Local rich-oil ignition and flameout device and aero-engine combustion chamber

Abstract

The invention discloses a local oil-rich ignition and flameout device and an aero-engine combustion chamber, and belongs to the technical field of aero-engine combustion chambers, the device comprises two oil gas generators arranged on the two sides of an ignition nozzle, and each oil gas generator comprises a nozzle and a cooling cover arranged on the periphery of the nozzle in a surrounding mode. The cooling cover is provided with a plurality of air inlet holes with tangential deflection angles in the circumferential direction, and the air inlet holes are used for introducing air in the outer ring channel and forming rotational flow airflow. An outlet of the nozzle extends out of the air outlet of the cooling cover, and an annular gap is formed between the outer wall of the nozzle and the inner wall of the air outlet, so that air is mixed with injected fuel oil at the outlet of the nozzle, and a stable oil-gas mixing area is generated. The injection paths of the two oil-gas generators oppositely face each other in the downstream direction of the ignition nozzle, a local oil-rich area is formed at the ignition nozzle, rapid and stable ignition can be achieved under ignition and low working conditions, the flameout risk is reduced, and the working reliability and adaptability of the combustion chamber are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of an aero-engine combustion chamber, in particular to a local rich oil point flameout device and an aero-engine combustion chamber. BACKGROUND

[0002] With the progress of aero-engine technology, the design direction of advanced aero-engine combustion chambers is increasingly developing towards high temperature rise and wide oil domain: high temperature rise refers to an inlet temperature of 800K or more, a temperature rise of 1100K or more, that is, an outlet temperature of 1900K or more; wide oil domain refers to, as the temperature rise of the combustion chamber becomes higher and higher, the ratio of the maximum state fuel consumption of the combustion chamber to the fuel consumption at the ground ignition state becomes larger and larger. With the increase of the temperature rise, the air quantity of the “main combustion zone” becomes larger and larger, and the oil-gas ratio of the main combustion zone of the combustion chamber at a small state becomes smaller and smaller, thereby causing the problems of difficult ignition of the combustion chamber and easy flameout.

[0003] Patent CN115978582A proposes a flame tube with a wall surface injection nozzle, which sprays a certain proportion of fuel into the outer recirculation zone at a small state of the combustion chamber to cause local fuel enrichment, thereby improving the stability of the combustion chamber and improving the ignition performance. However, the structure is to improve the oil-gas ratio in the existing recirculation zone by spraying fuel into it, and its ability to improve the point flameout performance is limited. SUMMARY

[0004] The present application provides a local rich oil point flameout device and an aero-engine combustion chamber to solve the technical problems of insufficient oil-gas ratio, difficult ignition and easy flameout of the combustion chamber at ignition or low operating conditions.

[0005] According to one aspect of the present application, a local rich oil point flameout device is provided, comprising two oil-gas generators arranged on both sides of an ignition nozzle, each oil-gas generator comprising a nozzle in communication with a fuel supply pipeline and a cooling cover surrounding the outer periphery of the nozzle; the cooling cover is provided with an air inlet hole and an air outlet hole, the air inlet hole is in communication with an outer ring channel of the combustion chamber for introducing air, and the air outlet hole is in communication with a combustion zone between the outer ring of the flame tube and the inner ring of the flame tube; the outlet of the nozzle extends out of the air outlet hole, and an annular gap is formed between the outer wall of the nozzle and the inner wall of the air outlet hole, the annular gap is used to guide the air entering through the air inlet hole to mix with the fuel jet at the outlet of the nozzle to form an oil-gas mixing zone; the jet paths of the two oil-gas generators are opposite and collide in the downstream direction of the ignition nozzle, and form a local rich oil zone at the corresponding position of the ignition nozzle.

[0006] Optionally, the cooling cover is circumferentially provided with a plurality of air inlet holes, the air inlet holes are provided with a tangential angle in the circumferential direction, so that the air entering the cooling cover forms a rotational flow, and the rotational flow is used to interact with the fuel jet sprayed by the nozzle to form a vortex mixing field with a shear layer at the outlet of the nozzle.

[0007] Optionally, the lower end of the cooling shroud is provided with a guide slope inclined toward the combustion zone, and the guide slope and the nozzle outlet form a flow channel to guide the cooling air to converge toward the combustion zone along the outer wall of the nozzle.

