Static generation equivalent simulation and measurement device oriented to AP particle pipeline conveying process

Abstract

The invention provides a static electricity generation equivalent simulation and measurement device for an ammonium perchlorate particle pipeline conveying process. In the device, particles enter the pipeline under the action of negative pressure, and in the process of moving in the pipeline, the particles collide with and rub against the inner wall of the pipeline and accumulate electrostatic charges. In the movement process, the high-speed camera records the particle movement condition in real time through the transparent observation section, image processing software is matched to track the particle track, parameters such as the density, the speed and the position of the particles are exported, and the dryer and the temperature and humidity monitor monitor and control the temperature and the humidity in the pipeline. Moving particles are collected into the Faraday cylinder by the branch pipe, and the charge-to-mass ratio of the particles at the position within the measurement time is obtained by combining a high-speed picoammeter and a computer. By changing the positions and the number of the branch pipes and replacing the pipeline paths, the particle electrostatic generation characteristics under different pipeline conditions are finally revealed.

Description

Technical Field

[0001] The present invention relates to the technical field of solid rocket engines, and in particular to an electrostatic generation equivalent simulation and measurement device for an AP particle pipeline transportation process. Background Art

[0002] In the production of propellants for solid rocket engines, ammonium perchlorate (AP) serves as the propellant's oxidizer. It is mixed and cured with metal powder, butane, and a curing agent to form the solid rocket propellant. AP has three key advantages in the solid rocket propellant production process: 1. High volume; 2. Strong insulation; and 3. Its granular form. During the charging process, AP granules can be loaded in quantities of several tons. Furthermore, AP granules are highly insulating and carry static electricity that is difficult to dissipate. Once the static electricity from the AP granules dissipates into the air, the static discharge can easily lead to explosion accidents.

[0003] Specifically, energetic particles including AP are prone to static electricity accumulation through friction or contact electrification with the inner walls of tools of different materials during screening, transportation, and feeding. Static electricity accumulation may cause great harm to the propellant production and transportation process. Dozens of serious explosions caused by static electricity discharge have occurred at home and abroad, including the US Pershing II missile and Peacekeeper solid engine, causing significant casualties.

[0004] Due to the particularity of the pyrotechnics industry, the safety issues of static electricity generation, accumulation, and release in the AP particle pipeline transportation process have not been deeply studied. Researchers in related industries, including coal powder, pharmaceutical particles, and flour electrostatic safety, have conducted various forms of similar research, including material-level electrostatic sensitivity research, particle electrostatic simulation research, and particle electrostatic emulation research. However, there is still a lack of a complete and mature set of classic safety equivalent simulation and testing devices for the AP particle pipeline transportation process to simulate the entire process and conduct real-time measurement of the AP particle electrostatic generation process in the pipeline transportation process. Summary of the Invention

[0005] In view of this, the present invention provides an equivalent simulation and measurement device for static electricity generation in the pipeline transportation process of AP particles. In this device, an air pump provides negative pressure, so that the AP particles stored in the silo enter the pipeline. The AP particles and the AP particles and the inner wall of the pipeline collide and rub against each other and accumulate charges. When the AP particles pass through the transparent observation section, the high-speed camera records their flow state. The Faraday cup collects the AP particles undergoing the pipeline transportation process through the branch pipe, and the mass of the particles in the measuring section is obtained in combination with the balance. The particle current is measured using a high-speed picoammeter, and the real-time current change curve of the AP particles at this position and the average charge-to-mass ratio during the measurement time are calculated using a computer. The AP particles that are not collected eventually fall into the receiving silo. Specifically, the high-speed camera can measure the number of particles, particle diameter, particle speed, motion state (sliding / rolling), motion trajectory, and particle density.

[0006] The static electricity generation simulation and measurement device for the AP particle pipeline conveying process includes an air pump, a high-speed picoammeter, a high-speed camera, a Faraday cup, a computer, a conveying pipe, a branch pipe, a transparent observation section, a filter, a dryer, a temperature regulator, a silo, a nitrogen cylinder, a receiving silo, an static electricity release grounding circuit and supporting circuits.

