A premixed pre-evaporation flame stabilizer with evaporation tube

Abstract

This invention provides a premixed, pre-evaporated flame stabilizer with an evaporator tube. An evaporator tube and an intake tube are added to the stabilizer, and an intake channel is formed using an intake ring and a flow divider ring to introduce high-temperature combustion gas. An outlet channel is formed between the inner and outer stabilizers to introduce the high-temperature combustion gas into the outer bypass, creating a localized high-temperature zone. Fuel is supplied by the injector rod, and the fuel rapidly evaporates in the evaporator tube and is evenly sprayed out from the evaporator tube's exhaust port, entering the recirculation zone at the tail of the stabilizer for combustion. This invention can achieve mixing of the inner and outer bypass airflows and the creation of a localized high-temperature zone in the recirculation zone at the tail of the stabilizer, ensuring high fuel evaporation and uniform fuel distribution. Therefore, this invention can achieve stable combustion and high ignition success rate over a wide operating range under multi-mode operation of a variable cycle engine.

Description

Technical Field

[0001] This application relates to the field of afterburner technology for adaptive variable cycle aero-engines, and more particularly to a premixed pre-evaporation flame stabilizer with an evaporator tube. Background Technology

[0002] To meet the demands of future aircraft for a large flight envelope, long range, and multi-mission capabilities, next-generation aero engines need to be able to achieve multiple different thermodynamic cycles. However, traditional single-cycle turbojet and turbofan engines can no longer meet these complex requirements. Against this backdrop, to meet the performance requirements of aero engines under various mission and environmental characteristics, the variable cycle engine (VCE) with flexible variable components has emerged as a highly attractive future aero engine solution.

[0003] The afterburner is a crucial component of aero-engines, significantly improving thrust-to-weight ratio and expanding the flight envelope. Currently, most VCE (Variable Cycle Engine) designs utilize afterburner configurations. Traditional turbofan engines typically have a fixed bypass ratio, resulting in relatively simple inlet conditions for their afterburners. However, variable cycle engines (VCEs) require stable and reliable operation within a wide bypass ratio range of 0.2–1.0 (i.e., inlet Mach numbers between 0.15 and 0.45). The resulting drastic changes in the external bypass flow parameters of the afterburner render traditional afterburner designs unsuitable for VCE systems, necessitating new designs that meet the requirements for ignition and flame stability under wide inlet flow conditions.

[0004] Based on the aforementioned technical issues, researchers have proposed improved solutions for flame stabilizers in afterburners. For example, Chinese patent CN115451430A discloses a premixed pre-evaporation flame stabilizer, and Chinese patent CN116293793A discloses an outer bypass flame stabilizer, a variable area ejector for the rear bypass, and an afterburner. Both of these improved solutions employ the technical approach of coupling the stabilizer with a flow divider ring and setting up channels to introduce internal air. Under the operating conditions of a variable cycle engine afterburner, these two improved solutions can improve fuel atomization, increase the temperature of the air-fuel mixture, and improve ignition performance. However, research has revealed that both of these improvement schemes still have shortcomings: On the one hand, the stabilizer's on-call fuel supply is directly injected into the airflow channel, resulting in a short residence time of fuel within the stabilizer. Coupled with the low-temperature incoming flow and the inlet temperature being lower than the initial boiling point of the fuel, the fuel evaporation rate is very low. The stabilizer can only achieve two-phase combustion dominated by fuel droplets, and the fuel droplets will deposit on the wall, increasing the difficulty of ignition and ultimately resulting in unstable combustion in the flame stabilizer. On the other hand, the internal combustion gas introduced into the flame stabilizer is directly injected into the tail recirculation zone along the axial direction through the outlet channel, which disrupts the stability of the recirculation zone, increases the probability of flame stabilizer flameout, and makes it difficult to cope with the extreme operating conditions of VCE. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a premixed pre-evaporation flame stabilizer with an evaporation tube, which can increase fuel residence time, ensure fuel atomization effect, improve fuel distribution, shorten stabilizer length, effectively improve the stability and width of the backflow zone behind the stabilizer, and better adapt to the wide bypass ratio operating characteristics of variable cycle engines.