[0008] Optionally, the top of the cooling cover is a flange structure formed by folding outwards, and the upper section of the nozzle is provided with an annular pressing boss. The pressing boss presses against the flange to fix the cooling cover and forms an airtight connection at the pressing point.

[0009] Optionally, the outer contour of the nozzle outlet section is a tapered cone, and the airflow outlet of the cooling shroud is a cylindrical straight opening, so that an expanding annular gap with a gradually increasing cross-sectional area along the airflow direction is formed between the outer wall of the nozzle and the inner wall of the cooling shroud.

[0010] Optionally, the width of the annular gap between the outer wall of the nozzle and the inner wall of the cooling shroud outlet is 1 to 3 mm.

[0011] Optionally, the outer wall of the nozzle is provided with an annular guide step at the outlet section. The guide step is located upstream of the nozzle outlet and is opposite to the guide slope of the cooling shroud. It is used to change the airflow direction in the annular gap and form a wall-adhering air film on the outer wall of the nozzle.

[0012] Optionally, the included angle between the injection axes of the two oil and gas generators is 90° to 150°.

[0013] Optionally, the ignition nozzle and the two oil-gas generators are located in the same radial section, and the axial position of the oil-gas generators relative to the ignition nozzle is adjustable to adjust the confluence position of the two jet streams.

[0014] According to another aspect of this application, an aircraft engine combustion chamber is also provided, which includes an outer casing, an outer ring of the flame tube, and an inner ring of the flame tube. The aforementioned local rich fuel point quenching device is provided between the outer casing and the outer ring of the flame tube. The injection path of the local rich fuel point quenching device is located on both sides of the ignition nozzle and faces each other. The confluence area is located in the combustion zone downstream of the ignition nozzle, so as to form a local rich fuel zone at the corresponding position of the ignition nozzle.

[0015] In summary, this application includes at least one of the following beneficial technical effects: This solution utilizes paired air-fuel generators positioned on either side of the ignition nozzle to create a locally rich fuel mixture zone near the nozzle outlet. This effectively mitigates ignition difficulties and flameout issues caused by a low overall fuel-air ratio in the combustion chamber during ignition and at low operating conditions. Specifically, each air-fuel generator introduces air from the outer annular channel through an intake port within the cooling shroud. As the air passes through the annular gap, it undergoes high-speed shear mixing with the fuel injected from the nozzle, forming a highly concentrated and stably distributed locally rich fuel-air mass at the nozzle outlet. The injection paths of the two air-fuel generators converge downstream of the ignition nozzle, generating strong turbulence and vortices at the convergence point, resulting in more thorough fuel-air mixing in this area. When the ignition nozzle ignites, a stable flame core can quickly form within this locally rich fuel zone. Because the flame first burns stably in the locally rich fuel zone before gradually expanding towards the main combustion zone, a smooth transition from ignition to main combustion is achieved, significantly improving ignition reliability at low operating conditions and reducing the risk of flameout.

[0016] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a cross-sectional view of the local rich oil point flameout device of this application along the combustion chamber axis; Figure 2 This is a cross-sectional view of the local rich oil point flameout device of this application along the radial direction of the combustion chamber.

[0018] Legend: 1. Main nozzle; 2. Combustion chamber head; 3. Swirler; 4. Ignition nozzle; 5. Outer casing; 6. Flame tube outer ring; 7. Flame tube inner ring; 8. Fuel generator; 9. Main combustion zone; 10. Local rich fuel zone; 11. Air inlet; 12. Nozzle; 13. Cooling shroud; 14. Guide ramp; 15. Guide step. Detailed Implementation

[0019] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0020] The following is in conjunction with the appendix Figures 1-2 This application will be described in further detail.

[0021] Reference Figure 1This embodiment provides a localized rich-fuel flameout device for the ignition and stable combustion process of an aero-engine combustor. It aims to solve the problems of ignition difficulties, flame instability, and high flameout risk caused by the low overall air-fuel ratio in existing combustors during ignition or low operating conditions. By actively forming a localized rich-fuel zone 10 near the igniter 4, ignition energy can quickly establish a flame core within the rich-fuel gas mass, thereby achieving reliable ignition and continuous stable combustion.

