Solid state tagged particle generation device and method

Abstract

The present application belongs to the technical field of physical measurement, and particularly relates to a solid-state tracer particle generating device and method, aiming at solving the problem that the existing device is difficult to meet the experimental requirements of microgravity environment. The device comprises a shell, a sieve partition plate, a vibrating diaphragm and a piezoelectric transducer. A particle cavity is arranged in the shell, the vibrating diaphragm is used as the bottom wall, and the sieve partition plate divides the vibrating diaphragm into a containing cavity and a carrier gas cavity. The piezoelectric transducer drives the vibrating diaphragm to generate mechanical vibration, so that the particles in the containing cavity are loosened and enter the carrier gas cavity, the carrier gas enters through the inlet and carries the particles to be discharged through the outlet. The structure design restricts the particle activity in the limited space of the containing cavity, avoids the particles from drifting and separating from the vibration action area, thereby achieving the powder starting and conveying with smaller vibration, reducing the requirements for mechanical vibration and carrier gas flow; at the same time, the sieve partition plate limits the size of the output particles, ensures the stable output under low flow, improves the controllability, and enables the device to be reliably applied to the flow field measurement in the microgravity environment.

Description

Technical Field

[0001] This invention belongs to the field of physical measurement technology, and specifically relates to a solid-state tracer particle generating device and method. Background Technology

[0002] Particle image velocimetry (PIV) requires the introduction of tracer particles with good motion characteristics into the flow field under test, and the particle displacement information is obtained by imaging with a sheet laser beam and a camera. For experiments such as gas-phase flow fields, combustion flow fields, and low-velocity jets, the particle size, concentration, spatial uniformity, and release stability of the tracer particles directly affect the quality of cross-correlation calculations, effective vector rate, and measurement repeatability.

[0003] Existing solid-state tracer particle generators mostly rely on large carrier gas flow rates or mechanical disturbances to generate and transport particles, which can easily lead to particle agglomerates entering the measurement area, affecting the uniformity of particle concentration distribution and output stability. In scenarios where the carrier gas is limited, problems such as insufficient particle generation, discontinuous release, and significant interference with the experimental flow field may also occur.

[0004] However, in space stations, drop towers, parabolic flights, recoverable satellite experimental platforms, or ground-based microgravity simulation chambers, tracer particles lack stable settling and bed recovery processes under gravity, making them susceptible to static electricity, wall adhesion, and aggregation. Simultaneously, carrier gas flow rate and mechanical disturbances are limited; excessive carrier gas flow rate may alter the measured flow field, and the reaction force generated by overall mechanical vibration may be transmitted to the PIV optical path or experimental area via the mounting interface. In other words, existing solid-state tracer particle generators are insufficient for experiments under microgravity conditions. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, namely the difficulty of existing solid-state tracer particle generating devices in meeting the experimental requirements under microgravity conditions, this invention provides a solid-state tracer particle generating device and method.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: A solid-state tracer particle generator includes a housing, a sieve partition plate, a vibrating diaphragm, and a piezoelectric transducer; The housing is provided with a particle chamber, the vibrating diaphragm serves as the bottom wall of the particle chamber, the sieve partition plate is disposed above the vibrating diaphragm and divides the particle chamber into a receiving chamber and a carrier gas chamber; the sieve partition plate is provided with sieve holes for connecting the receiving chamber and the carrier gas chamber; The receiving cavity is located below the carrier gas cavity and is used to contain solid tracer particles; The piezoelectric transducer is disposed below the vibrating diaphragm and is used to drive the vibrating diaphragm to generate mechanical vibration so that the solid tracer particles in the containment cavity enter the carrier gas cavity. The housing is also provided with a carrier gas inlet and a particle outlet that communicate with the carrier gas chamber, so that the carrier gas enters the carrier gas chamber from the carrier gas inlet and the solid tracer particles are discharged from the particle outlet.

[0007] Furthermore, the housing is also provided with a migration inlet communicating with the receiving cavity. The cross-screen carrier gas enters the receiving cavity through the migration inlet and then enters the carrier gas cavity through the sieve holes.

[0008] Furthermore, the solid-state tracer particle generator also includes a migration unit, which includes a main gas supply pipe and branch pipes; The main gas supply pipe is connected to the carrier gas inlet and is used to supply the carrier gas to the carrier gas chamber; One end of the branch pipe is connected to the main gas supply pipe, and the other end is connected to the migration inlet, for supplying the cross-screen carrier gas to the receiving cavity.