[0006] This invention provides a premixed pre-evaporation flame stabilizer with an evaporation tube, comprising:

[0007] An intake ring is disposed inside the flow divider ring and forms an intake channel with the flow divider ring;

[0008] An inner stabilizer is disposed outside the intake ring and extends outward to the outside of the splitter ring, and includes an inner front wall surface and an inner side wall surface.

[0009] An outer stabilizer is disposed outside the splitter ring and extends outward to the outside of the inner stabilizer. It includes an outer upper wall, an outer front wall, and an outer side wall. An upward channel is formed between the outer front wall and the inner front wall. An upper outlet channel is formed between the outer upper wall and the top of the inner stabilizer. Two side outlet channels are formed between the outer side wall and the inner side wall. The upper outlet channel and the two side outlet channels are connected to the intake channel through the upward channel.

[0010] An evaporator tube is disposed between the intake ring and the outer upper wall and is located behind the inner stabilizer. The evaporator tube has an air intake hole and an exhaust hole on its tube wall.

[0011] An air intake tube, the rear end of which is disposed on the evaporator tube and communicates with the air intake hole, and the front end of which extends into the rising channel; and

[0012] The fuel injector is located on the outside of the flow divider ring and extends into the interior of the outer stabilizer to inject fuel into the front end of the air intake pipe.

[0013] Preferably, the inner wall surface and the outer wall surface are parallel to each other, and in a cross section perpendicular to the radial direction, the distance between the two outer wall surfaces of the outer stabilizer gradually increases backward along the axial direction, and the angle between the outer wall surface and the axial direction is 12° to 20°.

[0014] Preferably, the width of the trailing edge of the external stabilizer is greater than 40 mm.

[0015] Preferably, the inner front wall surface and the outer front wall surface are parallel to each other, and in a cross section perpendicular to the circumferential direction, the inner front wall surface and the outer front wall surface are inclined outward relative to the axial direction.

[0016] Preferably, the sum of the axial projected areas of the upper outlet channel and the two side outlet channels is greater than the axial projected area of ​​the intake channel.

[0017] Preferably, the air intake hole is located on the axial front side of the evaporator tube, and the exhaust hole is located on both circumferential sides of the evaporator tube.

[0018] Preferably, the plurality of exhaust holes are evenly distributed along the length of the evaporator tube, the hole spacing between adjacent exhaust holes is 4mm to 6mm, and the total area of ​​the plurality of exhaust holes is 1 to 2.5 times the area of ​​the air intake hole.

[0019] Preferably, the front end opening of the air intake pipe faces inward and forward, and the fuel injection rod is provided with a fuel injection hole with a diameter of 0.4 mm to 1 mm. The opening direction of the fuel injection hole is at an angle of 40° to 50° with the axial direction and is directly opposite the front end opening of the air intake pipe.

[0020] Preferably, the axial distance between the tail edge of the inner stabilizer and the tail edge of the outer stabilizer is 10mm to 25mm.

[0021] Preferably, the radial dimension of the external stabilizer is 2 to 4 times the radial distance between the intake ring and the splitter ring.

[0022] Based on the above implementation scheme, this invention introduces high-temperature combustion gases and fuel into the evaporator tube for evaporation and atomization, thereby increasing fuel residence time, improving fuel atomization degree, and enhancing the lean ignition success rate of the stabilizer. Furthermore, since fuel atomization within the evaporator tube eliminates the need for a long intake ring to ensure fuel atomization time, this invention can shorten the existing intake ring length, reduce stabilizer weight, and improve engine performance. This invention also widens the stabilizer tail recirculation zone size and stability by adjusting the inner and outer stabilizer structures and controlling the angle between the stabilizer wall surface and the axial direction, thus improving the stabilizer's stable operation over a wide Mach number range. Additionally, it reduces the blockage area at the stabilizer front end and avoids sudden contraction of the outer bypass airflow channel area, thereby reducing flow losses caused by the stabilizer. Therefore, the present invention can form a recirculation zone with less interference from the Mach number of the inner and outer bypass flows after the evaporator tube and the inner stabilizer. The volume of the recirculation zone does not change with the change of the Mach number of the inner and outer bypass flows. The fuel is sprayed out from the exhaust port and is distributed relatively evenly in the recirculation zone. Furthermore, a local high-concentration fuel distribution zone is formed after the evaporator tube, which is conducive to successful on-call ignition under extreme conditions and can ensure the stable ignition capability of the stabilizer under the wide range of outer bypass parameters of the variable cycle engine. Attached Figure Description

[0023] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application, but do not constitute a limitation on the technical solutions of this application.

