Micro-flow granulation micromechanism experiment system and method for water suspension granulation

Abstract

The invention provides a micro-flow granulation micromechanism experiment system and method for water suspension granulation. The system comprises a temperature control and flow control unit, a granulation process experiment unit, a micro-flow control unit, a microscopic observation unit, a high-speed imaging unit and a surface interface measurement unit, the method comprises the following steps: measuring interface characteristic parameters of a granulation material through a surface interface measuring unit, and carrying out a pre-experiment by combining a micro-fluidic unit and a microscopic observation unit, so as to determine granulation process parameters; controlling the temperature control and flow control unit to configure a temperature field control parameter and a flow field control parameter according to the granulation process parameters so as to control the granulation process experiment unit to perform an experiment in a linkage manner; and the granulation process data of the granulation process experiment unit is observed based on the high-speed imaging unit, so that the experiment research on the micro-fluidic granulation micromechanism is realized. According to the application, synchronous coordination of granulation working condition simulation, accurate regulation and control of key process parameters and process in-situ observation is realized, and reliable support is provided for granulation mechanism analysis and process optimization.

Description

Technical Field

[0001] This application relates to the field of chemical granulation experimental equipment technology, and in particular to an experimental system and method for micro-flow granulation mechanism of water suspension granulation. Background Technology

[0002] Aqueous suspension granulation technology, due to its superior product dispersibility and environmental friendliness, has become a core preparation technology for functional granules in fields such as pesticide suspensions, chemicals, pharmaceuticals, and environmental protection. The performance of these products directly determines the effectiveness of end-applications. However, the current technology system suffers from significant bottlenecks, leading to a "black box" approach to research and a lack of parameter guidance. This severely restricts technological upgrades and industrial applications. The core problems are mainly concentrated in three aspects: First, the lack of in-situ observation means that the existing "offline sampling + post-observation" method cannot continuously capture dynamic processes such as droplet collisions and particle aggregation, resulting in gaps in the core granulation chain data. Second, the ambiguity in key parameter identification means that core parameters such as stirring intensity and temperature lack scientific classification, and control relies heavily on experience, failing to establish precise gradients. Third, the unclear influence of parameters means that without process data support, the role of parameters can only be inferred from the final product, making it impossible to clarify their control mechanisms at specific granulation stages. This leads to significant performance fluctuations when laboratory parameters are applied to industrial production. The combination of these problems results in long process optimization cycles and high costs. The lack of in-situ observation in existing water suspension granulation experimental equipment leads to the "black box" nature of the granulation process, unsystematic identification of key process parameters, and ambiguity in the influence of parameters, thus making it impossible to establish a quantitative correlation between "parameters-process-products".

[0003] Therefore, the development of an integrated device combining in-situ observation, parameter control, and operational simulation has become an urgent need. The key technical problem that needs to be solved is the lack of clarity regarding the granulation process and the unclear influencing factors in water suspension granulation. Summary of the Invention

[0004] The purpose of this application is to provide an experimental system and method for the micro-flow granulation mechanism of water suspension granulation, so as to realize the synchronous and coordinated simulation of granulation conditions, precise control of key process parameters and in-situ observation of the process, and provide reliable support for the analysis of granulation mechanism and process optimization.

[0005] To achieve the above objectives, as a first aspect of this application, this application provides an experimental system for the microscopic mechanism of microfluidic granulation in water suspension granulation. This system includes the following functional units: a temperature and flow control unit, a granulation process experimental unit, a microfluidic unit, a microscopic observation unit, a high-speed imaging unit, and a surface and interface measurement unit. Each of these functional units is integrated and deployed on the same platform for integrated collaborative operation. A track is provided on the platform, and the high-speed imaging unit, the microfluidic unit, and / or the surface and interface measurement unit are positioned on the track. Specifically, the surface and interface measurement unit measures the interfacial characteristic parameters of the granulated material, and then, in conjunction with the microfluidic unit and the microscopic observation unit, conducts preliminary experiments to determine the granulation process parameters. The temperature and flow control unit is configured with temperature field control parameters and flow field control parameters according to the granulation process parameters to control the granulation process experimental unit in a coordinated manner. Finally, the granulation process data of the granulation process experimental unit is observed based on the high-speed imaging unit. This enables experimental research on the microscopic mechanism of microfluidic granulation. The temperature and flow control unit controls the temperature and flow fields of the granulation process in the experimental unit. The experimental unit completes the entire process of droplet formation, particle formation, clustering, and agglomeration within the granulation chamber, allowing for in-situ observation. The microfluidic unit provides a controllable microflow environment through a microfluidic chip during shearing droplet formation, particle-droplet interaction, and droplet evaporation stages, allowing for pre-experiments to determine the granulation process parameters. The microscopic observation unit magnifies and observes the objects within the granulation chamber or the microfluidic chip. The high-speed imaging unit records the dynamic changes in granulation within the experimental unit, the microfluidic unit, or the microscopic observation unit. The interface measurement unit includes an infrared light source, a controllable enclosed chamber, and a camera, used for online measurement of the interface characteristics of the granulated material under different temperature or pressure conditions.

[0006] The micro-fluidic particle-forming micro-mechanism experimental system for water suspension granulation, as described above, includes a temperature and flow control unit comprising: a power supply box, a constant temperature module, a temperature sensor, a temperature controller, and a stirring assembly. The power supply box is electrically connected to the constant temperature module, the temperature controller, and the stirring assembly. The temperature sensor is located at the temperature measurement point of the constant temperature module and is electrically connected to the temperature controller, providing feedback of its measured temperature data. The temperature controller is electrically connected to the stirring assembly and the visually adjustable stirrer, used to synchronously adjust the stirring speed of the stirring assembly within a set temperature range.

