A pneumatic seed metering system and method

Abstract

The present application relates to the technical field of agricultural seeding, in particular to a pneumatic seeding system and method. The seeding system comprises an inlet channel, a fluid oscillation mixer and a distributor, and the inlet channel is communicated with the distributor through the fluid oscillation mixer; the distributor comprises a flow distribution cover at the top, a bottom plate at the bottom, spring leaves movably connected to the bottom plate, an elastic arc plate below the flow distribution cover in an arc curve shape, an elastic cavity between the elastic arc plate and the flow distribution cover above the elastic arc plate, a gas flow chamber between the elastic arc plate and the bottom plate below the elastic arc plate, and a seeding port arranged along the circumferential side of the distributor and communicated with the gas flow chamber. The present application realizes sufficient mixing of crop seeds and gas, ensures uniformity and stability of the airflow, improves the seeding effect and guarantees the seeding quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of agricultural seed metering, in particular to a pneumatic seed metering system and method. BACKGROUND

[0002] Seed metering device is one of the core components of seeding machine. Its main function is to uniformly discharge seeds from seed tank according to certain quantity and interval. There are many types of seed metering devices, common ones include external groove wheel type seed metering device, internal groove wheel type seed metering device, pneumatic seed metering device, etc. Pneumatic seed metering device uses airflow to discharge seeds: after seeds fall into seed conveying pipe from seed cavity, airflow carries seeds to move, and then seeds are conveyed to seed metering port through pipe.

[0003] The defects of existing pneumatic seed metering device are: (1) during the process of high-pressure gas carrying crop seeds for discharge, the mixture of seeds and high-pressure gas is not sufficient, which affects the uniformity of crop seed planting; (2) in order to realize wide-width planting, the existing distributor cover plate is mostly flat-top type, the structure of flat-top distributor may affect the uniformity of airflow, especially when high-pressure airflow conveys seeds, if the top is designed too flat, it is easy to cause airflow to form vortex or local pressure unevenness inside the distributor. This will cause uneven distribution of seeds in the conveying process, and seeds accumulate at the bottom, the amount of seeds in the seed guiding part of each row is too much or too little, and even the phenomenon of missing planting occurs, which reduces the seed metering efficiency.

[0004] In summary, the airflow generated by the fan is not evenly distributed in the pipe, which leads to poor uniformity of seed distribution, resulting in differences between seed flow in different rows or within the row, thereby affecting the seed metering quality. SUMMARY

[0005] The present application aims to overcome the above-mentioned defects of the prior art, and provides a pneumatic seed metering system and method, which realizes sufficient mixing of crop seeds and gas, ensures the uniformity and stability of airflow, improves the seed metering effect, and ensures the seed metering quality.

[0006] The technical scheme of the present application is: a pneumatic seed metering system, comprising an inlet channel, wherein, further comprising a fluid oscillation seed mixer and a distributor, the fluid oscillation seed mixer realizes the communication between the inlet channel and the distributor; the distributor comprises:

[0007] a flow divider cover located at the top;

[0008] a bottom plate located at the bottom, the bottom plate is movably connected with a spring sheet;

[0009] an elastic arc plate located below the flow divider cover, in an arc curve shape, the elastic arc plate and the flow divider cover above it form an elastic cavity, and the elastic arc plate and the bottom plate below it form a gas flow chamber;

[0010] Seed discharge ports are arranged along the circumferential side of the distributor, and the seed discharge ports are communicated with the gas flow chamber.

[0011] In the application, the inlet channel is in the shape of an elbow pipe, and a seed distribution mechanism is arranged at the elbow pipe of the inlet channel.

[0012] A seed distribution plate is fixed to the inner wall of the elbow pipe of the inlet channel, and the inner cavity of the seed distribution plate is divided into an upper flow channel and a lower flow channel.

[0013] An elastic baffle is hinged to the side of the seed distribution plate facing the seed inlet of the inlet channel, and the elastic baffle is connected to the inner wall of the inlet channel through a spring.

[0014] The fluid oscillation seed mixer comprises:

[0015] A resonance cavity is communicated with the inlet channel through a seed inlet at the bottom of the resonance cavity, the size of the seed inlet is smaller than that of the inlet channel, and suction force is generated at the seed inlet of the resonance cavity.

