An experimental device and experimental method for studying the disturbance of particle suspension by cleaning behavior

Abstract

The application discloses an experimental device and experimental method for studying the disturbance of particle suspension caused by cleaning behavior, relates to the technical field of building environment, intelligent control and airflow solution model, and comprises a conveying device, a reciprocating cleaning device, a material supply device, a power unit, a control system, a data recording system and a storage system. The application can complete the experimental research on the disturbance of particle suspension caused by the cleaning behavior of particles through a simple control system, and can satisfy the experimental scheme requirements under various working conditions by programming the control system and replacing the reciprocating cleaning device, thereby providing convenience for the experimental research on the disturbance of particle suspension caused by the cleaning behavior. In addition, the application can automatically control after the experimental working condition and parameters are determined, thereby effectively reducing the workload of manual operation while ensuring the experimental efficiency and accuracy.

Description

Technical Field

[0001] The present invention relates to building environment technology, intelligent control technology and airflow solution model technology, and in particular to an experimental device and an experimental method for studying the effect of cleaning behavior on the suspension of particulate matter. Background Art

[0002] According to WHO research, the death toll from air pollution is climbing year by year. In enclosed indoor environments, harmful substances emitted from indoor objects and building materials, along with HVAC equipment operation, human activity, and outdoor air pollution, can all lead to excessive levels of indoor pollutants and a range of other indoor air pollution issues, significantly impacting human health. Therefore, research on particulate matter is crucial.

[0003] Airborne particulate matter is closely related to human health. Particles suspended in the air are mainly inhalable particles with a diameter of less than 10μm (PM10), which pose a major threat to human health, especially particles smaller than 2.5μm (PM2.5). Since suspended particulate matter may contain heavy metals, acidic oxides, and organic pollutants, and may serve as carriers of pathogens such as bacteria, viruses, and fungi, or as individual biological particles themselves, once they enter the respiratory tract, they will be deposited in the lungs and even enter the human blood through the alveoli, which can easily cause illness. Studying the suspension mechanism of indoor particulate matter and exploring appropriate methods to suppress the content of suspended particulate matter in the air are of great significance to improving people's health.

[0004] Over a decade ago, a US Environmental Protection Agency (EPA) report indicated that the precise sources of 14% of PM2.5 and 26% of PM10 indoors were difficult to pinpoint. However, particle source tracing studies have shown that 30% of PM10 is caused by resuspension of particles deposited indoors. The role of human activity in resuspensing deposited particles cannot be ignored. Nearly 50 years ago, researchers published research on the resuspension of indoor dust caused by floor cleaning. Human activity can increase the concentration of respirable particulate matter indoors by 60%.

[0005] The resuspension of particles can be caused by air flow, vibration and scraping of attached surfaces, and collisions between particles. The resuspension of particles in air involves complex mechanical mechanisms, including fluid motion, mechanical interactions between the fluid and the contact surface, hydraulic forces between the fluid and particles, adhesion between particles and the attached surface, and even collisions or adhesion between particles. Human physiological behaviors, such as sweeping and wiping sleeves, can disrupt the surrounding airflow, exerting hydraulic forces on particles and even directly exerting forces on them. Understanding the mechanical mechanisms by which human activities cause particle suspension and exploring effective strategies for controlling the concentration of suspended particles in the air are of great value both in academic research and in real-life production.

[0006] In previous studies in this field, obtaining experimental data was very difficult and cumbersome. Not only did it require the design of complex experimental processes, but the experimental processes were also often very time-consuming and labor-intensive. In order to explore the particle resuspension mechanism and the factors affecting the particle resuspension rate, which are still not very clear, there is an urgent need for an experimental instrument with high integration and easy operation. Summary of the Invention

[0007] The present invention aims to provide an experimental device and experimental method for studying the disturbance of particle suspension caused by cleaning behavior, so as to solve the technical problem of inconvenience in obtaining data when conducting research on the disturbance of particle suspension caused by cleaning behavior, so as to better study the disturbance of particle suspension caused by cleaning behavior.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] An experimental device for studying the disturbance of particle suspension caused by cleaning behavior, comprising a conveying device, a reciprocating cleaning device, a material supply device, a power unit, a control system, a data recording system, and a storage system; the reciprocating cleaning device is installed at the middle and rear part of the conveying device; the material supply device is installed at the front end of the conveying device; the power unit comprises a DC motor and a servo, the DC motor is installed in the middle of the overall frame of the conveying device, and the servo is installed below the storage tank of the material supply device; the control system is installed in the middle of the conveying device; the data recording system is arranged on the upper part of the conveyor belt of the conveying device; and the storage system is located on the right side of the entire experimental device.

