Two-stage annular mixer and bypass ratio adaptive matching method for afterburner
By designing a two-stage annular mixer in the afterburner, the problems of reduced cooling gas volume and large mixing losses in aero engines are solved, achieving low flow resistance, high efficiency, and stable operation over a wide bypass ratio range, thus meeting cooling requirements.
Patent Information
- Application Number
- CN202511358790.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2045-09-23
AI Technical Summary
Existing aero-engine afterburners face problems such as reduced cooling gas volume, increased cooling gas temperature, and large mixing losses during the process of increasing thrust-to-weight ratio. Traditional mixers cannot meet the requirements of low flow resistance, high efficiency, and stable operation over a wide bypass ratio range.
The system employs a two-stage annular mixer with an afterburner, including a first-stage and a second-stage annular mixer. Through the design of the flow splitting channel and the mixing channel, it achieves adaptive matching of the bypass ratio, ensuring low flow resistance and low cooling gas temperature under different bypass ratio conditions.
With minimal overflow loss and flow separation risk, a smaller mixer mixing effect is achieved, ensuring a lower cooling gas temperature and meeting the requirements of low flow resistance, high efficiency, and stable operation over a wide bypass ratio range.
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Figure CN120890100B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aero-engine technology, specifically to a two-stage annular mixer for afterburners and an adaptive matching method for bypass ratio. Background Technology
[0002] With the development of aero engines, the thrust-to-weight ratio of engines is constantly improving. To achieve this improvement, on the one hand, the turbine and afterburner exit temperatures are continuously increased to enhance thrust. This leads to a continuous increase in the thermal load of the afterburner, while also facing the challenges of reduced cooling gas volume and increased cold gas temperature, posing a challenge to afterburner cooling. On the other hand, the use of lightweight metal materials to reduce engine structural weight, such as titanium alloy casings, is being implemented. However, lightweight metal materials often have lower temperature resistance, making efficient cooling design particularly important. Furthermore, it is necessary to reduce engine flow losses, increase useful work, and improve engine efficiency.
[0003] Aero-engine afterburners typically employ a lobed mixer to mix the high- and low-temperature gases from the inner and outer bypass pipes, improving the uniformity of the mixture. However, this mixing further increases the temperature of the downstream cooling gas, which does not meet current cooling requirements and results in significant mixing losses, negatively impacting engine thrust performance. Traditional annular mixers produce a significantly weaker mixing effect than lobed mixers, resulting in a smaller increase in cooling gas temperature, which is sufficient for cooling needs. However, with current engines exhibiting a wider bypass ratio range of 0.2–1.2 or higher, conventional mixers cannot meet the demands of the wide inlet operating range required by afterburners. Summary of the Invention
[0004] In view of this, the present invention provides a two-stage annular mixer for an afterburner and an adaptive matching method for bypass ratio, so as to achieve the goal of low flow resistance, high efficiency and stable operation of the afterburner with a wide range of outer / inner bypass ducts.
[0005] The present invention provides the following technical solution: a two-stage annular mixer for an afterburner, comprising: a casing; a first-stage annular mixer disposed inside the casing, with an outer bypass duct formed between the first-stage annular mixer and the casing; a second-stage annular mixer disposed inside the casing and located inside the first-stage annular mixer, with a flow divider formed between the first-stage annular mixer and the second-stage annular mixer, and a mixing channel formed between the casing and the second-stage annular mixer, wherein both the outer bypass duct and the flow divider duct are connected to the mixing channel.
[0006] This invention also provides a bypass ratio adaptive matching method, implemented using the aforementioned two-stage annular mixer in an afterburner. The bypass ratio adaptive matching method includes: when the pressure of the bypass airflow entering the split channel is less than the pressure of the inner airflow, the bypass airflow flows out through the bypass duct and the mixing channel; a portion of the inner airflow flows out through the split channel and the mixing channel, and the other portion flows out through the inner duct; when the pressure of the bypass airflow entering the split channel is greater than the pressure of the inner airflow, a portion of the bypass airflow flows out through the bypass duct and the mixing channel, and the other portion flows out through the split channel and the mixing channel; the inner airflow flows out through the inner duct.
[0007] Compared with the prior art, the beneficial effects that the above-mentioned at least one technical solution adopted by the present invention can achieve include at least the following: the embodiments of the present invention achieve a smaller mixing effect of the mixer with a smaller overflow loss and flow separation risk, ensuring a lower cooling gas temperature, while meeting the requirements of low flow resistance, high efficiency and stable operation in a wider range of outer / inner bypass channels. Attached Figure Description
[0008] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0009] Figure 1 A schematic diagram of a two-stage annular mixer with a wide bypass ratio range for an afterburner;
[0010] Figure 2 A cross-sectional view of a two-stage annular mixer with a wide bypass ratio range for an afterburner;
[0011] Figure 3 This is a schematic diagram of the first-stage toroidal mixer;
[0012] Figure 4 This is a schematic diagram of the overflow orifice of the first-stage annular mixer;
[0013] Figure 5 This is a schematic diagram of the second-stage toroidal mixer;
[0014] Figure 6 This is a schematic diagram of the sawtooth unit of the second-stage annular mixer;
[0015] Figure 7 This is a schematic diagram showing the connection between the first-stage ring mixer and the second-stage ring mixer;
[0016] Figure 8 This is a schematic diagram illustrating the working principle of a low bypass ratio duct.