[0016] A plurality of feedback channels are arranged on the annular outer side of the resonance cavity, the bottom end of the feedback channel is communicated with the seed inlet of the resonance cavity, the top end of the feedback channel is connected with the seed discharge port of the resonance cavity, and under the action of the suction force of the seed inlet of the resonance cavity, the gas in the resonance cavity can be sucked into the seed inlet of the resonance cavity again along the feedback channel.

[0017] An outlet channel is arranged at the seed discharge port of the resonance cavity, and the outlet channel is connected with the distributor through a gas flow channel.

[0018] The curve equation of the elastic arc plate is:

[0019]

[0020] The spring sheet is annular, a circular hole is arranged at the center of the spring sheet, a plurality of cylindrical rods are fixed to the annular inner wall of the circular hole in the radial direction, the cylindrical rods are arranged at intervals along the circumferential inner wall of the circular hole, a center hole is formed between the inner ends of the cylindrical rods, and the bottom end of the elastic arc plate is inserted into the center hole.

[0021] An annular groove is fixed to the bottom plate, the opening of the groove faces the spring sheet, and the annular outer ring of the spring sheet is movably arranged in the groove.

[0022] The depth of the groove is greater than the thickness of the spring sheet.

[0023] The application also discloses a seed distribution method using the above-mentioned pneumatic seed distribution system, which comprises the following steps:

[0024] S1, after the crop seeds are mixed with high-pressure gas, the high-pressure gas carrying the seeds is divided at the inlet channel, and the seeds are dispersed correspondingly;

[0025] S2, the dispersed seeds and the separated gas converge at the seed inlet of the fluid oscillation mixer, an oscillating gas flow is generated in the fluid oscillation mixer, and the seeds move in a wave-shaped trajectory under the driving of the oscillating gas flow, so that the seeds and the gas are fully and uniformly mixed;

[0026] S3, after the oscillating gas flow flows into the distributor, it flows into the gas flow chamber and flows into the seed discharge port along the arc-shaped surface of the elastic arc plate, and finally flows out through the seed discharge port.

[0027] In step S1, the rotation angle of the elastic baffle is automatically adjusted according to the speed of the gas flow, and during the rotation angle adjustment of the elastic baffle, the automatic adjustment of the gas flow entering the upper and lower flow channels is realized.

[0028] In step S2, after the high-pressure gas carrying seeds enters the resonance cavity, the high-pressure gas will randomly flow along the inner wall of the resonance cavity under the effect of the gas wall attachment, so that a biased flow is formed in the resonance cavity;

[0029] The side gas sucked into the resonance cavity through the feedback channel will cause boundary layer separation at the edge of the expansion cavity on the biased side, forming a vortex;

[0030] The gas flow on the biased side is fast, and the local pressure is low, while the gas flow on the other side is slow, and the pressure is high. The pressure difference is transmitted back to the seed inlet of the resonance cavity through the feedback channel, forming a reverse driving force. The reverse driving force forces the high-pressure gas carrying seeds to switch from the original biased side to the corresponding other side. The biased side after switching also separates and generates a vortex, and the above pressure fluctuation process is repeated;

[0031] Thus, an oscillating gas flow is formed in the resonance cavity, and the seeds move in a wave-shaped trajectory in the resonance cavity under the driving of the oscillating gas flow.

[0032] The beneficial effects of the present application are:

[0033] (1) The seed distribution mechanism arranged at the inlet channel breaks the inertial aggregation state of the seeds at the elbow, so that the seeds are dispersed for the first time at the elbow of the inlet channel, which is beneficial to the full mixing of the seeds. The adjustable baffle can adjust the angle according to the different air flow velocities of different seeds, so that different seeds can achieve better dispersion effect;

[0034] (2) At the fluid oscillation mixer, the gas flow is alternately injected at the front, rear, left and right four outlets by using the wall attachment effect and feedback mechanism of the fluid, instead of the traditional corrugated pipe. The oscillating jet forms a periodic sweeping, uniformly covering the seeding area. The seeds move in a wave-shaped trajectory under the driving of the oscillating gas flow, avoiding the center accumulation or edge sparseness problem caused by the traditional straight blowing gas flow. The oscillation frequency is matched with the traveling speed of the seeding machine, so as to ensure the consistency of the seed dropping amount per unit area.

