Particle trajectory tracing and online imaging method in chaotic flow field

Abstract

The invention provides a particle track tracing and on-line imaging method in a chaotic flow field, which adopts a system comprising a stirring system consisting of a stirring paddle, a transparent stirring reaction kettle and a transparent solution, and a light source and a camera arranged around the transparent stirring reaction kettle, adding fluorescent particles into the transparent solution in the transparent stirring reaction kettle to serve as observed particles in a flow field; the fluorescent particles are small resin particles containing fluorescent powder. And starting a driving device of the stirring paddle to stir the transparent solution. And turning on a light source to irradiate the stirring system to be placed under a dark condition. Turning off the light source, and shooting the transparent stirring reaction kettle by using a camera; during shooting, the exposure time of the camera is prolonged, and the motion trail of the observed particles in the flow field is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid mixing experiment testing. For the display of fluid mixing flow fields, in a solid-liquid mixed multiphase flow system, through this method, a motion trajectory diagram of particles in the flow field can be obtained. Background Art

[0002] The stirring process plays an important role in the production processes of various fields such as chemical engineering, biology, food, and pharmaceuticals, and is of great significance for ensuring the quality and output of products. During the fluid chaotic mixing process, a complex flow scenario is formed, and the flow field usually involves complex fluid dynamics phenomena such as eddies and vortices. Flow field visualization is indeed very important for the understanding of chaotic systems. Through visualization techniques, people can intuitively observe complex phenomena such as the movement, turbulence, and vortices of fluids in the stirring process, and can observe and analyze the complex dynamic behaviors in the fluid system, which helps to reveal the laws and patterns behind chaotic phenomena and thus understand fluid behavior more deeply. This is crucial for aspects such as studying fluid mechanics and optimizing system design. Through flow field visualization techniques, the stirring flow field can be observed and analyzed, thereby optimizing the stirring process, improving the mixing efficiency, and ensuring product quality.

[0003] Therefore, to observe complex phenomena such as the movement, turbulence, and vortices of fluids in the stirring process, people use a method combining experiments and simulations to study the flow field structure.

[0004] Currently, the research on the flow field structure mainly relies on experiments combined with fluid simulation, and verifies the model through acid-base color development experiments, fluorescein sodium color development experiments, and PLIF planar laser-induced fluorescence technology. However, these technologies visualize the single-phase flow field and cannot track the movement trajectories of solid particles in the multiphase flow, resulting in the simulation being unable to be experimentally verified. Summary of the Invention

[0005] The object of the present invention is to provide a method for particle trajectory tracing and online imaging in a chaotic flow field, which is characterized in that: the system adopted includes a stirring system composed of a stirring paddle (2), a transparent stirring reaction kettle (4), and a transparent solution (6), and a light source (1) and a camera arranged around the transparent stirring reaction kettle (4);

[0006] The method includes the following steps:

[0007] 1) Add fluorescent particles (3) as the observed particles in the flow field to the transparent solution (6) in the transparent stirring reaction kettle (4); the fluorescent particles (3) are resin small ball particles containing phosphor powder;

[0008] 2) Start the driving device of the stirring paddle (2) to stir the transparent solution (6);

[0009] 3) Turn on the light source (1) and irradiate the stirring system placed under dark conditions;

[0010] 4) Turn off the light source (1), and use a camera to take pictures of the transparent stirring reactor (4); when taking pictures, extend the exposure time of the camera to obtain the movement trajectories of the observed particles in the flow field.

[0011] Furthermore, the light source (1) used is an ultraviolet lamp, and the fluorescent agent used is a fluorescent agent that emits blue light or green light under ultraviolet irradiation.

[0012] A method for particle trajectory tracing and on-line imaging in a chaotic flow field - 1 -

[0013] Furthermore, the transparent solution (6) is glycerol, and the stirring impeller is a Rushton stirring impeller.

[0014] Furthermore, in step 1), two fluorescent particles (3) containing different fluorescent agents are added, one of which emits blue fluorescence and the other emits green fluorescence under ultraviolet irradiation.

[0015] Furthermore, in step 4), the aperture of the camera is f / 1.62, and the shutter speed is 5 - 10 seconds.

[0016] The technical effects of the present invention are beyond doubt:

[0017] 1) By exciting the self-luminescence of fluorescent particles in a dark environment, the present invention can realize on-line imaging of the movement trajectories of particles in fluid multiphase flow mixing through a camera, providing movement trajectories for experiments related to chaos theory.

[0018] 2) The technical solution of the present invention is simple, low-cost, high-value-added, and easy to operate. Brief Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the system adopted by the present invention

[0020] Figure 2 It is the movement trajectory of particles in the flow field in Example 1

[0021] Figure 3 It is the movement trajectory of particles in the flow field in Example 2.

[0022] In the figure: Detailed Embodiments

[0023] The present invention will be further described below in conjunction with embodiments, but it should not be understood that the above-mentioned subject matter scope of the present invention is limited to the following embodiments. Without departing from the above-mentioned technical idea of the present invention, various substitutions and changes made according to common general technical knowledge and customary means in the art should be included within the protection scope of the present invention.

