Visual experiment system and method for researching hot capillarity of liquid drops

Abstract

The invention relates to the technical field of liquid drop fluid mechanics, in particular to a visual experiment system and method for researching a liquid drop hot capillarity phenomenon. The visual experiment system for studying the thermal capillarity of the liquid drops comprises a liquid drop control device, a heating device and a collecting device, the liquid drop control device is used for generating two hovering liquid drops and controlling at least one hovering liquid drop in the two hovering liquid drops to be close to the other hovering liquid drop in the horizontal direction and collide with the other hovering liquid drop, and the collecting device is used for collecting the thermal capillarity of the liquid drops. Fluorescein and tracer particles are added into the two hovering liquid drops; the heating device is used for radiating ultraviolet rays to the two hovering liquid drops and controlling the temperature of the two hovering liquid drops; and the acquisition device is used for acquiring videos and real-time pictures that at least one of the two hovering liquid drops is close to the other hovering liquid drop along the horizontal direction and collides with the other hovering liquid drop.

Description

Technical Field

[0001] The invention relates to the technical field of droplet fluid mechanics, and in particular to a visual experimental system and method for studying droplet thermocapillary phenomena. Background Art

[0002] The interaction between droplets has always been the focus of attention in many fields such as cloud formation, spray combustion, and inkjet printing. Thermal effects have a significant impact on droplet coalescence and non-coalescing. When the temperature difference between two droplets exceeds a certain critical value, delayed coalescence or non-coalescing will occur. This is because the temperature gradient inside the droplet leads to a surface tension gradient, which causes the heat-induced Marangoni convection inside the droplet - thermocapillary convection. In recent years, thermocapillary phenomenon, as a fluid dynamics phenomenon driven by surface tension gradient caused by thermal effects, has attracted widespread attention. The Marangoni effect describes the phenomenon that when the surface tension of the liquid is unevenly distributed, the liquid flows from the area with lower surface tension to the area with higher surface tension. The temperature difference between droplets is one of the important factors that trigger the Marangoni effect. Therefore, the thermocapillary phenomenon between droplets has important research significance.

[0003] However, most of the existing experimental platforms for droplet-droplet coalescence under thermal effects use solid walls to directly or indirectly heat the droplets. Although a significant temperature gradient can be generated inside the droplets through heat conduction and thermocapillary convection can be observed, the solid walls will seriously affect the behavior of the droplets, and it is difficult to study the influence of the temperature difference between the droplets and the surrounding gas phase. Summary of the invention

[0004] The purpose of the present invention is to provide a visual experimental system for studying the thermocapillary phenomenon of droplets, so as to solve the problem that when studying the thermocapillary phenomenon between droplets, the solid wall of the experimental platform in the prior art affects the behavior of the droplets and it is difficult to study the influence of the temperature difference between the droplets and the surrounding gas phase.

[0005] In order to solve the above problems, the technical solution of the visualization experimental system for studying the thermocapillary phenomenon of droplets of the present invention is: A visualization experimental system for studying the thermocapillary phenomenon of droplets, comprising: Droplet control device, heating device and collection device, The droplet control device is used to generate two suspended droplets, and control at least one of the two suspended droplets to approach the other suspended droplet in a horizontal direction and collide with the other suspended droplet, and the two suspended droplets are added with fluorescent pigment and tracer particles; The heating device is used to radiate ultraviolet rays onto the two suspended droplets and control the temperature of the two suspended droplets; The collection device is used to collect videos and real-time pictures of at least one of the two suspended liquid droplets approaching the other suspended liquid droplet in the horizontal direction and colliding with the other suspended liquid droplet.

[0006] Furthermore, the height and volume of the two suspended liquid droplets are consistent, and the two suspended liquid droplets move relatively to each other and collide simultaneously in the horizontal direction.

[0007] Furthermore, the droplet control device includes a droplet suspension device and a driving device. The droplet suspension device is used to generate two suspended droplets; The driving device is connected to the droplet suspension device and is used to control at least one of the two suspended droplets to approach the other suspended droplet in a horizontal direction and collide with the other suspended droplet.

[0008] Furthermore, the driving device includes a lifting mechanism and a horizontal moving mechanism, and the two suspended droplets are arranged on the lifting mechanism to control the height of the two suspended droplets; the horizontal moving mechanism is used to control at least one of the two suspended droplets to approach the other suspended droplet in the horizontal direction and collide with it.

