A fluid oscillator with a single feedback channel

Abstract

The present invention provides a single feedback channel fluid oscillator, whose oscillation cavity includes a reaction chamber, a first channel and a nozzle, the reaction chamber is suitable for forming vortices on both sides of the main fluid, and the control pipe has gas, so that the low-pressure wave generated when the jet is attached to one side can be transmitted to the control port on the other side. The difference between this design and the traditional straight jet nozzle is that two control ports are set at the connection between the contraction section and the reaction chamber, so that the low-pressure wave generated when the jet is attached to one side can be transmitted to the control port on the other side, and finally generate a driving force to flip the jet. The oscillation frequency of the oscillator is much higher than that of the dual feedback channel oscillator.

Description

Technical Field

[0001] The invention belongs to the technical field of active flow control, and in particular relates to a fluid oscillator with a single feedback channel. Background Art

[0002] A fluid oscillator is a device that can produce a continuously oscillating jet at the outlet without the need for mechanical moving parts. Its basic principle is: when a fluid of a certain pressure enters the mixing chamber of the fluid oscillator from the inlet, due to the Coanda effect, the mainstream will inevitably adhere to the wall on one side, and then be divided into two parts along the wall. One part goes out from the throat to become an external jet, and the other part flows back to the root of the mainstream along the feedback channel, causing the mainstream to flip and attach to the wall on the other side. At this time, the external jet will flip to the other side at the same time to produce an oscillating effect, and at the same time, the remaining mainstream enters the feedback channel on this side, flows back to the root of the mainstream, and causes the mainstream to flip again. This cycle repeats, forming a continuous oscillation effect.

[0003] However, conventional fluid oscillators have the following disadvantages: the oscillation frequency of the dual-feedback channel oscillator is inversely proportional to the volume of the feedback pipe and the reaction chamber, so the oscillation frequency cannot be too high due to this limitation. In the field of flow control and mixing enhancement, high-frequency excitation can produce better results. Summary of the invention

[0004] In order to solve at least one of the above technical problems, the present invention provides a fluid oscillator with a single feedback channel to achieve the effect of generating high-frequency oscillation without increasing the flow rate. The purpose of the present invention is achieved through the following scheme:

[0005] A fluid oscillator with a single feedback channel comprises an oscillator body and an inlet pipe, wherein the oscillator body contains an oscillation cavity; the inlet pipe is connected to the oscillator body and is suitable for inputting fluid into the oscillation cavity; the oscillation cavity comprises a reaction chamber, a first channel and a nozzle, and the fluid passes through the first channel, the reaction chamber and the nozzle in sequence; a low-pressure portion is provided at the end of the first channel, and a first control port and a second control port are provided in opposite positions along the radial direction of the low-pressure portion, the first control port and the second control port are connected through a control pipe, the reaction chamber is suitable for forming vortices on both sides of the main fluid, and there is gas in the control pipe, so that the low-pressure wave generated when the jet adheres to one side can be transmitted to the control port on the other side.

[0006] Furthermore, the reaction chamber includes a first reaction chamber and a second reaction chamber; the first reaction chamber and the second reaction chamber are unequal in size, and the fluid passes through the first channel, the second reaction chamber, the first reaction chamber and the nozzle in sequence.

[0007] Furthermore, in the width direction of the oscillator body, both the first reaction chamber and the second reaction chamber have arc-shaped wall surfaces.

[0008] Furthermore, the oscillation cavity further comprises a contraction tube, a smaller port of the contraction tube is connected to the first channel, and a larger port of the contraction tube is connected to an inlet pipe.

[0009] Furthermore, the nozzle is an expansion port, and a cross section of the nozzle connected to the outside is larger than a cross section of the nozzle connected to the first reaction chamber.

[0010] Furthermore, a throat is formed at a connection between the nozzle and the reaction chamber.

[0011] Furthermore, a first control interface is provided at the end of the first control port, and a second control interface is provided at the end of the second control port, and the first control interface and the second control interface are connected via a PU tube.

