Vortex secondary rectification structure

Abstract

The vortex generator secondary rectification structure of the present application is suitable for the input of the airflow at the head of the flame tube, the high pressure airflow from the engine diffuser into the combustion chamber, the axial vortex generator (2) is installed at the head of the flame tube, the rectification structure (1) is installed at the air inlet end of the axial vortex generator (2), the high pressure airflow is converted from the total pressure air inlet mode to the static pressure air inlet mode under the rectification of the rectification structure (1), and is delivered to the axial vortex generator (2), so that the influence of poor airflow uniformity caused by the airflow dynamic pressure is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of aero-engine rectification structures, and more particularly to a vortex generator secondary rectification structure. Background Technology

[0002] With the increasing demands for variable operating conditions in aero-engines / gas turbines, the requirements for combustion stability during the transition state in the combustion chamber are constantly rising. Traditional axial vortex generators have low flow resistance and simple structure, and use a total pressure intake method. However, when the engine is under acceleration, deceleration, or variable operating conditions, the incoming flow rate changes significantly, resulting in poor uniformity. Summary of the Invention

[0003] In view of this, the present invention provides a secondary rectification structure for a vortex generator, which reduces the impact of poor flow uniformity caused by airflow pressure by converting the total pressure intake mode to the static pressure intake mode, thereby improving the flame stability of the transition combustion chamber and the reliability of engine operation.

[0004] A secondary rectification structure for a vortex generator is disclosed. High-pressure airflow enters the combustion chamber from the engine diffuser. An axial vortex generator is installed at the head of the flame tube. The structure includes a rectification structure installed at the inlet end of the axial vortex generator. Under the rectification effect of the rectification structure, the high-pressure airflow is transformed from total pressure intake to static pressure intake and delivered to the axial vortex generator, thereby reducing the impact of poor flow uniformity caused by airflow pressure.

[0005] Beneficial effects

[0006] When the operating conditions of an aero-engine / gas turbine change drastically and the uniformity of the incoming flow is poor, the rectification structure can realize the conversion from total pressure intake to static pressure intake. At the same time, the straight section of the rectification structure in front of the blade passage can further rectify the flow, effectively reducing the airflow velocity pulsation interference caused by dynamic pressure. This breaks through the limitation of traditional two-stage axial vortex generators in poor adaptability to turbulent incoming flow pulsation, improves the fuel-gas matching capability and flame stability during combustion, optimizes the head flow field, prevents gas backflow, and enhances the stability and reliability of the engine's transitional operation. Attached Figure Description

[0007] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram of the rectifier structure;

[0009] Figure 2 This is a front sectional view of the rectifier structure, where...

[0010] A. First airflow path; B. Second airflow path; 11. First rectifier ring; 12. Second rectifier ring; 13. Third rectifier ring; 14. First arc-shaped transition section; 15. Second arc-shaped transition section; 16. Third arc-shaped transition section; 2. Axial vortex generator; 5. First-stage swirl vane; 6. Second-stage swirl vane; 7. Venturi tube; 8. Sleeve. Detailed Implementation

[0011] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0012] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure 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 disclosure. 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 disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0013] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0014] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The drawings only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0015] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that these aspects can be practiced without these specific details.

[0016] See Figure 1 The vortex secondary rectification structure shown is suitable for the input of airflow at the head of the flame tube. The high-pressure airflow enters the combustion chamber from the engine diffuser. An axial vortex 2 is installed at the head of the flame tube, including a rectification structure installed at the intake end of the axial vortex 2. Under the rectification action of the rectification structure 1, the high-pressure airflow is transformed from total pressure intake to static pressure intake and delivered to the axial vortex 2. That is, the axial high-pressure airflow is transformed into radial airflow entering the axial vortex 2.

[0017] In conventional engines, the axial vortex generator 2 is preferably a two-stage vortex generator. In this invention, the axial vortex generator 2 is provided with independent first airflow path A and second airflow path B spaced apart. Therefore, see [link to relevant documentation]. Figure 2 The rectification structure includes a first rectification ring 11, a second rectification ring 12, and a third rectification ring 13 arranged at intervals. The first rectification ring 11 has a first arc-shaped transition portion 14 integrally formed; the second rectification ring 12 has a second arc-shaped transition portion 15 integrally formed; and the third rectification ring 13 has a third arc-shaped transition portion 16 integrally formed. The first arc-shaped transition portion 14 is connected to the first-stage inner ring of the vortex generator; the second arc-shaped transition portion 15 is connected to the second-stage inner ring of the vortex generator; and the third arc-shaped transition portion 16 is connected to the second-stage outer ring of the vortex generator.

