A phase-adjustable combined jet oscillator

Abstract

The present invention discloses a combined jet oscillator with adjustable phase, which includes two jet oscillators, upper and lower ones, sharing a common feedback channel; the flow space structure of the common feedback channel is variable, and by changing the flow space structure of the common feedback channel, the deflection directions of the jets in the upper and lower jet oscillators are controlled. The present invention can, by adjusting different states of the elastic wall surface, divide an incident main flow into two jets with the same or opposite deflection directions in the upper and lower oscillation cavities through the combined jet oscillator, and simultaneously generate sweeping jets with the same or opposite swinging directions at the two outlets, meeting the requirements for specific jets in fields such as fluid control.

Description

Technical Field

[0001] The present invention relates to a combined jet oscillator with adjustable phase. When the two elastic walls do not protrude, the deflection directions of the main jets in the two oscillation chambers are the same, and at the same time, sweeping jets with the same swinging direction are generated at the two outlets. When the two elastic walls protrude, the deflection directions of the main jets in the two oscillation chambers can be made opposite, and at the same time, sweeping jets with opposite swinging directions are generated at the two outlets. Background Art

[0002] A jet oscillator is a fluid component that can generate a spatially oscillating jet without any moving parts. Its oscillation effect is self-induced by its special spatial configuration, and only a stable pressure supply at the inlet end is required to generate a continuous and stable sweeping jet. In recent years, many scholars have found that jet oscillators have great potential in noise, combustion, flow separation, and drag control. There are many forms of fluid oscillators, which can be classified into wall attachment type, jet action type, cavity resonance type, etc. according to different characteristics of their internal structures. The working principle of the wall attachment type fluid oscillator can be basically summarized as follows: after the jet enters the oscillation chamber, it adheres to one side wall due to the Coanda effect. When the jet is completely attached, part of the fluid enters the feedback channel and interacts with the main flow at the inlet of the oscillation chamber, forcing the main flow to deflect to the other side. This cycle repeats, and a sweeping jet is formed at the outlet. The present invention is a wall attachment type jet oscillator with a combined structure.

[0003] Due to its simple structure, wide operable frequency range, and self-excitation and self-sustaining characteristics, it has been applied in many engineering and technical fields. For example, jet oscillators are often used in fluid vibration flowmeters. Such fluid vibration flowmeters utilize the law that the fluid vibration frequency in the jet oscillator is only related to the flow velocity to measure the fluid flow rate. Jet oscillators can also be used in gas wave refrigerators. The pulsed jet of the jet oscillator is output to the receiving tube, and a shock wave is generated in the tube, causing the gas pressure and temperature in the tube to rise. The high-temperature gas transfers heat through the fins, causing the temperature of the jet itself to drop significantly, achieving a refrigeration effect. Flow active control based on fluid oscillators or sweeping jet actuators is a new type of flow control method currently attracting attention. For example, using the sweeping jet or unsteady pulsed jet generated by the jet oscillator to disrupt the boundary layer, causing the main flow to transition earlier, can achieve the effect of controlling separation. In the field of aerospace science and technology, jet oscillators have broad application prospects in flow drag reduction, wing lift improvement, jet enhanced mixing, and nozzle vector control.

[0004] The first patent on jet oscillators was "Negative Feedback Oscillator" published by Warren in 1962. Since jet oscillators have good compatibility with many fields, patents on jet oscillators have emerged one after another since then. The present invention designs a combined jet oscillator with adjustable phase. When the elastic wall does not extend, the main jets in the two oscillation cavities have the same deflection direction, and sweeping jets with the same swinging direction are generated at the two outlets. When the elastic wall extends, the main jets in the two oscillation cavities can be deflected in opposite directions, and sweeping jets with opposite swinging directions are generated at the two outlets. Summary of the invention

[0005] The present invention designs a phase-adjustable combined jet oscillator. By controlling the expansion and contraction of the elastic wall through an actuating mechanism, an incident main stream can be formed into two sweeping jets with the same or opposite swinging directions through the combined jet oscillator.

[0006] like Figure 1 and Figure 2 As shown in the figure, two wall-attached jet oscillators share a common feedback channel, and elastic walls and actuating mechanisms are respectively arranged at both ends of the common feedback channel. The entire jet oscillator is symmetrically distributed along the central axis, and high-pressure fluid flows into the oscillation cavity from the inlet section of the oscillator. Under the action of the Coanda effect, the fluid flows along the wall surface, and after the action of the special internal structure, two sweeping jets with the same or opposite swinging directions are finally formed at the outlet. Figure 3 and Figure 4 This is a schematic diagram of the position of the actuating mechanism when the elastic wall does not extend. Figure 5 and Figure 6 Schematic diagram of the position of the actuating mechanism when the elastic wall extends.

