Experimental device and method for researching kinetics and evaporation characteristics of liquid drops

Abstract

The invention relates to an experimental device and method for researching liquid drop dynamics and evaporation characteristics. The experimental device comprises a liquid drop generation system, a metal flat plate control system, a height adjusting system and a data acquisition system, the liquid drop generation system is used for generating liquid drops impacting the metal flat plate; the metal flat plate system is used for adjusting the inclination angle of a metal flat plate to heat the metal flat plate; the height adjusting system is used for adjusting the height from the liquid drop generating system to the metal flat plate, so that the liquid drops impact the metal flat plate at different speeds; the data acquisition system comprises a high-speed camera, an infrared camera, a particle image velocity measurement device, a light source and a computer, and is used for measuring the morphological change, velocity field and temperature field of liquid drops in the process of impacting the metal flat plate; the invention further provides an experimental method. According to the invention, the morphological evolution process of the liquid drops can be measured, and the dynamics and evaporation characteristics of the liquid drops when impacting metal plates with different inclination angles and surface types can be studied.

Description

Technical Field

[0001] The present invention relates to the technical field of research on dynamics and evaporation characteristics of liquid droplets impacting a heated flat plate, and in particular to an experimental device and method for studying the dynamics and evaporation characteristics of liquid droplets. Background Art

[0002] The heating of a solid surface by a droplet impinging on it is a complex process involving coupled dynamics and thermodynamics, and is widely used in industry, such as spray cooling. In these industrial applications, the surface inclination angles, surface properties, and temperature ranges vary, and the droplet properties, size, and velocity parameters vary. Consequently, the dynamics of a droplet impinging on a heated surface and the interaction between the droplet's evaporation process have not been systematically studied.

[0003] Furthermore, existing experimental setups have limitations in adjusting droplet impact angles, controlling heating temperatures, and acquiring multi-parameter data, making it difficult to comprehensively study droplet behavior under different conditions. Therefore, an experimental setup that can precisely control droplet generation, impact conditions, and data acquisition is urgently needed to enable in-depth research into droplet dynamics and evaporation characteristics. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an experimental device and method for studying the dynamics and evaporation characteristics of droplets, and to provide an experimental device and method for studying the dynamic characteristics of droplets impacting metal plates and the evaporation characteristics of droplets impacting heated plates.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An experimental device for studying droplet dynamics and evaporation characteristics, comprising a droplet generation system 1, a metal plate control system 2, a height adjustment system 3 and a data acquisition system 4; the droplet generation system 1 comprises a push-pull syringe pump 101 and a syringe 102, with the help of the push-pull syringe pump 101, different types of syringes 102 are used to generate droplets with controllable quantity and diameter; the metal plate control system 2 comprises a metal plate 201, a clamp 202, a base 203, an angle adjustment device 204, an angle locking device, a heating electrode and a thermocouple, the metal plate 201 is fixed to the base 203 by the clamp 202, the base 203 is connected to the angle adjustment device 204, the tilt angle of the base 203 is set by manually adjusting the angle adjustment device 204 composed of a gear and a rotating shaft, and then the tilt angle of the metal plate 201 is adjusted, when the tilt angle of the metal plate 201 is adjusted to the experimental set value, the angle locking device is used to fix the base 203 to ensure the stability of the base during the experiment, and the heating electrode is used to adjust the metal plate 20 1 is heated, and the temperature of the metal plate is measured using a thermocouple; the height adjustment system 3 includes a lifting platform 301, a guide rail 302 and a stepping motor, the droplet generation system 1 is installed on the height-adjustable lifting platform 301, and the stepping motor drives the lifting platform 301 to move vertically along the guide rail 302 on the bracket; the data acquisition system 4 includes an LED lamp 401, a high-speed camera 402, a particle image velocimetry device 403, an infrared camera 404 and a computer 405, the LED lamp 401 is used as a light source to provide a shooting environment with suitable light and dark, two high-speed cameras 402 are used to respectively shoot the evolution of the droplet morphology during the process of impacting the metal plate from the front and above, two particle image velocimetry devices 403 are used to shoot the velocity of the droplet during the process of impacting the metal plate from the top and right side, and two infrared cameras 404 are used to shoot the temperature of the droplet during the process of impacting the metal plate from the top and left side, and the high-speed camera 402, the particle image velocimetry device 403 and the infrared camera 404 are connected to the computer 405 via a data cable.

[0007] The syringe 102 is replaceable and can produce droplets with controllable diameters.

[0008] The metal plate 201 is fixed to the base 203 by a fixture 202 and is easy to replace to study the effects of different surface types on droplet dynamics and evaporation characteristics.

[0009] The inclination angle of the metal plate 201 is measured using a protractor, which is a simple and accurate measurement method.

[0010] The droplet generation system 1 is installed on a height-adjustable lifting platform 301 , and gravity causes the droplets to have an initial velocity set in the experiment when they hit the metal plate 201 .