[0010] Furthermore, the conveying device includes an overall frame, a conveyor belt, a tensioning wheel, a roller, and a baffle. The conveyor belt is installed on the upper part of the overall frame and is fastened by the tensioning wheel and the roller. The baffle is installed on both sides of the conveyor belt.

[0011] Furthermore, the reciprocating cleaning device includes a reduction gear group, a transmission belt, a rocker arm, a fixed shaft, a swing arm, and a brush. The rocker arm and the fixed shaft are respectively connected to the swing arm, the swing arm is connected to the brush, and the transmission belt is connected to the reduction gear group fixed in the overall frame below the conveyor belt.

[0012] Furthermore, the reduction gear set consists of a group of gears fixed on a shaft.

[0013] Furthermore, the material replenishing device includes a storage tank, a bent pipe, a steering gear connecting rod, and a flap. The bottom of the storage tank is funnel-shaped and connected to a bent pipe. A flap is provided at the end of the bent pipe, and the flap is connected to the steering gear through the steering gear connecting rod.

[0014] Furthermore, the DC motor is controlled by a PWM method through a control chip to achieve DC motor speed regulation. The servo is also controlled by the chip, opening and closing at an angle of 15°. The opening time is set by the chip so that the particulate matter can be released at the required time and quantity for the experiment.

[0015] Furthermore, the chip model used in the control system is TB5128.

[0016] Furthermore, the data recording system includes a smoke generator, an ultrasonic velocimeter, a particle counter and a particle size spectrometer.

[0017] Furthermore, the storage system includes a data acquisition computer.

[0018] The present invention also provides an experimental method for studying the effect of cleaning behavior on the suspension of particles, comprising the following steps:

[0019] Step 1: Divide the required particle delivery amount by the particle delivery amount per unit time of the material supply device to determine the servo on / off time to obtain the appropriate amount of particles;

[0020] Step 2: Set the motor operating parameters according to the experimental conditions, determine the conveyor belt speed, and match it with the servo on / off interval to ensure that the overlap between the two particle releases does not affect the experimental results;

[0021] Step 3: Adjust the brush cleaning speed of the reciprocating cleaning device by setting the gear ratio of the reduction gear set to meet the experimental requirements. When the experiment requires one-way cleaning, adjust the linear speed of the brush tip to be the same as the conveyor belt speed; when the experiment requires two-way cleaning, adjust the linear speed of the brush tip to be greater than the conveyor belt speed;

[0022] Step 4: Input the servo opening and closing time, conveyor belt speed, and gear ratio of the reduction gear set determined in steps 1, 2, and 3 into the program of the single-chip microcomputer controller to achieve overall control of the entire experimental device through the program;

[0023] Step 5: Collect the required experimental data through the computer;

[0024] Step 6: Data processing and establishment of solution model.

[0025] The present invention has the advantages that:

[0026] (1) The device of the present invention integrates and compresses the traditional particle suspension mechanism research process into an experimental device. All systems of the device are linked by a motor and a servo, and are centrally controlled by a single-chip microcomputer. Systematic particle suspension research data can be obtained by simply inputting simple control parameters into the single-chip microcomputer controller.

[0027] (2) The present invention can replace different brushes in the reciprocating cleaning device, adjust the motor working parameters, and coordinate the conveying speed of the conveyor belt with the material delivery amount and the cleaning speed of the reciprocating cleaning device according to different experimental working conditions to meet the needs of different experimental working conditions.

[0028] (3) The device of the present invention is equipped with a system for the entire process from the placement to the recovery of particulate materials, which is convenient and efficient, allowing researchers to focus more on the experiment itself.