[0007] Grooves and sliding lock blocks are respectively arranged on the bottom plates of the two jet oscillation cavities, and the actuating mechanism is a rectangular baffle that can slide along the grooves, and the initial positions of the two rectangular baffles are respectively located at the two ends of the common feedback channel; when working, the actuating mechanism pushes the elastic wall surface to move toward the inside of the common feedback channel under the action of external force, and after reaching the designed position, the sliding lock block moves downward to press against the end of the rectangular baffle to prevent the elastic wall surface from rebounding it to the initial position.

[0008] The elastic wall is bonded to the rigid wall by strong glue. The elastic wall can be made of thermoplastic elastomer (TPE) with high elasticity, high strength and good temperature resistance, such as ethylene propylene diene rubber (EPDM), polyurethane elastomer rubber (TPU), polyolefin thermoplastic elastomer (TPO), etc.

[0009] The technical solution adopted by the present invention to solve the technical problem is: Figure 1As shown, two wall-attached jet oscillators share a common feedback channel. As the elastic wall expands and contracts, the feedback fluid can flow through the common feedback channels with different spatial structures and interact with the main jet, so as to achieve the effect that the deflection directions of the two incident mainstream jets in the oscillation cavity are the same or opposite.

[0010] For the convenience of explanation, Figure 7 、 Figure 8 The paths of the fluid flowing along different attached walls when the elastic wall does not extend during the operation of the oscillator are respectively given; Figure 9 、 Figure 10 The paths of the fluid flowing along different attached walls when the elastic wall extends during the operation of the oscillator are respectively given; the direction of the arrow represents the flow direction of the fluid. When the elastic wall does not extend, the special structure inside the combined oscillator can make the jet deflection directions in the two oscillation cavities the same, and a swept jet with the same frequency and the same deflection direction is formed at the oscillator outlet. When the elastic wall extends, since the extended wall changes the flow space structure of the common feedback channel, the jet deflection directions in the two oscillation cavities are opposite, so a swept jet with the same frequency and opposite deflection directions is formed at the oscillator outlet.

[0011] The beneficial effects of the present invention are: by adjusting different states of the elastic wall, a main incident flow can be divided into two jets with the same or opposite deflection directions in the upper and lower oscillation cavities by the combined jet oscillator, and at the same time, swept jets with the same or opposite swinging directions are generated at the two outlets, meeting the requirements for specific jets in the fields of fluid control and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used for further understanding of the present invention and form a part of this application. The schematic examples of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the attached

[0013] In the drawings:

[0014] Figure 1 、 2 are the three-dimensional structure schematic diagrams of the combined jet oscillator.

[0015] Figure 3 、 4 are the schematic diagrams of the positions of the front and rear actuating mechanisms when the elastic wall does not extend.

[0016] Figure 5 、 6 are the schematic diagrams of the positions of the front and rear actuating mechanisms when the elastic wall extends.

[0017] Figure 7 、 8 are the schematic diagrams of the fluid flow paths ① and ② when the elastic wall does not extend.

[0018] Figure 9 、 10 are schematic diagrams of the fluid flow paths ① and ② when the elastic wall surfaces extend.

[0019] Among them, the reference numerals with the same number in all the above-mentioned drawings have the same meaning:

[0020] 1. Upper oscillator inlet section; 2. Lower oscillator inlet section; 3. Upper oscillation cavity; 4. Lower oscillation cavity; 5. Upper feedback channel; 6. Lower feedback channel; 7. Upper oscillator outlet; 8. Lower oscillator outlet; 9. Attachment wall surface one; 10. Attachment wall surface two; 11. Attachment wall surface three; 12. Attachment wall surface four; 13. Common feedback channel; 14. Front elastic wall surface; 15. Rear elastic wall surface; 16. Front actuating mechanism; 17. Rear actuating mechanism; 18. Front sliding lock block; 19. Rear sliding lock block. Detailed implementation mode

[0021] As Figure 1 and Figure 2 shown, the entire combined jet oscillator is composed of an upper oscillator inlet section 1, a lower oscillator inlet section 2, an upper oscillation cavity 3, a lower oscillation cavity 4, an upper feedback channel 5, a lower feedback channel 6, an upper oscillator outlet 7, a lower oscillator outlet 8, an attachment wall surface one 9, an attachment wall surface two 10, an attachment wall surface three 11, an attachment wall surface four 12, a common feedback channel 13, a front elastic wall surface 14, a rear elastic wall surface 15, a front actuating mechanism 16, a rear actuating mechanism 17, a front sliding lock block 18, and a rear sliding lock block 19. The specific features between each structure are:

[0022] In Figure 1 , the upper oscillator inlet section 1 and the lower oscillator inlet section 2 are converging nozzles. The upper oscillation cavity 3 and the lower oscillation cavity 4 are diverging cavities. Each turning point of the upper feedback channel 5 and the lower feedback channel 6 is rounded to reduce the fluid flow loss of the feedback. The upper oscillator outlet 7 and the lower oscillator outlet 8 communicate with the outside atmosphere. The attachment wall surface one 9, the attachment wall surface two 10, the attachment wall surface three 11, and the attachment wall surface four 12 are all concave curved surfaces with a certain curvature, enabling the attached fluid to smoothly transition to the outlet and forming a certain deflection angle at the same time to ensure that most of the fluid can flow out smoothly from the upper oscillator outlet 7 and the lower oscillator outlet 8. The front elastic wall surface 14 and the rear elastic wall surface 15 controlled by the front actuating mechanism 16 and the rear actuating mechanism 17 at both ends of the common feedback channel 13 are the key structures of the present invention. During the operation of the oscillator, it does not extend ( Figure 1 ) or extends ( Figure 2 ) into the common feedback channel 13 as needed. When the elastic wall surface does not extend, the deflection directions of the main jets in the two oscillation cavities are the same, while when the elastic wall surface extends, the deflection directions of the main jets in the two oscillation cavities can be opposite. Figure 3 and Figure 4The schematic diagram of the actuator position when the elastic wall does not extend is given. At this time, the front actuator 16, the rear actuator 17, the front sliding lock block 18 and the rear sliding lock block 19 are all in their initial positions. Figure 5 and Figure 6 The schematic diagram of the actuator position when the elastic wall extends is given. At this time, the front actuator 16 and the rear actuator 17 push the front elastic wall 14 and the rear elastic wall 15 into the common feedback channel. The front sliding lock block 18 and the rear sliding lock block 19 move down to fix the actuator position and prevent the actuator from being bounced back to the initial position by the elastic wall.

[0023] Both ends of the front elastic wall 14 are fixed on the rigid wall of the inlet section of the upper and lower oscillators, and both ends of the rear elastic wall 15 are fixed on the rigid wall of the outlet section of the upper and lower oscillators. When the actuator pushes the elastic wall into the common feedback channel, it cannot block the common feedback channel. The distance that the elastic wall extends into the common feedback channel can be determined through experiments according to the oscillator size, flow rate, etc.

[0024] For the convenience of explanation, Figure 7 and Figure 8 respectively give the schematic diagrams of the fluid flow paths along different attached walls when the elastic wall does not extend during the operation of the oscillator; Figure 9 and Figure 10 respectively give the schematic diagrams of the fluid flow paths along different attached walls when the elastic wall extends during the operation of the oscillator; the direction of the arrow represents the fluid flow direction. The following is a specific description of the entire operation process of the oscillator:

[0025] When the elastic wall does not extend, the working process of the combined oscillator in a complete oscillation cycle is as follows: The air flow enters from the upper oscillator inlet section 1 and the lower oscillator inlet section 2, passes through the upper oscillation cavity 3 and the lower oscillation cavity 4, and the fluid adheres to the wall according to the Coanda effect. When the main jet fluid in the upper oscillation cavity 3 flows along the attachment wall surface two 10, most of the fluid flows out from the upper oscillator outlet 7, and a small amount of fluid flows into the lower oscillation cavity 4 and interacts with the fluid in the cavity, forming a counterclockwise vortex ring, causing the main jet in the lower oscillation cavity 4 to deflect and attach to the attachment wall surface four 12. At this time, the two incident jets of the oscillator respectively adhere to the attachment wall surface two 10 and the attachment wall surface three 11, and the jet deflection directions are the same. When the main jet in the lower oscillation cavity 4 is completely attached to the attachment wall surface four 12, most of the fluid flows out from the lower oscillator outlet 8, and a small amount of fluid flows through the lower feedback channel 6 into the lower oscillation cavity 4 and acts on the jet flowing into the lower oscillator inlet section 2, causing it to deflect and attach to the attachment wall surface three 11. When the main jet in the lower oscillation cavity 4 flows along the attachment wall surface three 11, a small amount of fluid flows into the upper oscillation cavity 3 and interacts with the fluid in the cavity, forming a clockwise vortex ring, causing the main jet in the upper oscillation cavity 3 to deflect and attach to the attachment wall surface one 9. At this time, the two incident jets of the oscillator respectively adhere to the attachment wall surface one 9 and the attachment wall surface three 11, and the jet deflection directions are still the same. When the jet is completely attached to the attachment wall surface one 9, a small amount of fluid flows through the upper feedback channel 5 into the upper oscillation cavity 3 and acts on the jet flowing into the upper oscillator inlet section 1, causing it to deflect and attach to the attachment wall surface two 10. Thus, a complete oscillation cycle of the combined oscillator is established. This cycle repeats continuously, forming two swept jets with the same deflection direction and a certain frequency, flowing out from the upper oscillator outlet 7 and the lower oscillator outlet 8 respectively.

