A variable parameter test system for flow control in S-type flow channel

Abstract

The present invention discloses an S-shaped flow channel active flow control variable parameter testing system, comprising a curved section and straight sections connected at both ends of the curved section, wherein a replaceable plug-in plate is detachably installed on the curved section, and a mounting slot is provided on the replaceable plug-in plate at a position to be tested; a replaceable fluid oscillator is installed in the mounting slot, and the replaceable fluid oscillator is detachably connected to the mounting slot; the jet outlet of the replaceable fluid oscillator faces the flow channel inside the curved section; the system can realize the replacement of the position to be tested by replacing the replaceable plug-in plate and the mounting slots at different positions on the replaceable plug-in plate, and simultaneously realize the change of factors such as the jet angle, the number of actuators, and the spacing by replacing the replaceable fluid oscillator, so that the system can quickly and conveniently adjust various influencing parameters affecting the active flow control inside the S-shaped air inlet channel.

Description

Technical Field

[0001] The present invention relates to the technical field of active flow control, in particular to an S-shaped flow channel flow control variable parameter testing system. Background Art

[0002] With advancements in fighter jet design technology, the survivability of modern fighter jets is receiving increasing attention, and stealth performance is a crucial factor. The engine is the primary heat emitter in fighter jets, and the degree of shielding on its components significantly impacts stealth performance. The S-shaped inlet, with its unique structure, can provide a certain degree of shielding for the engine blades, effectively reducing the reflective surface area available for radar detection. Therefore, it has become a solution to this problem and has been widely used in numerous stealth fighters and drones currently under development.

[0003] However, the study found that the geometric characteristics of the S-shaped inlet also make its internal flow field complex. In the large curvature bend section, there will be a strong adverse pressure gradient, which will eventually lead to flow separation. This may reduce the total pressure recovery coefficient of the inlet outlet section, thereby reducing the overall effective thrust of the engine. At the same time, this flow separation phenomenon will also cause a large total pressure distortion and secondary swirl in the inlet outlet section, which may induce engine surge. In order to improve the engine operating range and working efficiency, and thus enhance the performance of the fighter, it is very necessary to effectively control the separated flow of the S-shaped inlet and improve the flow field quality at the inlet outlet through passive or active flow control methods.

[0004] The most common passive flow control solution is a vortex generator, which, placed at appropriate locations in the pipeline, spontaneously induces vortices and other fluid structures to interact with the boundary layer. This intensifies energy exchange within the boundary layer, thereby suppressing boundary layer separation. However, although this control method is simple in structure, it generally only performs well under certain operating conditions. Active flow control solutions, on the other hand, are relatively more complex in structure, but they can be actively adjusted according to actual operating conditions and have good variable operating condition performance. Therefore, for fighter jets with variable operating conditions, a well-designed active flow control solution is a relatively ideal and feasible control solution.

[0005] Active flow control requires the introduction of external disturbances and energy injection. Compared to steady-state blowing / inhaling methods, active flow control methods based on periodic unsteady excitation are more efficient. Calculated using an additional momentum coefficient, the efficiency can be increased by two orders of magnitude, a fact that has been validated in applied research across various fields. These periodic unsteady disturbances are generated by various actuators, typically synthetic jets, plasma actuators, and fluid oscillators. However, the harsh operating conditions within aircraft engines place extremely high demands on the reliability of all components. The difficulty in using unsteady flow control lies in the lack of simple, reliable actuators.

[0006] A fluidic oscillator is an actively controlled device that generates a periodically oscillating jet at the outlet using a given pressure gas input at the inlet. Its advantages, including no moving parts, simple structure, high outlet flow rate, and self-oscillation and self-sustaining properties, have attracted significant interest among researchers.