[0007] The air pump draws out the protective gas in the pipeline, providing power for the AP particles to enter the conveying pipeline from the silo; the nitrogen cylinder stores the protective gas nitrogen required for the experiment. Before starting the air pump, the entire set of pipelines is filled with nitrogen. Nitrogen has extremely stable chemical properties and can effectively prevent dangerous situations such as AP particles from exploding; the high-speed camera, model Phantom TMX 7510, can capture particle behavior through a transparent observation section. The camera has a speed of up to 76,000 frames per second at a resolution of 1280*800. The captured image sequence can be processed by photron image processing software to track particle trajectories and derive parameters such as particle number, diameter, density, speed, position, motion state, and motion trajectory; the Faraday cup and high-speed picoammeter can measure the charge of the particles. The present invention uses a Keithley 6487 series high-speed picoammeter with a kHz sampling rate in combination with a Faraday cup to measure current and particle charge, and a real-time current change curve can be obtained.

[0008] Solid motor propellant oxidizer transportation production process safety technology, static electricity generation and release simulation and measurement technology, specifically involving the simulation and real-time measurement of the static electricity generation process when ammonium perchlorate particles are transported in a pipeline using negative pressure transportation.

[0009] The advantages of the present invention are:

[0010] 1. In view of the explosive characteristics of AP particles, a series of safety and explosion-proof designs were implemented, including using nitrogen to fill the pipeline as a protective gas, using negative pressure to provide power to the AP particles without destroying the protective gas environment in the pipeline, using a dryer and temperature regulator to control and monitor the temperature and humidity in the pipeline, adding a filter at the silo outlet to prevent impurities mixed with AP particles from entering the experimental pipeline, and adding a filter in front of the air pump to prevent AP particles from entering the air pump and causing danger.

[0011] 2. A spliced pipe design is proposed, which can adjust the friction length by changing the number of connected pipes. The straight pipe and elbow can be used in combination to simulate the actual transportation conditions on the production line. At the same time, the pipe material is adjustable, which can be used to simulate the effects of friction speed, friction length, pipe path, pipe material and inner surface treatment on the static electricity of the AP particle pipeline transportation process in the production line.

[0012] 3. The branch pipe, Faraday cup and high-speed picoammeter are used together to take real-time online samples from the AP particle flow, minimizing the impact on the state of the AP particles to obtain relatively original particle charge data. After connecting the picoammeter, a real-time current change curve is obtained, realizing the dynamic collection process of particle electrostatic accumulation. The particle charge over a period of time can be obtained by integration, and the mass of the particles falling into the Faraday cup is easy to measure, which is conducive to further analysis and the acquisition of other physical quantities including the average charge-to-mass ratio.

[0013] 4. A transparent observation section design was proposed. Under the premise of minimizing changes to the production line, a high-speed camera was used to record the movement state of AP particles in the pipeline in real time, monitor the particle translational velocity, rolling angular velocity, and whether there is eddy current phenomenon, which is conducive to further analysis.

[0014] Other features and advantages of the present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the static electricity generation simulation and measurement device in the AP particle pipeline transportation process;

[0016] Figure 2 This is a schematic diagram of the Faraday cup real-time collection device;

[0017] Among them, 1-air pump, 2-filter I, 3-high-speed picoammeter, 4-computer, 5-Faraday cup, 6-transparent observation section, 7-high-speed camera, 8-delivery pipe, 9-temperature regulator, 10-dryer, 11-filter II, 12-feed valve, 13-silo, 14-nitrogen cylinder, 15-receiving silo, 16-grounding circuit, 17-branch pipe. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0019] As attached Figure 1 As shown, the present invention provides a set of AP particle electrostatic generation simulation and measurement device, which includes an air pump 1, a filter I2, a high-speed picoammeter 3, a computer 4, a Faraday cup 5, a transparent observation section 6, a high-speed camera 7, a conveying pipe 8, a temperature regulator 9, a dryer 10, a filter II11, a feed valve 12, a silo 13, a nitrogen cylinder 14, a receiving silo 15, a grounding circuit 16, and a branch pipe 17.

[0020] Taking μm-sized AP particles as an example, the AP particles are stored in the silo 13. The nitrogen cylinder 14 is opened to fill the entire pipeline with nitrogen, a safety gas. Using nitrogen with extremely stable chemical properties to fill the pipeline acts as a protective gas, and using negative pressure delivery to provide power for the AP particles can ensure that the protective gas environment in the pipeline is not destroyed. After the air pump 1 is started, negative pressure is provided to the entire pipeline device, and then the feed valve 12 is opened. The AP particles enter the delivery pipe 8 under the action of negative pressure. After entering the delivery pipe 8, they immediately pass through the filter II11 to filter out impurities therein. Then the AP particles move along the pipeline. During this process, the AP particles constantly collide and rub with each other and between the AP particles and the pipeline wall to generate and accumulate static charges. Therefore, the above structure can simulate the pipeline transportation process of AP particles.