[0009] Furthermore, the migration unit also includes a buffer and a flow equalization component, and the branch pipe, the buffer, and the flow equalization component are connected in sequence; The buffer component has a buffer cavity, and the flow cross-sectional area of ​​the buffer cavity is larger than the flow cross-sectional area of ​​the branch pipe. The flow equalization component is provided with multiple flow limiting holes, which are used to connect the buffer cavity and the receiving cavity.

[0010] Furthermore, the piezoelectric transducer includes multiple piezoelectric units, which are disposed on the side of the vibrating diaphragm away from the screen separator plate.

[0011] Furthermore, the solid-state tracer particle generator also includes a drive controller for applying drive signals to the plurality of piezoelectric units; The drive controller can drive multiple piezoelectric units through at least one of the following methods: overall synchronous drive, alternating drive, frequency sweep drive, or pulse drive.

[0012] Furthermore, the solid-state tracer particle generating device also includes a grounding conductive element, which is disposed at the particle outlet to release the charge accumulated by the solid-state tracer particles during transportation.

[0013] In another aspect, the present invention provides a method for generating solid-state tracer particles, employing the aforementioned solid-state tracer particle generating apparatus, comprising the following steps: Solid tracer particles are filled into the containment cavity, and the piezoelectric transducer drives the vibrating diaphragm to generate mechanical vibration so that the solid tracer particles in the containment cavity are loosened and deagglomerated; Particles that meet the sieving conditions enter the carrier gas chamber through the sieve holes, while agglomerates that exceed the allowable size of the sieve holes are trapped in the receiving chamber by the sieve partition plate and continue to be subjected to vibration. Particles entering the carrier gas chamber are discharged from the particle outlet under the carrying of the carrier gas.

[0014] Furthermore, the piezoelectric transducer includes multiple piezoelectric units, which are driven by at least one of the following methods: overall synchronous driving, alternating driving, frequency sweep driving, or pulse driving.

[0015] Furthermore, a carrier gas is introduced into the receiving cavity, so that the carrier gas carries particles that meet the sieving conditions from the receiving cavity into the carrier gas cavity.

[0016] In summary, the technical effects achieved by this invention are as follows: The solid-state tracer particle generating device provided by the present invention includes a housing, a sieve partition plate, a vibrating diaphragm, and a piezoelectric transducer. The housing is provided with a particle cavity, the vibrating diaphragm serves as the bottom wall of the particle cavity, and the sieve partition plate is disposed above the vibrating diaphragm, dividing the particle cavity into a receiving cavity and a carrier gas cavity. The sieve partition plate has sieve holes for connecting the receiving cavity and the carrier gas cavity. The receiving cavity is disposed below the carrier gas cavity and is used to receive solid tracer particles. The piezoelectric transducer is disposed below the vibrating diaphragm and is used to drive the vibrating diaphragm to generate mechanical vibration so that the solid tracer particles in the receiving cavity enter the carrier gas cavity. The housing is also provided with a carrier gas inlet and a particle outlet communicating with the carrier gas cavity, carrying the carrier gas from the carrier gas inlet into the carrier gas cavity and carrying the solid tracer particles from the particle outlet out.

[0017] The solid tracer particle generating device provided by the present invention uses a vibrating diaphragm as the bottom wall of the particle cavity and a sieve partition plate above the vibrating diaphragm to form a receiving cavity for accommodating solid tracer particles and a carrier gas cavity for carrying out the output. This allows the solid tracer particles to loosen and enter the carrier gas cavity under the mechanical vibration generated by the piezoelectric transducer driving the vibrating diaphragm. The sieve holes on the sieve partition plate allow particles that meet the sieving conditions to pass through and restrict larger agglomerates from entering the carrier gas cavity. The carrier gas inlet and particle outlet are connected to the carrier gas cavity, so that the solid tracer particles entering the carrier gas cavity can be discharged with the carrier gas.