[0026] When the elastic wall extends, the working process of the combined oscillator in a complete oscillation cycle is: the airflow enters from the upper oscillator inlet section 1 and the lower oscillator inlet section 2, passes through the upper oscillating cavity 3 and the lower oscillating cavity 4, and flows along the wall according to the Coanda effect. When the main jet in the upper oscillating cavity 3 flows along the wall surface 10, most of the fluid flows out from the upper oscillator outlet 7, and a small amount of fluid flows in the opposite direction along the common feedback channel 13 due to the guiding effect of the rear elastic wall 15. When the feedback fluid flows to the front elastic wall 14, the feedback fluid is divided into two streams, which flow into the upper oscillating cavity 3 and the lower oscillating cavity 4 respectively and react with the main jet flowing into the upper oscillator inlet section 1 and the lower oscillator inlet section 2, so that the main jet in the upper oscillating cavity 3 is deflected to attach to the wall surface 19, and the main jet in the lower oscillating cavity 4 is deflected to attach to the wall surface 12. At this time, the two incident flows of the oscillator are attached to the wall surface 19 and the wall surface 12 respectively, and the jet deflection directions are opposite. When the main jets in the upper oscillation chamber 3 and the lower oscillation chamber 4 are attached to the wall surface 1 9 and the wall surface 4 12 respectively, most of the fluids flow out from the upper oscillator outlet 7 and the lower oscillator outlet 8 respectively, and the outlet fluids are deflected in opposite directions. A small amount of fluid flows in the upper oscillation chamber 3 and the lower oscillation chamber 4 in the reverse direction through the upper feedback channel 5 and the lower feedback channel 6 and acts on the jets flowing into the upper oscillator inlet section 1 and the lower oscillator inlet section 2, so that the main jet in the upper oscillation chamber 3 is deflected to attach to the wall surface 2 10, and the main jet in the lower oscillation chamber 4 is deflected to attach to the wall surface 3 11, and the main jets in the two oscillation chambers are deflected in opposite directions. At this point, a complete oscillation cycle of the combined oscillator is established when the elastic wall extends. This cycle is repeated over and over again, forming two sweeping jets with opposite deflection directions and a certain frequency that flow out from the upper oscillator outlet 7 and the lower oscillator outlet 8 respectively.

[0027] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A combined jet oscillator with adjustable phase, characterized in that: It comprises two upper and lower jet oscillators, which share a common feedback channel; the flow space structure of the common feedback channel is variable, and the direction of jet deflection in the upper and lower jet oscillators can be controlled by changing the flow space structure of the common feedback channel; Elastic walls and actuating mechanisms are respectively arranged at the upper and lower ends of the common feedback channel, the two ends of the elastic wall are fixed to the rigid wall on the jet oscillator, and the actuating mechanism can control the expansion and contraction of the elastic wall; when the elastic wall does not extend into the common feedback channel, the jet deflection directions in the two jet oscillation cavities are consistent, and when the two elastic walls extend into the common feedback channel respectively under the action of the actuating mechanism, the jet deflection directions in the two jet oscillation cavities are opposite.

2. The combined jet oscillator with adjustable phase according to claim 1, characterized in that: Grooves and sliding lock blocks are respectively arranged on the bottom plates of the two jet oscillation cavities, and the actuating mechanism is a rectangular baffle that can slide along the grooves, and the initial positions of the two rectangular baffles are respectively located at the two ends of the common feedback channel; when working, the actuating mechanism pushes the elastic wall surface to move toward the inside of the common feedback channel under the action of external force, and after reaching the designed position, the sliding lock block moves downward to press against the end of the rectangular baffle to prevent the elastic wall surface from rebounding it to the initial position.

3. The combined jet oscillator with adjustable phase according to claim 1, characterized in that: The inlet sections of the upper and lower jet oscillators are both convergent nozzles.

4. The combined jet oscillator with adjustable phase according to claim 1, characterized in that: Both the upper and lower jet oscillators are gradually expanding cavities.

5. A combined jet oscillator with adjustable phase according to claim 1, characterized in that: Each turn of the feedback channels of the upper and lower jet oscillators is rounded to reduce the flow loss of the feedback fluid.

6. A combined jet oscillator with adjustable phase according to claim 1, characterized in that: The wall surfaces of the upper and lower jet oscillators are both concave surfaces with curvature, so that the wall-attached fluid can smoothly transition to the outlet and form a deflection angle to ensure that most of the fluid can smoothly flow out of the jet oscillator outlet.

7. A combined jet oscillator with adjustable phase according to claim 1, characterized in that: The material of the elastic wall is EPDM rubber, polyurethane elastomer rubber or polyolefin thermoplastic elastomer.

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