Apparatus and method for experimentally observing flocculation and dispersion of fiber based on flow field visualization

Abstract

The present invention relates to the field of flow field visualization technology, and provides an apparatus and a method for experimentally observing flocculation and dispersion of fiber based on flow field visualization. The apparatus for experimentally observing flocculation and dispersion of fiber at least comprises: at least one pulp tank, used for containing and preparing a fiber suspension; an observation flow channel pipe, causing the fiber suspension to flow therethrough; a pulp pump, used for pumping the fiber suspension from the pulp tank to the observation flow channel pipe; the pulp tank, the pulp pump and the observation flow channel pipe being sequentially connected by means of a pipeline; a high speed camera system, used for capturing and analyzing an image of fiber in a flow field in the observation flow channel pipe, so as to obtain a flocculation size and dimension of the fiber. The present invention can simulate dynamic behavior of fiber in actual working conditions, so that a researcher can dynamically observe and analyze flocculation and dispersion behaviors of fiber, rather than only being able to perform static rough estimation. The dynamic analysis capability enables a researcher to more accurately understand the performance of fiber in practical applications.

Description

Fiber flocculation and dispersion experimental observation device and method based on flow field visualization Technical Field

[0001] The present invention belongs to the technical field of flow field visualization, and in particular relates to a fiber flocculation and dispersion experimental observation device and method based on flow field visualization. Background Art

[0002] The papermaking industry is extremely concerned with paper formation uniformity, which is directly related to the degree of fiber flocculation and dispersion. Different fibers exhibit very different flocculation and dispersion behaviors, necessitating research to provide a theoretical basis for subsequent product development.

[0003] Traditionally, fiber aggregation behavior has been studied in the laboratory using methods such as fiber suspension observation, paper formation observation, and sedimentation time. However, these methods provide rough estimates of fiber aggregation under static conditions. In actual industrial production, fibers are in a continuous state of motion from preparation and feeding to forming. The intensity and scale of turbulence, as well as the size of eddies, significantly influence fiber aggregation. Clearly, static assessment methods cannot truly reflect fiber aggregation and dispersion behavior. However, direct observation on industrial production equipment is often prohibitively expensive or even impossible. For example, installing transparent windows in extremely high-strength equipment compromises its structural strength. The poor wear and corrosion resistance of these window materials can lead to frequent equipment downtime. Existing light sources cannot penetrate high-concentration fiber suspensions, preventing cameras from accurately capturing details of fiber aggregation. Therefore, accurate observation and analysis of fiber dynamic behavior remains a major challenge in this field.

[0004] At present, in the field of fiber material research, the study of the flocculation and dispersion behavior of fibers in fluids mainly relies on traditional experimental observation methods. These methods are often unable to accurately capture and analyze the behavior of fibers in a flow state, nor can they effectively observe fibers of different lengths.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to propose a fiber flocculation and dispersion experimental observation device and method based on flow field visualization, which can truly simulate the flocculation behavior of fibers in actual working conditions and can clearly capture and analyze the flocculation behavior of fibers in the flow field.

[0007] The purpose of the present invention is to propose a fiber flocculation and dispersion experimental observation device based on flow field visualization, which can effectively capture and analyze the dynamic flocculation and dispersion behaviors of different fibers under different working conditions.

[0008] The second purpose of the present invention is to propose a fiber flocculation and dispersion experimental observation device based on flow field visualization, in which the height of the observation flow channel tube is adjustable, and the appropriate height is selected according to the different lengths of fibers, which can simulate the dynamic behavior of fibers in actual working conditions.

[0009] The third purpose of the present invention is to propose a fiber flocculation and dispersion experimental observation device based on flow field visualization, which can replace different hydraulic elements and add different chemicals to carry out corresponding experiments, making it multifunctional.

[0010] The fourth purpose of the present invention is to propose an observation method for a fiber flocculation and dispersion experimental observation device based on flow field visualization, which can simulate the real state of the fiber in the actual operating equipment and effectively capture and analyze the fiber flocculation and dispersion behavior as an experimental observation means.

[0011] To achieve the above-mentioned object, the present invention proposes a fiber flocculation and dispersion experimental observation device based on flow field visualization, wherein the fiber flocculation and dispersion experimental observation device at least comprises:

[0012] at least one slurry tank for receiving and preparing a fiber suspension;

[0013] an observation flow channel tube, allowing the fiber suspension to flow therein;

[0014] a slurry pump, used for pumping the fiber suspension from the slurry tank to the observation flow channel pipe, wherein the slurry tank, the slurry pump and the observation flow channel pipe are sequentially connected through pipelines;

[0015] The high-speed camera system is used to capture and analyze the image of the fiber in the flow field in the observation flow channel tube to obtain the flocculation condition of the fiber.