[0022] like Figure 1 As shown, the localized rich fuel point quenching device is integrally installed between the outer casing 5 and the outer ring 6 of the flame tube in the combustion chamber of the aero-engine, arranged circumferentially on both sides of the ignition nozzle 4. The device includes two identical fuel-air generators 8, arranged symmetrically opposite each other, with their injection paths opposing each other in the downstream region of the ignition nozzle 4, converging to form a localized rich fuel mixing zone. The ignition nozzle 4 is located in the middle of the combustion zone between the inner ring 7 and the outer ring of the flame tube, and is used to provide an ignition source.

[0023] Each fuel-air generator 8 is fixed to the outer casing 5 by a mounting base connected to a fuel supply line for supplying metered fuel to the nozzle 12. A cooling shroud 13 is installed around the nozzle 12, and the cooling shroud 13 is connected to the outer annular channel of the combustion chamber to introduce some air. After entering through the air inlet 11 inside the cooling shroud 13, the air flows along the outer wall of the nozzle 12 and forms a mixing zone with the fuel jet ejected from the nozzle 12 near the nozzle 12 outlet. The injection directions of the two fuel-air generators 8 are symmetrical about the axis of the ignition nozzle 4, and the jets collide downstream of the ignition nozzle 4, forming a highly turbulent mixing zone. The fuel-air equivalent in this mixing zone is relatively high, constituting a locally rich fuel zone 10 in the early stage of combustion. When the ignition nozzle 4 discharges and generates a spark, the mixture in the rich fuel zone is more easily ignited, and the flame can burn rapidly and stably in this area. As combustion continues, the flame core gradually expands towards the main combustion zone 9, forming a smooth flame propagation path. Through this symmetrical arrangement and aerodynamic design, this device can provide stable local rich fuel ignition conditions under low operating conditions, significantly improving the ignition reliability and anti-quench capability of the combustion chamber, and ensuring the continuous and stable operation of the engine under different altitudes, ambient temperatures and acceleration / deceleration conditions.

[0024] Each fuel-air generator 8 consists of a nozzle 12 and a cooling shroud 13 surrounding the nozzle 12. The nozzle 12 is connected to a fuel supply line via an internal channel for injecting metered fuel into the combustion zone. The cooling shroud 13 is fitted over the nozzle 12 and communicates with an outer annular channel of the combustion chamber to introduce a portion of cooling air. This air forms a controlled airflow inside the cooling shroud 13, interacting with the fuel injected from the nozzle 12 to generate a stable fuel-air mixture zone in the nozzle 12 outlet region.

[0025] The outlet end of nozzle 12 extends from the air outlet of cooling shroud 13, forming an annular gap between its outer wall and the inner wall of the air outlet of cooling shroud 13. The width of this annular gap is designed to be 1-3 mm, which ensures sufficient airflow and allows the airflow to form a high velocity at the outer wall of nozzle 12, thereby generating a significant shearing effect in the outlet area. After entering through the air inlet 11 in cooling shroud 13, the intake air flows along the outer wall of nozzle 12 and is ejected at high speed through the annular gap, meeting and mixing with the fuel jet ejected from nozzle 12 near the outlet. Since the airflow velocity is much higher than the fuel jet velocity, a strong turbulent shear zone is formed at the confluence of the two fluids, which further breaks up the fuel droplets and rapidly vaporizes them, forming a fine and uniform fuel-air mixture.

[0026] When the two fuel-gas generators 8 operate simultaneously, their jets collide downstream of the igniter 4, forming a locally rich fuel-mixing core in the confluence area. This core area has a high fuel-gas concentration and strong turbulence, which can be rapidly ignited and form a stable flame under the spark generated by the igniter 4. In the initial stage of combustion, the flame mainly burns stably in the locally rich fuel zone 10, and then gradually expands to the surrounding main combustion zone 9, achieving smooth flame propagation.

[0027] The cooling cover 13 serves both to guide and mix airflow, and to cool and protect the nozzle 12. The cooling cover 13 is a cylindrical structure that is fitted around the nozzle 12. Its inner cavity is connected to the outer ring channel of the combustion chamber to introduce cold air from the outer ring.

[0028] The cooling shroud 13 has multiple air inlets 11 distributed circumferentially. These air inlets 11 are evenly arranged along the circumference and have a certain tangential angle relative to the radial direction. This tangential angle design causes the air entering the cooling shroud 13 to no longer flow in a straight radial direction upon entering the inner cavity, but instead carries a significant tangential velocity component, thus forming a rotating flow field, or swirling air field, inside the cooling shroud 13. The presence of the swirling flow causes the air inside the cooling shroud 13 to generate angular momentum over a short distance, forming a spiral flow trajectory along the inner wall and creating an annular rotating air layer around the outer wall of the nozzle 12.

