A sealed dust cloud suspension test device and method

Abstract

This invention discloses a closed-loop dust cloud suspension test device and method, comprising a main body, a gas distribution system, and a data acquisition system. The main body includes a glass tube and a dust cloud generator, with a dust filter screen at the upper end of the glass tube. The gas distribution system adopts a dual-path structure with independent main and maintenance gas paths. The main path includes two parallel jetting branches, capable of outputting pulsed airflows at different pressures at different times. The maintenance gas path is used for precise adjustment and compensation of the gas flow rate. The data acquisition system enables simultaneous triggering and acquisition from multiple devices. The test method employs a three-stage gas distribution strategy: pre-dispersion, main dispersion, and quasi-steady-state maintenance. Concentration feedback cascade control is used to adjust the maintenance gas flow rate to compensate for dust settling losses, achieving quasi-steady-state suspension of the dust cloud and simultaneously acquiring multi-source test data. This invention significantly extends the effective suspension time of the dust cloud, meeting the requirements for time-series precision measurement and improving the reliability of test data.

Description

Technical Field

[0001] This invention relates to a closed-loop dust cloud suspension test device and method. Background Technology

[0002] Dust cloud suspension is a common physical phenomenon in industrial production, agricultural processing, and energy sectors. Industries such as chemical engineering, metallurgy, grain storage and transportation, and powder handling generate significant dust cloud suspension environments. Studying the suspension characteristics of different types of dust in free space, including parameters such as suspension concentration, suspension time, particle size distribution evolution, and spatial uniformity, is of significant scientific and engineering value for revealing dust explosion mechanisms, assessing explosion risks in industrial sites, and developing safety protection standards.

[0003] Existing dust cloud testing equipment mainly includes 20-Litre Spherical Explosion Test Apparatus, Hartmann Tubes, and various pipeline-type dust explosion testing systems. These devices typically employ a dispersion method using a powder storage tank combined with a single high-pressure gas injection. This involves instantaneously releasing high-pressure gas via a solenoid valve to inject the dust sample from the storage tank into the test chamber, forming an initial dust cloud, which is then ignited or measured. However, the aforementioned existing technologies have the following technical drawbacks:

[0004] First, existing devices all operate on an open-loop, single-jet mode, lacking active means to control the state of the dust cloud after the jetting process. The dust cloud settles rapidly under gravity, with an effective suspension time typically ranging from hundreds of milliseconds to several seconds. This fails to meet the need for time-series, precise measurements of the dust cloud suspension process, making it difficult to obtain the dynamic evolution patterns of key parameters such as concentration and velocity fields.

[0005] Second, in the existing device, each data acquisition device operates independently. There is a lack of a unified time reference and synchronization triggering mechanism between the laser dust particle counter, high-speed camera and pressure / temperature sensor. This results in the concentration data, image data and sensor data being out of sync in time, making it difficult to carry out multi-source data fusion analysis and cross-validation.

[0006] Third, most existing test chambers are either completely sealed or open pipe structures. Completely sealed chambers experience a continuous increase in internal pressure during continuous gas replenishment, making it impossible to maintain a stable low gas velocity environment; open pipe structures cause dust to escape with the airflow, making it impossible to maintain the concentration inside the pipe. Neither is suitable for test scenarios that require maintaining a quasi-steady-state suspension of dust clouds for a long time.

[0007] Therefore, there is an urgent need for a closed dust cloud suspension test device and method that can achieve quasi-steady-state maintenance of dust clouds and has the ability to collect multi-source data synchronously. Summary of the Invention

[0008] The present invention provides a closed dust cloud suspension test device and method to solve the problems existing in the prior art.

[0009] The technical solutions adopted in this invention are as follows:

[0010] A closed-loop dust cloud suspension test device includes a main body, a gas distribution system, and a data acquisition system;

[0011] The main body includes a dust cloud generator and a glass tube. The upper end of the glass tube is equipped with a dust filter screen. The dust cloud generator is sealed to the lower end of the glass tube, and the dust outlet is placed inside the glass tube.

[0012] The gas distribution system is connected to the dust cloud generator and the glass tube respectively to provide the test gas;

[0013] The data acquisition system includes a data acquisition unit and a laser dust particle counter, a high-speed camera, and a sensor electrically connected to the data acquisition unit. The laser dust particle counter is connected to a glass tube, the high-speed camera is positioned opposite to the glass tube, and the sensor is mounted on the glass tube.