[0007] The micro-fluidic granulation mechanism experimental system for water suspension granulation described above includes the following granulation process experimental unit: a transparent granulation chamber, a stirring assembly, and an exhaust device. The transparent granulation chamber includes a feed inlet and an exhaust outlet. The transparent granulation chamber is made of quartz, with an inner diameter of 10-100 mm, a height of 10-100 mm, and a sidewall thickness of 1-5 mm. The stirring assembly is installed within the transparent granulation chamber. The stirring assembly includes a stirrer and a stirring paddle. The stirring paddle is positioned above the stirrer. The stirrer has a cavity for holding the granulated material. The stirring assembly is used to control the stirring intensity, simulating the stirring flow field of actual granulation. The stirring paddle has a blade diameter of 10-50 mm and a rotational speed adjustment range of 100-2000 rpm. The exhaust device is located inside the transparent granulation chamber at the exhaust outlet, and controls the gaseous environment throughout the reaction by controlling the gaseous environment inside the transparent granulation chamber.

[0008] The microfluidic granulation micromechanism experimental system for water suspension granulation described above includes a microfluidic unit comprising multiple different microfluidic chips. The microfluidic chips analyze the influence of key parameters on droplet formation, clustering, and volatilization processes by setting single-factor variation experimental conditions. These single-factor variation experimental conditions include flow velocity, temperature, and / or shear rate. The key parameters include interfacial tension coefficient, liquid bridging force, and / or volatilization rate during the granulation process.

[0009] The microscopic mechanism experimental system for water suspension granulation described above, wherein the microscopic observation unit includes: a three-dimensional moving platform and an upright microscope; the upright microscope is set on the three-dimensional moving platform; the three-dimensional moving platform is used to adjust the observation position.

[0010] The micro-fluidic granulation micro-mechanism experimental system for water suspension granulation described above includes a high-speed imaging unit comprising a high-speed camera and a six-dimensional moving platform. The high-speed camera is mounted on the six-dimensional moving platform. The high-speed camera is used to record in real time the dynamic changes of particles gradually encapsulating droplets during the granulation process and gradually agglomerating into spheres as the droplets evaporate.

[0011] The micro-fluidic granulation micro-mechanism experimental system for water suspension granulation described above includes a high-speed imaging unit further comprising an edge AI chip, which embeds an aggregation critical state recognition model. This model can identify the corresponding cluster fractal dimension based on real-time image data. If the cluster fractal dimension reaches a preset experimental aggregation critical threshold, a real-time control command is sent to the temperature and flow control unit to suppress aggregation. The real-time control command includes at least one of the following: increasing the temperature according to a preset heating threshold, decreasing the stirring speed according to a preset reduction ratio, and decreasing the dropping speed according to a preset reduction ratio.

[0012] The experimental system for microfluidic particle formation mechanism of water suspension granulation described above, wherein the temperature control and flow control unit is further used to receive particle formation control commands triggered by a pre-constructed micromechanical model of particle formation evolution, and automatically adjust the stirring speed or dropping speed; wherein the micromechanical model of particle formation evolution is: ; ; ; ; ;in, This represents the distribution of particle size d at time t; This indicates the distribution change caused by the droplet addition process. This indicates the distribution change caused by the evaporation of solvent droplets; This indicates the distribution changes caused by clustering; This indicates the distribution change caused by agglomeration; f 0 represents the initial distribution. The dropping acceleration; k For undetermined coefficients, J c For cluster rate, The stirring speed of the stirring component; Indicates particle diameter; J s For evaporation rate, This refers to the stirring speed; and The subjects of coagulation are respectively and The undetermined coefficients; Indicates and Different particle sizes. As a second aspect of this application, this application provides an experimental method for the micro-flow granulation mechanism of water suspension granulation, applied to the aforementioned experimental system for the micro-flow granulation mechanism of water suspension granulation. The method includes: preparing an ethyl acetate solution containing 1% PVB and placing it in a syringe pump; adjusting the temperature field and flow field environment within the transparent granulation chamber to a preset target range; stirring pre-prepared melamine powder in an aqueous solution within a stirrer using a stirring paddle; adding an ethyl acetate solution containing 1% PVB dropwise into the stirrer using a syringe pump; and recording the granulation process by capturing a granulation video using a high-speed camera.

[0013] The experimental method for the micro-flow granulation mechanism of water suspension granulation described above includes, after capturing granulation video using a high-speed camera to record the granulation process, the method further includes: statistically analyzing particle size distribution data under different stirring speeds and different dropping speeds; and constructing the micromechanical model of granulation evolution based on the correspondence between the particle size distribution data, the stirring speed, and the dropping speed.

[0014] The beneficial effects achieved by this application are as follows: (1) This application realizes the synchronous coordination of granulation working condition simulation, precise control of key process parameters and in-situ process observation. It solves the technical defects of the lack of in-situ observation of granulation experimental equipment, which leads to the "black box" of granulation process, unsystematic identification of key process parameters and fuzzy parameter influence law, thus making it impossible to establish a quantitative correlation of "parameter-process-product". It provides reliable support for mechanism analysis and process optimization.

[0015] (2) This application uses three special chips to break down the particle formation into three independent sub-experiments: shearing into droplets, particle clusters, and droplet evaporation. The interfacial tension, liquid bridge force, and evaporation rate are measured respectively, and then a single-factor scan is performed to obtain which parameter determines which sub-process, thereby establishing a quantitative criterion.