[0018] Specifically, the limited space of the containment cavity strictly restricts the particle's range of motion, ensuring that the vast majority of particles remain within the effective range of the vibrating diaphragm and are continuously and effectively excited. This prevents particles from drifting away from the vibration source in a larger space, thus enabling powder generation and conveying with less vibration and reducing the demand for mechanical vibration and carrier gas flow rate. Simultaneously, the sieve partition plate restricts the particle size entering the carrier gas cavity, ensuring stable particle output with a lower carrier gas flow rate, improving the controllability and stability of the solid-state tracer particle output process. Therefore, the solid-state tracer particle generator provided by this invention can be reliably applied in microgravity environments. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the solid-state tracer particle generator provided in an embodiment of the present invention; Figure 2 This is another structural schematic diagram of the solid-state tracer particle generator provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a piezoelectric transducer; Figure 4 This is a schematic diagram of the overall synchronous drive of the piezoelectric transducer; Figure 5 A schematic diagram of alternating or frequency sweep drive for a piezoelectric transducer; Figure 6 This is a flowchart of a solid-state tracer particle generation method.

[0021] Explanation of reference numerals in the attached drawings: 100, shell; 110, receiving cavity; 120, air carrier cavity; 200, sieve partition plate; 210, sieve hole; 300, vibrating diaphragm; 400, piezoelectric transducer; 410, piezoelectric unit; 510, main air supply pipe; 520, branch pipe; 530, buffer; 540, flow equalization component; 600, drive controller; 700, grounding conductive component; 800, discharge pipe. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] The following combination Figures 1-6 The structure and shape of the solid-state tracer particle generator provided in this embodiment will be described in detail: The solid-state tracer particle generator provided in this embodiment is applied to particle image velocimetry, and is particularly suitable for flow field measurement experiments in microgravity or zero gravity environments such as space stations, drop towers, and parabolic flights. In such environments, traditional particle generators that rely on gravity to form a stable powder bed are difficult to operate effectively. Specifically, such as Figure 1 , Figure 2 As shown, the solid-state tracer particle generator includes a housing 100, a sieve partition plate 200, a vibrating diaphragm 300, and a piezoelectric transducer 400. The housing 100 has a particle chamber, with the vibrating diaphragm 300 serving as the bottom wall of the particle chamber. The sieve partition plate 200 is positioned above the vibrating diaphragm 300, dividing the particle chamber into a receiving chamber 110 and a carrier gas chamber 120. The sieve partition plate 200 has sieve holes 210 for connecting the receiving chamber 110 and the carrier gas chamber 120. The receiving chamber 110 is positioned below the carrier gas chamber 120 and is used to receive solid tracer particles. The piezoelectric transducer 400 is positioned below the vibrating diaphragm 300 and is used to drive the vibrating diaphragm 300 to generate mechanical vibration, causing the solid tracer particles in the receiving chamber 110 to enter the carrier gas chamber 120. The housing 100 also has a carrier gas inlet and a particle outlet communicating with the carrier gas chamber 120, with the carrier gas entering the carrier gas chamber 120 from the carrier gas inlet and the solid tracer particles exiting from the particle outlet.

[0026] In this embodiment, the periphery of the vibrating diaphragm 300 is detachably sealed to the housing 100 via a sealing element and a clamping structure, facilitating cleaning and maintenance of the device's interior. Alternatively, welding or bonding can be used to achieve a permanent seal, resulting in higher airtightness and structural reliability. The sealing element can be a sealing ring, and the clamping structure can be a pressure ring connected to the housing 100 using bolts.

[0027] In this embodiment, the vibrating diaphragm 300 can be a metal sheet, a ceramic composite diaphragm, or other elastic diaphragms that meet the requirements for sealing and vibration. Its material, thickness, and effective vibration area are determined according to the device pressure, particle material, and target operating frequency band.

[0028] In this embodiment, the sieve partition plate 200 is detachably connected to the housing 100 and divides the particle chamber vertically into two parts: the lower receiving chamber 110 and the upper carrier gas chamber 120. The sieve partition plate 200 has multiple sieve holes 210 penetrating its thickness, which connect the receiving chamber 110 and the carrier gas chamber 120. The size of the sieve holes 210 is determined based on the monomer particle size of the tracer particles and the maximum allowable aggregate size in the experiment.