[0009] Furthermore, the lifting mechanism includes a lifting track, and the two suspended droplets move up and down along the lifting track; the horizontal movement mechanism includes a horizontal track, and the lifting track is set on the horizontal track and moves horizontally along the horizontal track, thereby driving the two suspended droplets to move horizontally.

[0010] Furthermore, the droplet suspension device includes an injection structure, a capillary and a needle, the injection structure and the needle are respectively connected to the two ends of the capillary, and the needle is installed on a driving device; the liquid added with fluorescent pigment and tracer particle particles is injected into the injection structure, and the liquid added with fluorescent pigment and tracer particle particles passes through the capillary and produces suspended droplets on the needle.

[0011] Furthermore, the heating device includes ultraviolet light and an ultraviolet light power supply connected thereto, and the radiant heat of the ultraviolet light is adjustable.

[0012] Furthermore, the visualization experiment system also includes a data processing device, which is connected to the acquisition device and is used to observe and process the collected videos and real-time pictures of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding with it.

[0013] Furthermore, the visualization experiment system also includes a temperature measuring device, which is connected to the data processing device and is used to monitor the real-time temperature of the two suspended droplets.

[0014] The present invention also provides a visualization experimental method for studying the thermocapillary phenomenon of liquid droplets. Based on the visualization experimental system for studying the thermocapillary phenomenon of liquid droplets, the technical solution adopted is: A visualization experimental method for studying the thermocapillary phenomenon of a liquid droplet comprises the following steps: S1, turning on the droplet control device to generate two suspended droplets, wherein fluorescein and tracer particles are added to the two suspended droplets; turning on the heating device to radiate ultraviolet light onto the two suspended droplets; S2, controlling at least one of the two suspended droplets to approach the other suspended droplet in the horizontal direction and collide with it; at the same time, starting the collection device to collect a video and a real-time picture of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding with it.

[0015] Compared with the prior art, the visualization experimental system and method for studying the thermocapillary phenomenon of droplets of the present application can visualize the thermocapillary convection between droplets and observe the coalescence of droplets by adding fluorescein and tracer particles into the droplets; ultraviolet radiation can not only excite fluorescein, but also control and transfer the temperature of the droplets, thereby realizing the experiment of the influence of temperature on the circulation flow inside and around the droplets, and at the same time, it can well avoid interference with the droplets themselves, and the thermocapillary convection inside the droplets and the speed of the droplets' own rotation can be observed; at the same time, the image acquisition device in the present invention can observe the internal flow and deformation of the droplets when they approach and contact by collecting videos and real-time pictures of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding, and then obtain the results such as the droplet motion trajectory and circulation speed, providing effective data support for studying the mechanism of droplet-droplet coalescence / non-coalescence and droplet-wall interaction.

[0016] The driving device includes a lifting mechanism and a horizontal moving mechanism. The two suspended droplets are arranged on the lifting mechanism to control the height of the two suspended droplets; the horizontal moving mechanism is used to control at least one of the two suspended droplets to approach the other suspended droplet along the horizontal direction and collide with it, so as to well control the contact angle and position of the two droplets, and at the same time control the droplets to approach each other, thereby generating a temperature gradient to cause a thermal capillary phenomenon.

[0017] The lifting mechanism includes a lifting track, and the two suspended droplets move up and down along the lifting track; the horizontal movement mechanism includes a horizontal track, and the lifting track is set on the horizontal track and moves horizontally along the horizontal track, thereby driving the two suspended droplets to move horizontally. The structure is simple and easy to operate.

[0018] The droplet suspension device includes an injection structure, a capillary and a needle, wherein the injection structure and the needle are respectively connected to the two ends of the capillary, and the needle is installed on a driving device; a liquid added with fluorescein and tracer particle particles is injected into the injection structure, and the liquid added with fluorescein and tracer particle particles passes through the capillary and produces suspended droplets on the needle, thereby facilitating the precise production of two suspended droplets.

[0019] The heating device includes ultraviolet light and an ultraviolet light power supply connected thereto. The radiant heat of the ultraviolet light is adjustable and is used to control different temperatures and observe droplet-droplet coalescence / non-coalescing processes and droplet-wall interaction processes at different temperatures.

