center of the closed end and is used for injecting fuel, and the second end of the mixing pipe body is an open end; the mixing pipe body is provided with multi-stage rotational flow hole structures, each stage of the rotational flow hole structures is communicated with the inside of the mixing pipe body, air enters the mixing pipe body through the rotational flow hole structures and is mixed with fuel to spiral flow, so that the air and the fuel are uniformly mixed. Compared with the rotational flow mixing by using blades, the rotational flow hole structures shorten the axial length of the mixing pipe body, so that the structure of the combustion chamber is more compact, the flow loss is reduced, stable combustion is realized, and the combustion demand of a new generation of aero-engines is met.

Description

The main combustion stage mixing pipe of the central staged combustor, the combustor, and the aero-engine Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a main stage mixing pipe for a central staged combustion chamber, a central staged combustion chamber, and an aero-engine. Background Technology

[0002] The ignition performance, combustion performance, and cooling design of an aero-engine combustor are all closely related to the fuel concentration distribution in the combustion zone. The atomization characteristics of the nozzle are a crucial factor affecting the fuel concentration distribution in the combustion zone. The central stage structure is currently the mainstream aero-engine combustor structure. Its inner swirling flame is the pre-combustion stage, employing a diffusion flame, which can improve combustion efficiency in single-flame mode and play a role in stabilizing the flame under high operating conditions. The outer swirling flame is the main combustion stage, ensuring fuel efficiency and low emission requirements in dual-flame mode.

[0003] The main combustion stage, as a key structure of the central staged combustion chamber, affects the flow mixing and combustion efficiency of aviation kerosene, reduces pollutant emissions under high operating conditions, and forms a reasonably distributed combustion chamber outlet temperature field. Swirlers mix incoming air and fuel by creating a specific confined zone at the combustion chamber head. Traditional main combustion stages consist of main combustion stage blades and a main combustion stage fuel tank, ensuring high combustion efficiency and low emissions under high operating conditions such as approach, climb, and takeoff. However, due to their long axial dimensions, traditional main combustion stages have longer mixing times and distances, failing to meet the combustion performance requirements of next-generation aero-engines and are prone to backfire and auto-ignition. Summary of the Invention

[0004] This invention provides a main stage mixing pipe for a central staged combustion chamber, a central staged combustion chamber, and an aero-engine, to solve the defects in the prior art where the main stage has a long axial dimension, resulting in a long mixing time and mixing distance.

[0005] This invention provides a main combustion stage blending pipe for a central staged combustion chamber, comprising a blending pipe body. The first end of the blending pipe body is a closed end, and a through hole is provided at the center of the closed end for injecting fuel. The second end of the blending pipe body is an open end. The blending pipe body is provided with a multi-stage swirling hole structure, and each stage of the swirling hole structure is connected to the interior of the blending pipe body. Air enters the blending pipe body through the swirling hole structure and mixes with the fuel in a spiral flow to achieve uniform mixing.

[0006] According to the present invention, a main combustion stage mixing pipe for a central staged combustion chamber is provided, wherein the mixing pipe body is further provided with a plurality of atomizing structures, wherein the swirling hole structure and the atomizing structure are alternately arranged so that the mixed oil and gas are atomized in the atomizing structure.

[0007] According to the present invention, a main combustion stage mixing pipe for a central staged combustion chamber is provided, wherein the outer surface of the first end of the mixing pipe body is a conical surface, and the outer surface of the second end of the mixing pipe body is a cylindrical surface; the multi-stage swirl hole structure includes a primary swirl hole structure, wherein the primary swirl hole structure includes a plurality of first swirl holes, the plurality of first swirl holes being arranged in a ring along the conical surface, and the angle between the plane where the air outlet end of each first swirl hole is located and the plane where the air inlet end is located is an acute angle.

[0008] According to the present invention, the main combustion stage mixing pipe of the central staged combustion chamber includes a secondary swirling hole structure, wherein the secondary swirling hole structure includes a plurality of second swirling holes, the plurality of second swirling holes are arranged in a ring along the cylindrical surface, and the air outlet end and air inlet end of each second swirling hole are staggered.