[0007] Currently, testing and analysis of fluidic oscillators are primarily applied to external flows. However, the application and testing of oscillating jets for controlling separated flows within S-shaped inlets requires further refinement. Due to the small outlet size of the fluidic oscillator itself, the affected area is limited, while the controlled area is generally larger. To apply fluidic oscillators to practical flow separation control scenarios, a series of fluidic oscillator arrays must be arranged within the controlled flow area. This creates a series of discrete, periodic oscillating jet excitations on the surface of the controlled area. By integrating the internal flow channel of the fluidic oscillator with the inlet wall design, introducing a high-pressure air source from an external source or within the aircraft engine, and regulating the pressure at the inlet of the fluidic oscillator flow channel, the desired oscillating jet operating frequency and amplitude are generated at the oscillator outlet. This approach can simultaneously reduce aircraft flight drag and inlet duct dimensions, while significantly improving engine operating margins, without increasing the complexity of the existing aircraft structure or compromising its reliability and safety. Active control of flow separation in an S-shaped inlet, based on the active excitation of a self-excited oscillating jet, combines the high efficiency of active flow control with the high reliability and safety of passive flow control, achieving the benefits of active control in a passive form. This technology significantly reduces flow losses in the S-shaped inlet and improves the quality of the engine's inlet airflow, while also balancing safety, reliability, and system complexity. It holds great promise for practical engineering applications.

[0008] The effectiveness of active regulation and control of the flow inside an S-shaped inlet is closely related to the location of the jet excitation, the angle of excitation, the distribution of the exciters, the number of exciters, and the speed and frequency of the excitation jet. However, once the design geometry of the fluid oscillator is determined, when the characteristics of the working medium remain unchanged, its frequency response and speed response characteristics with changes in inlet pressure are also determined. The excitation speed and frequency can only be adjusted by adjusting the inlet pressure. In order to quantitatively study the impact of the above different excitation parameters on the flow quality within the S-shaped inlet / flow channel, a large number of parametric experimental studies are required. In addition to the excitation speed and frequency, the effects of the jet excitation location, excitation angle, number of exciters, and the distribution of the exciters are also included. Each combination of parameters requires the processing of a complex flow channel with multiple fluid oscillators on the wall of the S-shaped inlet, which leads to excessively high testing costs and long testing cycles. Summary of the Invention

[0009] In order to address the deficiencies in the prior art, this application proposes an S-type flow channel flow control variable parameter testing system, which can meet various design parameters and processing accuracy requirements through modular design, improving convenience while ensuring the accuracy of the test itself.

[0010] The technical solutions adopted in the present invention are as follows:

[0011] An S-type flow channel flow control variable parameter testing system, comprising:

[0012] curved section,

[0013] A replaceable plug-in plate is provided in the curved section, and the replaceable plug-in plate can be detachably installed in the curved section;

[0014] Setting a mounting slot on the replaceable plug-in board at the position to be tested;

[0015] A replaceable fluid oscillator is installed in the mounting groove, the replaceable fluid oscillator is detachably connected to the mounting groove, and the jet outlet of the replaceable fluid oscillator faces the internal flow channel of the curved section;

[0016] The straight sections are arranged at both ends of the curved section, and the straight sections are smoothly connected to the interior of the curved section.

[0017] Furthermore, there are multiple replaceable plug-ins at each position on the curved section, some replaceable plug-ins do not have mounting slots, and other replaceable plug-ins have mounting slots at different positions.

[0018] Furthermore, a single position to be tested or multiple test positions are set in the curved section.

[0019] Furthermore, the replaceable fluid oscillator includes a connecting portion and an upper convex portion on the upper portion of the connecting portion, wherein the upper convex portion is a convex block with a slope; the jet outlet of the oscillator array in the replaceable fluid oscillator is arranged on the upper surface of the upper convex portion.

[0020] Furthermore, the installation groove is a sloped groove that matches the upper protrusion, and the upper protrusion is buckled and connected to the installation groove; the connecting part and the replaceable plug-in plate are detachably connected through a connecting piece.

[0021] Furthermore, adjacent replaceable plug-ins and between the replaceable plug-ins and adjacent straight sections are designed to be stepped to fit with each other, and are then detachably connected using connectors.

[0022] Furthermore, an oscillator array is provided in the replaceable fluid oscillator, and the angle between the jet injection direction of the oscillator array and the internal flow channel is α, and the value range of α is 15° to 90°.

[0023] Furthermore, the jet outlet positions of the oscillator arrays with different jet angles are the same.