[0029] Specifically, the receiving cavity 110 is formed by the vibrating diaphragm 300, the sieve partition plate 200, and the circumferential inner wall of the shell 100 connecting the two, and is used to contain solid tracer particles. In this embodiment, the receiving cavity 110 is a shallow space, that is, the dimension of the receiving cavity 110 along the normal direction of the vibrating diaphragm 300 is significantly smaller than its characteristic dimension along the plane of the diaphragm, which is the diameter or side length; the dimension of the receiving cavity 110 along the normal direction of the vibrating diaphragm 300 is the distance between the vibrating diaphragm 300 and the sieve partition plate 200. This dimension and the particle loading amount are determined according to the particle material, particle size, agglomeration state, sieve aperture 210 size, and effective range of the vibrating diaphragm 300. In a microgravity environment, the structure of the shallow space ensures that even when particles are in a suspended and drifting state, their range of movement is strictly geometrically limited. This ensures that the vast majority of particles remain within the effective range of the vibrating diaphragm 300 and can be continuously and effectively excited, avoiding the problem of particles drifting around in a large space and escaping from the vibration source. This limitation also avoids the need for larger amplitudes for powder raising and transportation, which would cause mechanical disturbances and ensure the accuracy of the measurement.

[0030] When the vibrating diaphragm 300 vibrates, the particles adjacent to the vibrating diaphragm 300 are directly subjected to mechanical action, while the remaining particles acquire motion through collisions between particles, collisions between particles and the sieve partition plate 200, and collisions between particles and the sidewalls of the receiving cavity 110. This keeps the particles in the receiving cavity 110 in a state that can be repeatedly excited and deagglomerated, without requiring the particles to continuously adhere to the vibrating diaphragm 300 by gravity, and without requiring the formation of a stable powder bed. Thus, the particles under microgravity remain in a state that can be repeatedly excited without forming a stable gravity bed.

[0031] In this embodiment, the piezoelectric transducer 400 is disposed below the vibrating diaphragm 300, that is, on the side of the vibrating diaphragm 300 facing away from the receiving cavity 110. The piezoelectric transducer 400 is fixed to the lower surface of the vibrating diaphragm 300 by means of adhesive layers or pre-tightening components. During vibration, the piezoelectric transducer 400 will generate high-frequency expansion and contraction deformation due to the inverse piezoelectric effect. This deformation is converted into mechanical vibration by the vibrating diaphragm 300, which then acts on the solid tracer particles in the receiving cavity 110, providing the energy required for the loosening and deagglomeration of the solid tracer particles.

[0032] In this embodiment, the housing 100 is further provided with a carrier gas inlet and a particle outlet that are directly connected to the carrier gas chamber 120. The carrier gas enters the carrier gas chamber 120 from the carrier gas inlet and then exits from the particle outlet. When the tracer particles in the receiving cavity 110 enter the carrier gas chamber 120 through the sieve holes 210 under the action of vibration, they are captured and diluted by the carrier gas flowing in the carrier gas chamber 120, and are carried to the particle outlet, and finally transported to the downstream flow field to be measured.

[0033] To further improve the efficiency and controllability of particles crossing the sieve separator 200, a migration inlet communicating with the receiving cavity 110 is also provided on the housing 100. The cross-sieve carrier gas enters the receiving cavity 110 through the migration inlet and flows upwards, passing through the sieve holes 210 of the sieve separator 200 and converging into the carrier gas cavity 120. The cross-sieve carrier gas forms a cross-sieve airflow, providing a gentle and continuous directional migration force from the receiving cavity 110 to the carrier gas cavity 120 for particles that are sufficiently loosened under the action of the piezoelectric transducer 400 and whose size meets the sieving conditions. This helps the solid tracer particles overcome possible electrostatic adsorption forces or weak van der Waals forces between particles, thus smoothly passing through the sieve holes 210. This carrier gas does not directly impact the solid tracer particle powder at high speed, nor does it act as the sole active powder-raising force; it is formed by the pressure difference across the sieve separator 200. The flow rate of the carrier gas is greater than the flow rate of the cross-sieve carrier gas, and the cross-sieve carrier gas helps the particles maintain a dispersed and suspended state.

[0034] The solid-state tracer particle generator provided in this embodiment also includes a migration unit, such as... Figure 2As shown, the migration unit includes a main gas supply pipe 510 and a branch pipe 520. The main gas supply pipe 510 is connected to the carrier gas inlet of the device, serving as a channel for carrying the carrier gas. One end of the branch pipe 520 extends from the main gas supply pipe 510, and the other end is connected to the migration inlet. By installing a flow-limiting valve on the branch pipe 520, a small portion of the carrier gas can be diverted as an auxiliary gas source for cross-screen migration, i.e., cross-screen carrier gas; that is, the flow rate can be adjusted by adjusting the valve opening.