[0029] (4) The present invention combines CFD technology to track and simulate the motion state of particles that undergo secondary suspension in space, obtain their distribution characteristics in space, and compare the calculated particle concentration with the data provided by the particle testing equipment, thereby achieving positive and negative comparison and increasing the accuracy of the experimental results.

[0030] (5) The present invention solves the problem of complex operation and large workload of traditional experimental data acquisition methods. While ensuring experimental efficiency and accuracy, it effectively reduces the workload of manual operation, making experimental work gradually tend to be intelligent and digital, making the acquisition of experimental data for particle suspension research simple and efficient.

[0031] (6) The device of the present invention is of great value in academic research and actual production and life for exploring the particle resuspension mechanism caused by current human activities (such as cleaning behavior) and the factors affecting the resuspension rate, exploring the mechanical mechanism of particle suspension caused by it, and effective strategies for controlling the content of suspended particles in the air. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the experimental device of the present invention;

[0033] Figure 2 It is a structural schematic diagram of the material supply device of the present invention;

[0034] Figure 3This is a schematic diagram of the working principle of the steering gear of the present invention;

[0035] Figure 4 It is a front view schematic diagram of the reciprocating cleaning device of the present invention;

[0036] Figure 5 It is a schematic diagram of the back side of the reciprocating cleaning device of the present invention;

[0037] Figure 6 It is a schematic structural diagram of the reduction gear set of the present invention;

[0038] Figure 7 is a flow chart of the experimental method of the present invention;

[0039] Figure 8 It is a force analysis diagram of the cleaning process of the present invention;

[0040] Figure 9 This is the force analysis of the particle suspension process of the present invention. In the figure, left (a); right (b), where (a) is a smooth attachment surface; (b) is a rough attachment surface.

[0041] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0042] 1. Overall frame, 2. Reciprocating cleaning device, 3. Material supply device, 4. Control system, 5. Motor, 6. Servo, 7. Conveyor belt, 8. Reduction gear set, 9. Drive belt, 10. Tensioner, 11. Roller, 12. Baffle, 13. Data acquisition computer, 14. Servo connecting rod, 15. Flap, 16. Rocker arm, 17. Fixed shaft, 18. Swing arm, 19. Brush, 20. Gear. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that the embodiments of the present invention are illustrative, but this is not a limitation of the present invention, and therefore the present invention is not limited to the above embodiments. Based on the principles of the present invention, any other implementation methods obtained by ordinary technicians in this field without making creative work are deemed to be within the protection of the present invention.

[0044] like Figure 1-6As shown, an experimental device for studying the disturbance of particle suspension caused by cleaning behavior includes a conveying device, a reciprocating cleaning device 2, a material supply device 3, a power unit, a control system 4, a data recording system, and a storage system; the conveying device is a traction belt conveyor, and the reciprocating cleaning device 2 is installed at the middle and rear part of the conveying device; the material supply device 3 is installed at the front end of the conveying device; the power unit includes a DC motor 5 and a steering gear 6, the DC motor 5 is installed in the middle of the overall frame of the conveying device, and the steering gear 6 is installed below the storage tank of the material supply device 3; the control system can control the entire experimental device and is installed in the middle of the conveying device; the data recording system includes a smoke generator, an ultrasonic velocimeter, a particle counter and a particle size spectrometer, which are arranged on the upper part of the conveyor belt of the conveying device during the experiment; the storage system includes a data acquisition computer 13, which is located on the right side of the entire experimental device.

[0045] The conveying device includes an overall frame 1, a conveyor belt 7, a tensioning wheel 10, a roller 11, and a baffle 12. The conveyor belt 7 is installed on the upper part of the overall frame 1 and is tightened by the tensioning wheel 10 and the roller 11. The baffle 12 is installed on both sides of the conveyor belt 7, parallel to the direction of particle conveying. Under the action of the DC motor, the power is transmitted to the conveyor belt 7 and the reciprocating cleaning device 2 through the belt.