[0016] The present invention also proposes an observation method for a fiber flocculation and dispersion experimental observation device based on flow field visualization, wherein a fiber suspension is prepared; the fiber suspension is sent to an observation flow channel tube; and an image of the fibers in the fiber suspension in the observation flow channel tube is captured by a high-speed camera system and the image is analyzed to obtain the flocculation behavior and dispersion behavior of the fibers in the water in the observation flow channel tube.

[0017] Compared with the prior art, the present invention has the following characteristics and advantages:

[0018] The present invention can simulate the dynamic behavior of fibers in actual working conditions. Researchers can dynamically observe and analyze the aggregation and dispersion behavior of fibers, rather than just making static rough estimates. The ability of dynamic analysis enables researchers to more realistically understand the performance of fibers in actual applications.

[0019] The present invention significantly improves the efficiency of observing and evaluating the fiber dispersion properties in fiber suspensions by combining a high-speed camera system with real-time image processing and analysis technology. This method can quickly capture the dynamic behavior of fibers and, through automated processing and analysis, rapidly provide evaluation results of the fiber dispersion properties.

[0020] The present invention can flexibly prepare fiber suspensions with different properties by adjusting the shear rate and time of the agitator, provides multiple options for the preparation process and performance of the fiber suspension, and helps to customize the properties of the fiber suspension according to specific needs.

[0021] The present invention has multifunctionality and can carry out corresponding hydraulic element fiber dispersion experiments by replacing different hydraulic elements; and can also be used to evaluate the dispersion effect on fibers by adding different chemicals. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the drawings are merely illustrative and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to specific circumstances under the guidance of the present invention.

[0023] FIG1 is a schematic diagram of a fiber flocculation and dispersion observation device based on flow field visualization provided by an embodiment of the present invention;

[0024] FIG2 is a schematic diagram of the structure of an observation flow channel tube provided by an embodiment of the present invention;

[0025] FIG3 is a schematic diagram of a high-speed camera system provided by an embodiment of the present invention;

[0026] FIG4 is a schematic diagram of an agitator and a slurry tank provided by an embodiment of the present invention;

[0027] FIG5 is a schematic diagram of a special elbow provided by an example of the present invention;

[0028] FIG6 is a second schematic diagram of a special elbow provided by an example of the present invention;

[0029] FIG7 is a third schematic diagram of a special elbow provided by an example of the present invention;

[0030] FIG8 is a schematic diagram of a high-precision camera bracket provided by an example of the present invention.

[0031] Description of the accompanying figures:

[0032] 1-slurry tank a; 1'-slurry tank b; 2-agitator a;

[0033] 2'- agitator b; 3- slurry pump; 4- pressure transmitter a;

[0034] 5-Observation flow channel; 6-High-speed camera; 7-Light source;

[0035] 8-data processing unit; 9-pressure transmitter b; 10-temperature transmitter;

[0036] 11-Electromagnetic flowmeter; 12-Special elbow; 13-Transparent pipe;

[0037] 14- regulating valve; 15- inlet gradually expanding flow channel; 16- middle rectangular flow channel;

[0038] 17- outlet tapered flow channel; 18- agitator motor; 19- shaft;

[0039] 20- agitator impeller; 21- slurry tank bracket; 22- agitator adjustment bracket;

[0040] 28-Z-axis adjustment handwheel (H direction); 29-X-axis rotation platform (L direction);

[0041] 30-X axis adjustment hand wheel (L direction); 31-Y axis rotation platform (W direction);

[0042] 32-Y-axis adjustment handwheel (W direction); 33-Z-axis long distance slide rail (H direction);

[0043] 34-Bearing bracket; 35-Mounting base; 36-Adjustable feet and rollers. DETAILED DESCRIPTION

[0044] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only for the purpose of explaining the present invention and are not to be construed as limiting the present invention in any way. Based on the teachings of the present invention, a skilled person can conceive of any possible variations based on the present invention, and such variations should be considered to fall within the scope of the present invention.

[0045] The present invention proposes a fiber flocculation and dispersion experimental observation device based on flow field visualization, which includes at least: at least one slurry tank for accommodating and preparing a fiber suspension; an observation flow channel pipe 5 for allowing the fiber suspension to flow therein; a slurry pump 3 for pumping the fiber suspension from the slurry tank to the observation flow channel pipe 5, and the slurry tank, slurry pump 3 and observation flow channel pipe 5 are connected in sequence through pipelines; a high-speed camera system for capturing and analyzing images of fibers in the flow field in the observation flow channel pipe 5 to obtain the flocculation scale and dimension of the fibers.