[0024] Figure 1 A three-dimensional structural schematic diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention;

[0025] Figure 2 A rear-view structural schematic diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention;

[0026] Figure 3 for Figure 2 A cross-sectional view of the center section of a premixed pre-evaporated flame stabilizer with an evaporation tube, taken from section AA.

[0027] Figure 4 A schematic diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention, viewed from a radial inward perspective;

[0028] Figure 5 A three-dimensional perspective structural diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention;

[0029] Figure 6 A schematic diagram of the circumferential cross-sectional flow field structure of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention in a state without fuel combustion.

[0030] Figure 7 The circumferential cross-sectional temperature distribution diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention in the absence of fuel combustion.

[0031] Figure 8 The circumferential cross-sectional fuel-air ratio distribution diagram of the premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention in the absence of fuel combustion.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Split ring; 2-Intake ring; 3-Inner stabilizer; 3a-Inner front wall; 3b-Inner side wall; 4-Evaporator pipe; 4a-Pipe wall; 4b-Exhaust port; 4c-Air duct; 5-Air duct; 6-Outer stabilizer; 6a-Outer upper wall; 6b-Outer front wall; 6c-Outer side wall; 7-Injector rod; 7a-Injector hole;

[0034] in - intake passage; up - rise passage; out1 - upper outlet passage; out2 - both side outlet passages. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are not intended to limit the present invention or its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention clear and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0036] like Figure 1-8 As shown, to address the technical problems in the prior art, this invention designs a premixed pre-evaporated flame stabilizer with an evaporation tube, based on the structure of the premixed pre-evaporated stabilizer, which improves fuel atomization and distribution by adding an evaporation tube and adjusts the stabilizer structure to enhance the stability of the recirculation zone. To facilitate the description of the specific structure of the premixed pre-evaporated flame stabilizer, this invention establishes a cylindrical coordinate system with the central axis of the aero-engine as the axis. Directions X, Y, and Z represent the circumferential, radial (inner / outer), and axial (front / back) directions of the cylindrical coordinate system, respectively. The flow divider ring 1 serves as the dividing line, with the interior of the flow divider ring 1 being the inner region and the exterior of the flow divider ring 1 being the outer region.

[0037] like Figures 1-5As shown, the present invention provides a premixed pre-evaporation flame stabilizer with an evaporation tube, which is disposed at the rear of the inlet and outlet bypass ring 1 of the afterburner, and includes: an intake ring 2 disposed inside the bypass ring 1; an inner stabilizer 3 disposed outside the intake ring 2 and extending outward to the outside of the bypass ring 1; and an outer stabilizer 6 disposed outside the bypass ring 1 and extending outward to the outside of the inner stabilizer 3.

[0038] Those skilled in the art will understand that the split ring 1 and the intake ring 2 form a double-layer ring structure, and the split ring 1 and the intake ring 2 form an intake channel in, so as to draw the high-temperature gas in the afterburner into the premixed pre-evaporation stabilizer. The premixed pre-evaporation flame stabilizer with evaporation tube provided by the present invention is arranged at the rear of the double-layer ring structure and presents a double-layer shell structure. The inner front wall surface 3a and the outer front wall surface 6b form an upward channel up, and the high-temperature gas introduced by the intake channel in is introduced into the outer bypass region through the upward channel up. The top of the inner stabilizer 3 and the outer upper wall surface 6a form an upper outlet channel out1, and the inner side wall surface 3b and the outer side wall surface 6c form two side outlet channels out2. The introduced high-temperature gas is ejected through the upper outlet channel out1 and the two side outlet channels out2 and enters the axial rearward recirculation zone of the premixed pre-evaporation stabilizer. In the recirculation zone, it is mixed with the low-temperature outer bypass air from the outer bypass, thereby forming a local high-temperature area in the recirculation zone.