[0046] The reciprocating cleaning device 2 includes a reduction gear group 8, a transmission belt 9, a rocker arm 16, a fixed shaft 17, a swing arm 18, and a brush 19. The reciprocating cleaning device is a mechanism that realizes reciprocating motion by adding a rocker arm 16 to a swing arm 18 fixed to the upper part of the conveyor belt 7 by a fixed rod. The rocker arm 16 and the fixed shaft 17 are respectively connected to the swing arm 18, and the swing arm 18 is connected to the brush 19. The transmission belt 9 is connected to the reduction gear group 8 fixed in the overall frame below the conveyor belt 7. The reduction gear group 8 consists of a group of gears 20 fixed on the shaft. The power comes from the DC motor 5. By adjusting the gear ratio of the reduction gear group, reciprocating cleaning action at different speeds can be achieved.

[0047] The material supply device 3 includes a storage tank, a curved pipe, a steering gear connecting rod 14, and a flap 15. The storage tank is a cylindrical structure. The bottom of the storage tank is funnel-shaped and connected to a curved pipe. A flap 15 is provided at the end of the curved pipe. The flap 15 is connected to the steering gear 6 through the steering gear connecting rod 14. The steering gear 6 controls the opening and closing of the flap 15, so that the particulate matter can be delivered in a timely and quantitative manner.

[0048] The DC motor 5 of the power unit is controlled by a PWM method through a control chip to achieve speed regulation of the DC motor 5, so that the particles are transported at a set speed; the servo 6 is also controlled by the chip, opening and closing at an angle of 15°. The opening time is set by the chip so that the particles can be delivered at the required time and quantity required for the experiment. The chip model used in the control system is TB5128.

[0049] like Figure 7 As shown, an experimental method for studying the disturbance of particle suspension by sweeping behavior includes the following steps:

[0050] Step 1: Divide the required particle delivery amount by the particle delivery amount per unit time of the material supply device to determine the servo on / off time to obtain the appropriate amount of particles;

[0051] Step 2: Set the motor operating parameters according to the experimental conditions, determine the conveyor belt speed, and match it with the servo on / off interval to ensure that the overlap between the two particle releases does not affect the experimental results;

[0052] Step 3: Adjust the brush cleaning speed of the reciprocating cleaning device by setting the gear ratio of the reduction gear set to meet the experimental requirements. When the experiment requires one-way cleaning, adjust the linear speed of the brush tip to be the same as the conveyor belt speed; when the experiment requires two-way cleaning, adjust the linear speed of the brush tip to be greater than the conveyor belt speed;

[0053] Step 4: Input the servo opening and closing time, conveyor belt speed, and gear ratio of the reduction gear set determined in steps 1, 2, and 3 into the program of the single-chip microcomputer controller to achieve overall control of the entire experimental device through the program;

[0054] Step 5: Collect the required experimental data through the computer;

[0055] Step 6: Data processing and establishment of solution model.

[0056] During the test, smoke generated by a smoke generator was used to qualitatively observe the disturbance of the airflow during cleaning in the environmental laboratory, and photos were taken. At the same time, an ultrasonic velocimeter was used to quantitatively test the surrounding airflow. In order to test the condition of the cleaning disturbing the deposited particles on the ground, a particle feeding device was used to sprinkle solid particles (such as talcum powder) onto the conveyor belt. After the particles settled, the deposited particles were sent to the brush cleaning position on the left side via a pulley. The resuspension of the particles was then photographed to evaluate the resuspension of the particles. To quantitatively evaluate the suspension of the particles, a particle counter and a particle size spectrometer were used to measure the concentration and distribution range of the suspended particles in the air, and weighing methods could be considered to determine the amount of particles deposited on the ground.

[0057] Establish an airflow solution model for the airflow around particles disturbed by sweeping behavior:

[0058] Taking the cleaning process of the brush as the research object, the deformation law of the brush during the cleaning process is studied, and the force acting on the contact surface when the brush is bent is analyzed, such as Figure 8As shown in the figure, based on the elastic deformation and angular momentum theorem, the brush motion state equation during the cleaning process is established;

[0059] Based on the deformation and displacement laws of the brush, an airflow calculation model is established when the surrounding airflow is disturbed by the cleaning behavior, focusing on solving the airflow characteristics formed between the brush and the surface being cleaned during the cleaning process;

[0060] Analyze the hydraulic effect of the airflow between the brush and the contact surface on the particles, such as Figure 8 As shown in the figure, considering the drag force and buoyancy force exerted on the particles by the airflow generated by the swinging brush, based on the mechanism of particles rolling, sliding, and detaching from the attachment surface, a criterion for particles detaching from the brush and the contact surface is established;

[0061] The motion state of the particles that have undergone secondary suspension in space is tracked and simulated to obtain their distribution characteristics in space, and the calculated particle concentration is compared with the data provided by the particle testing equipment.

