Pipe flow field tracer particle injection system and injection method

Abstract

This invention provides a pipeline flow field tracer particle injection system and method for use in gas transmission pipelines. The system includes: a particle injection unit, a laser emission unit, and an image acquisition unit. The pipeline is divided into an injection zone and an emission / acquisition zone according to the particle's direction of travel. The particle injection unit is located in the injection zone and is used to inject tracer particles into the pipeline. The laser emission unit and image acquisition unit are located in the emission / acquisition zone and are respectively used to emit laser light into the detection zone within the pipeline and to acquire particle images of the detection zone. A control unit, connected to the particle injection unit and the image acquisition unit, is used to obtain the effective sampling number of tracer particles based on the particle images and to adjust the particle injection volume within the pipeline according to the effective sampling number. The pipeline flow field tracer particle injection system of this invention has a simple structure, can quickly and accurately adjust the particle injection volume, reduce particle loss, improve experimental efficiency, and enhance the accuracy and safety of the tracer particle injection process.

Description

Technical Field

[0001] This invention relates to the field of metrology, specifically to a pipeline flow field tracer particle injection system and a pipeline flow field tracer particle injection method. Background Technology

[0002] The changes in gas velocity and flow field within pipelines during natural gas transportation are of significant research importance. Currently, particle imaging velocimetry and laser Doppler velocimetry are commonly used to measure gas velocity and flow field changes.

[0003] During the measurement process, tracer particles are added to the natural gas pipeline. These particles follow the gas flow within the pipeline, and a high-speed camera captures and records their coordinates. Then, an algorithm is used to obtain the particle velocity, further revealing the gas flow state and velocity within the pipeline. However, current tracer particle injection is manually controlled, with particle concentration monitored by a dedicated person through a transparent viewing window section. On-site experimental personnel then control the flow rate of the particle injection device. Several prominent problems exist in practical applications: ① The tracer particle injection process requires multiple people to monitor particle concentration and repeatedly manually adjust valve openings to ensure sufficient tracer particle concentration enters the transparent viewing window section under different natural gas flow conditions, making the operation cumbersome; ② Manual adjustment of the flow control valve has a time lag and arbitrary opening control, making it impossible to continuously and quantitatively adjust the electric valve opening based on the particle concentration image processing results from the receiving unit. This results in inaccurate control of the particle injection amount and reduced experimental efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a pipeline flow field tracer particle injection system and injection method, which solves the problems of inaccurate particle injection volume control, complex adjustment, and low experimental efficiency mentioned above.

[0005] To achieve the above objectives, embodiments of the present invention provide a pipeline flow field tracer particle injection system for gas transmission pipelines, comprising:

[0006] Particle injection unit, laser emission unit, and image acquisition unit;

[0007] The pipeline is divided into an injection zone and an emission acquisition zone according to the direction of particle propagation; the particle injection unit is located in the injection zone and is used to inject tracer particles into the pipeline; the laser emission unit is located in the emission acquisition zone and is used to emit lasers into the detection zone inside the pipeline; the image acquisition unit is located in the emission acquisition zone and is used to acquire particle images of the detection zone inside the pipeline.

[0008] The control unit, connected to the particle injection unit and the image acquisition unit, is used to obtain the effective sampling number of tracer particles based on the particle image, and adjust the particle injection amount in the pipeline according to the effective sampling number of tracer particles.

[0009] Optionally, the laser emitting unit is electrically connected to the control unit and is used to start according to the start command of the control unit and to shut down according to the stop command of the control unit.

[0010] Optionally, the emission acquisition area of ​​the pipeline is provided with a transparent window, and the laser emitted by the laser emission unit passes through the transparent window to cover the detection area inside the pipeline.

[0011] Optionally, the laser emitting unit is a sheet laser.

[0012] Optionally, the image acquisition unit is used to acquire particle images within the detection area through the transparent window.

[0013] Optionally, the image acquisition unit is a CCD camera or an industrial camera.