[0029] The setting of the tangential deflection angle can significantly improve the momentum distribution of the incoming air. When the deflection angle is small, the airflow rotational angular velocity is low, mainly axial flow, the airflow is relatively stable, and the cooling effect is good, but the mixing enhancement effect is limited. When the deflection angle is large, the air rotational angular velocity within the cooling shroud 13 increases significantly, generating stronger centrifugal force and radial pressure gradient, causing the airflow to form a high-intensity swirling field at the nozzle 12 outlet. The preferred tangential deflection angle is 10° to 20°, which ensures that the air forms a significant swirling structure at the nozzle 12 outlet without causing flow field instability or energy loss due to excessive rotational speed.

[0030] As the swirling air passes through the outer wall of nozzle 12, it is guided by the conical guide on the outer surface of nozzle 12, causing the airflow velocity to gradually increase and be compressed to near the nozzle 12 outlet. Subsequently, the air is ejected at high speed through the annular gap between nozzle 12 and cooling shroud 13. Because the airflow already has strong rotational momentum before injection, the air flowing out of the annular gap forms an annular high-speed swirling jet. When this swirling jet meets the fuel jet ejected from the center of nozzle 12, there is a large velocity gradient and directional difference between the two, resulting in a significant shear layer at the interface. This shear layer becomes the starting point for turbulence development, causing the gas flow to rapidly transform into a strong turbulent state, promoting secondary breakup and uniform dispersion of fuel droplets.

[0031] Furthermore, the vortex structure formed near the outlet of the swirling jet can significantly increase the residence time of air at the outlet of nozzle 12, thereby improving the contact area and mixing efficiency between air and fuel. The centrifugal force generated by the swirling jet will also throw some fuel droplets to the outer edge, thus forming an oil-gas layer with a gradually changing equivalence ratio near the annular gap, making the local oil-rich zone 10 smoother and more stable.

[0032] The lower end of the cooling shroud 13 is provided with a guide slope 14 inclined towards the combustion zone, forming a flow channel between the nozzle 12 outlet and the guide slope 14. Through this channel, cooling air is guided to flow along the outer wall of the nozzle 12 and converge towards the combustion zone. This not only effectively cools the end of the nozzle 12 and the surrounding wall, but also maintains a certain angle between the air injection direction and the fuel jet direction, causing the two fluids to form strong shear and mixing at the inlet of the combustion zone, thereby further enhancing the local fuel-air mixing effect. The guide slope 14 also provides a certain aerodynamic damping, preventing high-temperature gas in the combustion zone from flowing back into the cooling shroud 13, thus providing backflow protection.

[0033] The top of the cooling cover 13 features an outward-folding flange structure that mates with the annular clamping boss on the upper section of the nozzle 12. The clamping boss is pressed against the flange via a threaded connection or a snap ring locking structure, forming a reliable airtight contact surface. This structure ensures the stable fixation of the cooling cover 13 under high-temperature combustion conditions while allowing for some thermal expansion and contraction compensation, preventing loosening or cracking due to thermal stress. A high-temperature resistant sealing gasket is installed at the flange clamping point to further ensure sealing performance and structural safety.

[0034] The outer contour of the nozzle 12 outlet section is designed as a tapered cone structure, while the air outlet of the cooling shroud 13 is a cylindrical straight opening. Between the two forms an expanding annular gap with a gradually increasing cross-sectional area along the airflow direction. As the airflow enters the expanding annular gap through the tapered cone, its velocity gradually decreases and its pressure increases, forming a velocity gradient that is beneficial for secondary fuel atomization and airflow rectification, thereby enhancing shear breakup and preventing flame backflow to the nozzle 12 end face. The width of the annular gap between the outer wall of the nozzle 12 and the inner wall of the air outlet of the cooling shroud 13 can be adjusted according to the air supply pressure and fuel injection rate, preferably within a range of 1–3 mm. When the gap is smaller, the airflow velocity increases, and the shearing effect is enhanced, making it suitable for ignition conditions at high altitudes or low temperatures; when the gap is larger, the airflow increases, which can enhance the cooling effect of the nozzle 12 and improve the stable combustion performance under high operating conditions.