[0039] Based on this structure, the present invention arranges an evaporator pipe 4, an air intake pipe 5 for supplying air to the evaporator pipe 4, and an oil injection rod 7 for supplying oil behind the inner stabilizer 3 and the outer stabilizer 6. The evaporator pipe 4 is located between the intake ring 2 and the outer upper wall surface 6a, and is situated behind the inner stabilizer 3; the rear end of the air intake pipe 5 is mounted on the evaporator pipe 4 and communicates with the air intake hole 4c, while the front end extends into the interior of the rising channel; the oil injection rod 7 is located outside the diversion ring 1 and extends into the interior of the outer stabilizer 6, thereby injecting oil into the front end of the air intake pipe 5.

[0040] The bleed pipe 5 has its front end located within the rising channel up to introduce high-temperature combustion gases. Simultaneously, the front end of the bleed pipe 5 also receives fuel injected by the fuel injector 7, allowing the fuel and high-temperature combustion gases to mix before entering the evaporator pipe 4 from the bleed pipe 5. The tubular structure of the evaporator pipe 5 increases the fuel's residence time, ensuring complete evaporation and mixing. Within the evaporator pipe 4, the fuel evaporates under the influence of the high-temperature combustion gases and mixes thoroughly. The fully evaporated and mixed premixed combustion gases are then ejected from the exhaust port 4b and enter the low-speed recirculation zone behind the stabilizer. This creates a high-temperature, low-speed recirculation zone with a locally high fuel concentration behind the stabilizer, ensuring a high success rate for on-call ignition in this area.

[0041] Therefore, the premixed pre-evaporation flame stabilizer with an evaporator tube provided by this invention can introduce high-temperature combustion gas into the outer casing. A portion of this high-temperature gas is ejected from the outlet channel, creating a localized high-temperature recirculation zone behind the stabilizer. The remaining gas enters the evaporator tube, where it assists in fuel atomization, increasing fuel evaporation. This ensures that fuel ejected from the exhaust port and entering the recirculation zone behind the stabilizer creates a stable ignition region. Thus, this invention forms a stable standby flame in the outer casing, reducing the difficulty of standby ignition within the wide operating range of a variable cycle engine. Simultaneously, the interaction between the outlet channel airflow and the evaporator tube improves fuel distribution, resulting in a more uniform fuel distribution behind the stabilizer.

[0042] Furthermore, this invention utilizes an outer stabilizer 6 to separate the interior of the premixed pre-evaporation stabilizer from the duct airflow outside the afterburner. Regarding the main duct flow, the outer stabilizer 6 acts as a blunt-body flame stabilizer. Since the outer stabilizer 6 contains high-temperature combustion gases ejected from the upper outlet channel out1 and the two side outlet channels out2, a low-speed recirculation zone is formed axially behind the outer stabilizer 6, which is affected by the incoming flow and thus increases in temperature. Regarding the high-temperature combustion gases ejected from the upper outlet channel out1 and the two side outlet channels out2, since the inner stabilizer 3 is arranged parallel to the outer stabilizer 6, the inner stabilizer 3 acts as a blunt-body flame stabilizer, thereby forming a low-speed recirculation zone behind the inner stabilizer 3. This low-speed recirculation zone is unaffected by the incoming flow from the inner and outer ducts, thus exhibiting better stability.

[0043] Furthermore, in this invention, only an upper outlet channel out1 and two side outlet channels out2 are provided between the inner stabilizer 3 and the outer stabilizer 6, and the lower outlet channel is eliminated. This avoids the internal combustion gas introduced into the flame stabilizer being directly injected into the tail recirculation zone at high speed through the lower outlet channel, which would damage the stability of the recirculation zone. As a result, compared with the prior art, the flame stabilizer has a lower probability of flameout and is more adaptable to the extreme working conditions of VCE.

