Local rich oil point flameout device and aeroengine combustion chamber

Abstract

The application discloses a local rich oil point 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. Each oil-gas generator comprises a nozzle and a cooling cover arranged around the nozzle. A plurality of air inlet holes with tangential deflection angles in the circumferential direction are formed in the cooling cover, which are used for introducing outer ring channel air and forming a rotational flow. The outlet of the nozzle extends from the air outlet hole 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 hole, so that air and injected fuel are mixed with each other at the outlet of the nozzle to generate a stable oil-gas mixing area. The injection paths of the two oil-gas generators are opposite to each other in the downstream direction of the ignition nozzle, and a local rich oil area is formed at the ignition nozzle, so that fast and stable ignition can be realized under the conditions of ignition and low working conditions, the risk of flameout 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 and easy flameout of the combustion chamber.

[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 cover is provided with a guide slope which is inclined towards the combustion zone, and the guide slope and the nozzle outlet form a flow guide channel for guiding the cooling air to converge towards the combustion zone along the outer wall of the nozzle.

[0008] Optionally, the top of the cooling cover is a folded-over structure which is folded over to the outside, and the upper section of the nozzle is provided with an annular pressing boss which is pressed against the folded-over portion for fixing the cooling cover and forming an air-tight connection at the pressing position.

[0009] Optionally, the outer contour of the outlet section of the nozzle is a tapered cone, and the air outlet of the cooling cover is a cylindrical straight mouth, so that the outer wall of the nozzle and the inner wall of the cooling cover form an expanding annular gap which gradually increases in cross-sectional area along the flow direction.

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

[0011] Optionally, the outer wall of the nozzle is provided with an annular flow guide step at the outlet section, the flow guide step is located upstream of the nozzle outlet and opposite to the guide slope of the cooling cover, for changing the flow direction in the annular gap and forming a wall-attached air film on the outer wall of the nozzle.

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

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

[0014] According to another aspect of the present application, an aero-engine combustion chamber is also provided, which comprises an outer casing, an outer flame tube ring and an inner flame tube ring, and the local rich oil point flameout device described above is arranged between the outer casing and the outer flame tube ring; the jet paths of the local rich oil point flameout device are located on both sides of the ignition nozzle and face each other, and the intersection area is located in the combustion zone downstream of the ignition nozzle, so as to form a local rich oil area at the corresponding position of the ignition nozzle.

[0015] In summary, the present application has at least one of the following beneficial technical effects:

[0016] The scheme is arranged with a pair of oil-gas generators on both sides of the ignition nozzle, so that the air and fuel form a local rich oil mixing area near the nozzle outlet in advance, thereby effectively improving the ignition difficulty and flameout problem caused by the low overall oil-gas ratio of the combustion chamber under ignition and low working conditions. Specifically, each oil-gas generator introduces the air in the outer ring channel through the air inlet hole in the cooling cover, and the air is sheared and mixed with the fuel sprayed by the nozzle at high speed when passing through the annular gap, forming a local fuel-rich gas cluster with high concentration and stable distribution at the nozzle outlet; the injection paths of the two oil-gas generators are opposite and collide downstream of the ignition nozzle, and the airflow at the intersection generates strong turbulence and vortex, so that the oil-gas mixing in this area is more sufficient, and when the ignition nozzle ignites, a stable flame core can be quickly formed in the local rich oil area. Since the flame first stably burns in the local rich oil area and then gradually expands to the main combustion area, a smooth transition from ignition to main combustion is realized, which significantly improves the ignition reliability under low working conditions and reduces the risk of flameout.

[0017] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The accompanying drawings do not constitute an inappropriate limitation on the present application. In the drawings:

[0019] Figure 1 Figure 1 is a sectional view of the local rich oil ignition and flameout device of the present application along the axial direction of the combustion chamber;

[0020] Figure 2 Figure 1 is a sectional view of the local rich oil ignition and flameout device of the present application along the axial direction of the combustion chamber;

[0021] LEGEND

[0022] 1, main nozzle; 2, combustion chamber head; 3, vortex finder; 4, ignition nozzle; 5, outer casing; 6, outer ring of flame tube; 7, inner ring of flame tube; 8, oil-gas generator; 9, main combustion area; 10, local rich oil area; 11, air inlet hole; 12, nozzle; 13, cooling cover; 14, guide slope; 15, flow guide step. DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below.