[0011] The metal plate 201 is heated by using a heating electrode so that the temperature of the metal plate 201 is adjusted according to experimental requirements before the droplet hits the metal plate 201 .

[0012] The lifting platform 301 moves along the guide rail 302 to ensure the stability of the lifting platform 301 when it moves up and down.

[0013] The experimental method of the experimental device for studying droplet dynamics and evaporation characteristics is as follows: before the experiment begins, the syringe 102 and the metal plate 201 preset in the experiment are replaced, and the syringe 102 sucks an appropriate amount of water; the height of the lifting platform 301 and the tilt angle of the metal plate 201 are adjusted; the height and distance of the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 are adjusted so that the position where the droplet hits the metal plate 201 is within the optimal field of view; the LED light background board is turned on and the light brightness is adjusted so that the image captured by the high-speed camera 402 is of moderate brightness;

[0014] When conducting a study on the dynamic characteristics of a droplet impacting an inclined metal plate, the high-speed camera 402 and the particle image velocimeter 403 are turned on; the push-pull syringe pump 101 is connected to push the syringe 102 to generate a droplet; the experiment is stopped when the droplet falls to the metal plate and stops or slides onto the edge of the metal plate; the high-speed camera 402 and the particle image velocimeter 403 are turned off, and the LED light 401 is turned off; the dynamic characteristics of the droplet impacting the metal plate are studied by filming the morphological evolution and velocity changes of the droplet impacting the heated metal plate;

[0015] When conducting a study on the evaporation characteristics of a droplet impacting a heated metal plate, a heating electrode is used to heat the metal plate 201 to the temperature required for the experiment; the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 are turned on; the push-pull injection pump 101 is connected to push the syringe 102 to generate droplets; the experiment is stopped when the droplet falls to the metal plate and stops or slides to the edge of the metal plate; the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 are turned off; the LED light 401 is turned off; and the evaporation characteristics of the droplet impacting the heated metal plate are studied by photographing the morphological evolution, velocity, and temperature changes during the process of the droplet impacting the heated metal plate.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The metal plate in the experimental device of the present invention is fixed to the base by a clamp, which is easy to disassemble and assemble, and is convenient for quickly replacing metal plates with different surface types;

[0018] 2. The syringe in the droplet generation system of the present invention is adaptable to a variety of liquids with different viscosities and surface tensions, and syringes of different sizes can be replaced according to the required droplet diameter, expanding the applicability of the device in cross-disciplinary fields such as materials science and energy engineering;

[0019] 3. The experimental device of the present invention can adjust the temperature of the metal plate and the tilt angle of the metal plate at the same time, realizing the dynamics and evaporation research of droplets impacting the inclined heated metal plate;

[0020] 4. The present invention uses a high-speed camera to record the morphological evolution of the droplet during the impact of the metal plate, an infrared camera to record the temperature field, and a particle image velocimetry device to synchronously collect the velocity field of the impact process, thereby realizing the coupled analysis of the dynamic characteristics and evaporation characteristics of the droplet impact process. Compared with the traditional single optical measurement relying on a high-speed camera, the device of the present invention can simultaneously analyze the morphological changes, velocity field and temperature field of the droplet, providing more comprehensive experimental data support for the thermal hydraulics research of the droplet impacting the wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of an experimental device for studying droplet dynamics and evaporation characteristics of the present invention;

[0022] Figure 2 A droplet generation system for an experimental device for studying droplet dynamics and evaporation characteristics of the present invention;

[0023] Figure 3 A metal plate control system for an experimental device for studying droplet dynamics and evaporation characteristics of the present invention;

[0024] Figure 4 A height adjustment system for an experimental device for studying droplet dynamics and evaporation characteristics of the present invention;

[0025] Figure 5 The invention discloses a data acquisition system for an experimental device for studying droplet dynamics and evaporation characteristics. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments:

[0027] like Figure 1 As shown, the present invention provides an experimental device for studying droplet dynamics and evaporation characteristics, which includes a droplet generation system 1, a metal plate control system 2, a height adjustment system 3 and a data acquisition system 4.

[0028] like Figure 2As shown, the droplet generation system 1 includes a push-pull syringe pump 101 and a syringe 102 . With the help of the push-pull syringe pump 101 , different types of syringes 102 generate droplets with controllable quantity and diameter.

[0029] like Figure 3 As shown, a metal plate 201 is fixed to a base 203 by a fixture 202. The base 203 is connected to an angle adjustment device 204. The tilt angle of the base is set by manually adjusting the angle adjustment device 204 composed of a gear and a rotating shaft. A protractor is used to measure the tilt angle of the metal plate 201. When the tilt angle of the metal plate 201 is adjusted to the experimental set value, the angle locking device is used to fix the base 203 to ensure the stability of the base during the test. A heating electrode is used to heat the metal plate, and a thermocouple is used to measure the temperature of the metal plate. The above is a metal plate control system 2;

[0030] like Figure 4 As shown, the droplet generation system 1 is installed on a height-adjustable lifting platform 301, and a stepper motor drives the lifting platform to move vertically along a guide rail 302 on a bracket. The lifting platform 301, the guide rail 302 and the stepper motor constitute a height adjustment system 3;