[0044] Preferably, the inner wall surface 3b and the outer wall surface 6c are parallel to each other, and in the cross section perpendicular to the radial direction, the distance between the two outer wall surfaces 6c of the outer stabilizer 6 gradually increases backward along the axial direction, forming an angle between the outer wall surface 6c and the axial direction in the range of 12° to 20°. Therefore, by adjusting the angle between the side wall surfaces of the inner and outer stabilizers and the axial direction, the present invention improves the width and stability of the axial rearward recirculation zone of the stabilizer, ensuring that the stabilizer can maintain the stability of the recirculation zone of the stabilizer in a wide Mach number operating range, thus widening the working range of the stabilizer and making it more suitable for VCE engines. At the same time, this design can reduce the flow loss of the stabilizer under non-afterburning operating conditions, thereby improving engine performance.

[0045] like Figure 4As shown, in a preferred embodiment, the angle between the inner wall surface 3b and the outer wall surface 6c and the axial direction is 18°. This inclined wall design, on the one hand, reduces the blockage area at the front of the stabilizer and avoids a sudden reduction in the area of ​​the bypass airflow channel while keeping the trailing edge width constant, thereby reducing the flow loss caused by the stabilizer and reducing the engine operating pressure loss under both afterburner and afterburner conditions; on the other hand, this inclined design, while keeping the trailing edge width constant, creates an angle between the airflow direction at the trailing edge of the stabilizer and the axial direction, thereby widening the size and stability of the recirculation zone at the tail of the stabilizer and increasing the probability of successful ignition in the recirculation zone.

[0046] Preferably, the trailing edge width of the outer stabilizer 6 is greater than 40 mm, thereby ensuring that the circumferential dimensions of the flame stabilizer can meet the minimum size requirements for stable ignition. The upper limit of the trailing edge width of the outer stabilizer 6 is determined based on the overall aerodynamic blocking ratio requirements of the flame stabilizer components.

[0047] Preferably, the inner front wall surface 3a and the outer front wall surface 6b are parallel to each other, and in a cross-section perpendicular to the circumferential direction, the inner front wall surface 3a and the outer front wall surface 6b are inclined outward relative to the axial direction. Figure 3 As shown, in a preferred embodiment, the angle between the inner front wall surface 3a and the outer front wall surface 6b and the axial direction is 55°. This inclined wall design avoids the sudden reduction of the area of ​​the bypass airflow channel, reduces the flow loss caused by the stabilizer, and thus reduces the engine working pressure loss under both afterburner and afterburner conditions.

[0048] Preferably, the air intake hole 4c is located on the axial front side of the evaporator tube 4, and the exhaust hole 4b is located on both circumferential sides of the evaporator tube 4. The included angle between the air intake hole 4c and the exhaust hole 4b ensures that the high-temperature combustion gas entering the evaporator tube 4 through the air intake hole 4c is not directly discharged from the exhaust hole 4b, thereby effectively increasing the effective residence time of the high-temperature combustion gas in the evaporator tube 4.

[0049] like Figure 3 As shown, preferably, multiple exhaust holes 4b are evenly distributed along the length of the evaporator tube 4, with a hole spacing of 4mm to 6mm between adjacent exhaust holes 4b to ensure uniform fuel distribution. Furthermore, the total area of ​​the multiple exhaust holes 4b is 1 to 2.5 times the area of ​​the air intake hole 4c, thereby ensuring that the premixed fuel does not clog the evaporator tube 4. In a preferred embodiment, the hole spacing between adjacent exhaust holes 4b is 5mm, further ensuring uniform fuel distribution. The total area of ​​the multiple exhaust holes 4b is preferably 2 times or more the area of ​​the air intake hole 4c, thereby further reducing the velocity of the fuel-air mixture exiting the evaporator tube 4 and improving the reliability of ignition and sustained combustion.

[0050] like Figure 3As shown, preferably, the opening at the front end of the air intake pipe 5 faces inward and forward (i.e., inclined inward and forward), and the fuel injector 7 has a fuel injection hole 7a with a diameter of 0.4 mm to 1 mm. The opening direction of the fuel injection hole 7a is at an angle of 40° to 50° with the axial direction and is directly opposite the front end opening of the air intake pipe 5, thereby ensuring that all fuel can be introduced into the evaporator pipe 4 by the air intake pipe 5. In a preferred embodiment, the diameter of the fuel injection hole 7a is 1 mm, and the angle between the fuel injection direction of the fuel injection hole 7a and the axial direction is 45°.