[0021] The conveying pipe 8 can adopt an integral molding design or a spliced pipe design. The friction length can be adjusted by changing the number of connected pipes. The straight pipe and elbow can be used in combination to simulate the actual conveying conditions on the production line. At the same time, the material of the pipe is adjustable, which can be used to simulate the influence of friction speed, friction length, pipe path, pipe material and its inner surface treatment on the static electricity generation in the AP particle pipeline conveying process in the production line.

[0022] After passing through the filter II11, the AP particles also pass through the dryer 10. The dryer 10 can dry the AP particles passing therethrough. In addition, a temperature regulator 9 is provided downstream of the dryer 10 in the direction of movement of the AP particles. The dryer 10 and the temperature regulator 9 can monitor and regulate the temperature and humidity conditions in the pipeline in real time. Downstream of the dryer, a transparent observation section 6 is preferably provided, and the conveying pipe 8 has a transparent part in the transparent observation section 6, so that the AP particles can be observed from the outside. Outside the conveying pipe 8, the position of the AP particles inside the conveying pipe 8 can be observed through the transparent observation section 6, and a high-speed camera 7 is provided as an observation device. Thus, the motion state of the AP particles can be observed and recorded by the high-speed camera 7 through the transparent observation section 6. In conjunction with the image processing software, the particle trajectory can be tracked and the parameters such as the density, speed, and position of the particles can be derived.

[0023] Downstream of the transparent observation section, a branch pipe 17 is installed in the conveying pipe 8. This branch pipe 17 has a portion parallel to the conveying pipe 8, positioned against the direction of AP particle movement and having an opening. The remaining portion of the branch pipe 17 extends outside the branch pipe 8 and connects to a Faraday cage 5, collecting the moving AP particles into the cage. The cage 5 is connected to a high-speed picoammeter 3 with a kHz sampling rate to measure the electrostatic dynamic accumulation characteristic (I = dQ / dt) after triboelectric charging of the particles. This data is then imported into a computer 4 to generate the experimental current curve, which can be integrated to obtain the charge carried by the AP particles. Further calculations can be performed to determine the transient average charge-to-mass ratio and the charge-to-mass ratio during the measurement time. By varying the position of the branch pipe 17, the charge of the AP particles at different locations can be measured, allowing for the study of the charge variations throughout the entire pipeline transport process. Alternatively, multiple branch pipes 17 and Faraday cages can be installed at different locations. After the experiment, the air pump 1 is turned off, and the AP particles fall into a recovery silo 15. By varying the length, number of straight pipes, number of elbows, and material, different simulation conditions can be used to simulate static electricity generation. A filter screen 12 is installed upstream of air pump 1 to prevent AP particles from being drawn into air pump 1. A grounding circuit 16 is connected to delivery pipe 8, grounding it and dissipating static electricity within it. Furthermore, multiple grounding circuits can be installed in other parts of delivery pipe 8, ensuring that the simulated delivery pipe is grounded at all locations. This allows for the timely diversion of friction-generated charges into the static electricity dissipation grounding circuit, preventing explosions caused by charge accumulation.

[0024] The instruments involved in the experiment, including air pumps, high-speed picoammeters, high-speed cameras, computers, etc., all meet the intrinsic safety and explosion-proof standards of dust-level equipment protection level under room temperature conditions.

[0025] During the operation of the device, AP particles enter the pipeline under the action of negative pressure. During the movement in the pipeline, the AP particles collide and rub against the inner wall of the pipeline and accumulate static charges. During the movement, the high-speed camera records the movement of the particles in real time through the transparent observation segment, and cooperates with the image processing software to track the trajectory of the particles, and derives the number, diameter, speed, position, motion state (sliding / rolling), motion trajectory, density and other parameters of the particles. The dryer and temperature regulator monitor and control the temperature and humidity in the pipeline. The branch pipe collects the moving AP particles into the Faraday cup. Combined with the balance, the mass of the particles in the measuring section can be measured. Combined with the high-speed picoammeter, the real-time current of the measuring section can be obtained, and the computer calculation method can be used to obtain the average charge-to-mass ratio of the AP particles at this position during the measurement time. Specifically, the picoammeter can obtain the real-time current I, and the charge Q of the measuring section can be obtained based on the time integration of the real-time current I, that is,

[0026]

[0027] and average charge-to-mass ratio

[0028]

[0029] is the average charge-to-mass ratio, Q is the charge of the measurement segment, n is the number of particles, q i is the electrostatic charge of the i-th particle; is the mass of i particles, and w is the mass of the measuring section, which can be obtained by pouring out the particles in the Faraday cage and measuring it with a balance after the experiment.

