An extremely cold flame tube, combustion chamber and aero-engine with a step-shaped flame tube
By using an ultra-cold quenching stepped flame tube design, the complexity of the vortex generator and the high NOx emissions of the existing RQL combustion chamber are solved, achieving low cost, low weight and high efficiency combustion conversion, and improving the engine's ignition performance and combustion stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AECC HUNAN AVIATION POWERPLANT RES INST
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-12
AI Technical Summary
Existing RQL combustors for aero engines suffer from problems such as complex vortex design, difficulty in balancing high-temperature gas cutoff and high-altitude ignition performance in the design of the main combustion port, long fuel-rich combustion conversion time, high NOx emissions, and heavy flame tube weight.
It adopts an ultra-cold quenching stepped flame tube design, including an outer ring and an inner ring, with a large cavity and high profile and stepped contraction section. Combined with the quenching and mixing structure of the outer and inner rings, multiple low-speed recirculation zones are formed, eliminating the precision vortex generator and optimizing the combustion zone design to achieve rapid combustion conversion and low NOx emissions.
It reduces the processing difficulty and cost of the combustion chamber, widens the engine ignition and starting height, significantly reduces NOx emissions, and reduces the weight of the flame tube, thus improving combustion stability.
Smart Images
Figure CN122191598A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aero-engine technology, and specifically relates to an extremely cold quenching stepped flame tube, combustion chamber, and aero-engine. Background Technology
[0002] The combustor is a core component of the combustion chamber of an aero-engine / gas turbine. Its function is to organize the mixing and combustion of fuel and air, generating the high-temperature combustion gases required to drive the turbine. One of the main development directions for civil aero-engine combustor technology is low-emission, and RQL (Rich Burn-Quench-Lean Burn) combustion technology is one of the key technological routes for low-emission combustion. Figure 1 As shown, its main principle is staged air combustion: the main combustion zone is a rich combustion zone 100, the middle zone is a quenched mixing zone 200, and the rear is a lean combustion zone 300, with the flame tube design playing a crucial role. RQL combustion organization typically employs a combination of a vortex generator and main combustion orifices to create a stable low-speed recirculation zone in the main combustion zone, maintaining flame stability; in the quenched mixing zone, single or double rows of mixing orifices are typically used to achieve the transition from rich to lean combustion.
[0003] Existing low-emission combustion chambers with RQL combustion organization in aero engines have the following problems: 1. Precision vortex generators are required to create a low-speed zone in the main combustion zone to stabilize the flame; 2. The design of the main combustion orifice, which requires a small cavity height to cut off the high-temperature gas jet, and a large cavity height to achieve excellent high-altitude ignition performance, is difficult to balance. 3. The transition from rich fuel combustion to lean fuel combustion takes a long time and there is a large stoichiometric combustion zone between the two processes, resulting in high NOx emissions. 4. The long residence time of the gas inside the flame tube results in high NOx emissions; 5. The flame tube is quite heavy. Summary of the Invention
[0004] To address the above problems, the present invention provides an ultracold quenching stepped flame tube, comprising a flame tube head, an inner ring, and an outer ring; The radial inner edge of the flame tube head is fixedly connected to the front end of the inner ring, and the radial outer edge of the flame tube head is fixedly connected to the front end of the outer ring; an annular flame tube flow channel is formed between the outer ring and the inner ring; a front cavity is formed between the front section of the outer ring and the front section of the inner ring, and a rear cavity is formed between the rear section of the outer ring and the rear section of the inner ring; the height of the first cavity between the front section of the outer ring and the front section of the inner ring is greater than the height of the second cavity between the rear section of the outer ring and the rear section of the inner ring. The front and rear sections of the outer ring are connected by an outer ring stepped contraction section, and the front and rear sections of the inner ring are connected by an inner ring stepped contraction section. The front section of the outer ring is provided with an outer main combustion port, the front section of the inner ring is provided with an inner main combustion port, the rear section of the outer ring is provided with an outer ring quenching and mixing structure, and the rear section of the inner ring is provided with an inner ring quenching and mixing structure.
[0005] Furthermore, 1.5 ≤ First cavity height / Second cavity height ≤ 2.5.
[0006] Furthermore, the area between the head of the flame tube and the outer and inner main combustion holes is the fuel-rich combustion zone, while the area after the outer and inner main combustion holes is the fuel-lean combustion zone.