[0014] Optionally, the particle injection unit includes: a storage device, a pumping device, an injection volume adjustment component, and an atomizing nozzle, which are connected in sequence via connecting pipes;

[0015] The outlet end of the atomizing nozzle is located inside the pipe;

[0016] The storage device stores tracer particles;

[0017] The pumping device is used to pump tracer particles into the pipeline;

[0018] The injection volume adjustment component is used to adjust the particle injection volume;

[0019] The outlet end of the atomizing nozzle is located inside the pipe;

[0020] The pumping device and the injection volume adjustment component are electrically connected to the control unit; the pumping device is used to start according to the start command of the control unit and to change the pumping pressure according to the pressure adjustment command of the control unit; the injection volume adjustment component is used to adjust the particle injection volume according to the injection volume adjustment command of the control unit.

[0021] Optionally, the pumping device is a pressure pump, and the injection volume adjustment component is an electric valve.

[0022] This invention also provides a method for injecting tracer particles into a pipeline, wherein the above-described pipeline flow field tracer particle injection system is used to inject tracer particles into the pipeline, and the method includes:

[0023] Real-time acquisition of the effective sampling number of tracer particles in the detection zone inside the pipeline;

[0024] The particle injection amount is adjusted based on the effective sampling number until the effective sampling number reaches the preset particle number, at which point particle injection stops.

[0025] Optionally, adjusting the particle injection amount based on the effective sampling number includes:

[0026] As the effective sampling number increases, the particle injection amount is gradually increased until the effective sampling number reaches the preset particle number.

[0027] The technical solution of this invention acquires particle images inside the pipeline through an image acquisition unit and obtains the effective sampling number in the particle images through a control unit. Based on this, the particle injection amount of the particle injection unit is adjusted. The system structure of this invention is simple, and it can realize continuous automatic injection of tracer particles inside the pipeline, saving manpower and having strong convenience. It can quickly and accurately adjust the tracer particle injection amount, effectively improve experimental efficiency, reduce particle loss, and avoid the risks caused by human operation, thereby improving the accuracy and safety of the tracer particle injection process.

[0028] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 This is a schematic diagram of the structure of the pipeline flow field tracer particle injection system provided by the present invention;

[0031] Figure 2 This is a structural block diagram of the pipeline flow field tracing particle injection system provided by the present invention;

[0032] Figure 3 This is a schematic flowchart of the pipeline flow field tracer particle injection method provided by the present invention;

[0033] Figure 4 This is a flowchart of the pipeline flow field tracer particle injection method provided by the present invention.

[0034] Explanation of reference numerals in the attached figures

[0035] 1-Particle injection unit; 2-Laser emission unit; 3-Image acquisition unit;

[0036] 4-Pipeline; 5-Control unit; 11-Storage device;

[0037] 12-Pumping device; 13-Injection volume adjustment component; 14-Atomizing nozzle;

[0038] 41 - Transparent window; 401 - Injection area; 402 - Emission acquisition area. Detailed Implementation

[0039] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0040] In the embodiments of the present invention, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use.

[0041] The terms “first,” “second,” “third,” etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0042] The terms "parallel" and "perpendicular" do not mean that the components must be absolutely parallel or perpendicular, but rather that they can be slightly tilted. For example, "parallel" simply means that its direction is more parallel than "perpendicular," not that the structure must be completely parallel, but that it can be slightly tilted.

[0043] The terms "horizontal," "vertical," and "sag" do not imply that a component must be absolutely horizontal, vertical, or sagging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0044] Furthermore, terms like "roughly" and "basically" are used to indicate that the content does not require absolute precision, but rather allows for a certain degree of deviation. For example, "roughly equal" does not simply mean absolute equality; in actual production and operation, achieving absolute "equality" is difficult, and a certain degree of deviation is generally present. Therefore, besides absolute equality, "roughly equal to" also includes the aforementioned situation where a certain degree of deviation exists. Using this as an example, in other cases, unless otherwise specified, terms like "roughly" and "basically" have similar meanings.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Figure 1 This is a schematic diagram of the structure of the pipeline flow field tracer particle injection system provided by the present invention; as shown. Figure 1 As shown, this invention provides a pipeline flow field tracer particle injection system for gas transmission pipelines, comprising:

[0047] Particle injection unit 1, laser emission unit 2, and image acquisition unit 3;

[0048] The pipeline is divided into an injection area 401 and an emission acquisition area 402 according to the direction of particle propagation; the particle injection unit 1 is located in the injection area 401 and is used to inject tracer particles into the pipeline 4; the laser emission unit 2 is located in the emission acquisition area 402 and is used to emit lasers into the detection area in the pipeline 4; the image acquisition unit 3 is located in the emission acquisition area 402 and is used to acquire particle images of the detection area in the pipeline 4.