[0024] Furthermore, the oscillator array adopts a relaxation type oscillator, a sonic wave type oscillator, a coanda sweep type oscillator or a jet coupling type oscillator.

[0025] Furthermore, the replaceable fluid oscillator is composed of an oscillator mounting side and a cover plate. The oscillator mounting side 7 is provided with an oscillator array, and the oscillator mounting side and the cover plate are fixedly connected.

[0026] Furthermore, the replaceable fluid oscillator is formed by CNC precision machining, integrated 3D printing, or other forming methods.

[0027] Beneficial effects

[0028] 1. This invention proposes a variable-parameter testing system for flow control in an S-shaped flow channel. It utilizes a dual interchangeable structure consisting of an interchangeable insert plate and an interchangeable fluid oscillator array. By changing the position of the interlocking slots on the interchangeable insert plate, the oscillator excitation position can be varied, thereby studying the effect of active excitation position on control performance. Simply by replacing the insert plate, as long as the shape of the interlocking slots is maintained, the effects of different excitation position parameters on active control can be studied without altering the original S-shaped flow channel structure or the oscillator array. This enables multivariable research, reduces the cost of parameter research, and improves both economic efficiency and experimental efficiency.

[0029] On the same replaceable plug-in board, by changing different fluid oscillator arrays, that is, changing the number of fluid oscillators on different arrays, oscillator size, oscillator distribution spacing, oscillator type, different jet excitation angles, etc., the influence of different excitation parameters on the flow control efficiency is studied.

[0030] 2. The replaceable plug-in plate and the S-shaped flow channel are connected in a stepped buckle manner, and the buckle surface is sealed with a sealing ring and fastening bolts to avoid gas leakage caused by processing errors and installation accuracy.

[0031] 3. The exciter array and the plug-in board are connected via a sloped snap-in groove. This sloped structure enables quick snap-in of the exciter array, ensuring the installation of large-angle oscillators within a compact space. The snap-in surface between the oscillator array and the replaceable plug-in board is not perpendicular, but uses a sloped design determined by the control jet angle, allowing for quick and easy assembly and disassembly while minimizing installation gaps and preventing gas leaks.

[0032] 4. In order to study the influence of the angle between the oscillator jet direction and the incoming flow direction, it is necessary to manufacture fluid oscillator arrays with different inclination angles. In this application, the replaceable fluid oscillators with different jet types and different jet angles are consistent with the assembly surface of the mounting slot on the plug-in board; ensure that the outlet jet position of the arrays with different angles is consistent.

[0033] 5. This test system can meet various design parameters and processing accuracy requirements through modular design, improving convenience while ensuring the accuracy of the test itself.

[0034] 6. The exciter is symmetrically fastened and sealed by countersunk bolts, making it possible to realize exciter control tests at various angles and reducing the influence of processing errors and the impact of processing defects on the results. At the same time, there are no longer specific requirements for the test section material, and metal processing or 3D printing parts can achieve relatively ideal results. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of the variable parameter test system for flow control of an S-type flow channel according to the present invention;

[0036] Figure 2 Schematic diagram of the replaceable plug-in board structure;

[0037] Figure 3 It is a schematic diagram of the replaceable exciter structure;

[0038] Figure 4 It is a schematic diagram of the assembly between the replaceable actuator, the replaceable plug-in plate and the S-shaped flow channel wall;

[0039] Figure 5 It is a schematic diagram of the replaceable exciter structure;

[0040] Figure 6 This is a schematic diagram of the structure of a 45° replaceable exciter;

[0041] Figure 7 This is a schematic diagram of the structure of a 90° replaceable exciter;

[0042] Figure 8 This is a diagram showing the superimposed state of the 45° replaceable actuator structure and the 90° replaceable actuator;

[0043] Figure 9 This is a schematic diagram of the assembly of the replaceable exciter and the replaceable plug-in board;

[0044] Figure 10 This is a schematic diagram of the oscillator array inside the replaceable exciter;

[0045] Figure 11 Arrays of fluidic oscillators with four different configurations: (a) relaxation type oscillator; (b) sonic type oscillator; (c) Coanda swept type oscillator; (d) jet-coupled type oscillator.