[0007] Furthermore, the inlet of the outer ring quenching and blending structure is located on the outer side of the outer ring, the outer ring quenching and blending structure penetrates the rear section of the outer ring, and the outlet of the outer ring quenching and blending structure is located in the lean combustion zone; the inlet of the inner ring quenching and blending structure is located on the outer side of the inner ring, the inner ring quenching and blending structure penetrates the rear section of the inner ring, and the outlet of the inner ring quenching and blending structure is located in the lean combustion zone.
[0008] Furthermore, the inlets of both the outer ring quenching and mixing structure and the inner ring quenching and mixing structure are parallel to the axial centerline of the flame tube flow channel.
[0009] Furthermore, the outlets of both the outer ring quenching and mixing structure and the inner ring quenching and mixing structure are located between the outer main combustion port and the inner main combustion port.
[0010] Furthermore, the outlet jet angle of the outer ring quenching and mixing structure is matched with the outer main combustion orifice and the flame tube profile, while the outlet jet angle of the inner ring quenching and mixing structure is matched with the inner main combustion orifice and the flame tube profile.
[0011] Furthermore, the outlet jet directions of both the outer and inner ring quenching mixing structures are parallel to the axial centerline of the flame tube flow channel.
[0012] Furthermore, the outlet jet direction of the outer ring quenching and mixing structure forms an angle with the axial centerline of the flame tube channel and extends towards the inner ring; the outlet jet direction of the inner ring quenching and mixing structure forms an angle with the axial centerline of the flame tube channel and extends towards the outer ring.
[0013] Furthermore, the outlet jet direction of the inner ring quenching and mixing structure forms an angle with the axial centerline of the flame tube channel and extends towards the outer ring; the outlet jet directions of both the outer ring quenching and mixing structure and the inner ring quenching and mixing structure are parallel to the axial centerline of the flame tube channel.
[0014] The present invention also provides a combustion chamber, including the above-mentioned ultra-cooled quenching stepped flame tube, wherein the flame tube is disposed between the inner casing and the outer casing of the combustion chamber.
[0015] The present invention also provides an aircraft engine including the above-described combustion chamber, wherein the combustion chamber is disposed in the aircraft engine.
[0016] The beneficial effects of this invention are: 1. The first cavity height between the front section of the outer ring and the front section of the inner ring of the present invention is greater than the second cavity height between the rear section of the outer ring and the rear section of the inner ring, so that the front section of the outer ring and the front section of the inner ring are large cavity height profiles, resulting in a low reference speed in the main combustion zone and good high-altitude ignition performance.
[0017] 2. The outer and inner rings of the present invention are provided with stepped contraction sections after the main combustion hole to reduce the height of the flame tube cavity, reduce the residence time of the gas in the flame tube, and the rapid stepped contraction flame tube greatly reduces the weight of the flame tube.
[0018] 3. The present invention has quenching and mixing structures in both the outer and inner rings. The airflow and the main combustion hole jet jointly cut off the high-temperature combustion gas, realizing the transition from rich combustion to lean combustion in an extremely short time.
[0019] 4. The outlet jet structure of the internal and external quenching mixing structure of the present invention is designed to match the main combustion hole and the flame tube profile to form a low backflow zone, maintain flame stability, and eliminate the need for a precision vortex generator.
[0020] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 A schematic diagram of the combustion chamber structure of RQL combustion organization according to the prior art is shown; Figure 2 A schematic diagram of an ultracold quenching stepped flame tube structure according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of a symmetrical low-speed recirculation zone structure formed inside the flame tube according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of a cross-symmetrical low-speed recirculation zone structure formed inside the flame tube according to an embodiment of the present invention is shown; Figure 5A schematic diagram of an enhanced low-speed recirculation zone structure formed inside the flame tube according to an embodiment of the present invention is shown.
[0023] In the diagram: 100, rich combustion zone; 200, quenched and mixed zone; 300, lean combustion zone; 1, head; 2, outer ring front section; 3, outer ring stepped contraction section; 4, outer ring rear section; 5, outer main combustion port; 6, outer ring quenched and mixed structure; 7, inner ring front section; 8, inner ring stepped contraction section; 9, inner ring rear section; 10, inner main combustion port; 11, inner ring quenched and mixed structure. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.
[0026] This invention provides an ultracooled quenching stepped flame tube, combustion chamber, and aero-engine, which can further reduce costs and processing difficulty, reduce NOx emissions, and increase engine ignition and start-up height compared to existing RQL combustion chambers.