[0017] Figure 9A schematic diagram illustrating the working principle of a high bypass ratio;
[0018] Figure 10 This is a schematic diagram showing the cross-sectional area of the downstream end of the duct, the cross-sectional area of the downstream end of the diversion channel, and the minimum area of the mixing channel.
[0019] The attached diagram shows the following labels: 1. Casing; 2. First-stage annular mixer; 21. Flat section of the first-stage mixer; 22. Overflow hole; 3. Second-stage annular mixer; 31. Serrated section; 32. Smooth section; 33. Second curved section; 4. Diffuser; 41. Straight section; 42. First curved section; 5. Heat shield; 6. Flame stabilizer; 61. Outer annular flame stabilizer; 62. Shift flame stabilizer; 63. Inner annular flame stabilizer; 7. Bow-shaped frame; 8. Outer duct; 9. Inner duct; 10. Cooling duct; 11. Diverter channel; 12. Mixing channel. Detailed Implementation
[0020] The embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0021] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] like Figures 1 to 9 As shown, this embodiment of the invention provides a two-stage annular mixer for an afterburner, including: a casing 1, a first-stage annular mixer 2, a second-stage annular mixer 3, a diffuser 4, a heat shield 5, a flame stabilizer 6, and an arc-shaped frame 7. The first-stage annular mixer 2 is disposed inside the casing 1, and an outer bypass duct 8 is formed between the first-stage annular mixer 2 and the casing 1; the second-stage annular mixer 3 is disposed inside the casing 1 and located inside the first-stage annular mixer 2, and a flow divider channel 11 is formed between the first-stage annular mixer 2 and the second-stage annular mixer 3. The casing 1 and the second-stage annular mixer 3 form a mixing channel 12, and both the outer bypass duct 8 and the flow divider channel 11 are connected to the mixing channel 12.
[0023] The embodiments of the present invention achieve a smaller mixing effect in the mixer with less overflow loss and flow separation risk, ensuring a lower cooling gas temperature, while meeting the requirements of low flow resistance, high efficiency and stable operation under a fixed area with a mass flow rate ratio of the outer bypass flow a to the inner bypass flow b (hereinafter referred to as bypass ratio, the range of the maximum bypass ratio / minimum bypass ratio is 1 to 4).
[0024] An outer bypass duct 8 is formed between the casing 1 and the first-stage annular mixer 2; an inner bypass duct 9 is formed between the first-stage annular mixer 2, the second-stage annular mixer 3, and the diffuser 4; and a cooling bypass duct 10 is formed between the casing 1 and the heat shield 5. Figure 7 As shown, a flow divider 11 is formed between the first-stage annular mixer 2 and the second-stage annular mixer 3. An arc-shaped frame 7 is installed within the flow divider 11, and the first-stage annular mixer 2 and the second-stage annular mixer 3 are connected by the circumferentially distributed arc-shaped frames 7. The arc-shaped frames 7 are conventional support structures. The casing 1 and the second-stage annular mixer 3 form a mixing channel 12. The diffuser 4 consists of a straight section 41 and a first curved section 42. The flame stabilizer 6 consists of an outer ring flame stabilizer 61, a standby flame stabilizer 62, and an inner ring flame stabilizer 63.
[0025] Both the first-stage annular mixer 2 and the second-stage annular mixer 3 are annular structures, with the second-stage annular mixer 3 located inside the first-stage annular mixer 2. The rightmost end of the first-stage annular mixer 2 is located in the first curved section 42 region, and the entire second-stage annular mixer 3 is located in the first curved section 42 region, meaning they are both located in the diffusion stage, which helps to reduce flow losses.
[0026] like Figure 3 As shown, the first-stage annular mixer 2 consists of a first-stage mixer flat section 21 and overflow holes 22. Multiple overflow holes 22 are evenly distributed circumferentially. Each overflow hole 22 has a triangular structure with a gradually increasing cross-sectional width along the airflow direction, ensuring the overflow capacity of the overflow holes 22 and effectively reducing flow losses. The specific structure of the overflow holes 22 is as follows... Figure 4 As shown, where Figure 4 The airflow direction indicates the direction of gas flow. The axis of the triangular structure used to illustrate the overflow hole 22 is parallel to the airflow direction, and the apex of the triangle is facing the incoming flow direction.