[0035] To further improve airflow organization, an annular guide step 15 is provided upstream of the nozzle 12 outlet section. This step is spaced apart from the guide ramp 14 of the cooling shroud 13. The guide step 15 can change the airflow direction, causing the annular airflow to form a wall-adhering gas film on the outer wall of the nozzle 12. This not only cools the nozzle 12 but also inhibits the high-temperature gas in the recirculation zone from eroding the outer wall of the nozzle 12. The presence of the gas film also stabilizes the airflow field within the annular gap, reducing the risk of uneven spray and carbon buildup.

[0036] The included angle between the injection axes of the two fuel-gas generators 8 is a crucial parameter determining the morphology and mixing intensity of the local rich fuel zone 10. In this embodiment, the included angle is designed to range from 90° to 150°, preferably approximately 120°. This angle directly affects the convergence position, convergence intensity, and local turbulence structure of the two fuel-gas jets in the downstream region of the ignition nozzle 4, thus significantly impacting fuel atomization, rich fuel zone formation, and flame stability.

[0037] When the angle is small, the relative velocity components of the two jet streams are large, resulting in the strongest counteracting effect. The confluence point is close to the center of the downstream region of the igniter 4. At this point, the airflow shear intensity is high, and the turbulent energy is concentrated, forming a strong vortex structure. This is beneficial for further fuel fragmentation and rapid mixing, enabling the formation of a high-concentration local rich fuel zone 10 in a short time, thus achieving rapid ignition. However, an excessively small angle may also lead to overly concentrated jet streams, strong local airflow impact, and a small rich fuel zone volume, which can easily generate high-temperature hot spots after ignition, affecting the uniform propagation of the flame. When the angle is large, the two jet streams tend to be parallel, the counteracting effect weakens, and the confluence point is farther from the igniter 4. At this point, the fuel-air mixing area is wider, the rich fuel zone expands and is more evenly distributed, and the flame envelope is smoother, which is beneficial for stable combustion under low operating conditions. However, an excessively large angle will cause the rich fuel zone to be too far from the igniter 4, making it difficult for the ignition spark to effectively couple with the rich fuel mixture, thus reducing ignition reliability.

[0038] The selection of the included angle also needs to comprehensively consider factors such as the combustion chamber structural dimensions, fuel supply pressure, outer ring intake flow rate, and inlet flow direction of the main combustion zone 9. For combustion chambers with narrow combustion zones and igniters 4 close to the center of the flame tube, a smaller included angle can be used to enhance counter-turbulence; while for combustion chambers with wide combustion zones and high mainstream velocities, a larger included angle is preferred to expand the rich fuel zone and enhance flame coverage. Therefore, this embodiment selects an included angle of approximately 120° as the comprehensive optimization value, which ensures both the intensity of counter-turbulence and the geometric alignment between the rich fuel zone and the flame channel of igniters 4, allowing spark energy to be directly coupled to the local rich fuel core area. This design can quickly establish a stable flame core during the ignition stage and maintain a wide combustion zone during the low-temperature stable combustion stage, thereby achieving dual optimization of ignition reliability and combustion stability.

[0039] To ensure symmetrical injection and stable offset effect, the ignition nozzle 4 and the two fuel-air generators 8 are arranged in the same radial section of the combustion chamber. That is, in a section perpendicular to the engine axis, the ignition nozzle 4 is located in the middle, and the two fuel-air generators 8 are located on its left and right sides, respectively, symmetrically arranged between the outer ring 6 of the flame tube and the outer casing 5. This arrangement allows the two jet streams to precisely offset each other downstream of the ignition nozzle 4, forming a stable local fuel-rich zone 10, ensuring that the flame is spatially aligned with the ignition energy center.

[0040] To adapt to different combustion chamber structures and operating conditions, in one embodiment, an eccentric sleeve-type adjustment structure is adopted between the mounting base and the outer casing 5. An eccentric sleeve is embedded in the mounting hole, and a slight axial displacement of the fuel-air generator 8 can be achieved by rotating the sleeve. This structure is compact, high-temperature resistant, and suitable for combustion chamber arrangements with limited space. Through the aforementioned adjustable mechanism, the axial distance between the fuel-air generator 8 and the ignition nozzle 4 can be adjusted. When the axial relative position of the fuel-air generator 8 and the ignition nozzle 4 is changed, the position of the intersection point of the two jet streams downstream of the ignition nozzle 4 also changes, thereby controlling the spatial distribution of the local fuel-rich zone 10. For example, under ground ignition conditions, the axial distance can be appropriately increased to bring the intersection point closer to the ignition nozzle 4, thereby improving the coupling efficiency of ignition energy; under high-altitude reignition or stable combustion conditions, the distance can be appropriately reduced to extend the fuel-rich zone downstream, preventing flame backflow and enhancing the stability of the main combustion zone 9.