[0030] The present invention enables real-time online sampling of AP particle flows, minimizing the impact on the state of the AP particles and obtaining relatively raw particle charge data. The branch pipes, Faraday cups, and high-speed picoammeters are used in conjunction to obtain real-time current curves, enabling dynamic acquisition of particle static electricity accumulation. Transient currents can be analyzed to determine the transient average charge-to-mass ratio of the particles, and the charge of the AP particles over the measurement time can be obtained through integration. The mass of the particles that fall into the Faraday cup is easily measured, yielding the charge-to-mass ratio of the AP particles over the measurement time. The branch pipes can be positioned and increased in number to capture static electricity accumulation throughout the entire AP particle movement process.

[0031] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles is characterized by: The device includes an air pump, a high-speed picoammeter, a computer, a branch pipe, a Faraday cup, a high-speed camera, a conveying pipe, a feed valve, a silo containing the ammonium perchlorate particles, and a receiving silo, wherein the air pump is arranged at one end of the conveying pipe, the silo is arranged at the other end of the conveying pipe, the feed valve is arranged downstream of the silo in the conveying pipe, the branch pipe is arranged in the conveying pipe, and the branch pipe is connected to the Faraday cup and is used to introduce the ammonium perchlorate particles from the conveying pipe into the Faraday cup. The conveying pipe has a transparent observation section, and the high-speed camera can collect the motion parameters of the ammonium perchlorate particles through the transparent observation section.

2. The static electricity generation equivalent simulation and measurement device for the ammonium perchlorate granule pipeline transportation process according to claim 1, characterized in that: The device as a whole adopts an explosion-proof design to carry out experimental research on ammonium perchlorate particles.

3. The static electricity generation equivalent simulation and measurement device for the ammonium perchlorate granule pipeline transportation process according to claim 1, characterized in that: A grounding circuit is provided to ground the conveying pipe at all locations, so as to promptly conduct the electric charge generated by friction into the earth to avoid explosion caused by accumulation of electric charge.

4. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles according to any one of claims 1 to 3, characterized in that: A nitrogen cylinder is also provided, which is connected to the delivery pipeline so that the nitrogen fills the pipeline to act as a protective gas and uses negative pressure delivery to provide power for the ammonium perchlorate particles to ensure that the protective gas environment in the pipeline is not destroyed.

5. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles according to any one of claims 1 to 3, characterized in that: A dryer and a temperature regulator are provided in the conveying pipeline to control and monitor the temperature and humidity in the pipeline to ensure that the pipeline environment is in a state that is not prone to combustion and explosion.

6. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles according to any one of claims 1 to 3, characterized in that: A filter is provided at the outlet of the silo to prevent impurities mixed with ammonium perchlorate particles from entering the conveying pipeline, and / or a filter is added in front of the air pump to prevent ammonium perchlorate particles from entering the air pump, thereby avoiding explosion.

7. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles according to any one of claims 1 to 3, characterized in that: The air pump, high-speed picoammeter, high-speed camera, and computer all meet the intrinsic safety explosion-proof standards for dust-level equipment protection at room temperature.

8. The static electricity generation equivalent simulation and measurement device for the pipeline transportation process of ammonium perchlorate particles according to any one of claims 1 to 3, characterized in that: The conveying pipeline adopts a splicable pipeline design, and the friction length can be adjusted by changing the number of connected pipelines. The conveying conditions on the actual production line can be simulated by the combination of straight pipes and elbows. At the same time, the material of the pipeline is adjustable, which can be used to simulate the influence of friction speed, friction length, pipeline path, pipeline material and its inner surface treatment on the static electricity generation in the ammonium perchlorate particle pipeline transportation process in the production line.

9. A method for operating the static electricity generation equivalent simulation and measurement device for the ammonium perchlorate granule pipeline transportation process according to any one of claims 1 to 8, characterized in that: The air pump and the feed valve are opened to allow the ammonium perchlorate particles to move from the silo to the air pump in the conveying pipeline. The movement state of the ammonium perchlorate particles in the pipeline is recorded in real time by the high-speed camera, and / or a branch pipe, a Faraday cup, and a high-speed picoammeter are used in conjunction to obtain a real-time current change curve, realize dynamic collection of particle electrostatic accumulation, and further obtain the average charge-to-mass ratio of the particles.

10. The method according to claim 9, wherein The motion state of ammonium perchlorate particles in the pipeline includes particle velocity, particle mass, particle number, particle translational velocity, rolling angular velocity, and whether eddy current exists.

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