[0020] The visualization experiment system also includes a temperature measuring device, which is connected to the data processing device and is used to monitor the real-time temperature of the two suspended droplets, so as to facilitate the observation of the temperature distribution on the surface of the droplets when the droplets approach and touch each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a visualization experimental system for studying the thermocapillary phenomenon of a liquid droplet according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of a droplet control device in a visualization experimental system for studying the thermocapillary phenomenon of droplets according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a driving device in a visualization experimental system for studying the thermocapillary phenomenon of a liquid droplet according to an embodiment of the present invention; Figure 4 It is a picture taken by a high-speed camera when a droplet approaches in a visualization experimental system for studying the thermocapillary phenomenon of a droplet according to an embodiment of the present invention; In the figure, 1-base A, 2-base B, 3-horizontal track, 4-lifting track A, 5-lifting track B, 6-lifting track holder A, 7-lifting track holder B, 8-needle A, 9-needle B, 10-capillary A, 11-capillary B, 12-syringe, 13-microinjection pump, 14-ultraviolet lamp A, 15-ultraviolet lamp B, 16-ultraviolet lamp power supply, 17-long-range lens, 18-high-speed camera, 19-computer, 20-infrared imager. DETAILED DESCRIPTION

[0022] As cited in the background technology, in the prior art, when studying the thermocapillary phenomenon between droplets, the experimental platform will seriously affect the behavior of the droplets due to the solid wall, and it is difficult to study the influence of the temperature difference between the droplets and the surrounding gas phase. Therefore, the present invention provides a visualization experimental system for studying the thermocapillary phenomenon of droplets, including: a droplet control device, a heating device and a collection device, the droplet control device is used to generate two suspended droplets, and control at least one of the two suspended droplets to approach another suspended droplet in the horizontal direction and collide, and fluorescent pigment and tracer particles are added to the two suspended droplets; the heating device is used to radiate ultraviolet rays to the two suspended droplets and control the temperature of the two suspended droplets; the collection device is used to collect videos and real-time pictures of at least one of the two suspended droplets approaching another suspended droplet in the horizontal direction and colliding. The visualization experimental system for studying the thermocapillary phenomenon of droplets in the present application can visualize the thermocapillary convection between droplets and observe the coalescence of droplets, that is, observe the internal flow and deformation of droplets when droplets approach and contact, and then obtain results such as droplet motion trajectory and circulation speed, providing effective data support for studying the mechanism of droplet-droplet coalescence / non-coalescence and droplet-wall interaction.

[0023] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] Specific embodiment 1 of the visualization experimental system for studying the thermocapillary phenomenon of liquid droplets of the present invention: In this embodiment, Figure 1As shown, the present invention provides a visual experimental system for studying the thermocapillary phenomenon of droplets, including a droplet control device, a heating device and a collection device. The droplet control device is used to generate two suspended droplets, and control at least one of the two suspended droplets to approach and collide with another suspended droplet in a horizontal direction, and fluorescent pigment and tracer particles are added to the two suspended droplets; the heating device is used to radiate ultraviolet rays to the two suspended droplets and control the temperature of the two suspended droplets; the collection device is used to collect videos and real-time pictures of at least one of the two suspended droplets approaching and colliding with another suspended droplet in a horizontal direction. Specifically, as Figure 4 As shown, when the collection device is collecting, the height and volume of the two suspended droplets are consistent, and the two suspended droplets move relative to each other and collide simultaneously in the horizontal direction; wherein the collection device is a high-speed camera 18, which is placed in front of the droplet control device, and a long-range lens 17 is provided at one end of the high-speed camera 18 close to the droplet, and the lens center of the high-speed camera 18 is at the same height as the center of the two suspended droplets.

[0026] In this embodiment, the heating device includes an ultraviolet light power supply connected thereto, and the radiant heat of the ultraviolet light is adjustable. The ultraviolet light is generated by an ultraviolet lamp, and the radiant heat can be controlled by changing the light intensity (0-100%), thereby controlling the temperature of the droplet. Specifically, the heating device includes two ultraviolet lamps, namely, ultraviolet lamp A14 and ultraviolet lamp B15, and ultraviolet lamp A14 and ultraviolet lamp B15 are connected to an ultraviolet lamp source; ultraviolet lamp A14 and ultraviolet lamp B15 are symmetrically placed at 45° above the two sides of the two suspended droplets, and the fluorescent substance is excited by irradiation of the ultraviolet lamp.