[0009] According to the present invention, a main combustion stage mixing pipe for a central staged combustion chamber includes a multi-stage swirling hole structure, which further includes a third-stage swirling hole structure. Along the flow direction of the fuel, the third-stage swirling hole structure is located downstream of the second-stage swirling hole structure. The third-stage swirling hole structure includes a plurality of third swirling holes, which are arranged in a ring along the cylindrical surface. The air outlet end and air inlet end of each third swirling hole are staggered.

[0010] According to the present invention, the main combustion stage mixing tube of a central staged combustion chamber is provided, wherein the first swirling orifice is a circular orifice, the second swirling orifice is a square orifice, and the third swirling orifice is a rectangular orifice.

[0011] According to the present invention, a main combustion stage mixing tube of a central staged combustion chamber includes a plurality of atomizing structures, wherein the inner wall of the mixing tube gradually contracts toward the center to form a first tapering structure, the first tapering structure is configured as the first atomizing structure, and the first atomizing structure is located between the first-stage swirling hole structure and the second-stage swirling hole structure.

[0012] According to the present invention, a main combustion stage mixing tube for a central staged combustion chamber includes a plurality of atomizing structures, which further include a second atomizing structure. The inner wall of the mixing tube body forms a venturi structure, which is configured as the second atomizing structure. A portion of the second atomizing structure is located between the secondary swirling hole structure and the tertiary swirling hole structure, and the remaining portion of the second atomizing structure is opposite to the tertiary swirling hole structure.

[0013] The present invention also provides a central staged combustion chamber, including a pre-combustion stage assembly and a plurality of main combustion stage mixing pipes as described above, wherein the plurality of main combustion stage mixing pipes are arranged around the pre-combustion stage assembly.

[0014] The present invention also provides an aircraft engine including a central staged combustion chamber as described above.

[0015] The main combustion stage mixing tube of the central staged combustion chamber provided by the present invention uses a multi-stage swirling hole structure to swirl and mix fuel and air. Compared with the use of blades for swirling mixing, the swirling hole structure shortens the axial length of the mixing tube body, thereby making the combustion chamber structure more compact, reducing flow losses, achieving stable combustion, shortening mixing time and distance, and meeting the combustion requirements of the new generation of aero engines. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 is a schematic diagram of the main combustion stage mixing pipe of the central staged combustion chamber provided by the present invention;

[0018] Figure 2 is a cross-sectional view of the main combustion stage mixing pipe of the central staged combustion chamber provided by the present invention;

[0019] Figure 3 is a side view of the head of the central staged combustion chamber provided by the present invention;

[0020] Figure label:

[0021] 10: Blending pipe body; 11: First pipe section; 12: Second pipe section; 21: First swirl hole; 22: Second swirl hole; 23: Third swirl hole; 31: First atomizing structure; 32: Second atomizing structure; 40: Pre-combustion stage component; 111: Through hole. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "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 this 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 this invention.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The following description, in conjunction with Figures 1-3, describes the main combustion stage mixing pipe of the central staged combustion chamber, the central staged combustion chamber, and the aero-engine of the present invention.

[0027] As shown in Figure 1, in an embodiment of the present invention, the main combustion stage mixing pipe of the central staged combustion chamber includes a mixing pipe body 10. The first end of the mixing pipe body 10 is a closed end, and a through hole 111 is provided at the center of the closed end for injecting fuel. The second end of the mixing pipe body 10 is an open end. The mixing pipe body 10 is provided with a multi-stage swirling hole structure. Each stage of the swirling hole structure is connected to the interior of the mixing pipe body 10. Air enters the mixing pipe body 10 through the swirling hole structure and mixes with the fuel in a spiral flow to achieve uniform mixing.

[0028] Specifically, the mixing pipe body 10 has a hollow structure, with a closed end at the first end and an open end at the second end. A through hole 111 is provided at the center of the closed end face, which is used to inject fuel into the mixing pipe body 10. The outer surface of the mixing pipe body 10 has a multi-stage swirling hole structure. Each stage of the swirling hole structure penetrates the inner wall of the mixing pipe body 10 and communicates with the interior of the mixing pipe body 10, allowing air to enter the mixing pipe body 10 through each stage of the swirling hole structure.