[0046] Figure 12 Schematic diagram of the external and internal fixed connection parts of the replaceable fluid oscillator;

[0047] In the figure, 1, curved section, 2, inlet straight section, 3, outlet straight section, 4, replaceable plug-in plate, 4a, first replaceable plug-in plate, 4b, second replaceable plug-in plate, 5, mounting groove, 6, replaceable fluid oscillator, 6-1, upper protrusion, 6-2, connecting portion, 6-3, lower protrusion, 6-4, jet outlet, 6-5, external connecting hole, 6-6, internal connecting hole, 7, oscillator mounting side, 8, cover plate, 9, oscillator, 10, countersunk hole. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0049] In view of the deficiencies in the prior art, this application designs Figure 1 The shown example is an S-shaped flow channel flow control variable parameter testing system, which includes a curved section 1 connected to a straight section.

[0050] In this embodiment, the cross section of the S-shaped flow channel is designed to be rectangular, but the shape is not limited to this and may be various shapes such as circular.

[0051] In this embodiment, an S-shaped flow channel with a rectangular cross section is used for further explanation:

[0052] The straight section includes an inlet straight section 2 and an outlet straight section 3. Flanges are respectively provided on the outermost sides of the inlet straight section 2 and the outlet straight section 3. The inlet straight section 2 flows through the flange wind tunnel to provide the flow conditions required for the S-type flow channel flow control experiment; the outlet straight section 3 is connected to the output pipeline using flanges.

[0053] The inlet straight section 2 and outlet straight section 3 are respectively arranged on both sides of the curved section 1. The curved section 1 is smoothly connected to the internal flow channel formed by the inlet straight section 2 and the outlet straight section 3. The curved section 1 is the experimental section, which produces flow structures such as flow separation and flow vortex.

[0054] More specifically, the curved section 1 can be made of various materials such as metal, organic glass plate, etc., and can be processed by various methods such as mechanical processing and laser cutting.

[0055] The curved section 1 is formed by smoothly connecting multiple replaceable inserts 4 to form an S-shaped flow channel. Figure 1 From a vantage point, the interchangeable plates 4 at the top and bottom of the curved section 1 are curved. For example, the two interchangeable plates 4 at the top are curved in opposite directions, forming an S-shape when connected. The two interchangeable plates 4 at the bottom are similarly designed, forming an S-shaped flow channel parallel to each other. Along the flow direction, the two interchangeable plates 4 must be smoothly connected to each other to ensure a smooth flow channel interior. The interchangeable plates 4 at the sidewalls are also S-shaped.

[0056] The system designed in this application is to be able to test the active regulation and control effect of the flow inside the S-shaped air inlet. Since the factors affecting the active regulation and control effect are closely related to the position of the jet excitation, the angle of the excitation, the distribution position of the exciter, the number of exciters, the speed and frequency of the excitation jet, in order to be able to change and quantitatively study the above parameters in the same test system, this application designs a replaceable plug-in plate 4 in the curved section 1. Figure 4 The adjacent replaceable plug-in plates 4 and the replaceable plug-in plates 4 and the adjacent straight sections are designed to be stepped to cooperate with each other. The stepped structures cooperate with each other, and the replaceable plug-in plates 4 can be detachably installed from the outside using connectors such as screws while being quickly positioned. Figure 4 The connection between the left end of the middle interchangeable plate 4 and the inlet straight section 2 is stepped, interlocking and then externally screwed. This allows for easy removal when the interchangeable plate 4 needs to be replaced. The right end of the interchangeable plate 4 also features a stepped connection with the other interchangeable plate 4, interlocking and then externally screwed. This external screw-locking design facilitates installation and prevents the screws from protruding into the internal flow path, ensuring a smooth flow path.

[0057] In this application, a mounting slot 5 is provided on the replaceable insert plate 4, and a replaceable fluid oscillator 6 is mounted in the mounting slot 5, with the jet outlet 6-4 of the replaceable fluid oscillator 6 facing into the flow channel. To enable the replaceable fluid oscillator 6 to be replaced, the replaceable fluid oscillator 6 is detachably mounted in the mounting slot 5, so that the replaceable fluid oscillator 6 with different jet types and different jet angles can be easily replaced.