[0012] Furthermore, the cross-section of the end of the first control port connected to the low-pressure part is smaller than the cross-section of the end connected to the first control interface; the cross-section of the end of the second control port connected to the low-pressure part is smaller than the cross-section of the end connected to the second control interface.

[0013] Furthermore, it also includes a second channel connected to the larger end of the shrink tube, the second channel has a uniform cross section perpendicular to the axis of the second channel, and the second channel is connected to the inlet pipe.

[0014] Furthermore, the oscillator body is provided with a fixing hole.

[0015] Compared with the prior art, the advantages of the present invention are: the present invention provides a single feedback channel fluid oscillator, whose oscillation cavity includes a reaction chamber, a first channel and a nozzle, the reaction chamber is suitable for forming vortices on both sides of the main fluid, and the control pipe has gas, so that the low-pressure wave generated when the jet is attached to one side can be transmitted to the control port on the other side. The difference between this design and the traditional straight jet nozzle is that two control ports are set at the connection between the contraction section and the reaction chamber, so that the low-pressure wave generated when the jet is attached to one side can be transmitted to the control port on the other side, and finally generate a driving force to flip the jet. The oscillation frequency of the oscillator is much higher than that of the dual feedback channel oscillator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0017] Figure 1It is an overall schematic diagram of the fluid oscillator with a single feedback channel of the present invention;

[0018] Figure 2 yes Figure 1 Front view of the fluid oscillator;

[0019] Figure 3 yes Figure 2 Section view in the AA direction;

[0020] Figure 4 yes Figure 1 Schematic diagram of the first phase of the fluid oscillator;

[0021] Figure 5 yes Figure 1 Schematic diagram of the second phase of the fluid oscillator;

[0022] Figure 6 is a dual feedback channel oscillator and Figure 1 Comparison of frequency spectrum distribution of fluid oscillators;

[0023] Figure 7 is a dual feedback channel oscillator and Figure 1 Comparison of the main frequencies of the fluid oscillators;

[0024] Figure 8 It is a schematic diagram of a dual feedback channel oscillator.

[0025] 1. Oscillator body; 2. Oscillation cavity; 21. Nozzle; 22. First reaction chamber; 23. Second reaction chamber; 24. First control port; 25. Second control port; 26. Low-pressure part; 27. First channel; 28. Contraction tube; 29. ​​Second channel; 3. Inlet pipe; 4. First control interface; 5. Second control interface; 6. Fixing hole; 100. Main fluid; 101. First vortex; 102. Second vortex; 103. Third vortex; 104. Fourth vortex; 201. First low-pressure wave; 202. Second low-pressure wave. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and implementations. It is to be understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present invention. It is also necessary to explain that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] See the instruction manual Figure 1The fluid oscillator with a single feedback channel includes an oscillator body 1, an oscillation cavity 2, an inlet pipe 3, a first control interface 4, a second control interface 5 and a fixing hole 6.

[0029] The oscillator body 1 is used to set the oscillation cavity 2, and can be fixedly connected to an external structure through a fixing hole 6 set on its upper part. An inlet pipe 3 is set at one end of the oscillator body 1 to introduce fluid into the oscillation cavity 2, and a fluid outlet can be set at the other end of the oscillator body 1.

[0030] Since the oscillator body 1 mainly plays the role of bearing the oscillation cavity and fixing, its appearance does not affect its functional implementation. However, since the purpose of the oscillator is to deflect the mainstream between the first phase and the second phase to form an umbrella-shaped jet, the width of the umbrella can be set according to the direction of the umbrella expansion, and the height of the oscillator body 1 can be set smaller according to the flat characteristics of the umbrella-shaped jet. As a result, the oscillator body 1 saves materials, reduces the occupied space and has a lighter weight. As a result, the oscillator body 1 is in the shape of a flat plate.