[0014] Furthermore, the pore size of the dust filter is 0.1μm~5μm.

[0015] Furthermore, the gas distribution system includes a main gas path, a sustaining gas path, an air tank, and an air compressor. A main air inlet is provided on the dust cloud generator, and a sustaining air inlet is provided at the bottom of the glass tube. The main gas path is connected to the main air inlet, the sustaining gas path is connected to the sustaining air inlet, the air tank is connected to the air compressor, and both the main gas path and the sustaining gas path are connected to the air tank.

[0016] Furthermore, the main air path includes a first injection branch and a second injection branch, which are connected in parallel and then connected to the main air inlet;

[0017] The first and second jetting branches are each equipped with a pressure reducing valve and a high-pressure solenoid valve, which are used to output pulsed airflows of different pressures in different time periods.

[0018] The maintaining gas line is equipped with a proportional valve and a mass flow meter.

[0019] Furthermore, the sensor is a pressure sensor and / or a temperature sensor.

[0020] This invention also discloses a test method for a closed-loop dust cloud suspension test device, comprising the following steps:

[0021] S1: Pre-dispersion stage:

[0022] The control gas distribution system applies a first pulse airflow to the dust cloud generator through the main gas path. The gas distribution pressure of the first pulse airflow is within the first pressure range and lasts for a first preset duration, so that the dust in the dust cloud generator is initially fluidized and the agglomeration is broken.

[0023] S2: Main Distributed Phase:

[0024] The control gas distribution system applies a second pulse airflow to the dust cloud generator through the main gas path. The gas distribution pressure of the second pulse airflow is in the second pressure range and lasts for a second preset duration, which fully disperses the dust in the dust cloud generator into the glass tube to form an initial dust cloud.

[0025] S3: Quasi-steady-state maintenance phase:

[0026] A laser dust particle counter is used to collect the dust concentration value inside the glass tube in real time, and the concentration deviation between the dust concentration value and the preset target concentration value is calculated.

[0027] Adjust the output flow rate of the maintenance gas path according to the concentration deviation, and control the rising gas velocity in the tube to maintain a quasi-steady-state concentration dynamic balance of the dust cloud in the glass tube within the preset target concentration range.

[0028] When the dust concentration exceeds the safe concentration threshold and / or the sensor detection value exceeds the safe threshold, the gas supply to the gas distribution system will be automatically cut off.

[0029] S4: Synchronous Data Acquisition Phase

[0030] During the quasi-steady-state maintenance phase, a synchronization trigger signal is sent to the laser dust particle counter, high-speed camera, and sensor via a data acquisition unit, enabling the laser dust particle counter, high-speed camera, and sensor to acquire dust concentration data, image data, and sensor data synchronized with the time reference.

[0031] Furthermore, the first pressure range is 0.1MPa~0.3MPa, and the first preset duration is 50ms~200ms;

[0032] The second pressure range is 0.5MPa~0.8MPa, and the second preset duration is 100ms~300ms.

[0033] Furthermore, in S3, the output flow rate of the maintenance gas path is cascaded, including inner loop flow control and outer loop concentration feedback, wherein:

[0034] The inner loop is the flow control loop, which adjusts the opening of the proportional valve according to the target flow rate;

[0035] The outer loop is a concentration control loop, which corrects the target flow rate based on the concentration deviation.

[0036] Furthermore, in S4, the data acquisition unit sends a hardware synchronization trigger signal to the laser dust particle counter, high-speed camera, and sensor, enabling the laser dust particle counter, high-speed camera, and sensor to start acquiring data synchronously under the same time reference.

[0037] Furthermore, in S3, when the dust concentration value remains within ±20% of the preset target concentration value and reaches the preset stable duration, it is determined that the dust cloud in the glass tube maintains a quasi-steady-state dynamic equilibrium.