[0018] A first conversion airflow path is formed between the first arc-shaped transition part 14 and the second arc-shaped transition part 15. The first conversion airflow path is used to convert the radially flowing high-pressure airflow into axial airflow in a gradual manner (radial gradually changing to axial), and flow into the first airflow path. Finally, it is input into the flame tube by the first stage of the axial vortex 2. It should be noted that under the action of this structure, the radial airflow has a small flow resistance loss under the action of the first arc-shaped transition part 14.

[0019] A second conversion airflow path is formed between the second arc-shaped transition section 15 and the third arc-shaped transition section 16. This second conversion airflow path is used to gradually convert the radially flowing high-pressure airflow into axial airflow, which then flows into the second airflow path. Finally, the airflow is input into the flame tube through the secondary input of the axial vortex generator 2. It should be noted that, under the action of this structure, the radial airflow experiences less flow resistance loss due to the action of the second arc-shaped transition section 15.

[0020] Furthermore, the arc transition angles of the first arc-shaped transition portion 14 and the second arc-shaped transition portion 15 are both 40°-120°, and the arc transition angle of the first arc-shaped transition portion 14 is greater than that of the second arc-shaped transition portion 15, so as to adapt to the stable operation of the axial vortex generator 2.

[0021] This improves the stability of the transition flow field and combustion reliability in the combustion chamber, enhancing the engine's ability to adapt to unexpected situations. An upstream rectifying structure is installed in the axial vortex generator 2, which converts axial intake into radial intake, i.e., converting total pressure intake into static pressure intake, reducing the impact of incoming flow pulsation on intake uniformity and achieving secondary rectification.

[0022] As a specific implementation provided in this case, the axial vortex generator 2 is equipped with a venturi tube 7, a first-stage swirl vane 5, a second-stage swirl vane 6, and a sleeve 8. It also includes a method for designing a first rectifying ring 11, a second rectifying ring 12, and a third rectifying ring 13. Under the action of the above structure, a portion of the high-pressure airflow transitions and is rectified from the first arc-shaped transition section 14 and the second arc-shaped transition section 15. After rectification, it leaves with a certain swirl intensity guided by the first-stage swirl vane 5, participating in the pre-filming of fuel in the venturi tube 7. Another portion of the air transitions and is rectified from the second arc-shaped transition section 15 and the third arc-shaped transition section 16. After rectification, it enters the second-stage swirl channel of the vortex generator, leaves under the guidance of the second-stage swirl vane 6, and participates in the secondary breaking of the fuel film and mixing of fuel and gas at the lip of the venturi tube 7. Under the constraint of the sleeve 8, a recirculation zone of suitable size and a stable fuel temperature field are formed. The method includes:

[0023] The first rectifier ring 11, the second rectifier ring 12, and the third rectifier ring 13 are all perpendicular to the central axis of the axial vortex generator 2. The outer diameters of the first rectifier ring 11 and the second rectifier ring 12 are flush with each other, and their outer diameter edges are on the same horizontal line. The ratio of the distance between the first rectifier ring 11 and the second rectifier ring 12 to the height of the first-stage swirl blade 5 of the axial vortex generator 2 is 0.7-1.2.

[0024] The position difference between the end face of the second rectifier ring 12 adjacent to the first rectifier ring 11 and the inlet end of the first-stage swirl blade 5 of the axial vortex generator 2 is taken as the first value, and the ratio of the first value to the height of the first-stage swirl blade 5 is -0.4 to 0.6.

[0025] The difference between the inner and outer diameters of the second rectifier ring 12 is 1-2 to the height of the first-stage vortex blade 5, and the outer diameter of the second rectifier ring 12 is higher than the outer diameter of the second stage of the axial vortex generator 2.

[0026] The ratio of the inner and outer diameter difference of the third rectifier ring 13 to the height of the second-stage swirl blade 6 is 0.7-1.4, and the ratio of the distance between the second rectifier ring 12 and the third rectifier ring 13 to the height of the second-stage swirl blade 6 is 0.6-1.15. The rectified air enters the first and second stage vortex generators respectively from the rectifier structure. Under the action of the venturi tube 7, it completes fuel pre-filming, secondary fragmentation, or enhanced combustion-air mixing. Under the action of the two-stage swirl and the guidance of the sleeve 8, a suitable flame-stabilizing recirculation zone of appropriate size is formed at an appropriate position at the head of the combustion chamber, ensuring the reliability of engine operation.