[0062] According to the dynamic mechanism of particle resuspension, calculating the drag force and buoyancy force exerted by the surrounding fluid on the particles requires solving the fluid flow field, and then finally judging whether the particles can be suspended from the attached surface based on the combined effects of various forces.

[0063] The mechanical forces involved in particle suspension are complex. The forces acting on particles include gravity, fluid drag and buoyancy, and adhesion forces between particles or between particles and the surface they adhere to. Calculating the drag and buoyancy forces exerted by the surrounding fluid on the particle requires solving the fluid's flow field. The calculation of these forces is even more complex when the flow is turbulent. Adhesion, at the microscopic level, primarily includes chemical bonds, electrostatic Columbus forces, polar molecular forces, van der Waals forces, molecular repulsion, and hydrogen bonding. At the macroscopic level, the two most important forces are van der Waals and electrostatic forces. Whether a particle can levitate from its surface depends on the combined effects of these forces.

[0064] Particle suspension involves many mechanical interactions. First, a method must be established to calculate the adhesion between the particle and the surface, the drag force of the airflow on the particle, and the buoyancy force. The adhesion between the particle and the contact surface is mainly composed of van der Waals force and electrostatic force, and the calculation formula is:

[0065]

[0066] Among them, F Adhis the adhesion force, the first term on the right is the van der Waals force, and the second term is the electrostatic force. Where A is the Hamaker constant, d is the particle size, L is the distance between the particle and the contact surface, ε0 is the dielectric constant of the medium, and E is the electric field strength. When the humidity in the air is high, the electrostatic force can usually be ignored.

[0067] If the turbulent fluid is at an intermediate Reynolds number, the drag force on the particle can be expressed as:

[0068]

[0069] Where, F D is the drag force, C D is the drag coefficient, u is the velocity of the mainstream fluid, u p is the speed of the particle movement, C c is the particle slip correction coefficient. If C is properly selected D , the turbulence effect can be included. Similarly, the buoyancy force based on the experimental solution can be expressed as:

[0070]

[0071] Where, F L is the buoyancy force on the particles, and v is the kinematic viscosity of the fluid.

[0072] The kinetic models of particle separation from the attached surface can be generally divided into quasi-static models (i.e., force / momentum balance models) and dynamic models (i.e., energy accumulation models). The former model analyzes the separation of particles from the attached surface by starting with the balance of force and momentum under static conditions. Figure 9 As shown in (a), the Ibrahim particle suspension model is:

[0073] F L >F Adh +m P g (4)

[0074] That is, when the buoyancy F L Greater than the adhesion force F between particles and surface Adh With gravity m P When the sum of g is satisfied, it is believed that the particles will float from the attachment surface.

[0075] F D >k s (F Adh +m P F L ) (5)

[0076] That is, when the drag force is greater than the static friction between the particle and the surface, the particle slides on the surface, where k sis the static friction coefficient. When the following relationship is satisfied,

[0077] (1.4r)F D +(0.63r ae )F L >(0.63r ae )(F Adh +m P g) (6)

[0078] The particle rolls. The fulcrum for calculating the angular momentum is "O", as shown in Figure 9 As shown in (a), (0.63r ae ) is the contact radius of the particle when it separates from the surface of adhesion. The above formula assumes that the particle rolls when the kinetic moment of the drag force and buoyancy force on the fulcrum "O" is greater than the kinetic moment of the adhesion force and gravity.