[0038] The present invention has the following beneficial effects:

[0039] This invention employs a three-stage pulsed gas distribution strategy comprising a pre-dispersion stage, a main dispersion stage, and a quasi-steady-state maintenance stage, and introduces concentration feedback closed-loop control. In the pre-dispersion stage, low-pressure pulsed airflow initially fluidizes the dust and breaks up agglomerations. In the main dispersion stage, high-pressure pulsed airflow fully disperses the dust throughout the glass tube. In the quasi-steady-state maintenance stage, based on the real-time dust concentration value collected by the laser dust particle counter, the output flow rate is dynamically adjusted through the maintaining gas path to compensate for dust settling losses, ensuring that the dust cloud within the glass tube maintains a quasi-steady-state concentration dynamic balance within a preset target concentration range. Compared to the open-loop single-jet mode of existing technologies, this invention significantly extends the effective suspension time of the dust cloud, enabling precise, time-sequential measurement of the dust cloud suspension process.

[0040] This invention employs a dual-path gas design, consisting of a main gas path and a maintenance gas path. The main gas path is equipped with a high-pressure solenoid valve and a pressure reducing valve, responsible for high-pressure pulse jetting during the pre-dispersion and main dispersion stages. The maintenance gas path is equipped with a proportional valve and a mass flow meter, responsible for accurate low-flow compensation during the quasi-steady-state maintenance stage. The two gas paths are controlled independently, solving the problem that a single control valve's range cannot simultaneously cover both high-pressure pulse and low-pressure maintenance conditions, thus improving the control accuracy and adaptability of the gas distribution system.

[0041] The present invention provides a dust filter screen at the upper end of the glass tube. The pore size of the dust filter screen is 0.1μm~5μm, which allows gas to escape to maintain a slightly positive pressure environment inside the tube, while preventing dust particles from escaping. This provides the physical conditions for continuous gas replenishment to maintain quasi-steady suspension and overcomes the technical contradiction of continuously increasing pressure in a completely sealed cavity or dust escaping in an open structure.

[0042] This invention sends synchronous trigger signals to a laser dust particle counter, a high-speed camera, and sensors via a data acquisition device, enabling each acquisition device to start acquiring data synchronously under the same time reference. This allows for the acquisition of dust concentration data, image data, and sensor data that are synchronized with the time reference, solving the problem of asynchronous multi-source data and difficulty in fusion analysis in existing technologies, and improving the reliability and comparability of experimental data.

[0043] This invention employs a cascade control strategy of inner-loop flow control and outer-loop concentration feedback. The inner loop rapidly adjusts the proportional valve opening based on the target flow rate, while the outer loop slowly corrects the target flow rate based on the concentration deviation. This adapts to the system characteristics of large inertia and large hysteresis in the dust concentration field, avoids the problem of easy oscillation in single-loop control, and improves the control stability during the quasi-steady-state maintenance phase. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0045] The invention will now be further described with reference to the accompanying drawings.

[0046] like Figure 1 As shown, the present invention provides a closed dust cloud suspension test device, which includes a main body, a gas distribution system and a data acquisition system. It can be used to conduct dust cloud suspension characteristic tests under different dust types, different injection pressures and different target concentrations, and to obtain multi-dimensional test data such as dust concentration, morphological evolution and pressure and temperature.

[0047] Glass tube 1 is a vertical cylindrical tube structure made of transparent organic glass, with openings at both the top and bottom. Its lower end is sealed to the upper protruding structure of dust cloud generator 2 through a silicone sealing gasket to ensure airtightness at the connection.

[0048] The dust cloud generator 2 has its outlet extending into the glass tube 1 to spray dust samples into the cavity. A dust filter 3 is fixedly installed at the upper end of the glass tube 1. The pore size of the dust filter 3 ranges from 0.1μm to 5μm, which allows the gas inside the tube to be discharged smoothly to maintain a slightly positive pressure environment in the cavity and avoids the continuous increase in internal pressure caused by continuous gas supply. At the same time, it can effectively trap the dust particles used in the test and prevent the dust from escaping with the airflow, causing concentration loss and environmental pollution.

[0049] The dust cloud generator 2 is made of stainless steel and has an internal dust-containing chamber and a dispersion channel. A main air inlet is located at the bottom. High-pressure airflow enters through the main inlet and evenly sprays the dust sample contained inside into the glass tube 1 through the dust outlet. Sensors, including pressure and temperature sensors, are installed on the upper part of the side wall of the glass tube 1 to monitor the pressure and temperature parameters inside the chamber in real time. A maintenance air inlet and a purging port are located on the lower side wall of the glass tube 1. The maintenance air inlet is used to connect to the compensating airflow during the steady-state maintenance phase. The airflow directly enters the chamber and forms an upward airflow to compensate for the gravitational settling of dust particles. The purging port is used to connect to an inert gas purging circuit.