[0029] Furthermore, the opening on the outer wall of the mixing pipe body 10 of each stage of the swirl hole structure is the air inlet, and the opening on the inner wall of the mixing pipe body 10 is the air outlet. In this embodiment, the projection of the plane where the air outlet of each stage of the swirl hole structure is located is on one side of the plane where the air inlet is located, thereby causing the airflow entering the mixing pipe body 10 from each stage of the swirl hole structure to flow in a spiral manner to mix with the fuel.

[0030] The main combustion stage mixing tube of the central staged combustion chamber provided in this embodiment of the invention uses a multi-stage swirling hole structure to swirl and mix fuel and air. Compared with using blades for swirling mixing, the swirling hole structure shortens the axial length of the mixing tube body, thereby making the combustion chamber structure more compact, reducing flow losses, achieving stable combustion, shortening mixing time and distance, and meeting the combustion requirements of the new generation of aero engines.

[0031] As shown in Figure 2, in an embodiment of the present invention, the mixing pipe body 10 is further provided with multiple atomizing structures, and the swirling hole structure and the atomizing structure are alternately arranged so that the mixed oil and gas are atomized in the atomizing structure.

[0032] Specifically, multiple atomizing structures are formed inside the mixing pipe 10. During the flow process, air and fuel are sequentially atomized through multiple atomizing structures to improve the fuel atomization effect, ensuring that parameters such as fuel atomization fineness, atomization uniformity, and spray cone angle meet the set standards. Furthermore, in this embodiment, the atomizing structure can be a tapered structure with a gradually narrowing opening, and the fuel is atomized on the contracting surface of the tapered structure.

[0033] The main combustion stage blending pipe of the central staged combustion chamber provided in this embodiment of the invention enhances the atomization effect by setting multiple atomization structures so that the blended fuel undergoes multiple atomizations.

[0034] As shown in Figure 1, in an embodiment of the present invention, the mixing tube 10 includes a first tube section 11 and a second tube section 12. The outer surface of the first tube section 11 is a conical surface, and the first tube section 11 is provided with the through hole 111. The second tube section 12 is connected to the first tube section 11, and the outer surface of the second tube section 12 is a cylindrical surface, wherein a multi-stage swirling hole structure is sequentially disposed on the conical surface and the cylindrical surface.

[0035] Further, as shown in Figure 2, in an embodiment of the present invention, the multi-stage swirling hole structure includes a first-stage swirling hole structure, which includes a plurality of first swirling holes 21. The plurality of first swirling holes 21 are arranged in a ring along the conical surface of the first pipe section 11, and the angle between the plane where the air outlet end of each first swirling hole 21 is located and the plane where the air inlet end is located is an acute angle.

[0036] Specifically, in this embodiment, the plane where the air outlet of the first swirling orifice 21 is located forms an angle with the plane where the air inlet is located, thereby creating a certain angle between the incoming air and the air outlet, and causing the air flowing out from multiple air outlets to form a spiral shape, so as to mix the air with the fuel. Furthermore, in this embodiment, the first swirling orifice 21 is a circular orifice. Compared with other shapes of orifices, circular orifices have a larger surface area, increasing the gas flow rate entering the mixing pipe body 10.

[0037] Optionally, in an embodiment of the present invention, the mixing pipe body 10 has an outer diameter of 17 mm, an inner diameter of 15 mm, and a length of 26.9 mm. The diameter of the first swirl hole 21 is 2 mm, the angle between the plane where the air outlet is located and the plane where the air inlet is located is 45°, and the number of first swirl holes 21 is 12. The diameter of the through hole 111 at the center of the first pipe section 11 is 2.4 mm.

[0038] As shown in Figure 2, in an embodiment of the present invention, the multi-stage swirling hole structure further includes a secondary swirling hole structure. The secondary swirling hole structure includes a plurality of second swirling holes 22, which are arranged in a ring along the cylindrical surface of the second pipe section 12. The air outlet end and the air inlet end of each second swirling hole 22 are staggered.

[0039] Specifically, in this embodiment, the second swirling hole 22 is a square hole, and the projection of the air outlet end of the square hole is located on one side of the projection of the air inlet end, so that the air entering the mixing tube 10 forms a spiral shape.

[0040] As shown in Figure 2, in an embodiment of the present invention, the multi-stage swirling hole structure further includes a three-stage swirling hole structure. Along the flow direction of the fuel, the three-stage swirling hole structure is located downstream of the two-stage swirling hole structure. The three-stage swirling hole structure includes multiple third swirling holes 23. The multiple third swirling holes 23 are arranged in a ring along the cylindrical surface of the second pipe section 12. The air outlet end of each third swirling hole 23 is staggered from the air inlet end.