[0027] like Figure 2 As shown, an ultracooled quenching stepped flame tube is installed in an aero-engine / gas turbine. The flame tube includes a flame tube head 1, an inner ring, and an outer ring.
[0028] Among them, the flame tube head 1 is located at the axial front end of the flame tube and is arranged in a ring along the circumference; the radial inner edge of the flame tube head 1 is fixedly connected to the front end of the inner ring, and the radial outer edge of the flame tube head 1 is fixedly connected to the front end of the outer ring. The flame tube head 1, the inner ring, and the outer ring form an integral closed structure at the front end.
[0029] The inner ring is located radially inside the flame tube and extends axially from the rear end of the flame tube head 1 to form the inner boundary of the flame tube; the outer ring is located radially outside the flame tube and extends axially from the rear end of the flame tube head 1 to form the outer boundary of the flame tube.
[0030] An annular flame tube flow channel is formed between the outer ring and the inner ring. The front section 2 of the outer ring and the front section 7 of the inner ring adopt a high-cavity profile design, while the rear section 4 of the outer ring and the rear section 9 of the inner ring adopt a low-cavity profile design after step-like contraction. That is, the front section cavity is formed between the front section 2 of the outer ring and the front section 7 of the inner ring, and the rear section cavity is formed between the rear section 4 of the outer ring and the rear section 9 of the inner ring. The first cavity height between the front section 2 of the outer ring and the front section 7 of the inner ring is greater than the second cavity height between the rear section 4 of the outer ring and the rear section 9 of the inner ring, where 1.5 ≤ first cavity height / second cavity height ≤ 2.5.
[0031] The outer ring front section 2 and the outer ring rear section 4 are connected by the outer ring stepped contraction section 3, and the inner ring front section 7 and the inner ring rear section 9 are connected by the inner ring stepped contraction section 8.
[0032] The outer ring front section 2 is provided with an outer main combustion hole 5, and the inner ring front section 7 is provided with an inner main combustion hole 10. For example, both the outer main combustion hole 5 and the inner main combustion hole 10 are circular. The outer ring rear section 4 is provided with an outer ring quenching and mixing structure 6, and the inner ring rear section 9 is provided with an inner ring quenching and mixing structure 11. The area from the flame tube head 1 to the outer main combustion hole 5 and the inner main combustion hole 10 is the fuel-rich combustion zone 100, and the area after the outer main combustion hole 5 and the inner main combustion hole 10 is the fuel-lean combustion zone 300.
[0033] High-pressure air, compressed by the compressor, enters the combustion chamber through the diffuser channel, and then enters the flame tube channel through openings in the inner ring, outer ring, and flame tube head 1. Fuel enters the flame tube channel through the fuel nozzle, mixes with the high-pressure air in the flame tube channel, and flows with it. When the engine is ignited, the electric spark generated by the ignition nozzle located near the flame tube wall ignites the fuel-air mixture, forming high-temperature and high-pressure combustion gas. Air entering from the outer main combustion port 5, inner main combustion port 10, outer ring quenching and mixing structure 6, and inner ring quenching and mixing structure 11 is rapidly quenched and mixed with the high-temperature and high-pressure combustion gas. Then, the high-temperature combustion gas with the required temperature distribution enters the turbine, driving it to do work.
[0034] For example, the inlet of the outer ring quenching and blending structure 6 is located on the outside of the outer ring, the outer ring quenching and blending structure 6 penetrates the rear section 4 of the outer ring, and the outlet of the outer ring quenching and blending structure 6 is located in the lean combustion zone 300.
[0035] The inlet of the inner ring quenching and blending structure 11 is located on the outer side of the inner ring. The inner ring quenching and blending structure 11 penetrates the rear section 9 of the inner ring. The outlet of the inner ring quenching and blending structure 11 is located in the lean combustion zone 300.
[0036] For example, the inlet of the outer ring quenching mixing structure 6 and the inlet of the inner ring quenching mixing structure 11 are both parallel to the axial centerline of the flame tube flow channel.
[0037] In this embodiment of the invention, the inlet of the outer ring quenching and mixing structure 6 and the inner ring quenching and mixing structure 11 adopts a parallel two-channel airflow design to make full use of the gas flow head and enhance the subsequent quenching and mixing capability.