[0035] To ensure a more uniform and gentle airflow across the screen, the migration unit also includes a buffer 530 and a flow equalizer 540, with the branch pipe 520, buffer 530, and flow equalizer 540 connected sequentially. Specifically, the buffer 530 has a buffer chamber inside, into which the gas flowing from the branch pipe 520 first enters. The flow cross-sectional area of ​​the buffer chamber is significantly larger than that of the branch pipe 520. According to the fluid continuity equation, the airflow slows down and stabilizes upon entering the buffer chamber, thereby eliminating potential airflow pulsations and serving as a buffer and energy storage mechanism. Subsequently, the gas flows from the buffer chamber to the flow equalizer 540. The flow equalizer 540 is equipped with multiple dispersed flow-limiting orifices that connect the buffer chamber and the receiving chamber 110. By dispersing a concentrated airflow into multiple finer and more uniform airflows entering the receiving chamber 110, the direct impact and scavenging of particles within the receiving chamber 110 by localized high-speed airflows can be avoided, ensuring the overall uniformity and gentleness of the cross-screen migration process.

[0036] Specifically, the flow equalization element 540 is configured as a diffuser plate, a porous plate, a porous medium, etc., to reduce the local jet velocity and make the cross-screen carrier gas more evenly distributed in the accommodating cavity 110.

[0037] To achieve more precise control over the particle release process, the piezoelectric transducer 400 includes multiple independent piezoelectric units 410. These piezoelectric units 410 can be arranged in a geometric array on the side of the vibrating diaphragm 300 facing away from the screen separator 200. Specifically, for example... Figure 3 As shown, one piezoelectric unit 410 is disposed at the center and six piezoelectric units 410 are evenly distributed around the central piezoelectric unit 410.

[0038] Accordingly, the solid-state tracer particle generator provided in this embodiment also includes a drive controller 600. The drive controller 600 has multiple independent output channels, which are electrically connected to multiple piezoelectric units 410 respectively, and are used to apply drive signals to each piezoelectric unit 410. By programming and controlling the drive signals, the drive controller 600 can realize a variety of drive modes, including but not limited to overall synchronous drive, alternating drive, frequency sweep drive, and pulse drive.

[0039] During overall synchronous driving, the drive controller 600 applies a drive signal of the same frequency and phase to all piezoelectric units 410, causing the entire vibrating diaphragm 300 to produce a uniform and large-amplitude vibration. This mode is suitable for the initial stage or when a rapid and large-scale release of particles is required, and can powerfully and comprehensively loosen the particles in the containment cavity 110.

[0040] When driven alternately, the multiple piezoelectric units 410 are divided into several groups, such as Figure 3 The six piezoelectric units 410 arranged in the central circumferential direction are numbered 1-6, with odd-numbered units forming one group and even-numbered units forming another. The drive controller 600 drives different groups sequentially at different time periods. This mode can form a localized, moving vibration region on the vibrating diaphragm 300, which can be used to break up particle agglomerates that are difficult to loosen and form in specific locations.

[0041] During frequency sweep driving, the drive controller 600 continuously or incrementally changes the frequency of the drive signal within a preset frequency range. Since particle agglomerates of different sizes or different regions of the vibrating diaphragm 300 may be more sensitive to vibration responses at specific frequencies, i.e., resonance occurs, frequency sweep driving can excite a wider range of resonance effects, thereby improving deagglomeration efficiency.

[0042] During pulse driving, the drive controller 600 outputs a drive signal in the form of a pulse train. By adjusting the duty cycle of the pulse, that is, the ratio of the energizing time in each cycle to the total cycle, the total input energy can be finely adjusted without changing the drive voltage and frequency, thereby achieving precise fine-tuning of the particle release rate.

[0043] By coordinating one or more of the above driving modes with the cross-screen carrier gas flow rate and the carry-on carrier gas flow rate, flexible and precise control of tracer particle concentration, uniformity, and release start and stop can be achieved according to experimental requirements.