[0016] (3) This application can observe the entire microscopic process of droplet-cluster-coagulation in real time through a microscopic observation unit or a high-speed imaging unit, analyze the grain formation law, and solve the problem of the difficulty in observing the grain formation process.

[0017] (4) Based on the micromechanical model of particle formation evolution, this application can quickly find the optimal stirring speed or droplet acceleration rate, reduce the cost of trial and error, and discover that the particle size distribution function of droplets / particles changes accordingly by controlling the stirring speed, thereby obtaining the law of particle formation controlled by stirring speed. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of the structure of an experimental system for microfluidic granulation mechanism of water suspension granulation according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram illustrating the experimental analysis of the microscopic process of droplet formation, clustering, and coagulation during the granulation process in an embodiment of this application.

[0021] Figure 3 This is a schematic diagram showing the particle size distribution of granulation under different working conditions according to an embodiment of this application.

[0022] Figure 4 This is a flowchart illustrating an experimental method for the micro-flow granulation mechanism of water suspension granulation, according to an embodiment of this application.

[0023] Figure 5 This is a schematic diagram of the physical structure of an experimental system for microfluidic granulation mechanism of water suspension granulation according to an embodiment of this application.

[0024] Figure labels: 1-Temperature and fluid control unit; 2-Particle formation process experimental unit; 3-Microfluidic unit; 4-Microscopic observation unit; 5-High-speed imaging unit; 6-Surface and interface measurement unit. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] like Figure 1As shown, this application provides an experimental system for the microscopic mechanism of water suspension granulation. The system includes the following functional units: a temperature and flow control unit 1, a granulation process experimental unit 2, a microfluidic unit 3, a microscopic observation unit 4, a high-speed imaging unit 5, and a surface and interface measurement unit 6, all integrated on the same platform. Each of these functional units is integrated and deployed on the same platform for integrated collaborative operation. A track is provided on the platform, and the high-speed imaging unit 5, the microfluidic unit 3, and / or the surface and interface measurement unit 6 are positioned on the track. Specifically, the surface and interface measurement unit 6 measures the interface characteristic parameters of the granulated material, and then, in conjunction with the microfluidic unit 3 and the microscopic observation unit 4, conducts preliminary experiments to determine the granulation process parameters. The temperature and flow control unit 1 is configured with temperature field control parameters and flow field control parameters according to the granulation process parameters to control the granulation process experimental unit 2 in a coordinated manner. Finally, the granulation process data of the granulation process experimental unit 2 is observed based on the high-speed imaging unit 5, thereby realizing the microfluidic granulation microscopic mechanism. The experiment includes the following components: a temperature and flow control unit 1, used to control the temperature and flow fields of the granulation process in the granulation process experimental unit; a granulation process experimental unit 2, used to complete the entire process of droplet formation, particle formation, clustering, and agglomeration within the granulation chamber, allowing in-situ observation; a microfluidic unit 3, used to provide a controllable microflow environment through a microfluidic chip during shearing droplet formation, particle-droplet interaction, and droplet evaporation stages, to conduct pre-experiments in the controllable microflow environment and determine the granulation process parameters; a microscopic observation unit 4, used to magnify and observe the objects within the granulation chamber or the microfluidic chip; a high-speed imaging unit 5, used to record the dynamic changes in granulation in the granulation process experimental unit 2, the microfluidic unit 3, or the microscopic observation unit 4; and a surface and interface measurement unit 6, including an infrared light source, a controllable enclosed chamber, and a camera, used to measure the surface tension of materials online under different temperature or pressure conditions, and to measure the interface characteristic parameters of the granulated materials online.

[0027] This application discloses an experimental system for the microscopic mechanism of water suspension granulation, suitable for the spherical granulation of powders. The granulation process is simulated by the granulation process experimental unit 2. The temperature and flow fields of the granulation process are controlled by the temperature and flow control unit 1. The granulation process parameters are determined by the microscopic observation unit 4 and the microfluidic unit 3. The process is observed in situ by the high-speed imaging unit 5 to obtain observation data. The surface and interface characteristic parameters of the granulated material are measured by the surface and interface measurement unit 6. Finally, the entire process of cross-scale transport and nonlinear growth mechanism of granulation is experimentally verified, providing reliable support for the analysis of granulation mechanism and process optimization.

[0028] In a specific embodiment of the present invention, the temperature control and flow control unit 1 includes: a power supply box, a constant temperature module, a temperature sensor, a temperature controller, and a stirring assembly. The power supply box is electrically connected to the constant temperature module, the temperature controller, and the stirring assembly, and supplies power to the constant temperature module, the temperature controller, and the stirring assembly. The constant temperature module is used to precisely lock the temperature at a set value. The temperature sensor is located at the temperature measuring point of the constant temperature module and is electrically connected to the temperature controller to provide feedback on the measured temperature data. The temperature controller is electrically connected to the stirring assembly to synchronously adjust the stirring speed of the stirring assembly within the set temperature range. The constant temperature module includes a heating surface, a temperature control plate, and a temperature measuring head. The temperature controller is an electronic device used for automatically adjusting the temperature.