[0038] For example, the outlet of the outer ring quenching and mixing structure 6 and the outlet of the inner ring quenching and mixing structure 11 are both located between the outer main combustion hole 5 and the inner main combustion hole 10.
[0039] The matching design of the main combustion jet and the quenching mixing structure jet in this embodiment of the invention forms a gas curtain that cuts off the high-temperature combustion gas, which instantly transforms rich combustion into lean combustion, greatly shortens the transition time from rich combustion to lean combustion, and reduces the flame volume above 1850°C that can generate a large amount of NOx pollutants.
[0040] For example, the outlet jet angle of the outer ring quenching and mixing structure 6 is matched with the outer main combustion hole 5 and the flame tube profile, and the outlet jet angle of the inner ring quenching and mixing structure 11 is matched with the inner main combustion hole 10 and the flame tube profile, forming three low-speed zones in the main combustion zone, which ensures the engine ignition and shutdown performance and the stability of the combustion flame.
[0041] like Figure 3 As shown, for example, the outlet jet direction of the outer ring quenching and mixing structure 6 and the inner ring quenching and mixing structure 11 is parallel to the axial centerline of the flame tube flow channel. The outlet of the inner and outer ring quenching and mixing structure is designed as a parallel flow guiding structure to form a symmetrical low-speed recirculation zone.
[0042] like Figure 4 As shown, for example, the outlet jet direction of the outer ring quenching and mixing structure 6 has an angle with the axial center line of the flame tube channel and extends in the inner ring direction to form a downward pressure guiding structure; the outlet jet direction of the inner ring quenching and mixing structure 11 has an angle with the axial center line of the flame tube channel and extends in the outer ring direction to form an upward extension guiding structure. The downward pressure guiding structure and the upward extension guiding structure form a cross-symmetrical low-speed recirculation zone.
[0043] like Figure 5 As shown, for example, the outlet jet direction of the inner ring quenching and mixing structure 11 has an angle with the axial centerline of the flame tube channel and extends outward to form an upward guiding structure; the outlet jet direction of the outer ring quenching and mixing structure 6 and the inner ring quenching and mixing structure 11 is parallel to the axial centerline of the flame tube channel, forming an enhanced low-speed recirculation zone only in the upper half of the flame tube channel.
[0044] In this embodiment of the invention, the outlet jet angle of the quenching and mixing structure is designed to match the main combustion hole and the flame tube profile to form three types of low-speed recirculation zones: symmetrical, cross-symmetrical, and top-enhanced. The precision eddy current generator is eliminated.
[0045] The flame tube provided in this invention can further reduce costs and processing difficulty, reduce NOx emissions, and increase the engine ignition and starting height, specifically through the following five aspects: 1. The outer ring front section 2 and the inner ring front section 7 adopt a large cavity and high profile design, with low reference speed in the main combustion zone and good high-altitude ignition performance.
[0046] 2. Reduce the height of the flame tube cavity in a stepped manner after the main combustion hole to reduce the residence time of the gas in the flame tube.
[0047] 3. The rapid stepped retractable flame tube greatly reduces the weight of the flame tube.
[0048] 4. Both the outer and inner rings are equipped with quenching and mixing structures, and the airflow and the main combustion hole jet jointly cut off the high-temperature combustion gas, achieving the transition from rich combustion to lean combustion in an extremely short time.
[0049] 5. The outlet jet structure of the internal and external quenching mixing structure is designed to match the main combustion hole and flame tube profile to form a low backflow zone, maintain flame stability, and eliminate the need for a precision vortex generator.
[0050] The present invention also provides a combustion chamber, including the above-mentioned ultra-cooled quenching stepped flame tube, wherein the flame tube is disposed between the inner casing and the outer casing of the combustion chamber.
[0051] The combustion chamber of this invention reduces NOx emissions further than existing RQL combustion chambers by forming a gas curtain to cut off high-temperature combustion gas, shortening the residence time of combustion gas, and especially greatly shortening the conversion time from rich combustion to lean combustion. At the same time, this combustion chamber has significant advantages over existing RQL combustion chambers in terms of cost and processing difficulty, flame stability and weight.
[0052] This invention also provides an aircraft engine, including the above-described combustion chamber, which is disposed in the aircraft engine.
[0053] The flame tube of this invention has been theoretically analyzed, numerically calculated, and experimentally verified, and the solution is feasible.