[0058] More specifically, in order to be able to change the test position of the replaceable fluid oscillator 6, multiple replaceable plates 4 are provided at each position on the curved section 1. Some replaceable plates 4 do not have mounting slots 5, while other replaceable plates 4 have mounting slots 5 at different positions. When the test position needs to be changed, only one replaceable plate 4 with a different mounting slot 5 position needs to be replaced. For example Figure 1 In the upper portion, a mounting slot 5 is provided at the top of the first replaceable insert plate 4a. When testing a different position of the first replaceable insert plate 4a, simply replace it with another first replaceable insert plate 4a with a mounting slot 5 at a different location to change the test position of the replaceable fluid oscillator 6. The same applies to other positions. Because the test position, jet type, and jet angle can be adjusted by replacing the replaceable insert plate and the replaceable fluid oscillator 6 in this application, the overall structure of the test system remains unchanged, eliminating the need for a separate test system design for each change. This reduces testing costs, and through quick replacement, multiple tests can be performed, shortening the test cycle.

[0059] More specifically, the system can also test multiple locations simultaneously, e.g. Figure 1 In the embodiment, the upper first replaceable plug-in plate 4a and the lower second replaceable plug-in plate 4b can be replaced with those with mounting slots 5, and the replaceable fluid oscillator 6 can be installed in the mounting slots 5; and testing can be performed at the first replaceable plug-in plate 4a and the lower second replaceable plug-in plate 4b at the same time.

[0060] More specifically, when it is necessary to test replaceable fluid oscillators 6 with different jet types and different jet angles at the same test position, it is necessary to replace the replaceable fluid oscillators 6 with different jet types and different jet angles; however, it is necessary to ensure that the positions of the jet outlets 6-4 of the replaceable fluid oscillators 6 are the same before and after replacement. To address this problem, the present application is implemented by optimizing the structure of the replaceable fluid oscillator 6 and the mounting slot 5. Figure 2 and 3 The mounting groove 5 is a sloped groove with a trapezoidal cross-section. The connection between the replaceable fluid oscillator 6 and the mounting groove 5 is an upper protrusion 6-1, which is a sloped cube. The slope of the upper protrusion 6-1 cooperates with the slope of the mounting groove 5 to achieve rapid positioning between the two. At the same time, the jet outlets 6-4 of the replaceable fluid oscillators 6 with different jet types and different jet angles are located in the same position; Figure 9 As shown, the center lines of the jet outlets 6 - 4 of all replaceable fluid oscillators 6 are at the same distance from the rear edge (divided into the leading edge and the rear edge according to the flow direction) of the mounting slot 5 .

[0061] More specifically, the replaceable fluid oscillator 6 is detachably connected to the first replaceable plug-in plate 4a where the mounting slot 5 is located. Figure 5 As shown, the replaceable fluid oscillator 6 includes a connecting portion 6-2 and an upper protrusion 6-1 above the connecting portion 6-2. The connecting portion 6-2 is detachably connected to the replaceable plug-in board 4 via screws or other connecting members. The lower protrusion 6-3 contains the oscillator array.

[0062] More specifically, the replaceable fluid oscillator 6 is a double-layer assembly type, and the replaceable fluid oscillator 6 is composed of an oscillator mounting side 7 and a cover plate 8. The oscillator mounting side 7 is provided with an oscillator array such as Figure 10 As shown, the oscillator mounting side 7 and the cover plate 8 are fixedly connected.

[0063] More specifically, the replaceable fluid oscillator 6 can be formed by CNC precision machining, integrated 3D printing, or other molding methods.

[0064] More specifically, the oscillator array can be used as Figure 11 The relaxation oscillator, sonic oscillator, Coanda sweep oscillator, or fluidic coupling oscillator shown in this design scheme offers greater scalability in terms of structural size and spacing of the oscillator array. Oscillator arrays requiring precision machining can be fabricated using various methods, such as metal processing and 3D printing. Compared to traditional experimental schemes, this reduces the size of precision-machined structures, avoids the drawbacks of insufficient machining precision on large structural components, and ensures the accuracy of experiments with less precisely machined flow channel structures.