[0035] (3) The elastic arc plate with unique streamline curve can make the airflow more stable, reduce the generation of vortex, optimize the balance of lift and resistance, guide the airflow to flow smoothly, so that the seeds are more evenly transported in the airflow, the airflow resistance is reduced, and the power demand of the fan is reduced. Meanwhile, the elastic arc plate can be elastically deformed correspondingly with the change of the airflow, and is suitable for seeding of various crops. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a perspective structural schematic diagram of the present application;

[0037] Figure 2 is a front view structural schematic diagram of the present application;

[0038] Figure 3 is a sectional view of C-C in Figure 2

[0039] Figure 4 is a structural schematic diagram of the seed distribution mechanism;

[0040] Figure 5 is a structural schematic diagram of the fluid oscillation seed mixer;

[0041] Figure 6 is an enlarged view of B in Figure 3

[0042] Figure 7 is a structural schematic diagram of the top cover and the elastic arc plate;

[0043] Figure 8 is a structural schematic diagram of the spring sheet.

[0044] In the figure: 1 inlet channel; 2 resonance cavity; 201 seed inlet; 3 feedback channel; 4 outlet channel; 5 gas flow channel; 6 distributor; 601 top cover; 602 elastic arc plate; 603 elastic cavity; 604 seed discharge port; 605 spring sheet; 606 bottom plate; 607 groove; 7 seed distribution mechanism; 701 seed distribution plate; 702 elastic baffle; 703 hinge spring; 608 cylindrical rod. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0046] In the following description, specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways other than those described herein, and skilled in the art can make similar extensions without departing from the spirit of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0047] ​​As Figure 1 and Figure 2 shown, the pneumatic seed metering system of the present application comprises an inlet channel 1, a fluid oscillation seed mixer and a distributor 6, one end of the inlet channel 1 is connected with a seed delivery pipe, the other end of the inlet channel 1 is communicated with the inlet of the fluid oscillation seed mixer, the outlet of the fluid oscillation seed mixer is communicated with the distributor 6 through a gas flow channel 5.

[0048] High pressure gas carrying seeds enters the seed metering system through the inlet channel 1. The inlet channel 1 is in the shape of a bend pipe, and a seed separating mechanism 7 is arranged at the bend of the inlet channel 1. The seed separating mechanism 7 comprises a seed separating plate 701, an elastic baffle 702 and a spring 703. The seed separating plate 701 is fixedly arranged in the tubular inlet channel 1, and divides the bend pipe into two spaces, i.e. an upper flow channel and a lower flow channel. The elastic baffle 702 is connected to the side of the seed separating plate 701 facing the seed inlet of the inlet channel, and is hinged between the seed separating plate 701 and the elastic baffle 702, and is connected between the elastic baffle 702 and the inner wall of the inlet channel by the spring 703.

[0049] Since the elastic baffle 702 is hinged with the seed separating plate 701, the angle of the elastic baffle 702 can be adjusted. The seed separating plate 701 and the angle-adjustable elastic baffle 702 can break the inertial aggregation state of the seeds at the bend pipe, so that the seeds are dispersed for the first time at the bend pipe of the inlet channel 1, which is beneficial to the subsequent full mixing of the seeds. In addition, the angle of the adjustable baffle can be adjusted according to different seed air flow velocities, so that the seeds achieve better dispersion effect.

[0050] As Figures 1 to 3 shown, the fluid oscillation seed mixer is located between the inlet channel 1 and the distributor 6, and the seeds entering through the inlet channel 1 are fully mixed in the fluid oscillation seed mixer.

[0051] As Figure 5 shown, the fluid oscillation seed mixer comprises a resonance cavity 2 and a feedback channel 3, the seed inlet of the resonance cavity 2 is communicated with the inlet channel 1, the seed outlet of the resonance cavity 2 is provided with an outlet channel 4, and the resonance cavity 2 is communicated with the gas flow channel 5 through the outlet channel 4. The seed inlet 201 of the resonance cavity 2 has a tendency of reducing in diameter, i.e. the diameter of the seed inlet of the resonance cavity 2 is smaller than the diameter of the inlet channel 1.