[0029] Please refer to the following: Figure 5 , Figure 5 This is a schematic diagram of the physical structure of an experimental system for the micro-flow granulation mechanism of water suspension granulation, according to an embodiment of this application. Figure 5 As shown, the temperature control and flow control unit 1 in this system includes a power supply box (not shown), which supplies power to the constant temperature module, the temperature controller, and the visually adjustable stirrer. A temperature sensor is located in the granulation process experimental unit above the constant temperature module to monitor the temperature of the transparent granulation chamber, providing a stable temperature field environment for the granulation process. The temperature controller establishes an electrical signal connection with the temperature sensor, which transmits the detected temperature data to the temperature controller via an electrical signal, allowing the temperature controller to adjust and control the temperature of the constant temperature module based on real-time temperature data. Furthermore, the constant temperature module includes a heating surface in direct contact with the transparent granulation chamber, a temperature control plate located below the heating surface, and a temperature measuring head (not shown) capable of measuring the temperature of the constant temperature module. In addition, the temperature controller can also be electrically connected to the stirring assembly, synchronously adjusting the stirring speed of the stirring assembly within a set temperature range to provide a stable flow field environment for the granulation process. Figure 5 The medium-to-high-speed imaging unit can be deployed on the right side, with backlighting provided on the left. The high-speed camera captures images from the right side, recording granulation process data in real time. In a specific embodiment of the invention, the stirring assembly includes a stirrer and a stirring paddle; the stirring paddle is positioned above the stirrer; the stirrer has a cavity for holding the granulated material. Preferably, the diameter of the stirring paddle blades is 10-50 mm, and the rotational speed is adjustable from 100-2000 rpm, precisely controlling the key parameter of stirring intensity to simulate the stirring flow field of actual granulation.

[0030] As a specific embodiment of the present invention, the temperature control and flow control unit 1 is linked with the granulation process experimental unit 2. Through unified scheduling by the central controller, the central controller sends temperature setpoints to the temperature controller and speed setpoints to the stirring assembly, and reads feedback signals from the temperature control sensor and / or speed sensor (optionally, the speed sensor is integrated at the tail of the motor or the shaft end of the gearbox of the stirring assembly) in real time, so as to realize synchronous adjustment of the temperature of the constant temperature module and the speed of the stirring assembly, one-button start and stop, and fault interlock.

[0031] Preferably, the central controller simultaneously sends out temperature settings, speed settings, and receives temperature / speed / high-speed camera frame synchronization signals. Through PID feedback control on the computer software interface of the central controller, the temperature of the granulation process is controlled to a fluctuation of no more than 1 K with an accuracy greater than 1 mK, and the stirring speed of the stirring component is controllable between 100-2000 rpm, thereby providing a stable temperature and flow field environment for the granulation process.

[0032] As a specific embodiment of the present invention, the granulation process experimental unit 2 includes: a transparent granulation chamber and an exhaust device; the transparent granulation chamber includes a feed inlet and an exhaust outlet; a stirring assembly is assembled inside the transparent granulation chamber; the stirring assembly is used to regulate the stirring intensity and simulate the stirring flow field of actual granulation; the exhaust device is set inside the transparent granulation chamber and located at the exhaust outlet, the exhaust device discharges unwanted gases (waste gas, hot gas, etc.) from the transparent granulation chamber, and the exhaust device controls the gaseous environment inside the transparent granulation chamber by controlling the gaseous environment inside the transparent granulation chamber.

[0033] As a preferred embodiment of the present invention, the transparent granulation chamber is made of quartz material, with an inner diameter of 10-100 mm, a height of 10-100 mm, and a sidewall thickness of 1-5 mm, which facilitates in-situ observation of the granulation process inside the transparent granulation chamber.

[0034] In a preferred embodiment of the present invention, an exhaust device is located above the interior of the transparent granulation chamber, and the exhaust device is, for example, an exhaust fan. The exhaust device controls the gaseous environment throughout the granulation process by controlling the gaseous environment inside the transparent granulation chamber.

[0035] As a specific embodiment of the present invention, the microfluidic unit 3 includes multiple different microfluidic chips, each specifically designed for processes such as shear droplet formation, particle-droplet interaction, and droplet evaporation. The microfluidic chips analyze the influence of key parameters on droplet formation, clustering, and evaporation processes by setting single-factor variation experimental conditions; wherein the single-factor variation experimental conditions include: flow velocity, temperature, and / or shear rate; wherein the key parameters include: interfacial tension coefficient, liquid bridging force, and / or evaporation rate during the granulation process.

[0036] As a preferred embodiment of the present invention, the microfluidic chip includes: a flow focusing chip, a cluster observation microcavity chip, and a vortex microcavity chip. The flow focusing chip is designed for the shearing droplet formation process. When the dispersed phase (ethyl acetate containing PVB) is sheared by the aqueous phases on both sides, monodisperse droplets are formed; changing the flow rate of the aqueous phase yields a series of particle sizes from 50 to 500 μm. The ability to shear the droplets is determined by analyzing the interfacial tension coefficient and critical capillary number. The cluster observation microcavity chip is designed for particle-droplet interaction (clustering). Equal amounts of melamine particles and droplets are placed together, and a high-speed camera can record the real-time process of particles being bridged and agglomerated by the droplets. The vortex microcavity chip is designed for the droplet evaporation process. Droplets are thrown against the annular cavity wall to form a thin liquid film, and dry nitrogen gas at 40 °C is passed through to accelerate solvent evaporation; the diameter shrinkage curve over time can be recorded. This invention uses three dedicated chips to break down particle formation into three independent sub-experiments: shearing into droplets, particle clustering, and droplet evaporation. Interfacial tension, liquid bridging force, and evaporation rate are measured separately, and single-factor scanning is performed to determine which parameter determines which sub-process, thus establishing quantitative criteria. The microfluidic chip supports single-particle analysis, and multiple microfluidic chips can simulate various microflow environments. The local shear rate generated by the fluid near the channel wall within the microfluidic chip can reach 200 s⁻¹, thereby quantifying the interfacial tension and critical conditions for droplet breakup in the "shearing into droplets" stage, complementing the 10–100 s⁻¹ shear of the macroscopic stirring impeller.