[0046] The fiber flocculation and dispersion experimental observation device based on flow field visualization proposed in the present invention is a fiber suspension in a flowing state in the observation flow channel tube 5, wherein the flocculation and dispersion behaviors of the fibers are basically consistent with the actual working conditions, that is, the dynamic behaviors of the fibers in the actual working conditions are simulated. Based on the fiber flocculation and dispersion experimental observation device based on flow field visualization of the present invention, researchers can dynamically observe and analyze the flocculation and dispersion behaviors of the fibers, rather than only making static rough estimates, thereby enabling researchers to have a more realistic understanding of the performance of the fibers in actual applications.

[0047] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device further includes: an electromagnetic flowmeter 11 for measuring and calculating the flow rate of the fiber suspension in the observation flow channel 5.

[0048] The electromagnetic flowmeter 11 can monitor the flow of the fiber suspension in real time, providing dynamic information on the fiber flocculation and dispersion process for experimental observation, thereby improving the technical level and application scope of the observation device.

[0049] In an optional embodiment of the present invention, the flow rate is calculated as follows:

[0050] Wherein, v1 is the flow velocity of the fiber suspension in the middle rectangular flow channel 16, QV is the system volume flow measured by the electromagnetic flowmeter 11, W is the width of the middle rectangular flow channel 16, and H is the height of the middle rectangular flow channel 16.

[0051] Flow velocity is one of the important factors affecting the fiber flocculation and dispersion behavior in the fiber suspension. Through the flow velocity calculation formula, a quantitative method can be used to evaluate the flow state of the fiber suspension in the middle rectangular flow channel 16. Accurately measuring and calculating the flow velocity can better understand the dynamic behavior of the fiber in the fluid and further study the mechanism and influencing factors of fiber flocculation and dispersion.

[0052] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device also includes: a special elbow 12 for observing the influence of the elbow on fiber flocculation in the fiber suspension, and the special elbow 12 is connected in series to the pipeline and is located downstream of the observation flow pipeline.

[0053] The special elbow 12 is installed in series on the transparent pipe 13 of the fiber flocculation and dispersion experimental observation device. The fluid flows through the special elbow 12. The special elbow 12 is transparent, and the transparent pipe 13 connected to the special elbow 12 is also transparent, so that the flocculation changes of the fibers in the fluid when passing through the elbow can be observed and studied, providing experimental observations with data information on the flocculation changes of the fiber suspension when passing through the elbow.

[0054] In the present invention, different special elbows 12 can be used according to the purpose of experimental observation to conduct experimental observations on the effects of different special elbows 12 on fiber flocculation in a fiber suspension.

[0055] In an optional example of this embodiment, the average flow velocity in the special elbow 12 is calculated as follows:

[0056] Wherein, v2 is the average flow velocity in the special elbow 12, QV is the system volume flow measured by the electromagnetic flowmeter 11, and D is the inner diameter of the special elbow 12.

[0057] The average flow velocity formula in the special elbow 12 can be used to quantitatively evaluate the effect of the special elbow 12 on fiber flocculation in the fiber suspension. By comparing the fiber flocculation at different flow rates, we can gain a deeper understanding of the mechanism of the effect of the elbow on fiber flocculation.

[0058] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device further includes: an agitator, used in conjunction with the pulp tank, and the agitator is used to prepare the chopped fiber bundles into a fiber suspension.

[0059] The agitator is mainly used to prepare the chopped fiber bundles in the slurry tank into a fiber suspension. As shown in Figure 4, the agitator includes: an agitator motor 18, a shaft 19 and an agitator impeller 20. The agitator is fixed to the top of the agitator adjustment bracket 22. The agitator adjustment bracket 22 stands on the outside of the slurry tank. The shaft 19 and the agitator impeller 20 extend into the slurry tank, and the slurry tank is placed on the slurry tank bracket 21. The mechanical force of the agitator can disperse the agglomerated chopped fiber bundles in the slurry tank and mix them evenly in the solution to form a relatively uniform fiber suspension. Fiber suspensions with different characteristics can be prepared by changing the impeller model of the agitator, adjusting the tangential speed of the agitator, and adjusting the installation angle of the agitator. The stirring of the agitator can accelerate the dispersion speed of the chopped fiber bundles in the slurry tank, thereby improving the efficiency of preparing the fiber suspension.