[0027] Furthermore, the length of the second arc-shaped transition section 15 is 1-3 times the height of the secondary swirl blade 6;

[0028] The first-stage swirl blade 5 and the second-stage swirl blade 6 employ a co-directional or counter-directional swirl design with an airfoil profile. Both blades have an angle of attack of 0° and a lag angle ranging from 10° to 30°, varying radially to enhance airflow guidance, ensure airflow close to the wall as much as possible, reduce angular vortex formation, and lower flow resistance. The lag angle of the two swirl blades directly affects the swirl intensity, the size and location of the recirculation zone, the degree of secondary fuel abruption, and the fuel-gas distribution.

[0029] The ratio of the length of the Venturi tube 7 to the diameter of the throat of the Venturi tube 7 is 0.9-1.2, and the ratio of the outlet diameter of the Venturi tube 7 to the diameter of the throat of the Venturi tube 7 is in the range of 1.15-1.35. This ensures that the fuel falls on the inner wall of the Venturi tube 7 near the upstream of the throat, and can form an oil film of appropriate thickness under the action of the first-stage swirling air.

[0030] The expansion angle of the sleeve 8 is 50°-65°, which can limit the radial expansion of the spray angle and airflow, ensure that the size and position of the combustion chamber head recirculation zone are appropriate, avoid the outward expansion of the strong turbulence zone, further limit the radial expansion of the spray angle and airflow, and improve the fuel atomization quality.

[0031] Under a typical operating condition, the flow field and pressure field of the traditional two-stage axial vortex generator 2 are compared with those of the vortex generator with secondary rectification structure. The simulation results show that the inlet fluid velocity of the vortex generator with secondary rectification structure is more uniform and no turbulent vortex structure is formed. The uniformity of the pressure field and velocity field in the blade channel is significantly improved, which provides certain support for improving the stability and safety of engine operation under large-state or transitional conditions.

[0032] Compared to the traditional two-stage axial vortex generator 2, the above-mentioned vortex generator secondary rectification structure realizes the conversion from total pressure intake to static pressure intake. At the same time, the straight section of the rectification structure in front of the blade passage can further rectify the flow, further reduce the influence of dynamic pressure, improve the adaptability of the vortex generator to the incoming flow pulsation, effectively improve the combustion chamber oil-gas matching capability and flame stability, and improve the engine's transitional operation stability and reliability.

[0033] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A secondary rectification structure for a vortex generator, suitable for the input of high-pressure airflow from the engine diffuser into the combustion chamber, wherein an axial vortex generator (2) is installed at the head of the flame tube, characterized in that, The axial vortex (2) includes a rectifier structure (1) installed at the air inlet end. Under the rectification effect of the rectifier structure (1), the high-pressure airflow is transformed from total pressure air intake to static pressure air intake and delivered to the axial vortex (2), reducing the influence of poor flow uniformity caused by airflow pressure. The axial vortex (2) is a two-stage vortex, with independent first and second airflow paths spaced apart. The rectification structure (1) includes a first rectification ring, a second rectification ring, and a third rectification ring arranged at intervals. The first rectification ring has a first arc-shaped transition portion integrally formed, the second rectification ring has a second arc-shaped transition portion integrally formed, and the third rectification ring has a third arc-shaped transition portion integrally formed. The first arc-shaped transition portion is connected to the first-stage inner ring of the vortex generator, the second arc-shaped transition portion is connected to the second-stage inner ring of the vortex generator, and the third arc-shaped transition portion is connected to the second-stage outer ring of the vortex generator. A first conversion airflow path is formed between the first arc-shaped transition portion and the second arc-shaped transition portion. The first conversion airflow path is used to convert the radially flowing high-pressure airflow into axial airflow in a gradual manner and flow into the first airflow path. A second conversion airflow path is formed between the second arc-shaped transition portion and the third arc-shaped transition portion. The second conversion airflow path is used to convert the radially flowing high-pressure airflow into axial airflow in a gradual manner and flow into the second airflow path.

2. The eddy current secondary rectification structure according to claim 1, characterized in that, The arc transition angle of both the first arc-shaped transition portion and the second arc-shaped transition portion is 40°-120°.

3. The eddy current secondary rectification structure according to claim 1, characterized in that, The arc transition angle of the first arc-shaped transition part is greater than that of the second arc-shaped transition part, so as to adapt to the stable operation of the axial vortex generator (2).

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