[0050] The gas distribution system provides gas sources for the unit under different operating conditions, including air storage tank 6, air compressor 7, main air line 5, maintenance air line 4, and purging air line (purging air line is shown for ease of drawing). Figure 1 (Not shown in the diagram). The air compressor 7 is connected to the air tank 6 and is used to fill the air tank 6 with compressed air and maintain a stable air source pressure. The output end of the air tank 6 is connected to the main air circuit 5 and the maintenance air circuit 4 respectively. The two air circuits are independently controlled and do not interfere with each other, corresponding to the two working conditions of pulse powder injection and steady-state maintenance respectively.

[0051] The main air path 5 is used to output pulsed airflows at different pressures to complete the pre-dispersion and main dispersion processes of dust. It includes a first jetting branch 51 and a second jetting branch 52, which are connected in parallel and jointly connected to the main air inlet at the bottom of the dust cloud generator 2. Each of the first jetting branch 51 and the second jetting branch 52 is equipped with a pressure reducing valve and a high-pressure solenoid valve. Different output pressures can be preset through the pressure reducing valves on the two branches, and the on / off time of the corresponding branch can be controlled by the high-pressure solenoid valve to output pulsed airflows with two different pressure parameters in a time-sharing manner, so as to meet the pressure requirements of the two-stage dust spraying.

[0052] The maintaining gas path 4 is used for precise adjustment of the gas supply flow during the quasi-steady-state maintenance phase. Its output end is connected to the maintaining gas inlet on the lower side wall of the glass tube 1. The airflow does not pass through the dust-containing cavity of the dust cloud generator 2, avoiding the continuous airflow from stirring up residual dust and interfering with the cavity concentration. A proportional valve and a mass flow meter are sequentially installed on the maintaining gas path 4. The mass flow meter detects the current gas supply flow in real time and feeds it back to the control system. The proportional valve adjusts its opening in real time according to the control signal, realizing closed-loop precise control of the gas supply flow.

[0053] The purging air path includes an inert gas source and a purging solenoid valve. The purging solenoid valve is installed on the pipeline between the inert gas source and the purging interface. It is used to control the on / off of inert gas (generally N2). Inert gas is introduced into the cavity after the safety interlock is triggered or the test is completed to achieve dust inerting and cavity cleaning.

[0054] The data acquisition system includes a data acquisition unit, a laser dust particle counter, a high-speed camera, and sensors mounted on glass tube 1. All acquisition devices are electrically connected to the data acquisition unit.

[0055] The sampling channel of the laser dust particle counter is connected to the sampling port on the side wall of the glass tube 1 through a silicone seal, and the dust concentration and particle size distribution data at a specified location inside the tube are collected in real time.

[0056] A high-speed camera is positioned to the side of glass tube 1, with its lens axis perpendicular to the axis of glass tube 1, to capture the spatial morphology and motion evolution of the dust cloud through the transparent tube wall.

[0057] The pressure sensor and temperature sensor are installed in the upper middle part of the side wall of glass tube 1, away from the interference area of ​​the air inlet jet, so as to accurately reflect the real pressure and temperature state inside the cavity.

[0058] The data acquisition unit can output a unified hardware synchronization trigger signal to all acquisition devices, ensuring that concentration data, image data, and sensor data are all acquired based on the same time reference, realizing time axis alignment of multi-source data, and providing a foundation for subsequent data fusion analysis and cross-validation.

[0059] Before conducting the experiment, a quantitative dust sample is loaded into the dust containment chamber of the dust cloud generator 2. The sealing connection of each component and the power-on debugging of the equipment are completed. According to the requirements of the test conditions, the low-pressure pulse pressure is preset through the pressure reducing valve of the first jet branch 51, and the high-pressure pulse pressure is preset through the pressure reducing valve of the second jet branch 52. At the same time, the target concentration value, cascade control parameters and various safety threshold parameters of the quasi-steady-state stage are set, and the connection and pressure debugging of the inert gas source are completed.