[0060] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device further includes: a light source 7 for illuminating the fiber flocculation clusters in the observation flow channel 5, so that the high-speed camera 6 can clearly capture the state of the fiber flocculation clusters during the flow process.

[0061] The primary function of light source 7 is to illuminate the fiber aggregates in observation flow tube 5, ensuring that high-speed camera 6 can clearly capture the state of the fiber aggregates during flow. Light source 7 can provide sufficient light to ensure that the fiber aggregates in observation flow tube 5 are fully illuminated, allowing high-speed camera 6 to clearly capture their images.

[0062] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device further includes a pressure transmitter, a temperature transmitter 10 and a regulating valve 14 installed on the pipeline.

[0063] The pressure transmitter can accurately measure the pressure of the fiber suspension in the pipeline in real time and convert the physical pressure into an electrical signal for analysis and recording by the data processing system. By installing a pressure transmitter in the device, we can understand how the fluid dynamics behavior affects the dispersion and flocculation of fibers in experimental observations. In this device, the pressure transmitter a4 is installed in the observation channel pipe 5.

[0064] The temperature transmitter 10 captures temperature changes in the fluid in the pipeline and converts them into electrical signals for analysis and recording by the data processing system. By installing the temperature transmitter 10 in the device, experimental observations can be used to understand how temperature affects the physical properties and chemical reactions of the fiber suspension, thereby gaining a deeper understanding of the mechanism by which temperature affects fiber aggregation and dispersion.

[0065] The regulating valve 14 can accurately adjust the fluid flow in the pipeline according to the needs of experimental observation. In this device, multiple regulating valves 14 are set at different positions in the pipeline as needed, so that the flow of the fiber suspension can be controlled in conjunction with devices with different functions.

[0066] In an optional embodiment of the present invention, the fiber flocculation and dispersion experimental observation device includes a slurry tank a1 and a slurry tank b1 ', and the two slurry tanks are arranged in parallel.

[0067] The apparatus of the present invention employs a design in which two slurry tanks are installed in parallel. Slurry tank a1 and slurry tank b1' can share the same input and / or output fluid paths. During experimental observations, the two slurry tanks can be used in a single configuration, with one used and the other as a backup. The choice of either slurry tank is arbitrary.

[0068] The double slurry tank setting enables more complex comparative experiments and increases the sample size in experimental observations, thus enhancing the experimental capability and flexibility of the fiber flocculation and dispersion experimental observation device.

[0069] In an optional embodiment of the present invention, a regulating valve 14 is connected between the slurry tank and the slurry pump 3. The regulating valve 14 is installed on the fluid path between the slurry tank and the slurry pump 3. Its main function is to switch between the slurry tank a1 and the slurry tank b1' by adjusting the regulating valve 14.

[0070] In an optional embodiment of the present invention, the observation flow channel tube 5 is in the shape of a transparent rectangular column, and both ends of the observation flow channel tube 5 are in a tapered shape with the diameter gradually decreasing toward the end.

[0071] As shown in Figure 2, the two ends of the observation channel tube 5 gradually reduce in diameter toward their ends, forming two constrictions. The middle rectangular columnar design produces a specific fluid dynamic effect at each constriction, which will affect the flow rate, flow field distribution and flow behavior of the fiber. The fiber suspension will experience different flow patterns and interactions when entering and leaving the constriction area. The two constrictions toward the ends are the inlet gradually expanding channel 15 and the outlet gradually contracting channel 17, that is, the inlet is gradually expanding and the outlet is gradually contracting. This design also helps to gather the fibers in the center of the observation area of ​​the middle rectangular channel 16, so that the fiber suspension is evenly distributed along the W direction of the observation channel tube 5, eliminating the interference caused by the uneven fluid flow and the observation of fiber flocculation, thereby better observing the state of the fiber and improving the experimental effect of the fiber flocculation and dispersion experimental observation device.

[0072] The transparent observation tube 5 allows for intuitive observation and analysis of the flow state of the fiber suspension in the tube during experimental observation. The transparent material of the observation tube 5 can be glass or transparent plastic, ensuring clear visualization of the fluid behavior. The observation tube 5 utilizes a central rectangular flow channel 16 with a central rectangular cross-section, providing a larger observation area and enabling easier observation and recording of fiber movement and distribution in multiple directions. This improves the performance and experimental capabilities of the fiber flocculation and dispersion experimental observation device and enhances intuitive visualization of fiber behavior.

[0073] In an optional embodiment of the present invention, the high-speed camera system includes: a high-speed camera 6 and a data processing unit 8.