[0027] In other embodiments, when the collection device is collecting, one of the two suspended droplets approaches the other suspended droplet in a horizontal direction and collides with the other suspended droplet.

[0028] In other embodiments, when the collection device is collecting, the heights and volumes of the two suspended droplets may be inconsistent, as long as the two suspended droplets can collide in the horizontal direction.

[0029] Specific embodiment 2 of the visualization experimental system for studying the thermocapillary phenomenon of liquid droplets of the present invention: Based on the above technical concept of the present invention, or based on the above specific embodiment of the present invention, another embodiment is provided below.

[0030] In this embodiment, Figure 2 and Figure 3As shown, the droplet control device includes a droplet suspension device and a driving device. The droplet suspension device is used to generate two suspended droplets; the driving device is connected to the droplet suspension device and is used to control at least one of the two suspended droplets to approach another suspended droplet in the horizontal direction and collide with it. The driving device includes a lifting mechanism and a horizontal moving mechanism. The two suspended droplets are arranged on the lifting mechanism to control the height of the two suspended droplets; the horizontal moving mechanism is used to control at least one of the two suspended droplets to approach another suspended droplet in the horizontal direction and collide with it. The lifting mechanism includes a lifting track, and the two suspended droplets move up and down along the lifting track; the horizontal moving mechanism includes a horizontal track 3, and the lifting track is arranged on the horizontal track 3 and moves horizontally along the horizontal track 3, thereby driving the two suspended droplets to move horizontally, wherein the edges of the lifting track and the horizontal track 3 are engraved with scales, which is convenient for observing the distance of up and down movement and horizontal movement.

[0031] Specifically, the lifting mechanism includes two lifting rails arranged opposite to each other, namely, lifting rail A4 and lifting rail B5; at the same time, lifting rail holders A6 and lifting rail holders B7 are arranged on lifting rail A4 and lifting rail B5, and two suspended droplets are arranged on lifting rail holders A6 and lifting rail holders B7. When in use, the two suspended droplets move up and down along the lifting rail A4 and lifting rail B5 through the lifting rail holders A6 and lifting rail holders B7, and the height is fixed by the lifting rail holders A6 and lifting rail holders B7. Base A1 and base B2 are arranged horizontally below the lifting rail A4 and lifting rail B5, and horizontal rail 3 is arranged below the base A1 and base B2, and the lifting rail A4 and lifting rail B5 are arranged perpendicular to the base A1 and base B2, and the lifting rail A4 and lifting rail B5 are moved horizontally along the horizontal rail 3 through the base A1 and base B2, thereby driving the two suspended droplets to move horizontally.

[0032] Specific embodiment 3 of the visualization experimental system for studying the thermocapillary phenomenon of liquid droplets of the present invention: Based on the above technical concept of the present invention, or based on the above specific embodiment of the present invention, another embodiment is provided below.

[0033] In this embodiment, Figure 1 and Figure 2As shown, the droplet suspension device includes an injection structure, a capillary and a needle. The injection structure and the needle are respectively connected to the two ends of the capillary, and the needle is installed on the driving device. The liquid with added fluorescein and tracer particles is injected into the injection structure, and the liquid with added fluorescein and tracer particles passes through the capillary and generates suspended droplets on the needle. Specifically, the droplet suspension device for generating two suspended drops includes two injection structures, two capillaries and two needles, namely, capillary A10 and capillary B11, needle A8 and needle B9, and the injection structure includes a micro-injection pump 13 and a syringe 12, where the syringe 12 is a needle tube. When in use, needle A8 and needle B9 are connected to the needle tube through capillary A10 and capillary B11 respectively, and needle A8 and needle B9 are installed on lifting rail holder A6 and lifting rail holder B7. By setting the liquid output of the micro-injection pump 13, droplets of different sizes are prepared and suspended on needle A8 and needle B9.

[0034] The visualization experiment system also includes a data processing device, which is connected to the acquisition device and is used to observe and process the collected video and real-time pictures of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding. Specifically, the data processing device is a computer 19, which is connected to the port of the high-speed camera 18 through a network cable, and the outline and internal movement of the droplet can be clearly observed on the computer 19; at the same time, the video and real-time pictures are processed.