[0049] The control unit 5 is connected to the particle injection unit 1 and the image acquisition unit 3, and is used to obtain the effective sampling number of tracer particles based on the particle image, and adjust the particle injection amount in the pipe 4 according to the effective sampling number of tracer particles.

[0050] Specifically, in the process of measuring the gas velocity and flow field changes within pipe 4, tracer particles are first added to pipe 4 through particle injection unit 1. These tracer particles are evenly distributed across most of pipe 4 and follow the gas flow. Laser is emitted into pipe 4 through laser emission unit 2, illuminating a specific detection area and displaying the spatial position of particles within that area. Image acquisition unit 3 then captures and records the spatial coordinates of the particles in that detection area, obtaining a particle image. Finally, a preset algorithm within control unit 5 processes and continuously calculates the particle image to obtain information such as the spatial position change and velocity vector of each tracer particle, as well as the effective sampling of particles in the particle image. The effective sampling number determines the particle velocity, further revealing the gas flow state and velocity within pipe 4. Control unit 5 then controls the number of particles injected by particle injection unit 1 based on the effective sampling number, enabling continuous automatic injection of tracer particles into pipe 4. This saves manpower, offers significant convenience, and allows for rapid and accurate adjustment of the tracer particle injection volume, effectively improving experimental efficiency, reducing particle loss, and mitigating the risks associated with manual operation. It enhances the accuracy and safety of the tracer particle injection process, possessing significant research value. The effective sampling number refers to particles with clear trajectories and no overlapping trajectories within a specific area, allowing for the clear determination of particle trajectories and the calculation of particle velocity. Pipe 4 can be a natural gas pipeline, etc. The tracer particles can be non-toxic, harmless, non-corrosive, and chemically stable substances such as water, DEHS, oxygen bubbles, and polystyrene, ensuring that the diameter of the particles injected into pipe 4 is less than or equal to 10 μm.

[0051] Furthermore, the laser emitting unit 2 is electrically connected to the control unit 5, and is used to start according to the start command of the control unit 5, and to shut down according to the stop command of the control unit 5.

[0052] Specifically, the laser emitting unit 2 is controlled by the control unit 5 to operate and stop. The laser frequency, energy, and irradiation time emitted by the laser emitting unit 2 can be preset in advance by the control unit 5 according to the estimated flow velocity of the medium in the pipe 4. In addition, during the filling process, the control unit 5 can fine-tune the laser frequency, energy, and irradiation time emitted by the laser emitting unit 2 to match the flow velocity of the medium in the pipe 4, so as to ensure the accuracy of particle collection.

[0053] Furthermore, the emission acquisition area 402 of the pipeline 4 is provided with a transparent window 41, and the laser emitted by the laser emission unit 2 passes through the transparent window 41 to cover the detection area inside the pipeline 4.

[0054] Specifically, a transparent window 41 is provided in the emission and acquisition area 402 of the pipeline 4. The laser emitted by the laser emission unit 2 passes through the transparent window 41 and irradiates the detection surface of the pipeline 4, thereby displaying the position of the particles on the detection surface.

[0055] Furthermore, the laser emitting unit 2 is a sheet laser.

[0056] Specifically, in this embodiment, a sheet light source laser is used as the laser emitting unit 2. The laser emitting unit 2 can be set on the top of the pipe 4 or on the side wall of the pipe 4. It emits laser light vertically downward or horizontally, so that the emitted sheet light source forms a detection surface along the medium flow direction, thereby displaying the position of the particles on the detection surface.

[0057] Furthermore, the image acquisition unit 3 is used to acquire particle images within the detection area through the transparent window 41.

[0058] Specifically, the image acquisition unit 3 also acquires particle images on the detection surface through the transparent window 41. This window can be located on the side wall of the pipe 4 or on the top (bottom) of the pipe 4, with the relative angle between the image acquisition unit 3 and the laser emission unit 2 on the pipe 4 being 90 degrees. More specifically, when the image acquisition unit 3 is located on the side wall of the pipe 4, the laser emission unit 2 is located on the top (bottom) of the pipe 4; when the image acquisition unit 3 is located on the top (bottom) of the pipe 4, the laser emission unit 2 is located on the side wall of the pipe 4. Furthermore, the transparent window 41 can be a single piece or two separate pieces; when set as two separate pieces, they are positioned on the pipe 4 with a relative angle of 90 degrees.