[0079] Under normal circumstances, the buoyancy force exerted by the fluid on the particles alone is insufficient to overcome the adhesion force, because the buoyancy force is much smaller than the adhesion force, that is, the situation described by equation (4) is difficult to occur; and current experimental research does not fully support the occurrence of particle slippage on the adhesion surface, that is, the situation described by equation (5) is not very consistent with the actual situation. Therefore, Ziskind believes that when particles separate from the adhesion surface, the first thing that occurs is the rolling phenomenon of the particles, that is, equation (6) is more reasonable. Even so, the force / moment balance model still cannot include the influence of fluid turbulence on particle separation, because experiments have found that when the fluid is turbulent, particle separation can occur even when the conditions of equation (6) are not satisfied.

[0080] The energy model of particle separation believes that the separation of particles from the adhesion surface is the result of energy accumulation, that is, when the fluid is turbulent, the turbulent kinetic energy of the fluid is transferred to the potential energy of the particles. In order for particles to separate from the adhesion surface, they must accumulate enough energy to escape from the "potential well" formed by the adhesion force. In turbulent fluids, buoyancy can change the shape and height of the "potential well", and the turbulence of the fluid can cause the particles and the adhesion surface to deform and oscillate randomly near the equilibrium state. The energy accumulation model proposed by Reeks et al. is:

[0081]

[0082] Where p is the probability of secondary suspension of particles, is the frequency of oscillation, H is the height of the "potential energy well", and PE is the average potential energy of the turbulent fluid accumulated on the particle. For rough surfaces, subsequent research by Reeks and Hall believed that the particles did not oscillate in the "potential energy well", but oscillated around the fulcrum P, such as Figure 9 As shown in (b), this describes the particle separation more accurately.

[0083] The mechanical mechanism involved in the cleaning process is quite complex, and the forces acting on the surface are quite different in different suspension processes. Figure 8 As shown in the figure, the process of brushing particles can be roughly divided into seven stages. In the first five stages, the brush contacts the particles on the conveyor belt, exerting a primarily downward and horizontal force to the right. The combined force of the brush causes the particles to slide or roll horizontally. Some particles, squeezed by the brush, form close contact between the brush and the particles, and adhere to the brush surface due to adhesion. During this period, the particles experience horizontal acceleration, accelerating their speed. When the cleaning process enters the sixth stage, the brush's acceleration of the particles is complete. At this point, due to inertia, the brush bends in the opposite direction. As shown in the seventh stage, the brush's speed slows down compared to the particles, and the particles begin to detach from the brush and become suspended. Furthermore, the cleaning process can also stimulate a strong airflow. When the airflow speed is faster than the particle speed, it exerts a significant hydraulic force on the particles, aiding their suspension. However, when the airflow speed is slower than the particle speed, the hydraulic force on the particles hinders their movement. Throughout the suspension process, particles are subject to forces including gravity, the force exerted by the brush on the particles, adhesion to the contact surface (including the brush and the table), friction between the contact surface, airflow and hydraulic forces, and other forces such as Saffman lift, thermophoresis, and Brownian diffusion. This research must consider both the elastic deformation of the brush and its force on the particles; it also requires a comprehensive force analysis of the particles based on Newton's second law to determine their motion state and ultimately establish the critical conditions for particle suspension.

[0084] Regarding the disturbance of the brush movement to the surrounding airflow, the FLUENT calculation software provides a dynamic mesh technology for simulating moving objects. The dynamic mesh technology transforms the boundary of the fluid domain according to the specified object motion displacement equation, and realizes the movement of the calculation mesh of the specified area relative to another area through mesh sliding. If the solid boundary moves during the calculation process, the newly generated fluid domain needs to be re-meshed. In the dynamic mesh calculation, the reference coordinate does not move, that is, the CFD mesh geometric parameters do not change with time, and the speed of entering and exiting the mesh control surface should be the speed of the actual fluid relative to the moving mesh. In the study, a simplified brush geometry model can be established first, and by solving the displacement equation of the brush, their respective movement routes and speeds can be specified in FLUENT through user-programmed functions (UDFs), and then the disturbance characteristics of the surrounding airflow can be solved.