[0024] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below. Figures 1-2 The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below.

[0025] Reference will be made to 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The outlet end of the nozzle 12 extends out of the air outlet hole of the cooling cover 13, and an annular gap is formed between the outer wall of the nozzle 12 and the inner wall of the air outlet hole of the cooling cover 13. The width of the annular gap is designed to be 1-3 mm, which can not only ensure sufficient air flow, but also make the air flow form a high flow rate at the outer wall of the nozzle 12, thereby generating a significant shearing effect in the outlet area. The inlet air enters through the inlet hole 11 in the cooling cover 13 and flows along the outer wall of the nozzle 12, and is sprayed out at high speed through the annular gap, and meets and mixes with the fuel jet sprayed out of the nozzle 12 near the outlet. Due to the fact that the air flow speed is much higher than the fuel jet speed, a strong turbulent shear zone is formed at the intersection of the two fluids, which further breaks up the fuel droplets and rapidly vaporizes them, forming fine and uniform oil-gas mixture clusters.

[0030] When the two oil-gas generators 8 work simultaneously, their jet flows collide with each other in the downstream direction of the ignition nozzle 4, and form a local rich oil mixture core in the intersection area. The oil-gas concentration in this core area is high, and the turbulent intensity is strong, which can be ignited rapidly under the action of the spark generated by the ignition nozzle 4 and form a stable flame. The flame mainly burns stably in the local rich oil area 10 at the beginning of combustion, and then gradually expands to the surrounding main combustion area 9, realizing the stable propagation of the flame.

[0031] The cooling cover 13 not only plays the role of air guiding and mixing, but also bears the cooling and protection functions of the nozzle 12. The cooling cover 13 is in a cylindrical structure, which is sleeved on the outer periphery of the nozzle 12, and its inner cavity is communicated with the outer ring channel of the combustion chamber for introducing the outer ring cold air.

[0032] The cooling cover 13 is circumferentially distributed with a plurality of inlet holes 11, which are uniformly arranged in the circumferential direction and have a certain tangential bias angle relative to the radial direction. Through the design of the tangential bias angle, the air entering the cooling cover 13 no longer flows in a straight line along the radial direction when entering the inner cavity, but has a significant tangential velocity component, thereby forming a rotating flow field, i.e. a rotational flow field, inside the cooling cover 13. The existence of the rotational flow makes the air in the cooling cover 13 generate angular momentum in a short distance, and the air forms a spiral flow trajectory along the inner wall and forms an annular rotating air layer around the outer wall of the nozzle 12.

[0033] The setting of the tangential bias angle can significantly improve the momentum distribution of the incoming air. When the bias angle is small, the rotational angular velocity of the air flow is low, and the air flow is mainly axial, which is stable and has good cooling effect, but the mixing enhancement effect is limited. When the bias angle is large, the rotational angular velocity of the air in the cooling cover 13 increases significantly, which can generate stronger centrifugal force and radial pressure gradient, so that the air flow forms a high-intensity rotational flow field at the outlet of the nozzle 12. It is preferred that the tangential bias angle is 10-20°, which can ensure that the air forms a clear rotational flow structure at the outlet of the nozzle 12, and will not cause flow field instability or energy loss due to too high rotational speed.

[0034] The swirling air is guided by the conical surface of the nozzle 12, and its velocity is gradually increased and compressed near the nozzle 12 outlet. Then, the air is ejected at high speed through the annular gap between the nozzle 12 and the cooling shroud 13. Since the air flow has a strong rotational momentum before being ejected, the air flow out of the annular gap forms a high-speed annular swirling jet. When the swirling jet meets the fuel jet ejected from the center of the nozzle 12, there is a large velocity gradient and direction difference between the two, resulting in a clear shear layer at the interface. This shear layer becomes the starting point for the development of turbulent flow, rapidly transforming the gas flow into a strong turbulent state, promoting the secondary breakup and uniform dispersion of fuel droplets.