[0059] Furthermore, the image acquisition unit 3 is a CCD camera or an industrial camera.

[0060] Specifically, since the medium flows at a relatively high speed in pipe 4, a CCD camera or industrial camera can be set up to capture the continuous displacement of particles on the detection surface through a high shooting frequency, forming a moving path. The particle velocity can then be calculated according to the velocity calculation formula based on the time corresponding to the movement of the path, thereby obtaining the flow rate of the medium.

[0061] More specifically, when acquiring particle images, an XY coordinate system is established based on the detection surface, with the origin at the intersection of the detection surface and the shooting interface of the image acquisition unit 3 (lower left position). In this embodiment, the medium flow direction is taken as the X-axis. Since the position of the image acquisition unit 3 is fixed, by continuously shooting particle images at a high frequency, the movement path of the particles in the particle image and the movement length (spatial position change) in the coordinate system can be obtained. Particles with clear motion trajectories and non-overlapping positions are selected from the coordinate system as the effective sampling number of particles. The velocity of each effective particle is calculated using the velocity calculation formula based on the shooting frequency, and the velocities of the effective particles are averaged to obtain the flow velocity of the medium.

[0062] Furthermore, the particle injection unit 1 includes: a storage device 11, a pumping device 12, an injection volume adjustment component 13, and an atomizing nozzle 14, which are connected in sequence via connecting pipes;

[0063] The storage device 11 stores tracer particles;

[0064] The pumping device 12 is used to pump tracer particles into the pipe 4;

[0065] The injection volume adjustment component 13 is used to adjust the particle injection volume;

[0066] The outlet end of the atomizing nozzle 14 is located inside the pipe 4;

[0067] The pumping device 12 and the injection volume adjustment component 13 are electrically connected to the control unit 5; the pumping device 12 is used to start according to the start command of the control unit 5 and to change the pumping pressure according to the pressure adjustment command of the control unit 5; the injection volume adjustment component 13 is used to adjust the particle injection volume according to the injection volume adjustment command of the control unit 5.

[0068] Specifically, the particle injection unit 1 includes a storage device 11, a pumping device 12, an injection volume adjustment component 13, and an atomizing nozzle 14, which are connected in sequence via connecting pipes. The storage device 11 is used to store tracer, which contains a number of tracer particles. The inlet of the pumping device 12 is connected to the storage device 11, and the outlet is connected to the injection volume adjustment component 13. The outlet of the injection volume adjustment component 13 is connected to the atomizing nozzle 14. A connection hole is provided on the pipe 4, and the atomizing nozzle 14 is installed on the connection hole. The operating frequency of the pumping device 12 is adjustable, and the outlet pressure can be changed by adjusting the operating frequency. By cooperating with the injection volume adjustment component 13, the pumping pressure and the particle injection volume can be changed. After the tracer is atomized by the atomizing nozzle 14, it forms particles with a smaller diameter and enters the pipe 4 and flows with the gas.

[0069] After obtaining the effective number of particle samples, the control unit 5 generates a corresponding control signal based on the effective number of samples and sends it to the pumping device 12 and the injection volume adjustment component 13. After receiving the control signal, the pumping device 12 starts working and changes the pumping pressure. At the same time, the injection volume adjustment component 13 adjusts the particle injection volume according to the control command of the control unit 5.

[0070] In another embodiment, the pumping device 12 operates at a fixed frequency, so the outlet pressure of the pumping device 12 is a fixed value. The control signal sent by the control unit 5 is only used to control the pumping device 12 to start and stop operating.

[0071] In another embodiment, the particle injection unit 1 includes a high-pressure storage device 11, an injection volume adjustment component 13, and an atomizing nozzle 14 connected in sequence by a connecting pipe; the high-pressure storage device 11 stores compressed tracer, and when adjusting the opening, the amount of tracer particles injected is changed directly through the injection volume adjustment component 13.

[0072] Furthermore, the pumping device 12 is a pressure pump, and the injection volume adjustment component 13 is an electric valve.