[0051] like Figure 3 As shown, preferably, the axial distance between the trailing edge of the inner stabilizer 3 and the trailing edge of the outer stabilizer 6 is 10mm to 25mm, so that the outer upper wall surface 6a and the outer outer wall surface 6c can protect the backflow area axially behind the stabilizer, preventing the backflow area of ​​the stabilizer from being affected by the wide Mach number variation range of the variable cycle engine's outer bypass, and ensuring reliable standby ignition of the afterburner outer bypass under various operating conditions of the variable cycle engine. In a preferred embodiment, the axial distance between the trailing edge of the inner stabilizer 3 and the trailing edge of the outer stabilizer 6 is 15mm.

[0052] Preferably, the sum of the axial projected areas of the upper outlet channel out1 and the two side outlet channels out2 is greater than the axial projected area of ​​the intake channel in, so that the gap between the inner stabilizer 3 and the outer stabilizer 6 is a gradually expanding channel, so that the airflow in the intake channel in is discharged from the upper outlet channel out1 and the two side outlet channels out2 after being diffused and decelerated, further improving the stability of the recirculation zone and avoiding flow blockage inside the stabilizer.

[0053] Preferably, the radial dimension of the outer stabilizer 6 is 2 to 4 times the radial distance between the intake ring 2 and the split ring 1, so as to avoid the outer stabilizer 6 being too large, resulting in an excessively high blockage ratio and excessive aerodynamic resistance, and to prevent the recirculation zone from becoming unstable due to the outer stabilizer being too small, thus affecting the flame stabilization effect.

[0054] like Figure 6 The figure shows a schematic diagram of the circumferential cross-sectional flow field structure of the premixed pre-evaporation flame stabilizer with evaporator tube of the present invention under a fuel-free combustion state. As can be seen from the velocity cloud diagram and streamlines in the figure, the present invention can form a stable recirculation zone axially rear of the stabilizer, and generate two low-speed vortices in this recirculation zone. The center of the upper low-speed vortex is close to the evaporator tube, while the center of the lower low-speed vortex is located a distance axially rear of the stabilizer. A portion of the high-temperature combustion gas from the inner casing and a portion of the low-temperature air from the outer casing are respectively drawn into the recirculation zone by the two low-speed vortices.

[0055] like Figure 7The figure shows the circumferential cross-sectional temperature distribution of the premixed pre-evaporation flame stabilizer with evaporation tube of the present invention under no-fuel combustion conditions. As can be seen from the temperature cloud distribution in the figure, the present invention can introduce a portion of the high-temperature combustion gas into the stabilizer and enter the recirculation zone behind the stabilizer through the outlet channel, forming a localized high-temperature recirculation zone within the recirculation zone.

[0056] like Figure 8 The figure shows the circumferential cross-sectional fuel-air ratio distribution of the premixed pre-evaporation flame stabilizer with evaporator tube of the present invention under a fuel-free combustion state. As can be seen from the fuel-air ratio cloud map distribution in the figure, after the fuel is injected from the injector, it enters the evaporator tube and is distributed within the stabilizer's recirculation zone, forming a relatively uniform and combustion-friendly fuel distribution in the local recirculation zone. Furthermore, the fuel is locally enriched at the top of the recirculation zone, thus ensuring a high ignition success rate for the afterburner culvert stabilizer even under extremely lean fuel conditions.

[0057] Based on the technical features in the above specific implementation examples, the beneficial technical effects of the present invention include at least the following: by introducing high-temperature combustion gas and fuel into the evaporator tube for evaporation and atomization, the fuel residence time is increased, ensuring complete fuel atomization, thereby improving the lean ignition success rate of the stabilizer; at the same time, fuel distribution through the exhaust port makes the fuel distribution more uniform; by controlling the inner and outer stabilizer walls to maintain a certain angle with the axial direction, the size and stability of the axial rear recirculation zone of the stabilizer can be widened, and the blockage area at the front end of the stabilizer can be reduced, avoiding the area of ​​the outer bypass airflow channel. The sudden reduction in flow loss caused by the stabilizer is a significant improvement. By introducing an evaporator tube for assisted atomization, this invention shortens the intake passage length without reducing fuel atomization, thus reducing stabilizer mass. Behind the evaporator tube and the inner stabilizer, a stable, high-temperature recirculation zone largely unaffected by incoming flow parameters is formed, with fuel evenly distributed within this zone. A localized high-concentration fuel zone is also formed behind the evaporator tube, ensuring stable combustion and ignition capabilities of the stabilizer within a wide range of incoming flow parameters in a variable-cycle engine, achieving reliable ignition in the Mach number range of 0.15–0.45.