[0035] In addition, the vortex structure formed by the swirling jet near the outlet can significantly increase the residence time of the air at the nozzle 12 outlet, improve the mutual contact area and mixing efficiency of the air and the fuel. The centrifugal force brought by the swirling jet also throws part of the fuel droplets to the outer edge, forming an oil and gas layer with gradually changing equivalence ratio near the annular gap, making the local rich oil area 10 more smooth and stable.

[0036] The lower end of the cooling shroud 13 is provided with a guide slope 14 inclined towards the combustion area, forming a flow guide channel between the nozzle 12 outlet and the guide slope 14. Through this channel, the cooling air is guided to flow along the outer wall of the nozzle 12 and converge towards the combustion area, not only effectively cooling the end of the nozzle 12 and the surrounding wall, but also keeping the air injection direction at a certain angle with the fuel jet direction, promoting the formation of strong shear and mixing of the two fluids at the entrance of the combustion area, thereby further strengthening the local oil and gas mixing effect. The guide slope 14 can also form a certain aerodynamic damping, preventing the backflow of high-temperature gas in the combustion area into the inside of the cooling shroud 13, and playing a protection role against backflow.

[0037] The top of the cooling shroud 13 adopts a folded edge structure that is folded outward, cooperating with the annular compression boss of the upper segment of the nozzle 12. The compression boss is pressed against the folded edge through threaded connection or snap ring locking structure, forming a reliable air-tight contact surface. This structure not only ensures the stable fixation of the cooling shroud 13 in the high-temperature combustion environment, but also allows for certain thermal expansion and contraction compensation, preventing loosening or cracking due to thermal stress. High-temperature resistant sealing gaskets are provided at the folded edge compression position, which can further ensure the sealing and structural safety.

[0038] The outlet section of the nozzle 12 is designed as a tapered cone structure, while the outlet of the cooling cover 13 is a cylindrical straight mouth. The two form an expanding annular gap with gradually increasing cross-sectional area along the direction of the airflow. As the airflow passes through the tapered cone and enters the expanding annular gap, its speed gradually decreases and the pressure rises, forming a velocity gradient that is conducive to the secondary atomization of fuel and the rectification of airflow, thereby strengthening the shearing and breaking and preventing the flame from flowing back to the end face of the nozzle 12. The annular gap between the outer wall of the nozzle 12 and the inner wall of the outlet of the cooling cover 13 can be adjusted and matched according to the air supply pressure and fuel injection rate, and the preferred range is 1-3 mm. When the gap is small, the airflow speed increases and the shearing effect is enhanced, which is suitable for ignition conditions under high altitude or low temperature conditions; when the gap is large, the air flow increases, which can enhance the cooling effect of the nozzle 12 and improve the stable combustion performance under high working conditions.

[0039] In order to further improve the airflow organization, an annular flow guide step 15 is arranged at the upstream position of the outlet section of the nozzle 12, which is arranged in a spaced manner with the guide slope 14 of the cooling cover 13. The flow guide step 15 can change the direction of the airflow, so that the annular gap airflow forms a wall-adhering gas film on the outer wall of the nozzle 12, which can cool the nozzle 12 and inhibit the high-temperature gas in the backflow area from eroding the outer wall of the nozzle 12. The existence of the gas film can also stabilize the airflow field in the annular gap, reduce the unevenness of the spray and the risk of carbon deposition.

[0040] The included angle between the injection axes of the two oil and gas generators 8 is an important parameter that determines the shape and mixing intensity of the local fuel-rich area 10. In this embodiment, the included angle is designed to be in the range of 90°-150°, and is preferably about 120°. This angle directly affects the intersection position, intersection intensity and local turbulent structure of the two oil and gas injection streams in the downstream area of the ignition nozzle 4, thereby having a significant effect on fuel atomization, the formation of the fuel-rich area and flame stability.