[0052] The resonant cavity 2 is provided with a plurality of feedback channels 3. In this embodiment, four feedback channels 3 are uniformly spaced along the annular outer side of the resonant cavity 2. The bottom end of the feedback channel 3 is in communication with the seed inlet 201 of the resonant cavity 2, and the top end of the feedback channel 3 is in communication with the top of the resonant cavity 2. Since the diameter of the seed inlet 201 of the resonant cavity 2 is smaller than the diameter of the inlet channel 1, the gas flow rate can be increased and the pressure can be reduced, thereby generating a suction force on the gas flow. Under the action of this suction force, a small amount of gas in the resonant cavity 2 is sucked into the feedback channel 3 and reenters the resonant cavity 2 through the feedback channel 3. In this application, the gas sucked into the resonant cavity and reentering the feedback channel is referred to as side gas.

[0053] After the high-pressure gas carrying seeds is injected into the resonant cavity 2 from the seed inlet 201, the high-pressure gas will randomly flow along the inner wall of the feedback channel under the effect of the gas wall attachment, thereby forming a biased flow in the resonant cavity. The side gas sucked into the resonant cavity 2 through the feedback channel will correspondingly cause boundary layer separation at the edge of the expansion cavity on the biased side, forming a vortex.

[0054] The gas flow rate on the biased side is fast, and the local pressure is low; while the flow rate of the side gas on the other side is slow, and the pressure is high. The pressure difference is transmitted back to the seed inlet 201 of the resonant cavity 2 through the feedback channel, forming a reverse pushing force. This reverse pushing force forces the high-pressure gas carrying seeds to switch from the original biased side to the corresponding other side, and the biased side after switching also separates and generates a vortex, and repeats the above pressure fluctuation process. The seeds move in a wave-like trajectory in the resonant cavity under the action of the oscillating gas flow, avoiding the problem of seed accumulation in the center or sparseness at the edge caused by traditional straight blowing gas flow. The oscillation frequency is matched with the traveling speed of the seeding machine to ensure consistent seed drop per unit area.

[0055] The above process is repeated at a fixed frequency to form a stable alternating jet oscillating gas flow. During the periodic oscillation of the high-pressure gas carrying seeds in the resonant cavity, the mixing between the seeds and the high-pressure gas can be fully realized, the distribution of the seeds in the high-pressure gas is more uniform, the seed dropping effect is improved, and the yield of crops is improved.

[0056] The periodically oscillating high-pressure gas carrying seeds generated in the resonant cavity 2 enters the airflow channel 5 through the outlet channel 4, and the flow direction of the high-pressure gas carrying seeds is guided through the airflow channel 5, so that the high-pressure gas carrying seeds can flow into the distributor 6 at the top along the airflow channel 5 arranged in the vertical direction.

[0057] As Figure 3 , Figure 6 and Figure 7As shown, the distributor 6 comprises a top cover 601 at the top, a bottom plate 606 at the bottom, and a plurality of seed discharge ports 604 at the circumferential side of the distributor, the upper part of the seed discharge port 604 is fixedly connected with the top cover 601, and the lower part of the seed discharge port 604 is fixedly connected with the bottom plate 606.

[0058] The bottom of the top cover 601 is provided with an arc-shaped elastic arc plate 602, which is fixedly connected with the top cover 601, and an elastic cavity 603 is formed between the elastic arc plate 602 and the top cover 601 above it. The surface of the elastic arc plate 602 is an arc-shaped curved surface, and the equation of the arc-shaped curved surface is:

[0059]

[0060] The elastic arc plate 602 and the bottom plate 606 form a gas flow chamber therebetween, and the seed discharge port 604 is in communication with the gas flow chamber. The high-pressure gas carrying seeds discharged from the gas flow channel 5 enters the gas flow chamber, flows along the arc surface of the elastic arc plate 602, and is discharged through the seed discharge port 604. The streamline curve of the elastic arc plate 602 can make the airflow more stable, reduce the generation of vortex, optimize the balance of lift and resistance, guide the airflow to flow smoothly, so that the seeds are more uniformly transported in the airflow; at the same time, it can also reduce the airflow resistance and reduce the power demand of the fan.

[0061] The elastic arc plate 602 is made of elastic material, and can dynamically produce corresponding elastic deformation with the change of airflow, at which time the shape of the elastic cavity 603 surrounded by the elastic arc plate 602 and the top cover 601 also changes. Different types of crop seeds have different sizes of high-pressure airflow carrying seeds, and the elastic arc plate 602 produces corresponding deformation, so it can be applied to the seeding of various crops.