[0074] The high-speed camera system includes two main parts: a high-speed camera 6 and a data processing unit 8. In fiber flocculation and dispersion experiments, the high-speed camera 6 can capture transient processes such as the rapid movement, collision, flocculation, and dispersion of fibers in a fluid. The high-speed camera 6 can also be equipped with appropriate optical lenses and lighting systems according to experimental requirements to ensure accurate and comprehensive recording of the fiber behavior in the observation flow tube 5. The high-speed camera 6 is a camera that can record dynamic images at a very high frequency. Compared to the 24 frames per second of a general camera, the high-speed camera 6 can capture at least 1,000 frames per second, and up to 2 billion frames per second, depending on the model. After shooting, the images can be played back at normal speed.

[0075] The data processing unit 8 is a hardware device or software system that includes a computer, a dedicated image processor, or related software platform for receiving, storing, and analyzing image data captured by the high-speed camera 6. The high-speed camera 6 generates a large amount of image data, and the data processing unit 8 can efficiently transmit, store, and process the data. Furthermore, the data processing unit 8 can receive image data from the high-speed camera 6 in real time and perform real-time processing or subsequent offline analysis. The data processing unit 8 is equipped with specialized image processing and analysis algorithms to extract useful information, such as the fiber's trajectory, size, speed, distribution, and degree of flocculation, and generate visual results or statistical data.

[0076] Specifically, during the process of visually capturing the flow field of the fiber aggregates, the high-speed camera system needs to place the camera as shown in Figure 3 for image acquisition, and the light source 7 shines upward at the bottom of the observation flow tube 5 to allow light to penetrate the observation flow tube 5 and enter the camera lens; the high-speed camera 6 is installed on the precision bracket shown in Figure 8, and the precision slide or pan-tilt head is controlled by the axis adjustment handwheel to adjust the camera lens plane parallel to the LW plane of the observation flow tube 5. The adjustment handwheel and the control precision slide or pan-tilt head are installed on the load-bearing bracket 34, and the bottom end of the load-bearing bracket 34 is installed on the mounting base 35. Adjustable feet and rollers 36 are installed under the mounting base 35. The stability of the high-precision camera bracket can be adjusted by the adjustable feet, and the rollers facilitate the movement of the high-precision camera bracket. By adjusting the Z-axis adjustment wheel (H direction) 28, the high-speed camera 6 moves on the Z-axis long-distance slide (H direction) 33 to adjust the height distance between the camera lens and the observation channel 5. By adjusting the X-axis adjustment wheel (L direction) 30, the high-speed camera 6 moves on the X-axis rotation platform (L direction) 29 to adjust the camera lens's position along the length (L direction) of the observation channel 5. By adjusting the Y-axis adjustment wheel (W direction) 32, the high-speed camera 6 moves on the Y-axis rotation platform (W direction) 31 to adjust the camera lens's position along the width (W direction) of the observation channel 5. After the trial image acquisition is completed and no problems are found, formal image acquisition can be carried out according to the different flow rates designed for the experiment. After the image acquisition is completed, the image is processed and analyzed using image processing software to obtain information such as the size and distribution of fiber clusters under different operating conditions.

[0077] The high-speed camera system can capture and record the rapid movement of fibers in fluids in real time, eliminating the inconvenience of traditional methods requiring manual observation and recording or other means. This significantly improves experimental efficiency and accuracy. The combination of the high-speed camera system and the data processing unit 8 provides a deeper understanding of the dynamic behavior of fibers under different flow conditions.

[0078] In an optional embodiment of the present invention, the flow rate is adjusted by adjusting the rotation speed of the slurry pump 3.

[0079] In the device of the present invention, the slurry pump 3 is designed to provide power to the fiber suspension, causing it to flow in the observation flow channel tube 5. The higher the rotation speed of the slurry pump 3, the greater the power provided by the slurry pump 3. In a pipeline flow system, the flow rate (i.e., the speed of the fluid in the pipeline) is usually positively correlated with the pump rotation speed. When the rotation speed of the slurry pump 3 increases, the flow rate will also increase accordingly; conversely, when the rotation speed decreases, the flow rate will decrease. By adjusting the rotation speed of the slurry pump 3, the flow rate of the fiber suspension in the observation flow channel tube 5 can be conveniently controlled.

[0080] The present invention also proposes an observation method for a fiber flocculation and dispersion experimental observation device based on flow field visualization, which comprises preparing a fiber suspension; sending the fiber suspension to an observation flow channel tube 5; and capturing an image of the fibers in the fiber suspension in the observation flow channel tube 5 through a high-speed camera system and analyzing the image to obtain the flocculation and dispersion behavior of the fibers in the water in the observation flow channel tube 5.