[0044] The drive controller 600 can perform a small-amplitude frequency sweep before startup or during operation to determine the effective operating frequency band based on at least one of the minimum impedance amplitude, peak admittance, zero-crossing phase, or peak diaphragm vibration response, and correct the drive frequency.

[0045] Considering that in long-term operation or high-dryness environments, particles are prone to generating and accumulating static charge due to friction during vibration, collision, and transport, which can lead to particle adhesion to the tube wall and affect output stability and concentration, the solid-state tracer particle generator provided in this embodiment also includes a grounding conductive element 700. The grounding conductive element 700 can be a metal ring, conductive coating, conductive liner, etc., and is disposed on the inner wall of the particle outlet and reliably connected to the equipment ground wire. When charged particles flow through the particle outlet, they can come into contact with or be sensed at close range by the grounding conductive element 700, thereby safely releasing the static charge they carry.

[0046] Specifically, the solid-state tracer particle generator provided in this embodiment also includes a discharge pipe 800, which is connected to the particle outlet, and a grounding conductive element 700 is installed on the inner wall of the discharge pipe 800.

[0047] The solid-state tracer particle generator provided in this embodiment also includes a monitoring module for detecting voltage, current, impedance, phase, or membrane response, and then determining the effective operating frequency band based on the extreme values ​​or zero crossings in the detection curve.

[0048] In summary, the solid-state tracer particle generator of this embodiment has successfully solved the technical problem of stable, uniform, and controllable release of solid-state tracer particles under microgravity environment through the deep synergy of multiple mechanisms, including the geometric limitation of the shallow containment cavity 110, the active deagglomeration and controllable transport of piezoelectric vibration, the size sieving of the sieve partition plate 200, and the directional migration of low-flow cross-sieve airflow.

[0049] Specifically, the shallow containment cavity 110 strictly constrains the free drift range of particles at the geometric level, ensuring that the vast majority of particles are always within the high-efficiency working area of ​​the vibrating diaphragm 300. This reduces the vibration intensity required for powder agglomeration and conveying, and also avoids airflow disturbance caused by powder agglomeration from high-flow-rate carrier gas. The piezoelectric transducer 400 achieves multiple driving modes such as overall synchronization, alternation, frequency sweeping, and pulse through multi-unit independent control. It flexibly adjusts the vibration mode and energy input according to the particle agglomeration state, and performs targeted deagglomeration and loosening of particles in the containment cavity 110. After deagglomeration, particles that meet the size requirements smoothly pass through the sieve holes 210 of the sieve separator 200 and enter the carrier gas cavity 120 under the gentle directional migration force of the low-flow-rate cross-sieve airflow, avoiding blockage or delayed release caused by electrostatic force and van der Waals force. After entering the carrier gas cavity 120, the particles are quickly captured, diluted, and conveyed to the particle outlet by the carrier gas.

[0050] Throughout the process, the limiting of the containment cavity 110 ensures the continuous effectiveness of the vibration, the controllable adjustment of the vibration mode provides a suitable particle state for sieving, the cross-screen airflow provides precise auxiliary power for the migration of sieved particles, and the mainstream airflow in the carrier gas cavity 120 completes the final transport of particles. The four elements are interlocked and complementary, forming a complete control chain from particle loosening, deagglomeration, sieving to migration and transport. This achieves stable, uniform, and controllable release of tracer particles under microgravity conditions and solves the problem of interference from large-flow carrier gas and mechanical vibration on the experiment.

[0051] Based on the solid-state tracer particle generator provided in this embodiment, a solid-state tracer particle generation method is proposed, which uses the above-mentioned solid-state tracer particle generator and specifically includes the following steps: S100: Preparation and Loading. Before the experiment begins, determine the dimensions of the receiving cavity 110 along the normal direction of the vibrating diaphragm 300 and the particle loading amount based on the particle material, particle size, agglomeration state, sieve aperture 210 size, and effective range of the vibrating diaphragm 300. Select a suitable solid tracer particle powder. Uniformly load the predetermined amount of solid tracer particles into the receiving cavity 110. The loading amount needs to be moderate; too much will result in excessive particle accumulation, preventing effective vibration of the bottom layer particles; too little may cause excessive dispersion of particles within the receiving cavity 110, weakening the collision and deagglomeration effect between particles. After loading, assemble all components of the device and ensure all interfaces are properly sealed.