[0085] This invention uses CFD technology to track and simulate the motion of particles undergoing secondary suspension within space, obtaining their spatial distribution characteristics. The calculated particle concentration is then compared with data provided by particle testing equipment, enabling forward and reverse comparisons to increase the accuracy of experimental results. Furthermore, this invention addresses the complex and labor-intensive nature of traditional experimental data acquisition methods. While ensuring experimental efficiency and accuracy, it effectively reduces the manual workload, gradually moving experimental work towards intelligent digitization and making experimental data acquisition for particle suspension research simpler and more efficient.

[0086] Although what is considered to be exemplary embodiments of the present invention has been described and illustrated, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the present invention without departing from the central concept of the invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but rather encompasses all embodiments and their equivalents falling within the scope of the present invention.

Claims

1. An experimental device for studying the effect of cleaning behavior on the suspension of particulate matter, characterized in that: It includes a conveying device, a reciprocating cleaning device, a material supply device, a power unit, a control system, a data recording system, and a storage system; the reciprocating cleaning device is installed in the middle and rear part of the conveying device; the material supply device is installed at the front end of the conveying device; the power unit includes a DC motor and a steering gear, the DC motor is installed in the middle of the overall frame of the conveying device, and the steering gear is installed below the storage tank of the material supply device; the control system is installed in the middle of the conveying device; the data recording system is arranged on the upper part of the conveyor belt of the conveying device; and the storage system is located on the right side of the entire experimental device; The conveying device includes an overall frame, a conveyor belt, a tensioning wheel, a roller, and a baffle. The conveyor belt is installed on the upper part of the overall frame and is fastened by the tensioning wheel and the roller. The baffle is installed on both sides of the conveyor belt. The reciprocating cleaning device includes a reduction gear set, a transmission belt, a rocker arm, a fixed shaft, a swing arm, and a brush. The rocker arm and the fixed shaft are respectively connected to the swing arm, the swing arm is connected to the brush, and the transmission belt is connected to the reduction gear set fixed in the overall frame below the conveyor belt. The material supply device includes a storage tank, a bent pipe, a steering gear connecting rod, and a flap. The bottom of the storage tank is funnel-shaped and connected to a bent pipe. A flap is provided at the end of the bent pipe, and the flap is connected to the steering gear through the steering gear connecting rod. The DC motor is controlled by a PWM method using a control chip to achieve DC motor speed regulation. The servo is also controlled by the chip, opening and closing at an angle of 15°. The opening time is set by the chip so that the particles can be released at the required time and quantity for the experiment. The data recording system includes a smoke generator, an ultrasonic velocimeter, a particle counter and a particle size spectrometer; An experimental method for studying the effect of sweeping behavior on the suspension of particles, using an experimental device for studying the effect of sweeping behavior on the suspension of particles, comprises the following steps: Step 1: Divide the required particle delivery amount by the particle delivery amount per unit time of the material supply device to determine the servo on / off time to obtain the appropriate amount of particles; Step 2: Set the motor operating parameters according to the experimental conditions, determine the conveyor belt speed, and match it with the servo on / off interval to ensure that the overlap between the two particle releases does not affect the experimental results; Step 3: Adjust the brush cleaning speed of the reciprocating cleaning device by setting the gear ratio of the reduction gear set to meet the experimental requirements. When the experiment requires one-way cleaning, adjust the linear speed of the brush tip to be the same as the conveyor belt speed; when the experiment requires two-way cleaning, adjust the linear speed of the brush tip to be greater than the conveyor belt speed; Step 4: Input the servo opening and closing time, conveyor belt speed, and gear ratio of the reduction gear set determined in steps 1, 2, and 3 into the program of the single-chip microcomputer controller to achieve overall control of the entire experimental device through the program; Step 5: Collect the required experimental data through the computer; Step 6: Data processing and establishing solution model; The solution model is established as follows: Taking the cleaning process of a brush as the research object, the deformation law of the brush during the cleaning process is studied, the force acting on the contact surface when the brush is bent is analyzed, and the state equation of the brush motion during the cleaning process is established based on the elastic deformation and momentum theorem. Based on the deformation and displacement laws of the brush, an airflow calculation model is established when the surrounding airflow is disturbed by the cleaning behavior. The airflow characteristics formed between the brush and the surface being cleaned during the cleaning process are solved. The hydraulic effect of the airflow between the brush and the contact surface on the particles is analyzed. The drag and buoyancy forces exerted on the particles by the airflow generated by the swinging brush are analyzed. Based on the mechanism of particles rolling, sliding, and detaching from the attachment surface, a criterion for particles detaching from the brush and the contact surface is established. Track and simulate the motion state of the particles that have undergone secondary suspension in space to obtain their distribution characteristics in space, and compare the calculated particle concentration with the data provided by the particle testing equipment; According to the dynamic mechanism of particle resuspension, the drag force and buoyancy force exerted by the surrounding fluid on the particle need to be solved. The flow field of the fluid is then solved, and the combined effect of various forces is used to determine whether the particle can be suspended from the attached surface. The specific solution model is as follows: A method for calculating the adhesion force between particles and surfaces, the drag force and buoyancy force of airflow on particles is established. The adhesion force between particles and the contact surface is composed of van der Waals force and electrostatic force, and the calculation formula is: （1） in, is the adhesion force, the first term on the right is the van der Waals attraction, and the second term is the electrostatic attraction. Where A is the Hamaker constant, d is the particle size, and L is the distance between the particle and the contact surface. is the dielectric constant of the medium, E is the electric field strength; If the turbulent fluid is at an intermediate Reynolds number, the drag force on the particle is expressed as: （2） Where, is the drag force, is the drag coefficient, u is the velocity of the mainstream fluid, is the speed of the particle movement, is the particle slip correction coefficient, if properly selected , the turbulence effect can be included; similarly, the buoyancy force based on the experimental solution is expressed as: （3） Where, is the buoyancy force on the particle, is the kinematic viscosity of the fluid; The kinetic models of particle separation from an attached surface are generally divided into quasi-static models and dynamic models. The former model analyzes the separation of particles from an attached surface by considering the force and momentum balance of the particles under static conditions. The Ibrahim particle suspension model is: （4） That is, when the buoyancy Greater than the adhesion between particles and surface With gravity When the sum of , it is believed that the particles will float from the attachment surface, and when the following formula is satisfied, （5） That is, when the drag force is greater than the static friction between the particle and the surface, the particle slides on the surface. is the static friction coefficient, and when the following relationship is satisfied, （6） The particle rolls, where the fulcrum for moment of momentum calculation is "O". is the contact circle radius when the particle separates from the adhesion surface. The above formula assumes that the particle rolls when the kinetic moment of the drag force and the buoyancy force on the fulcrum "O" is greater than the kinetic moment of the adhesion force and the gravity.