[0041] When the included angle is small, the relative velocity component of the two injection streams is large, and the impingement effect is the strongest, and the intersection point is close to the center of the downstream area of the ignition nozzle 4. At this time, the airflow shearing intensity is high, the turbulent energy is concentrated, and a strong vortex structure can be formed, which is beneficial to the further breaking and rapid mixing of fuel, and a high-concentration local fuel-rich area 10 can be formed in a short time, thereby achieving rapid ignition. However, too small an included angle can also lead to excessive concentration of the injection stream, strong local airflow impact, and a small fuel-rich area, which is easy to produce a high-temperature hot spot after ignition, affecting the uniform propagation of the flame. When the included angle is large, the two injection streams tend to be parallel, the impingement effect is weakened, and the intersection area is farther away from the ignition nozzle 4. At this time, the mixing area of fuel and air is wider, the fuel-rich area is expanded and uniformly distributed, and the flame envelope is smoother, which is beneficial to stable combustion under low working conditions. However, too large an included angle will make the fuel-rich area too far away from the ignition nozzle 4, and the ignition spark will not be able to effectively couple with the fuel-rich mixture, thereby reducing the ignition reliability.

[0042] The selection of the included angle also needs to comprehensively consider factors such as the structure size of the combustion chamber, the fuel supply pressure, the inlet flow of the outer ring, and the flow direction at the inlet of the main combustion zone 9. For the arrangement in which the combustion zone is narrow and the ignition nozzle 4 is close to the center of the flame tube, a smaller included angle can be used to enhance the impinging turbulent flow; and for the combustion chamber in which the combustion zone is wide and the main flow velocity is high, a larger included angle is preferably selected to expand the rich fuel area and enhance the flame coverage. Therefore, the included angle of about 120° is selected as the comprehensive optimization value in this embodiment, which not only ensures the strength of the impinging turbulent flow, but also maintains the geometric alignment relationship between the rich fuel area and the flame passage of the ignition nozzle 4, so that the spark energy can be directly coupled to the local rich fuel core area. This design can quickly establish a stable flame core during the ignition stage, and can maintain a relatively wide combustion area during the low working condition stable combustion stage, thereby realizing the dual optimization of ignition reliability and combustion stability.

[0043] To ensure the symmetrical injection and stable impinging effect, the ignition nozzle 4 and the two oil-gas generators 8 are arranged in the same radial section of the combustion chamber. That is, in the vertical section along the engine axis, the ignition nozzle 4 is located in the middle, and the two oil-gas generators 8 are respectively located on the left and right sides thereof and are symmetrically arranged between the outer ring 6 of the flame tube and the outer casing 5. Such an arrangement enables the two injection flows to impinge accurately in the downstream direction of the ignition nozzle 4, forms a stable local rich fuel area 10, and ensures that the flame is spatially aligned with the center of the ignition energy.

[0044] To adapt to different combustion chamber structures and working condition requirements, in one embodiment, an eccentric sleeve type adjusting structure is used between the mounting base and the outer casing 5. An eccentric sleeve is embedded in the mounting hole, and the oil-gas generator 8 can be axially slightly displaced by rotating the sleeve. This structure is compact and resistant to high temperature, and is suitable for combustion chamber arrangements with limited space. Through the above adjustable mechanism, the axial distance of the oil-gas generator 8 relative to the ignition nozzle 4 can be adjusted. When the axial relative position of the oil-gas generator 8 and the ignition nozzle 4 is changed, the intersection point position of the two injection flows downstream of the ignition nozzle 4 also changes, thereby the spatial distribution of the local rich fuel area 10 can be controlled. For example, in the ground ignition working condition, the axial distance can be appropriately increased to make the intersection point close to the ignition nozzle 4, so as to improve the coupling efficiency of the ignition energy; in the high-altitude re-ignition or stable combustion working condition, the distance can be appropriately reduced to make the rich fuel area extend downstream, prevent flame backflow, and enhance the stability of the main combustion zone 9.