[0037] As a specific embodiment of the present invention, the microscopic observation unit 4 includes: a three-dimensional moving platform and an upright microscope; the upright microscope is set on the three-dimensional moving platform; the three-dimensional moving platform drives the upright microscope to translate in three directions: front-back, left-right, and up-down; the three-dimensional moving platform is used to adjust the observation position or observation height. Through the microscopic observation unit 4 or the high-speed imaging unit 5, the entire microscopic process of droplet formation-clustering-coagulation can be observed in real time, the grain formation rules can be analyzed, and the problem of difficulty in observing the grain formation process can be solved.

[0038] In a preferred embodiment of the present invention, the upright microscope employs a variable light-gathering method. The optical path of the upright microscope can utilize either a coaxial light source or a transmitted light source. The upright microscope can be fitted with lenses of various magnifications, such as 4x, 10x, 20x, and 40x.

[0039] As a specific embodiment of the present invention, the high-speed imaging unit 5 includes: a high-speed camera and a six-dimensional moving platform; the high-speed camera is mounted on the six-dimensional moving platform, which is a parallel mechanism capable of translation in the forward, backward, left, right, and up / down directions, as well as pitch, roll, and yaw rotation, thereby driving the high-speed camera to translate in the forward, backward, left, right, and up / down directions, and to pitch, roll, and yaw rotation; the high-speed camera is used to record in real time the dynamic changes of particles gradually coating droplets during the granulation process, and gradually agglomerating into spheres as the droplets evaporate. The high-speed camera supports multiple magnification conversions and convenient focal length adjustment, and can be installed and applied to miniaturized granulation units, microscopic observation units 4, or microfluidic units 3. The high-speed camera can achieve high spatial resolution of single particle formation analysis of less than 1 mm, a frame rate frequency of over 1000 fps, and an observation time resolution of 1 ms. As a specific embodiment of the present invention, the interface measurement unit 6 includes: an infrared light source, a controllable environmental sealed chamber, and a camera. The controllable environmental sealed chamber forms a 2 cm³ area around the measurement point. A miniature isothermal and isobaric chamber isolates the droplet from external airflow and evaporation, ensuring stable droplet volume. An infrared light source provides 850 nm near-infrared parallel light, which penetrates the controlled, enclosed chamber and is strongly scattered / absorbed by the droplet profile, forming a high-contrast grayscale profile and avoiding interference from visible light scattering in the milky suspension. The infrared light source is aligned with one side of the controlled, enclosed chamber, coaxial with the camera's optical axis or offset by 10° to ensure constant image brightness at different temperatures. The camera captures the droplet's side profile, extracting the equatorial diameter *de* and vertex curvature *1 / R* in real time. The interfacial tension, i.e., the interfacial tension coefficient, is obtained by fitting the Young-Laplace equation. In essence, in the pendant drop method, the droplet profile is fitted to a Young-Laplace curve. Given the density difference Δρ and gravity *g*, an iterative algorithm is used to calculate the unique interfacial tension γ that coincides with the theoretical profile and the experimental image, thus obtaining the interfacial tension coefficient. Surface tension measurements of various substances under different temperatures and pressures are performed to obtain the interfacial tension coefficient during the particle formation process.

[0040] In a specific embodiment of the present invention, a track is arranged along the length of the platform, and the high-speed imaging unit 5, the microfluidic unit 3, and / or the surface and interface measurement unit 6 are arranged on the track. Preferably, the temperature control / fluid control unit is located at the upper left of the platform. The high-speed imaging unit 5 is located in the middle of the track. The microfluidic unit 3 is located on the right side of the track, and the microfluidic unit 3 is linked with the microscopic observation unit 4. The surface and interface measurement unit 6 is located above the track. The microscopic observation unit 4 is located at the upper right of the platform.

[0041] In a preferred embodiment of the present invention, a base is provided on the platform, and an installation slot is provided on the top side of the base. The granulation process experimental unit 2 is installed in the installation slot, so that the granulation process experimental unit 2 is stably and reliably connected to the platform.

[0042] As a specific embodiment of the present invention, a heating base plate is provided at the bottom of the transparent granulation cavity, and the heating base plate is used to realize the heating function.

[0043] As a specific embodiment of the present invention, an injection pump is provided above the transparent granulation chamber, through which an ethyl acetate solution containing 1% PVB can be dripped into the stirrer inside the transparent granulation chamber.

[0044] In a preferred embodiment of the present invention, the high-speed imaging unit further includes an edge AI chip, which embeds an aggregation critical state recognition model. The aggregation critical state recognition model can identify the corresponding cluster fractal dimension based on real-time image data. If the cluster fractal dimension reaches a preset experimental aggregation critical threshold, a real-time control command is sent to the temperature and flow control unit to suppress aggregation. The real-time control command includes at least one of the following: increasing the temperature according to a preset heating threshold, decreasing the stirring speed according to a preset stirring speed reduction ratio, and decreasing the dropping speed according to a preset dropping speed reduction ratio. In a specific embodiment of the present invention, the edge AI chip can be an NVIDIA Jetson Nano, and the aggregation critical state recognition model can be a YOLOv7-tiny. A training set of ≥100,000 in-situ images is used to train the model, enabling it to recognize the cluster fractal dimension. Specifically, when the cluster fractal dimension Df ≥ 1.85 (the experimentally calibrated critical threshold for aggregation) is detected, the system can automatically execute the following closed-loop actions within 1 ms: instantaneously reduce the stirring speed by 10%, instantaneously reduce the dropping speed by 15%, and instantaneously increase the temperature by 2 K.