[0058] In summary, the features and working principles of the present invention have been described in detail through examples, but these examples do not limit the scope of the invention. Any simple changes or substitutions made by those skilled in the art within the scope of the technology stated in this application are covered by the protection scope of this application. The scope of the present invention is defined by the appended claims.

Claims

1. A premixed pre-evaporation flame stabilizer with an evaporation tube, characterized in that, include: An intake ring (2) is disposed inside the flow divider ring (1) and forms an intake channel with the flow divider ring (1); An inner stabilizer (3) is disposed outside the intake ring (2) and extends outward to the outside of the split ring (1), and includes an inner front wall surface (3a) and an inner side wall surface (3b). An outer stabilizer (6) is disposed outside the diverter ring (1) and extends outward to the outside of the inner stabilizer (3). It includes an outer upper wall (6a), an outer front wall (6b), and an outer side wall (6c). An upward channel is formed between the outer front wall (6b) and the inner front wall (3a). An upper outlet channel is formed between the outer upper wall (6a) and the top of the inner stabilizer (3). A two-sided outlet channel is formed between the outer side wall (6c) and the inner side wall (3b). The upper outlet channel and the two-sided outlet channels are connected to the intake channel through the upward channel. An evaporator tube (4) is disposed between the intake ring (2) and the outer upper wall surface (6a) and is located behind the inner stabilizer (3). The evaporator tube (4) has an air intake hole (4c) and an exhaust hole (4b) on its tube wall (4a). The exhaust pipe (5) has its rear end set on the evaporation pipe (4) and connected to the exhaust hole (4c), and its front end extends into the interior of the rising channel; as well as The fuel injector (7) is located on the outside of the flow divider (1) and extends into the interior of the outer stabilizer (6) to inject fuel into the front end of the air intake pipe (5).

2. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The inner wall surface (3b) is parallel to the outer wall surface (6c), and in a cross section perpendicular to the radial direction, the distance between the two outer wall surfaces (6c) of the outer stabilizer (6) gradually increases backward along the axial direction, and the angle between the outer wall surface (6c) and the axial direction is 12° to 20°.

3. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 2, characterized in that, The trailing edge width of the external stabilizer (6) is greater than 40 mm.

4. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The inner front wall surface (3a) and the outer front wall surface (6b) are parallel to each other, and in a cross section perpendicular to the circumferential direction, the inner front wall surface (3a) and the outer front wall surface (6b) are inclined outward relative to the axial direction.

5. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The sum of the axial projected areas of the upper outlet channel and the two side outlet channels is greater than the axial projected area of ​​the intake channel.

6. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The air intake hole (4c) is located on the axial front side of the evaporator tube (4), and the exhaust hole (4b) is located on both circumferential sides of the evaporator tube (4).

7. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 6, characterized in that, The plurality of exhaust holes (4b) are evenly distributed along the length of the evaporator tube (4), the hole spacing between adjacent exhaust holes (4b) is 4mm to 6mm, and the total area of ​​the plurality of exhaust holes (4b) is 1 to 2.5 times the area of ​​the air intake hole (4c).

8. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The front end opening of the air intake pipe (5) faces inward and forward. The oil injection rod (7) is provided with an oil injection hole (7a). The diameter of the oil injection hole (7a) is 0.4mm to 1mm. The opening direction of the oil injection hole (7a) is at an angle of 40° to 50° with the axial direction and is directly opposite the front end opening of the air intake pipe (5).

9. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The axial distance between the trailing edge of the inner stabilizer (3) and the trailing edge of the outer stabilizer (6) is 10mm to 25mm.

10. The premixed pre-evaporation flame stabilizer with evaporation tube according to claim 1, characterized in that, The radial dimension of the external stabilizer (6) is 2 to 4 times the radial distance between the intake ring (2) and the diverter ring (1).

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