[0073] Specifically, the pumping device 12 is a pressurizing pump, which can rapidly pressurize the tracer and ensure the atomization effect; the injection volume adjustment component 13 is an electric valve, which uses an electric valve for opening control. It has a simple structure, is not affected by air pressure, can achieve rapid response, has little delay, and has high control precision, enabling rapid signal conversion and action.

[0074] Figure 2 This is a structural block diagram of the pipeline flow field tracer particle injection system provided by the present invention; as shown below. Figure 2 As shown, the control unit 5 may specifically include an electric valve control subunit, an image processing subunit, and a laser control subunit. The electric valve control subunit is dedicated to controlling the opening degree of the electric valve to change the particle injection amount. The image processing subunit is connected to the image acquisition unit 3 and is used to control the operation of the image acquisition unit 3 and to process particle images to obtain an effective number of samples. The laser control subunit is used to control the laser emitting unit to start and stop working, and to adjust the laser frequency, energy, and laser irradiation time emitted by the laser emitting unit 2.

[0075] Figure 3 This is a schematic flowchart of the pipeline flow field tracer particle injection method provided by the present invention. Figure 4 This is a flowchart of the pipeline flow field tracer particle injection method provided by the present invention. Figure 3-4As shown, this embodiment provides a method for injecting tracer particles into a pipeline flow field. The method uses the aforementioned pipeline flow field tracer particle injection system to inject tracer particles into the pipeline. The method includes:

[0076] Step 101: Real-time acquisition of the effective sampling number of tracer particles in the detection area inside the pipeline;

[0077] Step 102: Adjust the particle injection amount based on the effective sampling number until the effective sampling number reaches the preset particle number, then stop particle injection.

[0078] Specifically, before refueling begins, the electric valve is closed and the particle injection volume is zero. Based on the estimated medium flow rate, the control unit 5 determines the frequency, energy, and irradiation time of the emitted laser. Once the gas flow stabilizes, refueling begins. The control unit 5 controls the laser emitting unit 2 to emit the laser, simultaneously controls the image acquisition unit 3 to acquire particle images, and opens the electric valve to a first preset opening degree. The control unit 5 performs real-time calculation and analysis on the acquired particle images to obtain the effective sampling number of tracer particles in the particle images. Based on the effective sampling number, the opening degree of the electric valve is adjusted until the effective sampling number in the latest acquired particle image reaches the preset particle number, at which point the electric valve is closed.

[0079] Further, adjusting the particle injection amount based on the effective sampling number includes:

[0080] As the effective sampling number increases, the particle injection amount is gradually increased until the effective sampling number reaches the preset particle number.

[0081] Specifically, after refueling begins, the control unit controls the laser emitting unit to emit a laser, simultaneously controlling the image acquisition unit to acquire particle images and opening the electric valve to a first preset opening degree. The control unit performs real-time analysis on the acquired particle images to obtain the effective sample number of tracer particles in the particle images. From the moment the electric valve is opened, after a preset time interval, based on the corresponding preset interval in which the number of effective samples in the latest captured particle image falls, the control unit increases the opening degree of the electric valve by the corresponding preset degree. After another preset time interval, based on the corresponding preset interval in which the number of effective samples in the latest captured particle image falls, the control unit again increases the opening degree of the electric valve by the corresponding preset degree. This includes:

[0082] If the number of valid samples is within a first preset range, control the electric valve to increase the opening by the first preset range based on the current opening.

[0083] If the number of valid samples is within the second preset range, control the electric valve to increase the second preset opening based on the current opening;

[0084] If the effective number of samples is within the third preset range, control the electric valve to increase by a third preset opening degree based on the current opening degree;

[0085] Among them, the first preset range is smaller than the second preset range, the second preset range is smaller than the third preset range, and any value within the third preset range is smaller than the preset number of particles; the first preset opening degree is greater than the second preset opening degree, and the second preset opening degree is greater than the third preset opening degree.

[0086] In this embodiment, the preset number of particles is set to N = 1000, and correspondingly:

[0087] If the effective number of samples is such that N ≤ 300, control the electric valve to increase by 5% based on the current opening degree;

[0088] If the effective number of samples is such that 300 < N < 700, control the electric valve to increase by 3% based on the current opening degree;

[0089] If the effective number of samples is such that 700 ≤ N < 1000, control the electric valve to increase by 1% based on the current opening degree.