[0024] Example 1:

[0025] A method for particle trajectory tracing and on-line imaging in a chaotic flow field, characterized in that the system adopted includes a stirring system composed of a six-blade Rushton turbine agitator (2), a cylindrical transparent stirring reactor (4) with a diameter of 0.2 m and a height of 0.4 m, and a transparent solution (6), and a light source (1) and a camera arranged around the transparent stirring reactor (4);

[0026] The method comprises the following steps:

[0027] 1) Adding fluorescent particles (3) as the observed particles in the flow field into the transparent solution (6) in the transparent stirring reactor (4); the transparent solution (6) is glycerol, and the fluorescent particles (3) are two resin small ball particles containing phosphor powder, one of which emits blue fluorescence under ultraviolet irradiation and the other emits green fluorescent agent under ultraviolet irradiation. The density of the resin small ball particles is 1000 kg / m3 and the diameter is 8 mm.

[0028] 2) Starting the driving device of the agitator (2) to stir the transparent solution (6); the height of glycerol in the stirring tank is 0.22 m, starting the agitator, and the rotation speed of the agitator is 300 rpm.

[0029] 3) Turning on the light source (1) and irradiating the stirring system placed in the dark condition for 60 s; the light source (1) adopted is an ultraviolet lamp with a wavelength of 400 nm. The ultraviolet lamp is placed above the stirring system.

[0030] 4) Turning off the light source (1) and using the camera to photograph the transparent stirring reactor (4); A method for particle trajectory tracing and on-line imaging in a chaotic flow field - 2 -

[0031] The camera is placed in the front or above the mixing device. When photographing, the shutter is 6 s to obtain the movement trajectory of the observed particles in the flow field.

[0032] Example 2:

[0033] A method for particle trajectory tracing and on-line imaging in a chaotic flow field, characterized in that the system adopted includes a stirring system composed of a six-blade Rushton turbine agitator (2), an elliptical transparent stirring reactor (4) with a minor axis of 0.163 m, a major axis of 0.244 m and a height of 0.4 m, and a transparent solution (6), and a light source (1) and a camera arranged around the transparent stirring reactor (4);

[0034] The method comprises the following steps:

[0035] 1) Add fluorescent particles (3) as the observed particles in the flow field to the transparent solution (6) in the transparent stirring reactor (4); the transparent solution (6) is glycerol, and the fluorescent particles (3) are two resin microsphere particles containing phosphor. The density of the resin microsphere particles is 1000 kg / m3, and the diameter is 8 mm. One emits blue fluorescence under ultraviolet irradiation, and the other is a fluorescent agent that emits green fluorescence under ultraviolet irradiation.

[0036] 2) Start the driving device of the stirring paddle (2) to stir the transparent solution (6); the height of glycerol in the stirring tank is 0.22 m. Start the stirring paddle, and the rotation speed of the stirring paddle is 300 rpm.

[0037] 3) Turn on the light source (1) and irradiate the stirring system placed in the dark condition for 60 s; the light source (1) used is a ultraviolet lamp with a wavelength of 400 nm. The ultraviolet lamp is placed above the stirring system.

[0038] 4) Turn off the light source (1), and use a camera to take pictures of the transparent stirring reactor (4). The camera is placed in front of or above the mixing device; when taking pictures, the shutter is 5 s to obtain the movement trajectories of the observed particles in the flow field.

Claims

1. A method for particle trajectory tracing and online imaging in a chaotic flow field, characterized in that: The system adopted includes a stirring system composed of the stirring paddle (2), a transparent stirring reaction kettle (4), and a transparent solution (6), as well as a light source (1) and a camera arranged around the transparent stirring reaction kettle (4); The method includes the following steps: 1) Add fluorescent particles (3) as the observed particles in the flow field to the transparent solution (6) in the transparent stirring reaction kettle (4); the fluorescent particles (3) are resin small ball particles containing phosphor powder; 2) Turn on the driving device of the stirring paddle (2) to stir the transparent solution (6); 3) Turn on the light source (1) to irradiate the stirring system placed under dark conditions; 4) Turn off the light source (1), and use the camera to take pictures of the transparent stirring reaction kettle (4). When taking pictures, extend the exposure time of the camera to obtain the movement trajectories of the observed particles in the flow field.

2. A method for particle trajectory tracing and on-line imaging in a chaotic flow field according to claim 1, characterized in that: The light source (1) adopted is an ultraviolet lamp, and the fluorescent agent adopted is a fluorescent agent that emits blue light or green light under ultraviolet irradiation.

3. A method for particle trajectory tracing and on-line imaging in a chaotic flow field according to claim 1 or 2, characterized in that: The transparent solution (6) is glycerol, and the stirring paddle is a 6-blade Rushton paddle.

4. A method for particle trajectory tracing and on-line imaging in a chaotic flow field according to claim 1 or 3, characterized in that: In step 1), add two fluorescent particles (3) containing different fluorescent agents, one of which emits blue light fluorescence under ultraviolet irradiation and the other emits green light fluorescence under ultraviolet irradiation.

5. A method for particle trajectory tracing and on-line imaging in a chaotic flow field according to claim 1, characterized in that: In step 4), the aperture is f / 1.62, and the shutter of the camera is 5 to 10 seconds.

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