[0054] 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 stepped flame tube with ultra-cold quenching, characterized in that, Includes the flame tube head (1), inner ring, and outer ring; The inner radial edge of the flame tube head (1) is fixedly connected to the front end of the inner ring, and the outer radial edge of the flame tube head (1) is fixedly connected to the front end of the outer ring; an annular flame tube flow channel is formed between the outer ring and the inner ring; a front cavity is formed between the front section (2) of the outer ring and the front section (7) of the inner ring, and a rear cavity is formed between the rear section (4) of the outer ring and the rear section (9) of the inner ring; the first cavity height between the front section (2) of the outer ring and the front section (7) of the inner ring is greater than the second cavity height between the rear section (4) of the outer ring and the rear section (9) of the inner ring; The outer ring front section (2) and the outer ring rear section (4) are connected by an outer ring stepped contraction section (3), and the inner ring front section (7) and the inner ring rear section (9) are connected by an inner ring stepped contraction section (8); the outer ring front section (2) is provided with an outer main combustion hole (5), the inner ring front section (7) is provided with an inner main combustion hole (10), the outer ring rear section (4) is provided with an outer ring quenching and mixing structure (6), and the inner ring rear section (9) is provided with an inner ring quenching and mixing structure (11).
2. The ultracooled quenching stepped flame tube according to claim 1, characterized in that, 1.5≤First cavity height / Second cavity height≤2.
5.
3. The ultracooled quenching stepped flame tube according to claim 1, characterized in that, The area between the head of the flame tube (1) and the outer main combustion port (5) and the inner main combustion port (10) is the rich fuel combustion zone (100), and the area after the outer main combustion port (5) and the inner main combustion port (10) is the lean fuel combustion zone (300).
4. The ultracooled quenching stepped flame tube according to claim 3, characterized in that, The inlet of the outer ring quenching and mixing structure (6) is located outside the outer ring, the outer ring quenching and mixing structure (6) penetrates the rear section (4) of the outer ring, and the outlet of the outer ring quenching and mixing structure (6) is located in the lean combustion zone (300); the inlet of the inner ring quenching and mixing structure (11) is located outside the inner ring, the inner ring quenching and mixing structure (11) penetrates the rear section (9) of the inner ring, and the outlet of the inner ring quenching and mixing structure (11) is located in the lean combustion zone (300).
5. The ultracooled quenching stepped flame tube according to claim 4, characterized in that, The inlet of the outer ring quenching mixing structure (6) and the inlet of the inner ring quenching mixing structure (11) are both parallel to the axial centerline of the flame tube channel.
6. The ultracooled quenching stepped flame tube according to claim 4, characterized in that, The outlets of the outer ring quenching and mixing structure (6) and the inner ring quenching and mixing structure (11) are both located between the outer main combustion hole (5) and the inner main combustion hole (10).
7. The ultracooled quenching stepped flame tube according to any one of claims 4-6, characterized in that, The outlet jet angle of the outer ring quenching and mixing structure (6) is matched with the outer main combustion hole (5) and the flame tube profile, and the outlet jet angle of the inner ring quenching and mixing structure (11) is matched with the inner main combustion hole (10) and the flame tube profile.
8. The ultracooled quenching stepped flame tube according to claim 7, characterized in that, The outlet jet direction of the outer ring quenching mixing structure (6) and the inner ring quenching mixing structure (11) is parallel to the axial centerline of the flame tube channel.
9. The ultracooled quenching stepped flame tube according to claim 7, characterized in that, The outlet jet direction of the outer ring quenching and mixing structure (6) has an angle with the axial center line of the flame tube channel and extends towards the inner ring; the outlet jet direction of the inner ring quenching and mixing structure (11) has an angle with the axial center line of the flame tube channel and extends towards the outer ring.
10. The ultracooled quenching stepped flame tube according to claim 7, characterized in that, The outlet jet direction of the inner ring quenching and mixing structure (11) has an angle with the axial center line of the flame tube channel and extends towards the outer ring; the outlet jet direction of the outer ring quenching and mixing structure (6) and the inner ring quenching and mixing structure (11) is parallel to the axial center line of the flame tube channel.
11. A combustion chamber, characterized in that, Includes the ultracooled quenching stepped flame tube as described in any one of claims 1-10, wherein the flame tube is disposed between the inner casing and the outer casing of the combustion chamber.
12. An aircraft engine, characterized in that, It includes the combustion chamber of claim 11, wherein the combustion chamber is disposed in an aircraft engine.