[0060] After the experiment starts, it first enters the pre-dispersion stage. The control system triggers the high-pressure solenoid valve of the first jet branch 51 to open, and then closes after a first preset time, outputting a low-pressure pulsed airflow within the first pressure range. After the low-pressure airflow enters the dust cloud generator 2, it initially fluidizes the dust bed accumulated inside, breaking the agglomeration structure between dust particles and preventing large particle agglomerates from forming during subsequent high-pressure jetting, thus providing a basis for full dispersion. In this embodiment, the first pressure range is 0.1MPa~0.3MPa, and the first preset time is 50ms~200ms. The specific parameters can be adaptively adjusted according to the type of dust and the test objective.

[0061] Immediately after the pre-dispersion stage, the main dispersion stage begins. The control system triggers the high-pressure solenoid valve of the second jet branch 52 to open, and then closes after a second preset duration, outputting a high-pressure pulsed airflow within the second pressure range. This high-pressure airflow fully lifts the dust in the dust cloud generator 2 and transports it throughout the entire space of the glass tube 1, forming a relatively uniformly distributed initial dust cloud. During the main dispersion stage, the pressure value inside the glass tube 1 is simultaneously detected by a pressure sensor. When the pressure exceeds a preset safety pressure threshold, the air supply to the second jet branch 52 is immediately cut off, and the purge solenoid valve is opened to introduce inert gas for depressurization and inerting, preventing overpressure in the cavity from causing sealing failure or equipment damage. In this embodiment, the second pressure range is 0.5MPa~0.8MPa, and the second preset duration is 100ms~300ms. Specific parameters can be adjusted according to actual operating conditions.

[0062] After the main dispersion phase, the system enters a quasi-steady-state maintenance phase. A laser dust particle counter collects the dust concentration value inside glass tube 1 in real time at a fixed sampling frequency. The control system calculates the concentration deviation between the current measured concentration and the preset target concentration value, and adjusts the output flow rate of the maintenance gas path 4 using a cascade control method. The inner loop is a flow control loop, which rapidly adjusts the opening of the proportional valve according to the target flow rate to ensure the gas supply flow rate stably follows the target value and responds quickly to flow disturbances. The outer loop is a concentration control loop, which slowly corrects the target flow rate value of the inner loop according to the concentration deviation. It compensates for the gravity settling loss of dust by continuously supplementing the rising airflow, causing the dust concentration inside glass tube 1 to dynamically fluctuate within ±20% of the preset target concentration value. When the concentration remains within this range and reaches a preset stable duration, the dust cloud is determined to have entered a quasi-steady-state dynamic equilibrium state. During the quasi-steady-state maintenance phase, full-parameter safety interlock monitoring is performed simultaneously. When the dust concentration exceeds the safety concentration threshold, or when the parameters detected by the pressure sensor and temperature sensor exceed the corresponding safety threshold, the control system automatically cuts off the gas supply to the maintenance gas path 4 and simultaneously opens the purging solenoid valve to introduce inert gas to inertize and replace the dust cloud in the chamber, thereby terminating the test process and ensuring the safety of equipment and personnel.

[0063] During the quasi-steady-state maintenance phase, synchronous data acquisition can be initiated according to experimental requirements. The data acquisition unit sends a unified hardware synchronization trigger signal to enable the laser dust particle counter, high-speed camera, and sensors to synchronously start acquisition, obtaining concentration data, image data, and pressure and temperature data that are completely aligned with the time reference. This data can then be used for subsequent analysis of the dust cloud's concentration evolution, spatial distribution, and suspension stability.

[0064] After the test is completed, close all the air supply valves of the main air circuit 5 and the maintenance air circuit 4, open the purging solenoid valve to continuously introduce inert gas, remove the dust filter 3 from the upper port of the glass tube 1, and use the inert gas to push the residual dust in the tube out with the airflow to complete the cleaning and inerting treatment of the cavity, reduce the safety hazards caused by residual dust, and prepare for the next test.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A closed-loop dust cloud suspension test device, characterized in that: Includes the main body, gas distribution system, and data acquisition system; The main body includes a dust cloud generator and a glass tube. The upper end of the glass tube is equipped with a dust filter screen. The dust cloud generator is sealed to the lower end of the glass tube, and the dust outlet is placed inside the glass tube. The gas distribution system is connected to the dust cloud generator and the glass tube respectively to provide the test gas; The data acquisition system includes a data acquisition unit and a laser dust particle counter, a high-speed camera, and a sensor electrically connected to the data acquisition unit. The laser dust particle counter is connected to a glass tube, the high-speed camera is positioned opposite to the glass tube, and the sensor is mounted on the glass tube.