[0045] The embodiment also discloses an aero-engine combustion chamber, which mainly comprises an outer casing 5, an outer ring 6 of a flame tube, and an inner ring 7 of the flame tube. The annular combustion zone is formed between the outer ring 6 of the flame tube and the inner ring, which is the main space for mixing and burning fuel and air. The outer casing 5 and the outer ring 6 of the flame tube form an outer ring passage, which is used for introducing cooling air and providing a gas source for various auxiliary devices.

[0046] The local rich oil point flameout device is installed between the outer casing 5 and the flame tube outer ring 6, the ignition nozzle 4 is arranged at the middle position of the combustion zone, and the two oil and gas generators 8 are symmetrically distributed on the two sides of the ignition nozzle 4 and located in the same radial section. The oil and gas generator 8 is fixed on the outer casing 5 through the mounting seat, and the spraying direction is towards the combustion zone and slightly inclined to the downstream direction of the ignition nozzle 4. The spraying paths of the two oil and gas generators 8 are opposite and collide, and a high-turbulence oil and gas mixed intersection area is formed in the combustion zone downstream of the ignition nozzle 4. The intersection area is the local rich oil area 10, and the equivalence ratio distribution is higher than that of the main combustion zone 9, which can provide a rich oil fuel environment for the flame at the initial ignition stage.

[0047] The implementation principle of the local rich oil point flameout device in the embodiment of the application is as follows: when the engine is in the ignition or low-power operating condition, the overall air flow of the combustion chamber is small, and the fuel sprayed by the traditional main nozzle 121 is easily diluted, which leads to a low local oil and gas ratio, thereby causing ignition difficulty or unstable flame. In the embodiment, the symmetric oil and gas generators 8 are arranged on the two sides of the ignition nozzle 4, so that the air and the fuel are mixed in advance at the outlet of the nozzle 12, and a local rich oil area 10 with a high equivalence ratio is formed in the downstream area of the ignition nozzle 4, thereby providing an ideal fuel environment for the establishment and maintenance of the flame.

[0048] Specifically, the fuel enters the oil and gas generator 8 nozzle 12 through the fuel supply pipeline, and the fuel jet sprayed by the nozzle 12 meets the air introduced through the air inlet hole 11 in the inside of the cooling cover 13 at the outlet of the nozzle 12. The air is sprayed at high speed along the outer wall of the nozzle 12 through the annular gap, and under the shearing action, the fuel is further atomized. The multiple air inlet holes 11 of the cooling cover 13 are provided with a tangential bias angle, so that the entering air forms a rotational flow in the cover, and the rotational flow and the fuel jet interact to generate a vortex mixing field with a shear layer near the outlet of the nozzle 12. The mixing field enhances the uniformity of the oil and gas distribution, and forms high-concentration mixed gas clusters on the two sides of the ignition nozzle 4.

[0049] The spraying paths of the two oil and gas generators 8 are opposite and collide along the two sides of the ignition nozzle 4, and the intersection is located in the combustion zone downstream of the ignition nozzle 4. The mutual collision of the colliding air flows produces strong turbulence, further refines the fuel droplets, and forms a stable rich oil mixed core. When the ignition nozzle 4 generates a spark, the mixed gas in the local rich oil area 10 is quickly ignited and forms a stable flame core in a short time. The flame core is kept stable by the surrounding effect of the colliding air flow and the rotational flow and is not easy to be blown out by the main air flow. With the continuous combustion, the flame core gradually expands to the main combustion zone 9, establishes a stable flame propagation channel, and realizes the natural transition from the ignition stage to the normal combustion stage.

[0050] In addition, the guide channel formed between the guide slope 14 of the cooling cover 13 and the outlet of the nozzle 12 enables the air to flow along the outer wall of the nozzle 12 and form a cooling air film, which not only prevents the flame from flowing back to the end of the nozzle 12, but also continuously removes the attached carbon particles, thereby improving the anti-coking performance and service life of the device. Through the above structure and flow organization, the present embodiment realizes active regulation of the local oil-gas ratio, significantly improving the ignition success rate and stable combustion reliability of the combustion chamber under low working conditions.

[0051] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present 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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