[0035] The visualization experiment system also includes a temperature measuring device, which is connected to the data processing device and is used to monitor the real-time temperature of the two suspended droplets. Specifically, the temperature measuring device is an infrared imager 20, which is arranged behind the droplet control device. The port of the infrared imager 20 is connected to the computer 19 through a network cable. The center of the lens of the infrared imager 20 is at the same height as the center of the lens of the high-speed camera 18 and the center of the droplet, which is convenient for observing the temperature distribution inside the droplet.

[0036] In other embodiments, the droplet can be suspended by ultrasonic suspension, electromagnetic suspension, etc. For those skilled in the art, different methods can be set according to specific circumstances.

[0037] The present invention provides a visualization experimental system for studying the thermocapillary phenomenon of liquid droplets, and the specific working process is as follows: First, use a syringe 12 to draw a proper amount of liquid dyed with fluorescein and added with tracer particles, place the syringe 12 on a microinjection pump 13 and connect one end of the capillary, and the other end is connected to the needle; Secondly, by setting the propulsion speed and time of the syringe 12, two droplets of equal volume are generated and suspended, and the lifting track A4 and the lifting track B5 are adjusted to make the two droplets at the same height and within the camera recording frame, and then the base A1 and the base B2 are moved horizontally on the horizontal track 3 to control the droplets to approach each other; Then, the UV lamp A14 and UV lamp B15 placed at equal heights on both sides of the two droplets are turned on to excite the fluorescein inside the droplets and heat the droplets. At the same time, the high-speed camera 18 is used to shoot the entire process of the two droplets approaching each other. The fluorescein makes the droplets clearly appear on the computer 19, and the circulation of the droplets can be clearly observed through the movement of the tracer particles. Finally, the images and videos of the entire close contact process of the two droplets are collected by post-processing by computer 19 to form the droplet-droplet coalescence / non-coalescence process and the droplet-wall interaction process.

[0038] Specific Example 1 of the visualization experimental method for studying the thermocapillary phenomenon of liquid droplets of the present invention: First, the droplet control device is turned on to generate two suspended droplets, in which fluorescent pigment and tracer particles are added; the heating device is turned on to radiate ultraviolet light onto the two suspended droplets; Then, at least one of the two suspended droplets is controlled to approach the other suspended droplet in the horizontal direction and collide with it; at the same time, the collection device is turned on to collect a video and a real-time picture of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding with it.

[0039] Specifically, the visualization experimental method for studying the thermocapillary phenomenon of liquid droplets of the present invention comprises the following steps: First, before the experiment begins, take 10 ml of the liquid to be tested, dye it with 1-2 drops of fluorescein, and add 1-2 g of micron-sized polystyrene tracer particles and stir evenly; Secondly, use a needle tube to extract the above liquid and fix it on two micro-injection pumps 13 respectively, one end of the capillary A10 and the capillary B11 are connected to the needle tube respectively, and the other end is connected to the needle A8 and the needle B9, and the needle A8 and the needle B9 are tilted and fixed on the lifting track holder A6 and the lifting track holder B7, and the lifting track A4 and the lifting track B5 are fixed on the base A1 and the base B2. At the same time, the base A1 and the base B2 are set on the horizontal track 3, and the lifting track A4 and the lifting track B5 are adjusted to make the two droplets in a suitable position; Next, place UV lamp A14 and UV lamp B15 at 45° above the outside of the two droplets, and turn on the UV lamp power 16 to set 100% illumination; Then, the high-speed camera 18 and the infrared imager 20 are turned on and connected to the computer 19, the observation software in the computer 19 is opened, and the droplet image is clear by adjusting the focal length of the long-range lens 17 and the parameters of the high-speed camera 18, and the continuous shooting mode and manual triggering are set; Next, the microinjection pump 13 is turned on to discharge the air in the capillary and clean the needle. The pushing time of the microinjection pump 13 is set to last for 1 second each time, and the pushing speed is 20 ml / min. The liquid flows out of the needle through the capillary to form droplets. Droplets of different sizes can be prepared by changing the pushing time. Then, the high-speed camera 18 is triggered to shoot, and the base A1 and the base B2 are adjusted to move on the horizontal track 3, so that a droplet slowly approaches another stationary droplet horizontally until the two droplets come into contact and stop moving. The coalescence / non-coalescing phenomenon of the droplets is observed by the computer 19, and the shooting is terminated after a certain period of time, during which the infrared temperature map of the droplets at the critical moment is saved; Finally, the images and videos of the entire close contact process of the two droplets are collected by post-processing by computer 19 to form the droplet-droplet coalescence / non-coalescence process and the droplet-wall interaction process.