2. The closed-loop dust cloud suspension test device as described in claim 1, characterized in that: The pore size of the dust filter is 0.1μm~5μm.

3. The closed-loop dust cloud suspension test device as described in claim 1, characterized in that: The gas distribution system includes a main gas path, a sustaining gas path, a gas storage tank, and an air compressor. A main air inlet is provided on the dust cloud generator, and a sustaining air inlet is provided at the bottom of the glass tube. The main gas path is connected to the main air inlet, the sustaining gas path is connected to the sustaining air inlet, the gas storage tank is connected to the air compressor, and both the main gas path and the sustaining gas path are connected to the gas storage tank.

4. The closed-loop dust cloud suspension test device as described in claim 3, characterized in that: The main air path includes a first injection branch and a second injection branch, which are connected in parallel and then connected to the main air inlet. The first and second jetting branches are each equipped with a pressure reducing valve and a high-pressure solenoid valve, which are used to output pulsed airflows of different pressures in different time periods. The maintaining gas line is equipped with a proportional valve and a mass flow meter.

5. The closed-loop dust cloud suspension test device as described in claim 1, characterized in that: The sensor is a pressure sensor and / or a temperature sensor.

6. A test method for a closed dust cloud suspension test device as described in any one of claims 1-5, characterized in that: Includes the following steps: S1: Pre-dispersion stage: The control gas distribution system applies a first pulse airflow to the dust cloud generator through the main gas path. The gas distribution pressure of the first pulse airflow is within the first pressure range and lasts for a first preset duration, so that the dust in the dust cloud generator is initially fluidized and the agglomeration is broken. S2: Main Distributed Phase: The control gas distribution system applies a second pulse airflow to the dust cloud generator through the main gas path. The gas distribution pressure of the second pulse airflow is in the second pressure range and lasts for a second preset duration, which fully disperses the dust in the dust cloud generator into the glass tube to form an initial dust cloud. S3: Quasi-steady-state maintenance phase: A laser dust particle counter is used to collect the dust concentration value inside the glass tube in real time, and the concentration deviation between the dust concentration value and the preset target concentration value is calculated. Adjust the output flow rate of the maintenance gas path according to the concentration deviation, and control the rising gas velocity in the tube to maintain a quasi-steady-state concentration dynamic balance of the dust cloud in the glass tube within the preset target concentration range. When the dust concentration exceeds the safe concentration threshold and / or the sensor detection value exceeds the safe threshold, the gas supply to the gas distribution system will be automatically cut off. S4: Synchronous Data Acquisition Phase During the quasi-steady-state maintenance phase, a synchronization trigger signal is sent to the laser dust particle counter, high-speed camera, and sensor via a data acquisition unit, enabling the laser dust particle counter, high-speed camera, and sensor to acquire dust concentration data, image data, and sensor data synchronized with the time reference.

7. The test method of the closed dust cloud suspension test device as described in claim 6, characterized in that: The first pressure range is 0.1MPa~0.3MPa, and the first preset duration is 50ms~200ms; The second pressure range is 0.5MPa~0.8MPa, and the second preset duration is 100ms~300ms.

8. The test method of the closed dust cloud suspension test device as described in claim 6, characterized in that: In S3, the output flow rate of the maintenance gas path is cascaded, including inner loop flow control and outer loop concentration feedback, wherein: The inner loop is the flow control loop, which adjusts the opening of the proportional valve according to the target flow rate; The outer loop is a concentration control loop, which corrects the target flow rate based on the concentration deviation.

9. The test method of the closed dust cloud suspension test device as described in claim 6, characterized in that: In S4, the data acquisition unit sends a hardware synchronization trigger signal to the laser dust particle counter, high-speed camera, and sensor, enabling the laser dust particle counter, high-speed camera, and sensor to start data acquisition synchronously under the same time reference.

10. The test method of the closed dust cloud suspension test device as described in claim 6, characterized in that: In S3, when the dust concentration value remains within ±20% of the preset target concentration value and reaches the preset stable duration, it is determined that the dust cloud in the glass tube maintains a quasi-steady-state dynamic equilibrium.

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