[0081] The observation method of the fiber flocculation and dispersion experimental observation device based on flow field visualization proposed in the present invention can prepare fiber suspensions with different characteristics, and can study the effects of different fiber types and conditions on flocculation and dispersion behaviors. The design of the observation flow channel tube 5 allows the flow rate to be adjusted and measured, and the changes in the flocculation and dispersion behaviors of the fibers under different flow rates can be studied. The high-speed camera system can capture and analyze the dynamic behavior of the fibers in the flow field in real time, thereby providing detailed information about the fiber flocculation and dispersion behavior. Combined with real-time image processing and analysis technology, it can more accurately and efficiently observe and evaluate the dispersion properties of the fibers in the fiber suspension. This method has significant beneficial effects in improving observation and evaluation efficiency, enhancing research depth and breadth, optimizing preparation technology and performance, promoting practical application innovation, promoting interdisciplinary communication and cooperation, and achieving a balance between cost and benefit.

[0082] The observation method of the present invention first requires the preparation of a stable fiber suspension. Chopped fibers are placed into a water-filled slurry tank. After adjusting the tangential speed of the agitator, the fibers in the slurry tank are dispersed into a suspension using the agitator. In practice, fiber suspensions with different properties can be obtained by adjusting the shear rate and time of the agitator. Secondly, the fiber suspension needs to be delivered to the observation flow tube 5. The valve connecting the slurry pump 3 to the slurry tank is opened, the slurry pump 3 is started, and the fiber suspension is pumped into the observation flow tube 5 at an appropriate flow rate. In practice, flow rate is a key parameter, which can be adjusted by varying the rotational speed of the slurry pump 3. The flow rate is measured using an electromagnetic flowmeter 11, and the flow rate is used to calculate the flow rate of the fiber suspension in the observation flow tube 5. Finally, images are captured and analyzed using a high-speed camera system. Light source 7 illuminates the fiber suspension in the observation flow tube 5 to make the fiber clumps more visible. High-speed camera 6 captures images of the fiber clumps, which are analyzed and processed using image analysis software to determine the size and distribution of the fiber clumps. Using light source 7 to illuminate the fiber aggregates in observation channel 5 ensures that high-speed camera 6 can clearly capture the dynamic behavior of the fibers, enhancing the observation effect. During experimental operation, the regulating valve 14 in the observation device is adjusted to ensure stable pressure and flow. Through components such as pressure transmitter a4, pressure transmitter b9, and temperature transmitter, the parameters of the fiber suspension can be obtained in real time, ensuring that the experiment is carried out under constant pressure and temperature conditions.

[0083] In an optional embodiment of the present invention, the observation method further comprises passing the fiber suspension through a special elbow 12 and observing the effect of the special elbow 12 on the fiber flocculation in the fiber suspension.

[0084] The effect of the special elbow 12 on the fiber flocculation in the fiber suspension is studied by adding the special elbow 12 to the observation device, that is, by using a high-speed camera system to capture and analyze the fiber suspension as it passes through the special elbow 12. The high-speed camera system can capture dynamic images of the fiber suspension passing through the special elbow 12 at a high frame rate, allowing us to observe and analyze the movement and flocculation state of the fibers in the special elbow 12 in real time. When the fiber suspension encounters a turning situation, when the fiber suspension passes through the special elbow 12, its flow state will be affected by factors such as the shape and curvature of the elbow, resulting in specific flocculation behavior of the fibers inside the fluid. By adding the design of the special elbow 12, the fiber suspension is made to pass through the special elbow 12 to simulate the situation where the fiber suspension turns. In addition, by replacing the special elbows 12 of different types (such as equal-diameter elbows, accelerating elbows, etc.) as shown in Figures 5, 6 and 7, where DA, DE and DJ are the inner diameters of elbows of different sizes, RM is the curvature of the elbow, and α is the angle between the elbow axis and the horizontal axis. The design of the special elbow 12 provides an effective means to observe and study the effect of the special elbow 12 on the fiber flocculation in the fiber suspension, thereby helping the experiment to deeply study the behavior of the fiber in the fluid and optimize related engineering applications. By replacing different special elbows 12, it is possible to study and understand how different design parameters of the elbow (such as curvature, inner diameter, etc.) affect the flocculation behavior of the fiber, and to better study, understand and control the behavior of the fiber in the actual fluid.