2. The experimental device for studying the effect of cleaning behavior on the suspension of particles according to claim 1, characterized in that: The reduction gear set consists of a set of gears fixed on a shaft.

3. The experimental device for studying the effect of cleaning behavior on the suspension of particles according to claim 1, characterized in that: The chip model used in the control system is TB5128.

4. The experimental device for studying the effect of cleaning behavior on the suspension of particles according to claim 1, characterized in that: The storage system includes a data acquisition computer.

5. An experimental method for studying the effect of cleaning behavior on the suspension of particulate matter, comprising: The following steps are involved: Step 1: Divide the required particle delivery amount by the particle delivery amount per unit time of the material supply device to determine the servo on / off time to obtain the appropriate amount of particles; Step 2: Set the motor operating parameters according to the experimental conditions, determine the conveyor belt speed, and match it with the servo on / off interval to ensure that the overlap between the two particle releases does not affect the experimental results; Step 3: Adjust the brush cleaning speed of the reciprocating cleaning device by setting the gear ratio of the reduction gear set to meet the experimental requirements. When the experiment requires one-way cleaning, adjust the linear speed of the brush tip to be the same as the conveyor belt speed; when the experiment requires two-way cleaning, adjust the linear speed of the brush tip to be greater than the conveyor belt speed; Step 4: Input the servo opening and closing time, conveyor belt speed, and gear ratio of the reduction gear set determined in steps 1, 2, and 3 into the program of the single-chip microcomputer controller to achieve overall control of the entire experimental device through the program; Step 5: Collect the required experimental data through the computer; Step 6: Data processing and establishment of solution model.

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