[0040] Here, those skilled in the art will appreciate that the specific operations of each step in the above-mentioned visualization experimental method for studying the thermocapillary phenomenon of droplets have been described in the above reference. Figures 1 to 4 The description of the visualization experimental system for studying the thermocapillary phenomenon of droplets has been introduced in detail, so its repeated description will be omitted.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A visualization experimental system for studying the thermocapillary phenomenon of droplets, characterized in that: include: Droplet control device, heating device and collection device, The droplet control device is used to generate two suspended droplets, and control at least one of the two suspended droplets to approach the other suspended droplet in a horizontal direction and collide with the other suspended droplet, and the two suspended droplets are added with fluorescent pigment and tracer particles; The heating device is used to radiate ultraviolet rays onto the two suspended droplets and control the temperature of the two suspended droplets; The collection device is used to collect videos and real-time pictures of at least one of the two suspended liquid droplets approaching the other suspended liquid droplet in the horizontal direction and colliding with the other suspended liquid droplet.

2. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 1, characterized in that: The heights and volumes of the two suspended liquid droplets are consistent, and the two suspended liquid droplets move relatively to each other and collide simultaneously in a horizontal direction.

3. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 1, characterized in that: The droplet control device includes a droplet suspension device and a driving device. The droplet suspension device is used to generate two suspended droplets; The driving device is connected to the droplet suspension device and is used to control at least one of the two suspended droplets to approach the other suspended droplet in a horizontal direction and collide with the other suspended droplet.

4. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 3, characterized in that: The driving device includes a lifting mechanism and a horizontal moving mechanism. The two suspended droplets are arranged on the lifting mechanism to control the height of the two suspended droplets; the horizontal moving mechanism is used to control at least one of the two suspended droplets to approach the other suspended droplet in the horizontal direction and collide with it.

5. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 4, characterized in that: The lifting mechanism includes a lifting track, and the two suspended droplets move up and down along the lifting track; the horizontal movement mechanism includes a horizontal track, and the lifting track is arranged on the horizontal track and moves horizontally along the horizontal track, thereby driving the two suspended droplets to move horizontally.

6. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 3, characterized in that: The droplet suspension device includes an injection structure, a capillary and a needle, wherein the injection structure and the needle are respectively connected to two ends of the capillary, and the needle is installed on a driving device; a liquid added with fluorescein and tracer particles is injected into the injection structure, and the liquid added with fluorescein and tracer particles passes through the capillary and generates suspended droplets on the needle.

7. The visualization experimental system for studying the thermocapillary phenomenon of droplets according to claim 1, characterized in that: The heating device comprises ultraviolet light and an ultraviolet light power supply connected thereto, and the radiant heat of the ultraviolet light is adjustable.

8. The visualization experimental system for studying the thermocapillary phenomenon of liquid droplets according to claim 1, characterized in that: The visualization experiment system also includes a data processing device, which is connected to the acquisition device and is used to observe and process the collected video and real-time pictures of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding with it.

9. The visualization experimental system for studying the thermocapillary phenomenon of liquid droplets according to claim 8, characterized in that: The visualization experiment system also includes a temperature measuring device, which is connected to the data processing device and is used to monitor the real-time temperature of the two suspended droplets.

10. A visual experimental method for studying the thermocapillary phenomenon of liquid droplets, characterized in that: The visualization experimental system for studying the thermocapillary phenomenon of droplets according to any one of claims 1 to 9 comprises the following steps: S1, turning on the droplet control device to generate two suspended droplets, wherein fluorescein and tracer particles are added to the two suspended droplets; turning on the heating device to radiate ultraviolet light onto the two suspended droplets; S2, controlling at least one of the two suspended droplets to approach the other suspended droplet in the horizontal direction and collide with it; at the same time, starting the collection device to collect a video and a real-time picture of at least one of the two suspended droplets approaching the other suspended droplet in the horizontal direction and colliding with it.

Images