[0031] The inlet pipe 3 is connected to the oscillating body. Since the high-pressure liquid delivery pipe is generally a regular-shaped pipe, the inlet pipe 3 and the end of the high-pressure liquid delivery pipe are pipes with a circular cross-section. The oscillator has a flat plate-like structure, resulting in the oscillation cavity 2 set inside it also presenting a small gap (attached) spread along the length and width of the oscillator body 1. Figure 2 ). The inlet pipe 3 is connected to the oscillation cavity 2 inside the oscillation body, and its input cavity needs to be smoothly connected to the oscillation cavity 2, so the thickness of the connection end of the inlet pipe 3 and the oscillation body gradually shrinks to be consistent with the thickness of the oscillator body 1.

[0032] The present invention is attached Figure 1 The example shows one of the position schemes of the fixing holes 6 and the oscillator body 1, and there are two fixing holes 6, which are symmetrically distributed on both sides of the oscillator body 1, so that when the oscillator body 1 is fixed, the force is parallel. It is worth noting that this scheme is only an exemplary scheme, and the scheme that can avoid the internal oscillation cavity of the oscillator body 1 and make the oscillator body 1 stably fixed should be within the scope of the disclosure of the present invention.

[0033] The first control interface 4 and the second control interface 5 are erected on both sides of the flat oscillator body 1. The inner diameter of the first control interface 4 and the second control interface 5 is set according to the size of the low-pressure wave to be absorbed, and the inner diameter is 6mm-7mm. Preferably, the inner diameter is 6.5mm.

[0034] See attached Figure 2The surface of the oscillator body 1 corresponding to the oscillation cavity 2 has a raised profile, and the raised profile corresponds to the oscillation cavity 2 . The raised profile can ensure that the oscillation cavity 2 also has sufficient wall thickness.

[0035] Along the attached Figure 2 The AA section is attached Figure 3 The oscillation cavity 2 includes a nozzle 21, a reaction chamber, a first control port 24, a second control port 25, a first channel 27, a contraction tube 28 and a second channel 29. The reaction chamber is further divided into a first reaction chamber 22 and a second reaction chamber 23.

[0036] Specifically, the fluid needs to pass through the first channel 27 and the reaction chamber in sequence, and form an umbrella-shaped jet from the nozzle 21. The present invention is provided with a low-pressure portion 26 at the outlet of the first channel 27, and the low-pressure portion 26 is provided with a first control port 24 and a second control port 25 that are opposite to each other in the radial direction. It is worth noting that when the low-pressure portion 26 is cylindrical, the radial direction refers to a diameter direction, and when the low-pressure portion 26 is flat, the radial direction refers to a direction perpendicular to the first channel 27.

[0037] The reaction chamber has a larger longitudinal cross-section (from the side) than the first channel 27. Figure 2 ), and both sides of the reaction chamber have non-smoothly transitioned surfaces, so that when a high-speed fluid passes through the reaction chamber, the fluid at the edge is affected by the protrusions of the non-smoothly transitioned surface to form a vortex.

[0038] The reaction chamber presents a symmetrical shape. When the fluid passes through the reaction chamber, Figure 4-5 , the main fluid 100 can be ejected directly through the nozzle 21, and the vortex can be formed on both sides of the main fluid 100. The generation of the vortex can accelerate the flow rate of the fluid near the vortex, thereby forming a low-pressure area. The vortices on the left and right sides are not equal, so the mainstream can flow along one side. Since the mainstream flows at a high speed, the flow speed on the other side that is not attached to the mainstream is relatively slow, and the mainstream forms a low pressure at the control port. There is gas in the control pipe, so that the low-pressure wave generated when the jet is attached to one side can be transmitted to the control port on the other side. When the low-pressure wave accumulates to a certain extent, it causes the main fluid to deflect again and attach to the wall on the other side to achieve the deflection of the main body. The oscillation frequency of the oscillator using the present invention will be much higher than that of the dual feedback channel oscillator.