[0041] Specifically, in this embodiment, the third swirl hole 23 is a rectangular hole, and the projection of the air outlet end of the rectangular hole is located on one side of the projection of the air inlet end, so that the air entering the mixing pipe body 10 forms a spiral shape.

[0042] Optionally, in an embodiment of the present invention, the length of the second swirling hole 22 is 4.5 mm, the length of the third swirling hole 23 is 6.2 mm, and the number of the second swirling hole 22 and the third swirling hole 23 is 24.

[0043] As shown in Figure 2, in an embodiment of the present invention, a plurality of atomizing structures include a first atomizing structure 31. The inner wall of the mixing tube 10 gradually contracts toward the center to form a first tapered structure. The first tapered structure is constructed as the first atomizing structure 31, which is located between the primary swirling hole structure and the secondary swirling hole structure.

[0044] Specifically, fuel is injected into the mixing pipe body 10 through the through hole 111 of the first pipe body section 11, and air enters the mixing pipe body 10 through the first swirling hole 21. The air moves in a spiral motion to mix with the fuel, and the mixed fuel gas is atomized once on the tapered surface of the first atomizing structure 31.

[0045] As shown in Figure 2, in an embodiment of the present invention, the multiple atomizing structures further include a second atomizing structure 32. The inner wall of the mixing tube 10 forms a venturi structure, and the venturi structure is configured as the second atomizing structure 32. A portion of the second atomizing structure 32 is located between the secondary swirling hole structure and the tertiary swirling hole structure, and the remaining portion of the second atomizing structure 32 is opposite to the tertiary swirling hole structure.

[0046] Specifically, in this embodiment, the second atomizing structure 32 is a venturi structure. Specifically, as shown in Figure 2, the venturi structure includes a second tapered structure and a diffusing structure connected in sequence. The second tapered structure is located between the second swirling hole 22 and the third swirling hole 23, while the diffusing structure is opposite to the third swirling hole 23. After the mixed oil and gas undergo a first atomization on the tapered surface of the first atomizing structure 31, it continues to flow towards the second end of the mixing tube body 10. Air enters the mixing tube body 10 through the second swirling hole 22 and spirals, mixing again with the oil and gas mixture to improve mixing uniformity. The mixed oil and gas undergo a second atomization on the tapered surface of the venturi structure to improve the fuel atomization effect. The atomized fuel enters the diffusing structure of the venturi structure, and air also enters the diffusing structure through the third swirling hole 23, spiraling and mixing again with the atomized fuel to further improve mixing uniformity.

[0047] Furthermore, in an embodiment of the present invention, considering the narrow spacing between the first atomizing structure 31 and the second atomizing structure 32, the second swirl hole 22 is designed as a square hole. The third swirl hole 23 is opposite to the gradually expanding structure of the venturi structure; increasing the length of the third swirl hole 23 can increase the air intake of the third swirl hole 23, thereby making the air and fuel mix more evenly within the gradually expanding structure.

[0048] The main combustion stage mixing pipe of the central staged combustion chamber provided in this embodiment of the invention enhances the swirling effect and optimizes the flow field by designing the first swirling orifice as a circular orifice, the second swirling orifice as a square orifice, and the third swirling orifice as a rectangular orifice. At the same time, it rationally distributes the gas volume to ensure complete combustion of fuel, thereby improving combustion performance and emission performance. In addition, the multiple swirling stages result in good fuel-air mixing effect, and the axial length of the mixing pipe is shortened, making the structure of the combustion chamber more compact. In the fuel mist field, the fuel vapor phase is distributed throughout the entire fluid domain behind the nozzle, resulting in uniform fuel distribution and good atomization effect.

[0049] As shown in Figure 3, this embodiment of the invention also provides a central staged combustion chamber, including a pre-combustion stage assembly 40 and multiple main combustion stage mixing pipes for the central staged combustion chamber. The multiple main combustion stage mixing pipes are arranged around the pre-combustion stage assembly 40.