[0062] The bottom plate 606 is provided with a spring sheet 605. As shown, Figure 8 The spring sheet 605 is in the shape of a ring, the center of the spring sheet 605 is provided with a circular hole, a plurality of radially arranged cylindrical rods 608 are fixedly arranged at the annular inner wall of the circular hole, and the cylindrical rods 608 are uniformly and spacedly arranged along the circumferential inner wall of the circular hole. A central hole is formed between the inner ends of all the cylindrical rods 608, and the bottom tip of the elastic arc plate 602 is inserted into the central hole.

[0063] The spring sheet 605 is movably connected with the bottom plate 606. In this application, the annular outer side of the bottom plate 606 is fixedly provided with a groove 607, the annular outer ring of the spring sheet 605 is arranged in the groove 607, and the depth of the groove 607 is greater than the thickness of the spring sheet 605, so that the annular outer ring of the spring sheet 605 can move up and down in the groove 607.

[0064] The gas flow from the gas flow channel 5 impacts the cylindrical rod 608 on the spring sheet, generating a Karman vortex street effect, inducing the spring sheet 605 to vibrate, preventing the accumulation of crop seeds on the bottom plate 606. In this application, by setting the depth of the groove 607, the vibration amplitude of the spring sheet can be limited within 1.2mm, thereby fixing the vibration frequency of the spring sheet within a certain range.

[0065] The application also discloses a pneumatic seed distribution method, which specifically comprises the following steps.

[0066] Firstly, after mixing the crop seeds with high-pressure gas, the high-pressure gas carrying the seeds enters the inlet channel 1 through the seed delivery pipe, and the high-pressure gas is divided into two parts by the seed distribution mechanism in the inlet channel, one part of the gas carrying the seeds flows along the upper flow channel, and the other part of the gas flows along the lower flow channel, thereby realizing the first dispersion of the crop seeds at the inlet channel.

[0067] Secondly, the dispersed seeds converge at the seed inlet 201 of the resonance cavity. After the high-pressure gas carrying the seeds enters the resonance cavity 2, the high-pressure gas will randomly flow along the inner wall of one side of the resonance cavity under the effect of the gas wall attachment, thereby forming a biased flow in the resonance cavity 2. The side gas sucked into the resonance cavity 2 through the feedback channel 3 will correspondingly separate from the boundary layer at the edge of the expansion cavity on the biased side, forming a vortex.

[0068] The gas flow rate on the biased side is fast, and the local pressure is low; while the flow rate of the side gas on the other side is slow, and the pressure is high. The pressure difference is transmitted back to the seed inlet 201 of the resonance cavity through the feedback channel, forming a reverse pushing force. The reverse pushing force forces the high-pressure gas carrying the seeds to switch from the original biased side to the corresponding other side, and the switched biased side also separates and generates a vortex, and repeats the above pressure fluctuation process. Therefore, an oscillating gas flow is formed in the resonance cavity. The seeds move in a wave-shaped trajectory in the resonance cavity under the driving of the oscillating gas flow.

[0069] Thirdly, the oscillating gas flow from the resonance cavity flows into the distributor under the guidance of the gas flow channel, flows into the gas flow chamber composed of the bottom plate and the elastic arc plate, and flows into the seed discharge port along the arc surface of the elastic arc plate, and finally flows out through the seed discharge port, thereby realizing the seed distribution process.