[0045] Specifically, reducing the stirring speed can prevent shear breakage, reducing the dropping speed can reduce the collision frequency, and increasing the temperature can reduce the liquid phase viscosity and suppress bridging. This transforms "post-processing parameter tuning" into millisecond-level suppression of agglomeration, reducing the particle size distribution CV value from the traditional 12% to 3%.

[0046] As a specific embodiment of the present invention, in the micro-flow granulation mechanism experiment of water suspension granulation, a micro-mechanical model of granulation evolution was established. The dropping rate of ethyl acetate solution containing 1% PVB and the stirring speed of the stirring component were controlled to obtain the particle size distribution function including the effects of stirring and dropping. f ( d,t ).

[0047] The micromechanical model of granulation evolution is as follows: Where f(d,t) represents the distribution of particle size d at time t; This indicates the distribution change caused by the droplet addition process. This indicates the distribution change caused by the evaporation of solvent droplets; This indicates the distribution changes caused by clustering; This indicates the distribution change caused by agglomeration; This represents the divergence operation.

[0048] in, For the particle size convection term, the "movement" of particles along the particle size coordinate due to growth / dissolution is treated as a kind of "velocity," and its net outflow rate in the particle size space is calculated, thus describing the effect of particle size change on the particle size distribution function. f ( d,t The impact of ). Among them, ; f 0 represents the initial distribution. u 滴加 The dripping speed is denoted as . ; k For undetermined coefficients, J c For cluster rate, u 搅拌 The stirring speed of the stirring component; d This indicates the particle diameter. Among them, k The value range can be 1-10. ; J s For evaporation rate, u 搅拌 This refers to the stirring speed. ; and The subjects of coagulation are respectively u 搅拌 and u 滴加 The undetermined coefficients; Indicates and Particles of different sizes. The undetermined coefficients are based on actual... and The influence relationship on the distribution changes during the coagulation stage was constructed, and in practice... , The value of varies u 搅拌 and u 滴加 The values ​​change with the particle size distribution, fluctuating within a wide range. Based on the micromechanical model of particle formation evolution, the "operating parameters" can be directly translated into "particle size distribution," making experimental results reproducible, predictable, and scalable. Specifically, based on the given... u 滴加 andu 搅拌 With time, it can be calculated f ( d,t This eliminates the need for a full set of experiments. By using a particle evolution micromechanical model for reverse search, the optimal stirring speed or dropping rate can be quickly found, reducing the trial-and-error cost from weeks to minutes. Furthermore, by embedding the particle evolution micromechanical model into an AI closed loop, it enables real-time comparison between the "measured distribution" and the "target distribution," automatically fine-tuning the stirring component speed or dropping rate to achieve millisecond-level correction.

[0049] In a preferred embodiment of the present invention, the temperature control and flow control unit is further configured to receive a particle formation control command triggered by a pre-constructed micromechanical model of particle formation evolution, and automatically adjust the stirring speed or the dropping speed.

[0050] like Figure 4 As shown, this application provides an experimental method for the micro-flow particle formation mechanism of water suspension granulation, applied to an experimental system for the micro-flow particle formation mechanism of water suspension granulation. The method includes: Step S1: Prepare an ethyl acetate solution containing 1% PVB and place it in a syringe pump.

[0051] Step S2: Adjust the temperature field and flow field environment inside the transparent granulation chamber to the preset target range.

[0052] Step S3: The pre-prepared melamine powder is stirred in the aqueous solution in the stirrer using a stirring paddle.

[0053] Step S4: Add an ethyl acetate solution containing 1% PVB dropwise into the stirrer using a syringe pump.

[0054] Step S5: Capture the granulation process using a high-speed camera to record the granulation video.

[0055] In this process, based on a pre-established micromechanical model of granulation evolution, the dropping rate of an ethyl acetate solution containing 1% PVB and the stirring speed of the impeller are controlled.

[0056] As a specific embodiment of the present invention, melamine and ethyl acetate raw materials are used as examples, with melamine having a purity of 99% and ethyl acetate having a purity of 99%. The ethyl acetate contains 1% PVB by mass. The influence of process parameters on the granulation process is investigated. Specifically, the experimental method for the micro-flow granulation mechanism of water suspension granulation is as follows: Turn on the experimental system power, set the target heating temperature to 40°C using the temperature feedback control, and heat 200mL of water in a beaker to the same temperature. Set the shooting parameters in the high-speed camera control panel. Preferably, to reduce the computational burden of particle size analysis during testing, the high-speed camera's shooting frame rate is set to 200 fps.

[0057] Prepare a mixture of ethyl acetate and 1% PVB beforehand, and fill the syringe with the prepared mixture. Place the syringe on the syringe pump and its support. Set the planned drip rate value on the syringe pump panel. u 滴加 .

[0058] Install the stirring paddle and stirrer on the heating base plate of the granulation process experimental unit. Measure 3.0 mL of water from the beaker using a graduated cylinder and add it to the stirrer. The temperature probe is installed at the bottom of the side wall of the stirrer.

[0059] Adjust the shooting position of the high-speed camera, observe through the high-speed camera, and check whether the stirrer and stirring paddle are installed in place. After they are in place, raise the stirring paddle and wait for the melamine powder to be added.

[0060] Weigh 0.0280 ± 0.0010 g of melamine using an electronic balance. Gently transfer the powder from the weighing paper to the aqueous solution in the stirrer using a sampling spoon. Lower the stirrer to the preset height in the solution and stir at the planned speed. u 搅拌 Start stirring.