[0050] Specifically, multiple main combustion stage mixing pipes are arranged around the pre-combustion stage assembly 40 in a trapezoidal structure. These pipes are fixed at the air inlet at the head of the central staged combustion chamber, mixing and swirling the air and fuel to ensure complete combustion. The pre-combustion stage assembly 40 uses a diffusion flame, which improves combustion efficiency in single-flame mode and also stabilizes the flame under heavy operating conditions.

[0051] Optionally, in this embodiment, there are 11 main combustion stage mixing tubes and 3 oil circuits in the central staged combustion chamber. Different oil circuits can be selected to supply oil according to different operating conditions in order to achieve stable flame and improve combustion efficiency.

[0052] The central staged combustion chamber provided in this embodiment of the invention shortens the mixing time and distance by setting the main combustion stage mixing pipe, making the combustion chamber structure more compact, reducing flow loss, and achieving stable combustion; at the same time, the pre-combustion stage and the main combustion stage can be well coupled, resulting in complete combustion and stable flame.

[0053] This invention also provides an aero engine, including a central staged combustion chamber.

[0054] The aero-engine provided in this embodiment of the invention has the advantages of simple structure, no mechanical stirring, continuous production, low operating cost and high mixing efficiency by setting a central staged combustion chamber.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A main combustion stage mixing pipe in a centrally staged combustion chamber, characterized in that, The system includes a mixing pipe body, the first end of which is a closed end with a through hole at its center for fuel injection, and the second end of which is an open end. The mixing pipe body has a multi-stage swirling hole structure, each stage of which is connected to the interior of the mixing pipe body. Air enters the mixing pipe body through the swirling hole structure and mixes with the fuel in a spiral flow to ensure uniform mixing. The mixing pipe body also has multiple atomizing structures, with the swirling hole structure and the atomizing structure alternating to atomize the mixed fuel-air mixture. The outer surface of the first end of the mixing pipe body is conical, and the outer surface of the second end is cylindrical. The multi-stage swirling hole structure includes a single-stage swirling hole structure, which includes multiple first swirling holes arranged in a ring along the conical surface. The angle between the plane of the air outlet of each first swirling hole and the plane of the air inlet is acute.

2. The main combustion stage mixing pipe of the central staged combustion chamber according to claim 1, characterized in that, The multi-stage swirling hole structure also includes a secondary swirling hole structure, which includes multiple second swirling holes arranged in a ring along the cylindrical surface, with the air outlet end and air inlet end of each second swirling hole being staggered.

3. The main combustion stage mixing pipe of the central staged combustion chamber according to claim 2, characterized in that, The multi-stage swirling hole structure also includes a third-stage swirling hole structure. Along the flow direction of the fuel, the third-stage swirling hole structure is located downstream of the second-stage swirling hole structure. The third-stage swirling hole structure includes multiple third swirling holes, which are arranged in a ring along the cylindrical surface. The air outlet end and air inlet end of each third swirling hole are staggered.

4. The main combustion stage mixing pipe of the central staged combustion chamber according to claim 3, characterized in that, The first swirling orifice is a circular orifice, the second swirling orifice is a square orifice, and the third swirling orifice is a rectangular orifice.

5. The main combustion stage mixing pipe of the central staged combustion chamber according to claim 2, characterized in that, The plurality of atomizing structures include a first atomizing structure, wherein the inner wall of the mixing tube gradually contracts toward the center to form a first tapering structure, the first tapering structure is configured as the first atomizing structure, and the first atomizing structure is located between the primary swirling hole structure and the secondary swirling hole structure.

6. The main combustion stage mixing pipe of the central staged combustion chamber according to claim 3, characterized in that, The plurality of atomizing structures further includes a second atomizing structure, wherein the inner wall of the mixing tube body forms a venturi structure, the venturi structure is configured as the second atomizing structure, a portion of the second atomizing structure is located between the secondary swirling hole structure and the tertiary swirling hole structure, and the remaining portion of the second atomizing structure is opposite to the tertiary swirling hole structure.

7. A centrally staged combustion chamber, characterized in that, It includes a pre-combustion stage assembly and a plurality of main combustion stage mixing pipes in a central staged combustion chamber as described in any one of claims 1-6, wherein the plurality of main combustion stage mixing pipes are arranged around the pre-combustion stage assembly.

8. An aircraft engine comprising the central staged combustion chamber as described in claim 7.

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