[0085] In an optional embodiment of the present invention, the fiber suspension is prepared by a pulp vat and an agitator, and the fiber suspensions with different properties are prepared by adjusting the shear rate and time of the agitator.

[0086] The process of preparing a fiber suspension involves placing a fiber bundle into a slurry tank filled with water and stirring it with an agitator. The degree of fiber dispersion in the suspension is controlled by adjusting the shear rate and stirring time. By adjusting the shear rate, fiber suspensions of varying sizes and distributions can be prepared. Increasing the shear rate enhances the shearing effect on the fiber bundle, helping to separate the bundle into individual fibers. Different fibers require different shear rates and half-life times. Too low a shear rate or too short agitation time may not completely disperse the chopped fiber bundle, while too high a shear rate and too long agitation time may damage the fibers or increase flocculation. This stirring action helps to disperse the fiber bundle, forming a uniform suspension in the liquid. By adjusting the shear rate and stirring time, the degree of fiber dispersion and properties in the suspension can be controlled, resulting in fiber suspensions with different characteristics, such as varying fiber length, concentration, and distribution. Studying different fiber suspensions can further investigate the flocculation and dispersion behavior of fibers under different conditions.

[0087] In an optional embodiment of the present invention, the dispersion performance of the fibers in the fiber suspension is evaluated by real-time processing and analysis of images captured by a high-speed camera system.

[0088] Images captured by the high-speed camera system are processed and analyzed in real time to evaluate the dispersion properties of the fibers in the fiber suspension. As the fiber suspension flows in the observation flow channel 5, the high-speed camera system captures dynamic images of the fibers at a very high frame rate. These images provide information about the real-time distribution and state of the fibers in the suspension. During the real-time processing and analysis of the images captured by the high-speed camera system, specialized image processing software or algorithms are used to automatically identify and track the fibers in the image. In this way, various fiber parameters such as length, width, orientation, and concentration can be obtained. Specifically, for example, dispersion uniformity: by analyzing the distribution of fibers in the image, we can determine whether the fibers are evenly dispersed in the suspension and whether there are areas where the fibers are too concentrated or too sparse. The degree of flocculation: by identifying and calculating the number and size of fiber aggregates (i.e., flocculation clusters) in the image, we can evaluate the degree of fiber flocculation. Dispersion stability: by comparing images taken at different time points, we can observe the changes in the fiber dispersion state over time and thus evaluate its dispersion stability.

[0089] The high-speed camera system can evaluate the dispersion properties of fibers in fiber suspensions by analyzing the changes in these parameters in time and space, providing an accurate, efficient and intuitive tool for research and application in related fields.

[0090] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0091] The present invention uses high-transmittance materials to make the corresponding flow field visualization device, ensuring that the real state of the fibers in the actual operating equipment can be simulated and the fiber flocculation and dispersion behaviors can be captured and analyzed.

[0092] 1 to 3 , this embodiment is a fiber flocculation and dispersion experimental observation device based on flow field visualization, including a stirrer, a slurry pump 3 , an observation flow channel tube 5 , a high-speed camera system, an electromagnetic flowmeter 11 , etc.;

[0093] The slurry tank a1 and the slurry tank b1' can be selected arbitrarily, and the stirrers a2 and b2' can be selected according to the selected slurry tank. In this embodiment, the slurry tank a1 is selected as the starting point, and a specific volume of clean water is added according to the experimental design. Then, the stirrer a2 is adjusted to an appropriate tangential speed (adjustable range is 1.5m / s to 12m / s), and the weighed chopped fibers are added for stirring and dispersion.

[0094] The slurry pump 3 in the device can be interlocked with the electromagnetic flowmeter 11 to control the speed of the slurry pump 3 by setting the flow rate; in this embodiment, the flow rate setting values ​​are 162L / min, 325L / min and 650L / min respectively;

[0095] The observation channel tube 5 in the device can be selected with different specifications for experiments, so that only one flocculent group passes through the observation channel tube 5 in the height H direction at a time, thereby reducing the observation deviation caused by the overlap of multiple flocculent groups. In this embodiment, the size of the observation channel tube 5 is selected to be 2000mm L×W×H×150mm×12mm, so the flow rate of the fiber suspension in the observation channel tube 5 is:

[0096] The high-speed camera system in the device can capture images of fiber aggregates on the LW surface; in this embodiment, the camera model used is TMX5010, the light source 7 used is a flicker-free LED light source 7, and the data processing unit 8 is a ThinkPad P15 computer.