[0039] It is worth noting that only two vortices can be generated in the reaction chamber, and the two vortices are distributed on both sides of the main fluid. However, the structural design of generating two vortices can better meet the requirements of high-frequency oscillation.

[0040] At the same time, six vortices can also be set in the reaction chamber, and three vortices are distributed on each side of the main fluid. However, when three vortices are generated, the oscillation of the main fluid will show irregularity. Therefore, the preferred technical solution is to set two vortices on each side of the main fluid, so that the high-frequency oscillation requirements of the fluid oscillator can be met, and the control requirements can also be met at the same time.

[0041] See attached Figure 3-5 , the reaction chamber of the present invention includes a first reaction chamber 22 and a second reaction chamber 23; the first reaction chamber 22 and the second reaction chamber 23 are not equal in size, and the fluid passes through the first channel 27, the second reaction chamber 23, the first reaction chamber 22 and the nozzle 21 in sequence. In the width direction of the oscillator body 1, the first reaction chamber 22 and the second reaction chamber 23 both have arc-shaped walls. Specifically, the arc-shaped wall of the first reaction chamber 22 and the arc-shaped wall of the second reaction chamber 23 are connected in a discontinuous manner (the connection point cannot be differentiated). Thus, a cavity capable of accommodating the first vortex 101 and the second vortex 102 is formed on one side of the main fluid 100, and a cavity capable of accommodating the third vortex 103 and the fourth vortex 104 is formed on the other side.

[0042] In the portion where the second vortex 102 and the fourth vortex 104 are in contact with the main fluid 100 , the liquid flow direction is the same as that of the main fluid 100 .

[0043] In the parts where the first vortex 101 and the fourth vortex 104 are in contact with the main fluid 100 , the liquid flow direction is the same as that of the main fluid 100 .

[0044] The rotation speeds of the first vortex 101 and the second vortex 102 and the third vortex 103 and the fourth vortex 104 are difficult to be consistent, which inevitably causes the main fluid 100 to sway. Figure 4 In the embodiment, when the third vortex 103 and the fourth vortex 104 are in a dominant position, the main fluid is brought close to the wall of the first control port. In this process, the vortices on both sides of the first control port are accelerated because they are close to the mainstream, and the two vortices on the other side are connected at the boundaries of the two vortices because the mainstream gives up some space, that is, the two vortices are partially merged. Therefore, the suction force on both sides of the first control port is further strengthened, the main fluid flows closely to the first control port, and transmits the first low-pressure wave through the first control port.

[0045] As described above, the generated first low-pressure wave causes the pressure at the second control port to decrease, and the attraction is greater than the vortex on the first control port side. The main fluid gradually approaches the wall of the second control port, causing the vortex on the second control port side to strengthen, while the vortex on the first control port side merges and slows down. When the main fluid flows close to the second control port, the high-speed flowing fluid will generate a second low-pressure wave.

[0046] In order to generate a jet with sufficient velocity, the present invention provides a contraction tube 28 , wherein a smaller port of the contraction tube 28 is connected to the first channel 27 , and a larger port of the contraction tube 28 is connected to the inlet pipe 3 .

[0047] Furthermore, the second channel 29 connected to the larger end of the shrink tube 28 has a uniform cross section perpendicular to the axis of the second channel 29, and the second channel 29 is connected to the inlet pipe 3. Thus, the fluid can be instantly accelerated at the control port to obtain a higher speed.

[0048] In order to further expand the range of the jet, the nozzle 21 is connected to the reaction chamber to form a throat, and the nozzle 21 is an expansion port, and the cross section of the nozzle 1 connected to the outside is larger than the cross section connected to the first reaction chamber. The outlet of the trumpet-shaped nozzle 21 can utilize the wall effect (Coanda effect) of the jet to further enhance the oscillation range of the jet.