[0065] More specifically, the jet angle of the oscillator array is the angle α between the jet ejection direction of the oscillator array and the incoming flow direction. α can vary between 15 and 90 degrees. Variations in the angle α will produce different flow control effects. Figure 6 、 7 , 8, where Figure 6 The array shown is tilted at 45°. Figure 7 It is a 90° inclination array. In order to clearly show the different jet angles, the jet outlet 6-4 of the replaceable fluid oscillator 6 is at the same position. Figure 8 As shown, Figure 6 and Figure 7 The schematic diagram of the overlap of two replaceable fluid oscillators 6 shows that the upper protrusions 6 - 1 of the two replaceable fluid oscillators 6 are completely overlapped.

[0066] More specifically, for the installation of the replaceable fluid oscillator 6, in the actual assembly process, different connection methods can be adopted between the replaceable fluid oscillator 6 and the replaceable plug-in plate 4 according to the installation position of the replaceable fluid oscillator 6 and the structure of the replaceable fluid oscillator 6. According to the installation direction of the connecting part between the replaceable fluid oscillator 6 and the replaceable plug-in plate 4, it can be divided into two forms: fixed connection from the outside and fixed connection from the inside.

[0067] For example Figure 6 、 7 The two types of replaceable fluid oscillators 6 shown in the figure, if the width of the connecting portion 6-2 of the replaceable fluid oscillator 6 is sufficient, and the connecting portion 6-2 can fit well with the replaceable plug-in plate 4 to be installed, as shown in FIG. Figure 12 In the middle A area; the replaceable fluid oscillator 6 and the replaceable plug-in plate 4 in the A area are connected by a connecting member such as a bolt, and the bolt is connected from the outside of the entire flow channel to the inside of the flow channel. The bolt passes through the external connection hole 6-5 on the connecting part 6-2 and the connection hole on the replaceable plug-in plate 4 in sequence to connect the two; a plurality of the above-mentioned external connection holes 6-5 are evenly arranged on the connecting part 6-2, and are also installed from the outside to the inside by bolts; at this time, the connection holes on the replaceable plug-in plate 4 corresponding to the external connection holes 6-5 are blind holes, that is, the bolts cannot extend into the flow channel, which can ensure the smoothness of the flow channel.

[0068] However, the width of the connecting portion 6-2 is not enough for the installation of the fastener, and there is an arc between the connecting portion 6-2 and the replaceable plug-in plate 4 to be installed, which cannot fit well. Figure 12 Middle B area (or Figure 6 In the example of the connection part 6-2 on the left side of the middle, the installation condition is from the outside to the inside of the fasteners). In this case, if the B area still adopts the connection method from the outside to the inside as in the A area, the connection part 6-2 in the B area cannot be evenly distributed with fasteners on all sides. Asymmetric bolt fastening can easily lead to gaps and local deformations. These gaps and local deformations can also cause gas leakage, flow field distortion and other problems, affecting the experimental results. In response to this problem, the present invention adopts the method of installing the fasteners from the inside of the flow channel to the outside of the flow channel in the B area. A plurality of countersunk holes 10 are opened on the surface of the replaceable plug-in plate 4 located in the flow channel in the B area. Figure 9As shown, multiple countersunk holes 10 are evenly spaced along the side edge of the jet outlet 6-4; multiple internal connecting holes 6-6 are evenly arranged on the connecting portion 6-2, with each internal connecting hole 6-6 corresponding to the countersunk holes 10. During installation, connecting members such as bolts are inserted through the countersunk holes 10 into the corresponding internal connecting holes 6-6, thereby connecting the replaceable insert 4 to the replaceable fluid oscillator 6. Because the countersunk holes 10 are located on the surface of the replaceable insert 4 located within the flow channel, they would damage the smoothness of the flow channel. To ensure the smoothness of the flow channel in area B, the countersunk holes 10 are filled with a material such as gypsum after the bolts are installed.