[0090] As the effective number of samples of the tracer particles obtained each time gradually increases, correspondingly reduce the growth amount of the single - time opening degree adjustment of the electric valve, which can achieve precise adjustment of the particle injection amount, and on the basis of ensuring that the effective number of samples can reach the preset number of particles, reduce particle loss.

[0091] The embodiment of the present invention also provides a machine - readable storage medium, on which instructions are stored, and these instructions are used to make a machine execute the method for injecting tracer particles into the internal flow field of the pipeline as described above in this application.

[0092] The optional embodiments of the embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0093] In addition, it should be noted that, among the various specific technical features described in the above - mentioned specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the embodiments of the present invention do not separately describe various possible combination methods.

[0094] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0095] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A pipeline flow field tracer particle injection system for use in gas transmission pipelines, characterized in that, include: Particle injection unit (1), laser emission unit (2) and image acquisition unit (3); The pipeline is divided into an injection area (401) and an emission acquisition area (402) according to the direction of particle movement. The particle injection unit (1) is set in the injection area (401) and is used to inject tracer particles into the pipeline (4). The particle injection unit (1) includes: a storage device (11), a pumping device (12), an injection volume adjustment component (13), and an atomizing nozzle (14) connected in sequence through the connecting pipeline. The injection volume adjustment component (13) is used to adjust the particle injection volume and is an electric valve. The laser emission unit (2) is set in the emission acquisition area (402) and is used to emit laser light into the detection area in the pipeline (4). The image acquisition unit (3) is set in the emission acquisition area (402) and is used to acquire particle images of the detection area in the pipeline (4). The control unit (5), connected to the particle injection unit (1) and the image acquisition unit (3), is used to obtain the effective sampling number of tracer particles based on the particle image. The effective sampling number is the number of particles with clear motion trajectories and no trajectory overlap, which can clearly determine the motion trajectory of the particles, calculate the motion speed of the particles, and adjust the particle injection amount in the pipe (4) according to the effective sampling number of tracer particles until the effective sampling number reaches the preset number of particles, and then stop the particle injection, including: If the number of valid samples is within a first preset range, control the electric valve to increase the opening by the first preset range based on the current opening. If the number of valid samples is within the second preset range, control the electric valve to increase the second preset opening based on the current opening; If the number of valid samples is within a third preset range, control the electric valve to increase the opening by the third preset range based on the current opening. Wherein, the first preset interval is smaller than the second preset interval, the second preset interval is smaller than the third preset interval, and any value within the third preset interval is smaller than the preset number of particles; the first preset opening degree is greater than the second preset opening degree, and the second preset opening degree is greater than the third preset opening degree.

2. The pipeline flow field tracer particle injection system according to claim 1, characterized in that, The laser emitting unit (2) is electrically connected to the control unit (5) and is used to start according to the start command of the control unit (5) and to stop according to the stop command of the control unit (5).

3. The pipeline flow field tracer particle injection system according to claim 1, characterized in that, The emission acquisition area (402) of the pipeline (4) is provided with a transparent window (41), and the laser emitted by the laser emission unit (2) passes through the transparent window (41) to cover the detection area inside the pipeline (4).

4. The pipeline flow field tracer particle injection system according to claim 3, characterized in that, The laser emitting unit (2) is a sheet laser.

5. The pipeline flow field tracer particle injection system according to claim 3, characterized in that, The image acquisition unit (3) is used to acquire particle images in the detection area through the transparent window (41).

6. The pipeline flow field tracer particle injection system according to claim 5, characterized in that, The image acquisition unit (3) is a CCD camera or an industrial camera.

7. The pipeline flow field tracer particle injection system according to claim 1, characterized in that, The storage device (11) stores tracer particles; The pumping device (12) is used to pump tracer particles into the pipe (4); The outlet end of the atomizing nozzle (14) is located inside the pipe (4); The pumping device (12) and the injection volume adjustment component (13) are electrically connected to the control unit (5); the pumping device (12) is used to start according to the start command of the control unit (5) and to change the pumping pressure according to the pressure adjustment command of the control unit (5); the injection volume adjustment component (13) is used to adjust the particle injection volume according to the injection volume adjustment command of the control unit (5).

8. The pipeline flow field tracer particle injection system according to claim 7, characterized in that, The pumping device (12) is a pressure pump.

Images