[0052] S200: Parameter Setting and Start-up. The control system of the start-up device sets various initial operating parameters, including the drive mode, drive frequency, drive voltage or amplitude, pulse drive duty cycle, and participating piezoelectric units 410 of the piezoelectric transducer 400, set via the drive controller 600. In the initial stage, an overall synchronous drive mode can be selected. Simultaneously, the flow rate of the carrier gas and the flow rate of the cross-screen carrier gas entering the receiving cavity 110 via the migration unit are set.

[0053] S300: Vibration-induced loosening and deagglomeration. The piezoelectric transducer 400 is activated, and the drive controller 600 applies a high-frequency alternating voltage to it, causing the vibrating diaphragm 300 to vibrate mechanically. This vibrational energy is transferred to the solid tracer particles within the containment cavity 110, causing the particle aggregates that were originally bound together by electrostatic forces, van der Waals forces, or capillary forces to loosen and deagglomerate, restoring them to smaller particles or particle clusters. Due to the shallow structure design of the containment cavity 110, all particles are confined within the effective range of the vibrating diaphragm 300, ensuring the high efficiency of the loosening and deagglomeration process.

[0054] S400: Screening, migration, and output. The carrier gas and cross-screen carrier gas begin operating simultaneously with the vibration.

[0055] Within the containment cavity 110, particles smaller than the sieve apertures 210 on the sieve partition plate 200 after vibrational deagglomeration will pass through the sieve apertures 210 under the combined effect of two factors: first, the random kinetic energy gained by the particles due to vibration gives them the opportunity to collide with the sieve apertures 210; second, the gentle upward airflow formed by the low-flow cross-sieve carrier gas entering from the migration inlet provides a directional migration force for the particles, guiding them through the sieve apertures 210 into the upper carrier gas cavity 120. Larger aggregates still larger than the sieve apertures 210 will be effectively trapped by the sieve partition plate 200, remaining within the containment cavity 110 and undergoing continuous vibration until they are broken down to a sufficiently small size.

[0056] Within the carrier gas chamber 120, the carrier gas flows horizontally from the carrier gas inlet to the particle outlet. When particles pass through the sieve holes 210 and enter the carrier gas chamber 120, they are immediately captured, mixed, and diluted by the carrier gas, forming a uniformly concentrated particle-gas mixture. Finally, the mixture, driven by the carrier gas, exits from the particle outlet and is transported to the designated PIV measurement area.

[0057] That is, piezoelectric vibration is responsible for the active loosening and deagglomeration of the main powder, low-flow cross-screen carrier gas is responsible for the directional cross-screen migration of qualified particles, and carry-on carrier gas is responsible for the carry-on output of particles after sieving.

[0058] S500: Dynamic Control. During particle release, the operating parameters of the device can be dynamically adjusted according to experimental needs or feedback signals from a downstream particle concentration monitoring system. Specifically, concentration parameters can be obtained through a light-scattering-based particle counter. When a decrease in particle output rate is detected, it may be due to the formation of stubborn agglomerates that are difficult to decompose. In this case, the drive controller 600 can automatically or manually switch to alternating drive or frequency sweep drive modes to enhance the ability to break down local agglomerates, such as... Figure 5 As shown. Furthermore, the particle release rate can be linearly adjusted by regulating the amplitude of the driving voltage or by using pulsed drive and changing its duty cycle. Simultaneously, the cross-screen carrier gas flow rate and the carry-over carrier gas flow rate can be fine-tuned to change the concentration of output particles.

[0059] S600: Stop and Maintenance. After the experiment, first stop the vibration of the piezoelectric transducer 400. The carrier gas flow can be maintained for a short period to purge and empty any residual particles from the carrier gas chamber 120 and downstream pipeline. Then, turn off the gas and power sources. Maintenance can be performed on the device as needed, such as disassembling the device to clean any potentially clogged sieve holes 210 on the sieve separator 200, cleaning the inner walls of the receiving chamber 110 and the carrier gas chamber 120, and replenishing with new tracer particles.