[0069] In addition, the inner connection hole 6-6 and the outer connection hole 6-5 opened on the same side of the connection portion 6-2 need to be staggered by a certain distance and cannot overlap. Figure 3 As shown on the left, Figure 3 Only the inner connection hole 6-6 and the outer connection hole 6-5 on the left connection part 6-2 are shown. In actual use, the inner connection hole 6-6 and the outer connection hole 6-5 on the right connection part 6-2 can also be arranged in the same way.

[0070] The connection between the replaceable fluidic oscillator 6 and the replaceable insert plate 4 described above effectively balances stress on both sides of the oscillator array, preventing warping, gaps, and localized deformation, thereby maintaining the characteristics of the main flow. After installing the fastening bolts on one side of the main channel, filling the bolt holes with a filler such as sealant can prevent the flow field from being affected by localized gaps and deformation.

[0071] The above embodiments are intended only to illustrate the design concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The scope of protection of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design concepts disclosed in the present invention are within the scope of protection of the present invention.

Claims

1. An S-type flow channel flow control variable parameter testing system, characterized in that: include: curved section (1), A replaceable plug-in plate (4) is provided on the curved section (1), wherein the replaceable plug-in plate (4) is detachably mounted on the curved section (1); A mounting groove (5) is provided on the replaceable plug-in board (4) at the position to be tested; A replaceable fluid oscillator (6) is installed in the mounting groove (5), the replaceable fluid oscillator (6) is detachably connected to the mounting groove (5), and the jet outlet of the replaceable fluid oscillator (6) faces the internal flow channel of the curved section (1); Straight sections are provided at both ends of the curved section (1), and the straight sections are smoothly connected to the interior of the curved section (1); There are multiple replaceable plug-ins (4) at each position on the bending section (1), a portion of the replaceable plug-ins (4) does not have a mounting groove (5), and another portion of the replaceable plug-ins (4) has a mounting groove (5) at different positions. A single position to be tested or multiple test positions are set in the curved section (1).

2. The S-type flow channel flow control variable parameter testing system according to claim 1, characterized in that: The replaceable fluid oscillator (6) comprises a connecting portion (6-2) and an upper convex portion (6-1) on the upper portion of the connecting portion (6-2), wherein the upper convex portion (6-1) is a convex block with a slope; The jet outlet (6-4) of the oscillator array in the replaceable fluid oscillator (6) is arranged on the upper surface of the upper convex part (6-1).

3. The S-type flow channel flow control variable parameter testing system according to claim 2, characterized in that: The installation groove (5) is a groove with a slope that matches the upper convex portion (6-1), and the upper convex portion (6-1) is buckled and connected to the installation groove (5); The connecting portion (6-2) and the replaceable plug-in plate (4) are detachably connected via a connecting piece.

4. The S-type flow channel flow control variable parameter testing system according to claim 2, characterized in that: The adjacent replaceable plug plates (4) and the replaceable plug plates (4) and the adjacent straight sections are designed to be in a step-like shape that fits with each other and are detachably connected using a connecting piece.

5. The S-type flow channel flow control variable parameter testing system according to claim 2, characterized in that: An oscillator array is provided in the replaceable fluid oscillator (6), and an angle α is formed between the jet injection direction of the oscillator array and the internal flow channel, and the value range of α is 15° to 90°.

6. The S-type flow channel flow control variable parameter testing system according to claim 2 or 5, characterized in that: The positions of the jet outlets (6-4) of the oscillator arrays with different jet angles are the same.

7. The S-shaped flow channel flow control variable parameter testing system according to claim 5, characterized in that: The oscillator array adopts a relaxation type oscillator, a sonic wave type oscillator, a Coanda sweep type oscillator or a jet coupling type oscillator.

8. The S-shaped flow channel flow control variable parameter testing system according to claim 5, characterized in that The replaceable fluid oscillator (6) is composed of an oscillator mounting side (7) and a cover plate (8); an oscillator array is provided on the oscillator mounting side (7); and the oscillator mounting side (7) and the cover plate (8) are fixedly connected.

9. The S-shaped flow channel flow control variable parameter testing system according to claim 7, characterized in that: The replaceable fluid oscillator (6) is formed by CNC precision machining, integrated 3D printing, or other forming methods.

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