[0041] This embodiment also discloses an aero-engine combustion chamber, which mainly includes an outer casing 5, an outer ring 6 of the flame tube, and an inner ring 7 of the flame tube. An annular combustion zone is formed between the outer ring 6 and the inner ring, which is the main space for fuel and air mixing and combustion. An outer ring channel is formed between the outer casing 5 and the outer ring 6 of the flame tube, used to introduce cooling air and provide an air source for various auxiliary devices.

[0042] A localized rich-fuel flameout device is installed between the outer casing 5 and the outer ring 6 of the flame tube. The ignition nozzle 4 is positioned in the middle of the combustion zone, while two fuel-air generators 8 are symmetrically distributed on both sides of the ignition nozzle 4 and located within the same radial section. The fuel-air generators 8 are fixed to the outer casing 5 by mounting brackets, with their injection direction facing the combustion zone and slightly inclined downstream of the ignition nozzle 4. The injection paths of the two fuel-air generators 8 are opposite to each other, forming a highly turbulent fuel-air mixing and convergence zone in the combustion zone downstream of the ignition nozzle 4. This convergence zone is the localized rich-fuel zone 10, whose equivalence ratio is higher than that of the main combustion zone 9, providing a rich-fuel environment for the flame in the initial stage of ignition.

[0043] The implementation principle of the local rich fuel point flameout device in this embodiment is as follows: When the engine is in ignition or low-power operation, the overall air flow in the combustion chamber is relatively small. The fuel injected by the conventional main nozzle 121 is easily diluted, resulting in a low local fuel-air ratio, which causes ignition difficulties or flame instability. In this embodiment, by arranging symmetrical fuel-air generators 8 on both sides of the ignition nozzle 4, the air and fuel are pre-mixed at the nozzle 12 outlet, and a local rich fuel zone 10 with a high equivalence ratio is formed in the downstream area of ​​the ignition nozzle 4, thereby providing an ideal fuel environment for flame establishment and maintenance.

[0044] Specifically, fuel enters the nozzle 12 of the fuel-air generator 8 via the fuel supply line. The fuel jet ejected from the nozzle 12 meets the air introduced into the cooling shroud 13 through the air inlet 11 at the outlet of the nozzle 12. The air is ejected at high speed along the outer wall of the nozzle 12 through the annular gap, and the shearing action further atomizes the fuel. The multiple air inlets 11 of the cooling shroud 13 are provided with tangential deflection angles, causing the incoming air to form a swirling flow inside the shroud. The swirling airflow interacts with the fuel jet, generating a vortex mixing field with a shear layer near the outlet of the nozzle 12. This mixing field enhances the uniformity of the fuel-air distribution and forms a high-concentration mixed gas mass on both sides of the ignition nozzle 4.

[0045] The injection paths of the two fuel-air generators 8 are opposite each other along both sides of the ignition nozzle 4, and their intersection is located in the combustion zone downstream of the ignition nozzle 4. The mutual collision of the opposing airflows generates strong turbulence, which further refines the fuel droplets and forms a stable fuel-rich mixture core. When the ignition nozzle 4 discharges and generates a spark, the mixture in the local fuel-rich zone 10 is rapidly ignited and forms a stable flame core in a short time. This flame core remains stable due to the surrounding effect of the opposing and swirling airflows and is not easily extinguished by the main airflow. As combustion continues, the flame core gradually expands into the main combustion zone 9, establishing a smooth flame propagation channel and achieving a natural transition from the ignition stage to the normal combustion stage.