[0061] Move the dropper containing 1% PVB ethyl acetate solution to the preset position above the stirrer, test and ensure that the dropper outlet is unobstructed, wipe away any droplets that have flowed out of the outlet, and prepare for the next drop.

[0062] Once the temperature feedback controller indicates that the temperature inside the reactor of the granulation process experimental unit has reached 40 ± 1°C, the ethyl acetate solution containing 1% PVB can be added dropwise. After the addition begins, the granulation process is recorded by capturing video footage of the granulation process using a high-speed camera.

[0063] like Figure 2 The diagram shown illustrates the granulation process. It allows for the observation and high-resolution analysis of microscopic processes in water suspension granulation, such as emulsification into droplets, particle-droplet clustering, solvent evaporation and aggregation into spheres, and droplet-droplet coagulation, making microscopic quantitative modeling possible.

[0064] For this micro-granulation experiment, the granulation process was basically completed approximately 10-20 seconds after the initial droplet addition, at which point filming was stopped. The captured video was analyzed using particle size analysis software. The time starting point for granulation was defined as t = 0s, with the first droplet appearing in the image. Particle size statistics were analyzed, and the percentage of particle size distribution at different stirring speeds was recorded.

[0065] like Figure 3 The diagram shown illustrates the percentage particle size distribution at different stirring speeds. This is achieved by controlling the stirring speed. u 搅拌The droplet / particle size distribution function was discovered. f ( d,t ) then changes, thus obtaining u 搅拌 Controlling the grain formation process involves recording the grain formation process by capturing video footage of the process with a high-speed camera. Based on the correlation between particle size distribution data, stirring speed, and dropping speed, the aforementioned micromechanical model of grain formation evolution is constructed.

[0066] This application also provides a computer storage medium storing computer instructions, which, when invoked, execute the address mapping method of the large-capacity solid-state drive. The computer storage medium includes one or more program instructions, which are executed by a processor to perform an experimental method for the micro-flow granulation mechanism of water suspension granulation.

[0067] The embodiments disclosed in this invention provide a computer-readable storage medium storing computer program instructions. When the computer program instructions are executed on a computer, the computer performs the above-described experimental method for the micro-flow granulation mechanism of water suspension granulation.

[0068] This invention provides a processor for processing the above-described experimental method for the micro-flow granulation mechanism of water suspension granulation.

[0069] In this embodiment of the invention, the processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0070] The various methods, steps, and logic diagrams disclosed in the embodiments of this invention can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The processor reads information from the storage medium and, in conjunction with its hardware, completes the steps of the above methods.

[0071] The storage medium can be memory, such as volatile memory or non-volatile memory, or may include both volatile and non-volatile memory.

[0072] The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EEPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DRRAM).

[0073] The beneficial effects achieved by this application are as follows: (1) This application realizes the synchronous coordination of granulation working condition simulation, precise control of key process parameters and in-situ process observation. It solves the technical defects of the lack of in-situ observation of granulation experimental equipment, which leads to the "black box" of granulation process, unsystematic identification of key process parameters and fuzzy parameter influence law, thus making it impossible to establish a quantitative correlation of "parameter-process-product". It provides reliable support for mechanism analysis and process optimization.

[0074] (2) This application uses three special chips to break down the particle formation into three independent sub-experiments: shearing into droplets, particle clusters, and droplet evaporation. The interfacial tension, liquid bridge force, and evaporation rate are measured respectively, and then a single-factor scan is performed to obtain which parameter determines which sub-process, thereby establishing a quantitative criterion.

[0075] (3) This application can observe the entire microscopic process of droplet-cluster-coagulation in real time through a microscopic observation unit or a high-speed imaging unit, analyze the grain formation law, and solve the problem of the difficulty in observing the grain formation process.

[0076] (4) Based on the micromechanical model of particle formation evolution, this application can quickly find the optimal stirring speed or droplet acceleration rate, reduce the cost of trial and error, and discover that the particle size distribution function of droplets / particles changes accordingly by controlling the stirring speed, thereby obtaining the law of particle formation controlled by stirring speed.

[0077] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0078] In the description of this application, the word "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0079] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An experimental system for the microscopic mechanism of microfluidic granulation in water suspension granulation, characterized in that, The system comprises the following functional units: a temperature and flow control unit, a granulation process experimental unit, a microfluidics unit, a microscopic observation unit, a high-speed imaging unit, and a surface and interface measurement unit. All these functional units are integrated and deployed on the same platform for coordinated operation. A track is provided on the platform, and the high-speed imaging unit, the microfluidics unit, and / or the surface and interface measurement unit are positioned on the track. Specifically, the surface and interface measurement unit measures the interface characteristics of the granulated material, and then, in conjunction with the microfluidics unit and the microscopic observation unit, conducts preliminary experiments to determine the granulation process parameters. The temperature and flow control unit configures temperature field control parameters and flow field control parameters according to the granulation process parameters, thereby controlling the granulation process experimental unit to conduct experiments. The high-speed imaging unit observes the granulation process data of the granulation process experimental unit, thus enabling experimental research on the microscopic mechanism of microfluidic granulation. The temperature and flow control unit controls the temperature and flow fields of the granulation process in the granulation process experimental unit. The granulation process experimental unit is used to complete the entire process of droplet, particle, cluster, and coagulation within the granulation chamber, and allows for in-situ observation; The microfluidic unit is used to provide a controllable microflow environment through the microfluidic chip during the shearing and droplet formation, particle-droplet interaction, and droplet evaporation stages, so as to conduct pre-experiments in the controllable microflow environment and determine the granulation process parameters. The microscopic observation unit is used to magnify and observe the object inside the granulation cavity or the microfluidic chip. The high-speed imaging unit is used to record the dynamic changes of particle formation in the particle formation process experimental unit, the microfluidic unit, or the microscopic observation unit. The interface measurement unit includes an infrared light source, a controllable enclosed chamber, and a camera; it is used to measure the interface characteristic parameters of granulated materials online under different temperature or pressure conditions.

2. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The temperature and flow control unit includes: a power supply box, a constant temperature module, a temperature sensor, a temperature controller, and a visually adjustable stirrer; The power supply box is electrically connected to the constant temperature module, the temperature controller and the stirring assembly; The temperature control sensor is set at the temperature measuring point of the constant temperature module. The temperature control sensor is electrically connected to the temperature controller and is used to feed back the measured temperature data to the temperature controller. The temperature controller is electrically connected to the visual adjustable stirrer and is used to synchronously adjust the stirring speed within a set temperature range.

3. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The granulation process experimental unit includes: a transparent granulation chamber, a stirring assembly, and an exhaust device; The transparent granulation chamber includes a feed inlet and an exhaust outlet; and the transparent granulation chamber is made of quartz material, with an inner diameter of 10-100 mm, a height of 10-100 mm, and a sidewall thickness of 1-5 mm. The stirring assembly is assembled inside the transparent granulation chamber; the stirring assembly includes a stirrer and a stirring paddle; the stirring paddle is positioned above the stirrer; the stirrer has a cavity for holding granulated materials; the stirring assembly is used to adjust the stirring intensity to simulate the stirring flow field of actual granulation; wherein, the diameter of the stirring paddle blade is 10-50 mm, and the rotation speed is adjustable from 100-2000 rpm; The exhaust device is located inside the transparent granulation chamber and at the exhaust port. The exhaust device controls the gaseous environment inside the transparent granulation chamber, thereby controlling the gaseous environment during the entire reaction.

4. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The microfluidic unit includes multiple different microfluidic chips; The microfluidic chip analyzes the influence of key parameters on droplet formation, clustering, and volatilization processes by setting single-factor variation experimental conditions. Among them, the single-factor variation experimental conditions include: flow velocity, temperature and / or shear rate; Key parameters include: interfacial tension coefficient, liquid bridging force, and / or evaporation rate during the granulation process.

5. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The microscopic observation unit includes: a three-dimensional moving platform and an upright microscope; The upright microscope is mounted on the three-dimensional moving platform; The three-dimensional moving platform is used to adjust the observation position.

6. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The high-speed imaging unit includes: a high-speed camera and a six-dimensional mobile platform; The high-speed camera is mounted on the six-dimensional mobile platform; The high-speed camera is used to record in real time the dynamic changes of particles gradually coating droplets during the granulation process and gradually agglomerating into spheres as the droplets evaporate.

7. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 6, characterized in that, The high-speed imaging unit also includes an edge AI chip, which embeds an aggregation critical state recognition model. The aggregation critical state recognition model can identify the corresponding cluster fractal dimension based on real-time image data. If the cluster fractal dimension reaches a preset experimental aggregation critical threshold, a real-time control command is sent to the temperature control and flow control unit to suppress aggregation. The real-time control command includes at least one of the following: increasing the temperature according to a preset heating threshold, decreasing the stirring speed according to a preset stirring speed reduction ratio, and decreasing the dropping speed according to a preset dropping speed reduction ratio.

8. The experimental system for the micro-flow granulation mechanism of water suspension granulation according to claim 1, characterized in that, The temperature and flow control unit is also used to receive particle formation control commands triggered by a pre-constructed micromechanical model of particle formation evolution, and automatically adjust the stirring speed or dropping speed; wherein, the micromechanical model of particle formation evolution is: ; ; ; ; ;in, This represents the distribution of particle size d at time t; This indicates the distribution change caused by the droplet addition process. This indicates the distribution change caused by the evaporation of solvent droplets; This indicates the distribution changes caused by clustering; This indicates the distribution change caused by agglomeration; f 0 represents the initial distribution. The dropping acceleration; k The range is the undetermined coefficient determined by the granulation system. J c For cluster rate, The stirring speed of the stirring component; Indicates particle diameter; J s For evaporation rate, This refers to the stirring speed; and The subjects of coagulation are respectively and The undetermined coefficients; Indicates and Particles of different sizes.

9. An experimental method for the microscopic mechanism of microfluidic granulation in water suspension granulation, characterized in that, The method, applied to the microfluidic particle formation micromechanism experimental system for water suspension granulation according to any one of claims 1-8, comprises: Prepare an ethyl acetate solution containing 1% PVB and place it in a syringe pump; Adjust the temperature and flow field environment inside the transparent granulation chamber to the preset target range; The pre-prepared melamine powder was stirred in an aqueous solution in a stirrer using a stirring paddle. An ethyl acetate solution containing 1% PVB is added dropwise into the stirrer using a syringe pump. The granulation process is recorded by capturing granulation videos using a high-speed camera.

10. The experimental method for the micro-flow granulation mechanism of water suspension granulation according to claim 9, characterized in that, After capturing the granulation process using a high-speed camera to record the granulation video, the method further includes: Statistical analysis of particle size distribution data under different stirring speeds and different dropping rates; Based on the correspondence between the particle size distribution data, the stirring speed, and the dropping speed, the micromechanical model of particle formation evolution is constructed.

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