[0049] See attached Figure 1 And attached Figure 4 The first control port 24 is provided with a first control interface 4 at the end, and the second control port 25 is provided with a second control interface 5 at the end. The first control interface 4 and the second control interface 5 are connected through a PU tube. The cross section of the end of the first control port 24 connected to the first channel 27 is smaller than the cross section of the end connected to the first control interface 4; the cross section of the end of the second control port 25 connected to the first channel 27 is smaller than the cross section of the end connected to the second control interface 5. See Appendix Figure 6 , which is the oscillation frequency cloud diagram result measured by the hot wire experiment, where (a) represents the dual feedback channel oscillator ( Figure 8 (a) shows the measurement results of the oscillator shown in the figure, and (b) shows the measurement results of the new oscillator. It can be seen that for both, the oscillation frequency increases with the increase of flow rate. In addition, since the dual-feedback channel oscillator captures the fundamental frequency and multiple harmonics at the same time, its oscillation waveform is closer to a square wave. Since the new oscillator only captures one fundamental frequency (although the frequency band is wider), the oscillation waveform is more similar to a sine wave. The difference in oscillation waveform makes the jet momentum of the new oscillator more uniform in space, making it more popular in the field of flow control and mixing enhancement.

[0050] See attached Figure 7 , which will be attached Figure 6 The main frequencies of (a) and (b) are plotted in a graph. It can be seen that the oscillation frequency of the new oscillator is approximately the same as that of the dual feedback channel oscillator ( Figure 8 ), thus realizing the original intention of developing a high-frequency oscillator.

[0051] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0053] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A fluid oscillator with a single feedback channel, comprising an oscillator body and an inlet pipe, wherein the oscillator body contains an oscillation cavity; the inlet pipe is connected to the oscillator body and is suitable for inputting fluid into the oscillation cavity; characterized in that: The oscillation cavity comprises a reaction chamber, a first channel and a nozzle, and the fluid passes through the first channel, the reaction chamber and the nozzle in sequence; a low-pressure portion is provided at the end of the first channel, and a first control port and a second control port are provided in opposite positions along the radial direction of the low-pressure portion, and the first control port and the second control port are connected through a control pipe, and the reaction chamber is suitable for forming vortices on both sides of the main fluid, and there is gas in the control pipe, so that the low-pressure wave generated when the jet adheres to one side can be transmitted to the control port on the other side; A first control interface is provided at the end of the first control port, a second control interface is provided at the end of the second control port, and the first control interface and the second control interface are connected via a PU tube; The cross section of the end portion of the first control port connected to the low pressure portion is smaller than the cross section of the end portion connected to the first control interface; the cross section of the end portion of the second control port connected to the low pressure portion is smaller than the cross section of the end portion connected to the second control interface; the reaction chamber includes a first reaction chamber and a second reaction chamber; In the width direction of the oscillator body, both the first reaction chamber and the second reaction chamber have arc-shaped wall surfaces; The oscillation cavity further comprises a contraction tube, wherein a smaller end of the contraction tube is connected to the first channel, and a larger end of the contraction tube is connected to an inlet pipe; A throat is formed at a connection between the nozzle and the reaction chamber.

2. A single feedback channel fluid oscillator as claimed in claim 1, characterized in that: The first reaction chamber and the second reaction chamber are of different sizes, and the fluid passes through the first channel, the second reaction chamber, the first reaction chamber and the nozzle in sequence.

3. A single feedback channel fluid oscillator as claimed in claim 1, characterized in that: The nozzle is an expansion port, and a cross section of the nozzle connected to the outside is larger than a cross section connected to the first reaction chamber.

4. A single feedback channel fluid oscillator as claimed in claim 1, characterized in that: The invention also comprises a second channel connected to the larger end of the shrink tube, wherein the second channel has a uniform cross section perpendicular to the axis of the second channel, and the second channel is connected to the inlet pipe.

5. A single feedback channel fluid oscillator as claimed in claim 1, characterized in that: The oscillator body is provided with a fixing hole.

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