[0046] Furthermore, the flow channel formed between the guide slope 14 of the cooling shroud 13 and the outlet of the nozzle 12 allows air to flow along the outer wall of the nozzle 12 and form a cooling gas film. This not only prevents the flame from flowing back to the end of the nozzle 12, but also continuously removes attached carbon particles, improving the anti-coking performance and service life of the device. Through the above structure and flow organization, this embodiment achieves active control of the local air-fuel ratio, significantly improving the ignition success rate and stable combustion reliability of the combustion chamber under low operating conditions.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A localized oil-rich point flameout device, characterized in that: It includes two fuel generators (8) located on both sides of the ignition nozzle (4), each fuel generator (8) including a nozzle (12) for communicating with the fuel supply line and a cooling shroud (13) surrounding the nozzle (12); The cooling cover (13) is provided with an air inlet (11) and an air outlet. The air inlet (11) is used to communicate with the outer ring channel of the combustion chamber and to introduce air. The air outlet is used to communicate with the combustion zone between the outer ring (6) of the flame tube and the inner ring (7) of the flame tube. The nozzle (12) extends out of the air outlet, and an annular gap is formed between the outer wall of the nozzle (12) and the inner wall of the air outlet. The annular gap is used to guide the air entering through the air inlet (11) to mix with the injected fuel at the nozzle (12) outlet to form an oil-gas mixing zone. The injection paths of the two oil and gas generators (8) are opposite each other in the downstream direction of the ignition nozzle (4), and a local oil-rich area (10) is formed at the corresponding position of the ignition nozzle (4).

2. The local oil-rich point flameout device according to claim 1, characterized in that: The cooling shroud (13) is provided with a plurality of air inlets (11) in the circumferential direction. The air inlets (11) are provided with a tangential deflection angle in the circumferential direction, so that the air entering the cooling shroud (13) forms a swirling airflow. The swirling airflow is used to interact with the fuel jet sprayed from the nozzle (12) to form a vortex mixing field with a shear layer at the outlet of the nozzle (12).

3. The local oil-rich point flameout device according to claim 2, characterized in that: The lower end of the cooling shroud (13) is provided with a guide slope (14) that is inclined toward the combustion zone. The guide slope (14) and the nozzle (12) outlet form a flow channel to guide the cooling air to converge toward the combustion zone along the outer wall of the nozzle (12).

4. The local oil-rich point flameout device according to claim 3, characterized in that: The top of the cooling cover (13) is a flange structure formed by folding outwards. The upper section of the nozzle (12) is provided with an annular pressing boss. The annular pressing boss presses against the flange to fix the cooling cover (13) and forms an airtight connection at the pressing point.

5. The local oil-rich point flameout device according to claim 1, characterized in that: The outer contour of the nozzle (12) outlet section is a tapered cone, and the airflow outlet of the cooling shroud (13) is a cylindrical straight opening, so that an expanding annular gap with a gradually increasing cross-sectional area along the airflow direction is formed between the outer wall of the nozzle (12) and the inner wall of the cooling shroud (13).

6. The local oil-rich point flameout device according to claim 5, characterized in that: The width of the annular gap between the outer wall of the nozzle (12) and the inner wall of the air outlet of the cooling cover (13) is 1 to 3 mm.

7. The local oil-rich point flameout device according to claim 6, characterized in that: The outer wall of the nozzle (12) is provided with an annular guide step (15) at the outlet section. The annular guide step (15) is located upstream of the nozzle (12) outlet and is spaced apart from the guide slope (14) of the cooling cover (13). It is used to change the airflow direction in the annular gap and form a wall-adhering air film on the outer wall of the nozzle (12).

8. The local oil-rich point flameout device according to claim 7, characterized in that: The included angle between the injection axes of the two oil and gas generators (8) is 90° to 150°.

9. The local oil-rich point flameout device according to claim 1, characterized in that: The ignition nozzle (4) and the two oil and gas generators (8) are located in the same radial section. The axial position of the oil and gas generators (8) is adjusted according to the working conditions with the ignition nozzle (4) as the reference, so as to adjust the confluence position of the two jet streams.

10. An aircraft engine combustion chamber, characterized in that: It includes an outer casing (5), an outer ring (6) of the flame tube, and an inner ring (7) of the flame tube. A local rich oil point quenching device as described in any one of claims 1-9 is provided between the outer casing (5) and the outer ring (6) of the flame tube. The injection path of the local rich oil point quenching device is located on both sides of the ignition nozzle (4) and faces each other. The intersection area is located in the combustion zone downstream of the ignition nozzle (4) so ​​as to form a local rich oil zone (10) at the corresponding position of the ignition nozzle (4).

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