[0060] By clearly separating and coordinating the functions of piezoelectric vibration depolymerization, low-flow airflow-assisted migration, screen size selective passage, and carrier gas-carried output, stable, precise, and flexible control of the solid tracer particle release process can be achieved under the special working condition of microgravity.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solid-state tracer particle generating device, characterized in that, It includes a housing (100), a screen partition plate (200), a vibrating diaphragm (300), and a piezoelectric transducer (400). The housing (100) is provided with a particle chamber, the vibrating diaphragm (300) serves as the bottom wall of the particle chamber, and the sieve partition plate (200) is disposed above the vibrating diaphragm (300) and divides the particle chamber into a receiving chamber (110) and a carrier gas chamber (120); the sieve partition plate (200) is provided with sieve holes (210) for connecting the receiving chamber (110) and the carrier gas chamber (120). The receiving cavity (110) is disposed below the carrier gas cavity (120) and is used to contain solid tracer particles; The piezoelectric transducer (400) is disposed below the vibrating diaphragm (300) and is used to drive the vibrating diaphragm (300) to generate mechanical vibration so that the solid tracer particles in the receiving cavity (110) enter the carrier gas cavity (120). The housing (100) is also provided with a carrier gas inlet and a particle outlet communicating with the carrier gas chamber (120), carrying carrier gas from the carrier gas inlet into the carrier gas chamber (120) and carrying solid tracer particles from the particle outlet.

2. The solid-state tracer particle generator according to claim 1, characterized in that, The housing (100) is also provided with a migration inlet communicating with the receiving cavity (110). The cross-screen carrier gas enters the receiving cavity (110) through the migration inlet and then enters the carrier gas cavity (120) through the sieve hole (210).

3. The solid-state tracer particle generator according to claim 2, characterized in that, It also includes a migration unit, which includes a main gas supply pipe (510) and a branch pipe (520). The gas supply main pipe (510) is connected to the carrier gas inlet and is used to supply the carrier gas to the carrier gas chamber (120); One end of the branch pipe (520) is connected to the main gas supply pipe (510), and the other end is connected to the migration inlet, for supplying the cross-screen carrier gas to the receiving cavity (110).

4. The solid-state tracer particle generator according to claim 3, characterized in that, The migration unit further includes a buffer (530) and a flow equalization component (540), and the branch pipe (520), the buffer (530) and the flow equalization component (540) are connected in sequence; The buffer (530) has a buffer cavity, the flow cross-sectional area of ​​which is larger than the flow cross-sectional area of ​​the branch pipe (520); The flow equalization element (540) is provided with a plurality of flow limiting holes, which are used to connect the buffer cavity and the receiving cavity (110).

5. The solid-state tracer particle generator according to claim 4, characterized in that, The piezoelectric transducer (400) includes a plurality of piezoelectric units (410), which are disposed on the side of the vibrating diaphragm (300) away from the screen separator (200).

6. The solid-state tracer particle generator according to claim 5, characterized in that, It also includes a drive controller (600) for applying drive signals to the plurality of piezoelectric units (410); The drive controller (600) can drive multiple piezoelectric units (410) by at least one of the following methods: overall synchronous drive, alternating drive, frequency sweep drive, or pulse drive.

7. The solid-state tracer particle generator according to claim 1, characterized in that, It also includes a grounding conductive element (700), which is disposed at the particle outlet and is used to release the charge accumulated by the solid tracer particles during transportation.

8. A method for generating solid-state tracer particles, employing the solid-state tracer particle generating apparatus as described in any one of claims 1-7, characterized in that, Includes the following steps: Solid tracer particles are filled into the containment cavity (110), and the piezoelectric transducer (400) drives the vibrating diaphragm (300) to generate mechanical vibration so that the solid tracer particles in the containment cavity (110) are loosened and deagglomerated. Particles that meet the sieving conditions enter the carrier gas chamber (120) through the sieve holes (210), while agglomerates that exceed the allowable size of the sieve holes (210) are trapped in the receiving chamber (110) by the sieve partition plate (200) and continue to be subjected to vibration. Particles entering the carrier gas chamber (120) are discharged from the particle outlet under the carrying of the carrier gas.

9. The solid-state tracer particle generation method according to claim 8, characterized in that, The piezoelectric transducer (400) includes a plurality of piezoelectric units (410), which are driven by at least one of the following methods: overall synchronous drive, alternating drive, frequency sweep drive, or pulse drive.

10. The solid-state tracer particle generation method according to claim 8, characterized in that, Carrier gas is introduced into the receiving cavity (110) so that the carrier gas carries particles that meet the sieving conditions from the receiving cavity (110) into the carrier gas cavity (120).

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