[0070] The above describes in detail the pneumatic seed metering system and method provided by the present application. The principles and implementation manners of the present application are described by using specific examples, and the above description of the examples is only used to help understand the method of the present application and the core idea thereof. It should be noted that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The above description of the disclosed examples enables those skilled in the art to implement or use the present application. Various modifications of the examples will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other examples without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the examples shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pneumatic seed metering system comprising an inlet channel, characterized in that, The fluid oscillation mixer and the distributor are further included, and the inlet channel is communicated with the distributor through the fluid oscillation mixer; the distributor comprises: a top flow divider; a bottom plate at the bottom, and spring sheets movably connected to the bottom plate; a flexible arc plate below the flow divider, in an arc shape, and forming a flexible cavity with the flow divider above it, and a gas flow chamber with the bottom plate below it; a seed discharge port arranged along the circumferential side of the distributor, and communicated with the gas flow chamber; the fluid oscillation mixer comprises: a resonance cavity communicated with the inlet channel through a seed inlet at the bottom, and the seed inlet is smaller than the inlet channel, so that suction force is generated at the seed inlet of the resonance cavity to suck the gas; a feedback channel, a plurality of feedback channels are arranged on the annular outer side of the resonance cavity, the bottom end of the feedback channel is communicated with the seed inlet of the resonance cavity, and the top end of the feedback channel is connected with the seed discharge port of the resonance cavity, so that the gas in the resonance cavity is sucked into the seed inlet of the resonance cavity again along the feedback channel under the action of the suction force at the seed inlet of the resonance cavity; the spring sheet is annular, a circular hole is arranged at the center of the spring sheet, a plurality of cylindrical rods are fixed to the annular inner wall of the circular hole and arranged along the radial direction, the cylindrical rods are arranged at intervals along the circumferential inner wall of the circular hole, the inner ends of the cylindrical rods form a central hole, and the bottom end of the flexible arc plate is inserted into the central hole.

2. A pneumatic seed metering system according to claim 1, wherein, the inlet channel is in the shape of a bent pipe, and a seed distribution mechanism is arranged at the bend of the inlet channel, the seed distribution mechanism comprises: a seed distribution plate fixed to the inner wall of the bend of the inlet channel, dividing the inner cavity of the seed distribution plate into an upper flow channel and a lower flow channel; a flexible baffle hinged to one side of the seed distribution plate facing the seed inlet of the inlet channel, and connected to the inner wall of the inlet channel through a spring.

3. The pneumatic seed metering system of claim 1, wherein, an outlet channel is arranged at the seed discharge port of the resonance cavity, and the outlet channel is connected with the distributor through a gas flow channel.

4. The pneumatic seed metering system of claim 1, wherein, the curve equation of the flexible arc plate is: 。 5. The pneumatic seed metering system of claim 1, wherein, an annular groove is fixed to the bottom plate, the opening of the groove faces the spring sheet, and the annular outer ring of the spring sheet is movably arranged in the groove; the depth of the groove is greater than the thickness of the spring sheet.

6. A method of seed metering for a pneumatic seed metering system according to any one of claims 1 to 5, characterized in that the steps comprise: S1, after the crop seeds are mixed with high-pressure gas, the high-pressure gas carrying the seeds is divided at the inlet channel, and the seeds are dispersed correspondingly; S2, the dispersed seeds and the separated gas are combined at the seed inlet of the fluid oscillation mixer, an oscillating gas flow is generated in the fluid oscillation mixer, the seeds move in a wave-shaped trajectory under the driving of the oscillating gas flow, and the seeds and the gas are fully and uniformly mixed; S3, after the oscillating gas flow flows into the distributor, the flowing gas flows into the gas flow chamber, and then flows into the seed discharge port along the arc surface of the flexible arc plate, and finally flows out through the seed discharge port.

7. The seed metering method of claim 6, wherein, In step S1, the rotation angle of the flexible baffle is automatically adjusted according to the speed of the gas flow, and the rotation angle of the flexible baffle is adjusted to automatically adjust the gas flow entering the upper flow channel and the lower flow channel.

8. The seed metering method of claim 6, wherein, In step S2, after the high-pressure gas carrying the seeds enters the resonance cavity, the high-pressure gas will randomly flow along one side of the inner wall of the resonance cavity under the effect of the gas wall, thereby forming a biased flow in the resonance cavity. The side gas sucked into the resonance cavity through the feedback channel corresponds to the boundary layer separation at the edge of the expansion cavity on the deflection side, forming a vortex; The gas flow rate on the deflection side is fast, and the local pressure is low, while the side gas flow rate on the other side is slow, and the pressure is high. The pressure difference is transmitted back to the seed inlet of the resonance cavity through the feedback channel, forming a reverse driving force. This reverse driving force forces the high-pressure gas carrying seeds to switch from the original deflection side to the corresponding other side. The deflection side after switching also separates and generates a vortex, and the pressure fluctuation process is repeated; Thus, an oscillating air flow is formed in the resonance cavity, and the seeds move in a wave-shaped trajectory in the resonance cavity under the driving of the oscillating air flow.

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