[0027] like Figure 5As shown, the second-stage annular mixer 3 consists of a serrated section 31, a smooth section 32, and a second curved section 33. The serrated section 31 includes multiple serrated units, each of which has a triangular structure with the top of the triangle facing the intake direction. The multiple serrated units are evenly distributed circumferentially along the smooth section 32. The profile of the second curved section 33 is designed according to the flow field matching method of "gradual flow followed by rapid flow," "gradual flow followed by rapid flow," and "rapid flow followed by gradual flow" (the gradual flow and rapid flow mentioned in the text refer to the angle between the tangent at a certain set point on the second curved section 33 and the axis. The gradual flow and rapid flow are also relative. When in the gradual flow followed by rapid flow stage, the angle between the tangent in the first part and the axis should be greater than the angle between the tangent in the second part and the axis. The gradual flow and rapid flow followed by gradual flow are analogous to the above methods and will not be elaborated here). This design avoids flow separation inside the second curved section 33. Figure 6 The diagram shown is a schematic of the sawtooth unit of the second-stage annular mixer. The sawtooth unit is triangular in shape. The airflow direction mentioned above refers to the gas flow direction entering the second-stage annular mixer 3, and is only used to illustrate that the front end of the triangular structure faces the incoming flow direction.
[0028] The rightmost cross-section of the first-stage annular mixer 2 has a cross-sectional area of S1 at the downstream end of the outer bypass duct 8, a cross-sectional area of S2 at the downstream end of the diversion channel 11, and a minimum area of S3 for the mixing channel 12. To ensure efficient and reliable operation of the two-stage annular mixer, it is necessary to ensure that S1 + S2 > S3. Figure 10 As shown.
[0029] During aero-engine operation, the bypass ratio varies with engine altitude, speed, and throttle position. Therefore, the afterburner needs to operate stably under varying bypass ratio conditions. However, when the bypass ratio range is too wide, the afterburner bypass area design struggles to accommodate both large and small bypass ratio requirements. To ensure a low cooling gas temperature, this invention employs a non-adjustable annular mixer with mixing capabilities. However, this annular mixer has a narrow applicable bypass ratio range; generally, the maximum / minimum bypass ratio range is 1 to 2.5. Therefore, this invention proposes a two-stage annular mixer structure and further provides a wide-range adaptive bypass ratio matching method to broaden the applicable bypass ratio range of the annular mixer. Details are as follows... Figure 8 and Figure 9 As shown, it includes the following steps:
[0030] like Figure 8As shown, in the low bypass ratio operating state, when the flow rate of the bypass airflow a is small, the velocity of the flow entering the mixing channel 12 is low. A portion of the inner airflow b enters the mixing channel 12 through the diversion channel 11, occupying part of the flow area of the mixing channel 12, which accelerates the bypass airflow a entering the mixing channel 12, improves the reasonable mixing and diffusion of the downstream airflow and cools the intake of the bypass 10. Since S1+S2>S3, the mixing channel 12 cannot completely circulate the bypass airflow a and the inner airflow b. Therefore, a portion of the inner airflow b overflows and flows downstream through the inner channel 9. Under the action of the serrated section 31 evenly distributed along the circumference, the overflow loss can be significantly reduced.
[0031] like Figure 9 As shown, in the high bypass ratio operating state, when the flow rate of the outer bypass airflow a is large, part of it directly enters the mixing channel 12, and the other part enters the diversion channel 11 through the overflow hole 22 and then enters the mixing channel 12, occupying the flow area of the diversion channel 11. The amount of airflow b entering the mixing channel 12 through the diversion channel 11 is reduced, and most of the inner bypass airflow b flows through the inner bypass 9. Under the action of the serrated section 31 evenly distributed along the circumference, the overflow loss can be significantly reduced.
[0032] The magnitude of the flow rate of the bypass airflow a is directly reflected as follows: when the air pressure of the bypass airflow entering the diversion channel 11 is less than the air pressure of the inner airflow, the flow rate of the bypass airflow a is considered to be small; when the air pressure of the bypass airflow a entering the diversion channel 11 is greater than the air pressure of the inner airflow, the flow rate of the bypass airflow a is considered to be large.
[0033] It should be noted that, Figure 8 and Figure 9 In the diagram, 'a' represents the bypass airflow, and the arrow at 'a' indicates the direction of the bypass airflow. 'b' represents the core airflow, and the arrow at 'b' indicates the direction of the core airflow.
[0034] The embodiments of the present invention can achieve a small mixing effect in the mixer while meeting the requirements of low flow resistance, high efficiency and stable operation of the afterburner.
[0035] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A two-stage annular mixer for a thrust chamber, characterized in that, The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber.
2. The thrust chamber two-stage annular mixer of claim 1, wherein, The application relates to a two-stage annular mixer of a thrust chamber.
3. The strutted combustor two-stage annular mixer of claim 1, wherein, The application relates to a two-stage annular mixer of a thrust chamber.
4. The strutted combustor two-stage annular mixer of claim 3, wherein, The application relates to a two-stage annular mixer of a thrust chamber.
5. The strutted combustor two-stage annular mixer of claim 1, wherein, The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber.
6. The strutted combustor two-stage annular mixer of claim 5, wherein, The application relates to a two-stage annular mixer of a thrust chamber.
7. A method of adapting the bypass ratio, using the two-stage annular mixer of any one of claims 1 to 6, characterized in that, The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. The application relates to a two-stage annular mixer of a thrust chamber. 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Citation Information
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