[0097] During the process of visualizing the flow field of the fiber aggregates, the camera needs to be placed as shown in FIG3 for image acquisition. The second light source 7 needs to illuminate upward from the bottom of the observation flow channel 5 so that the light penetrates the observation flow channel 5 and enters the camera lens. The high-speed camera 6 is mounted on the precision bracket shown in FIG8 , and the camera lens plane is adjusted to be parallel to the LW plane of the observation flow channel 5 by three precision slide rails / pan-tilt heads. After the image trial acquisition is completed without any problems, the formal image acquisition can be carried out according to the different flow rates designed in the experiment.

[0098] After completing the image acquisition, the image can be processed and analyzed using image processing software to obtain the size and distribution data of fiber agglomerates under different working conditions.

[0099] The detailed explanations of the above-mentioned embodiments are intended only to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions cannot be interpreted as limiting the present invention for any reason. In particular, the various features described in different embodiments may also be arbitrarily combined with each other to form other embodiments. Unless otherwise clearly described, these features should be understood to be applicable to any embodiment and are not limited to the described embodiments.

Claims

1. A fiber flocculation and dispersion experimental observation device based on flow field visualization, characterized in that: The fiber flocculation and dispersion experimental observation device comprises at least: at least one slurry tank for containing and preparing a fiber suspension; an observation flow channel tube, allowing the fiber suspension to flow therein; a slurry pump, used for pumping the fiber suspension from the slurry tank to the observation flow channel pipe, wherein the slurry tank, the slurry pump and the observation flow channel pipe are sequentially connected through pipelines; The high-speed camera system is used to capture and analyze the image of the fiber in the flow field in the observation flow channel tube to obtain the flocculation condition of the fiber.

2. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device further comprises an electromagnetic flowmeter for measuring and calculating the flow rate of the fiber suspension in the observation flow channel tube.

3. The fiber flocculation and dispersion experimental observation device according to claim 2, characterized in that: The flow rate is calculated as follows: Where v1 is the flow velocity of the fiber suspension in the middle rectangular flow channel, QV is the system volume flow rate measured by the electromagnetic flowmeter, W is the width of the middle rectangular flow channel, and H is the height of the middle rectangular flow channel.

4. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device also includes: a special elbow, which is connected in series to the pipeline and located downstream of the observation flow channel pipe. The special elbow is transparent and is used to observe the influence of the elbow on fiber flocculation in the fiber suspension.

5. The fiber flocculation and dispersion experimental observation device according to claim 4, characterized in that: The calculation formula for the average flow velocity in the special elbow is: Where v2 is the average flow velocity in the special elbow, QV is the system volume flow measured by the electromagnetic flowmeter, and D is the inner diameter of the special elbow.

6. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device further comprises: a stirrer used in conjunction with the pulp tank, and the stirrer is used to prepare the chopped fiber bundles into the fiber suspension.

7. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device further includes: a light source for illuminating the fiber flocculation clusters in the observation flow channel tube, so that the high-speed camera system can clearly capture the state of the fiber flocculation clusters during the flow process.

8. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device further comprises a pressure transmitter, a temperature transmitter and a regulating valve installed on the pipeline.

9. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The fiber flocculation and dispersion experimental observation device comprises two slurry tanks, which are arranged in parallel.

10. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: A regulating valve is connected between the slurry tank and the slurry pump.

11. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The observation flow channel tube is in the shape of a transparent rectangular column, and both ends of the observation flow channel tube are in a constricted shape with the diameter gradually decreasing toward the end.

12. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The high-speed camera system includes a high-speed camera and a data processing unit.

13. The fiber flocculation and dispersion experimental observation device according to claim 1, characterized in that: The flow rate of the fiber suspension is adjusted by adjusting the rotation speed of the pulp pump.

14. An observation method for a fiber flocculation and dispersion experimental observation device based on flow field visualization, characterized in that: A fiber suspension is prepared; the fiber suspension is sent to an observation flow channel tube; and an image of the fibers in the fiber suspension in the observation flow channel tube is captured by a high-speed camera system and the image is analyzed to obtain the flocculation behavior and dispersion behavior of the fibers in the water in the observation flow channel tube.

15. The observation method according to claim 14, wherein: The observation method further includes passing the fiber suspension through a specially made elbow and observing the effect of the specially made elbow on the fiber flocculation in the fiber suspension.

16. The observation method according to claim 14, wherein: The fiber suspension is prepared by a pulp vat and an agitator, and fiber suspensions with different properties are prepared by adjusting the shear rate and time of the agitator.

17. The observation method according to claim 14, wherein: The dispersion performance of the fibers in the fiber suspension is evaluated by real-time processing and analysis of images captured by a high-speed camera system.

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