[0031] like Figure 5 As shown, two groups of LED lights 401 are used as light sources to provide a shooting environment with suitable brightness and darkness, two high-speed cameras 402 are used to respectively shoot the evolution of the droplet morphology during the impact of the metal plate from the front and above, two particle image velocimetry devices 403 are used to shoot the speed of the droplet during the impact of the metal plate from the top and right side, and two infrared cameras 404 are used to shoot the temperature of the droplet during the process of being loaded into the metal plate from the top and left side. The high-speed camera 402, the particle image velocimetry device 403 and the infrared camera 404 are connected to the computer 405 via a data cable. The above LED lights 401, high-speed camera 402, the particle image velocimetry device 403, the infrared camera 404 and the computer 405 constitute the data acquisition system 4.

[0032] The experimental method for studying droplet dynamics and evaporation characteristics of an experimental device is implemented by the following steps:

[0033] Before the experiment begins, replace the preset syringe 102 and metal plate 201, and inhale an appropriate amount of water into the syringe 102; adjust the height of the lifting platform 301 from the center of the metal plate 201 to 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 100 cm, 120 cm, and 150 cm, respectively, and the angles between the normal line of the upper surface of the metal plate 201 and the vertical direction are 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 85°; adjust the height and distance of the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 so that the position where the droplet hits the metal plate 201 is within the optimal field of view; turn on the LED light background board and adjust the light brightness so that the picture taken by the high-speed camera 402 is moderately bright and dark;

[0034] When conducting a study on the dynamic characteristics of a droplet impacting an inclined metal plate, the high-speed camera 402 and the particle image velocimetry device 403 are turned on; the push-pull syringe pump 101 is connected to push the syringe 102 to generate droplets with diameters of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm; the experiment is stopped when the droplet falls to the metal plate and stops or slides to the edge of the metal plate; the high-speed camera 402 and the particle image velocimetry device 403 are turned off, and the LED light 401 is turned off; the dynamic characteristics of the droplet impacting the metal plate are studied by photographing the morphological evolution and velocity changes of the droplet impacting the inclined metal plate;

[0035] When studying the evaporation characteristics of a droplet impacting a heated metal plate, an electric heating electrode is used to heat the metal plate 201 to 50°, 100°, 150°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, and 270°, respectively; the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 are turned on; the push-pull injection pump 101 is connected to push the syringe 102 to generate droplets; the experiment is stopped when the droplet falls onto the metal plate and stops or slides onto the edge of the metal plate; the high-speed camera 402, the infrared camera 404, and the particle image velocimetry device 403 are turned off; and the LED light 401 is turned off; and the evaporation characteristics of the droplet impacting the heated metal plate are studied by photographing the morphological evolution, velocity, and temperature changes during the process of the droplet impacting the heated metal plate.

[0036] The above content is a further detailed description of the present invention in combination with specific principles. It cannot be determined that the specific implementation scheme of the present invention is limited to this. For practitioners to whom the present invention belongs, simple deductions or replacements made without departing from the concept of the present invention should be within the scope of protection of the present invention.

Claims

1. An experimental device for studying droplet dynamics and evaporation characteristics, characterized by: The invention comprises a droplet generation system (1), a metal plate control system (2), a height adjustment system (3) and a data acquisition system (4); the droplet generation system (1) comprises a push-pull injection pump (101) and a syringe (102); with the help of the push-pull injection pump (101), different types of syringes (102) are used to generate droplets with controllable quantity and diameter; the metal plate control system (2) comprises a metal plate (201), a fixture (202), a base (203), an angle adjustment device (204), an angle locking device, a heating electrode and a thermocouple; The metal plate (201) is fixed on the base (203) by the clamp (202), and the base (203) is connected to the angle adjustment device (204). The tilt angle of the base (203) is set by manually adjusting the angle adjustment device (204) composed of a gear and a rotating shaft, thereby adjusting the tilt angle of the metal plate (201). When the tilt angle of the metal plate (201) is adjusted to the experimental setting value, the angle locking device is used to fix the base (203) to ensure the stability of the base during the test. The heating electrode is used to heat the metal plate (201) to make the metal plate (201) The temperature of the metal plate is measured using a thermocouple; the height adjustment system (3) comprises a lifting platform (301), a guide rail (302) and a stepper motor; the droplet generation system (1) is mounted on the height-adjustable lifting platform (301); the stepper motor drives the lifting platform (301) to move vertically along the guide rail (302) on the bracket; the data acquisition system (4) comprises an LED lamp (401), a high-speed camera (402), a particle image velocimetry device (403), an infrared camera (404) and a computer (405); the LED lamp (401) is used as the A light source provides a shooting environment with suitable brightness and darkness. Two high-speed cameras (402) are used to respectively shoot the evolution of the morphology of the liquid droplets during the process of impacting the metal plate from the front and the top. Two particle image velocimetry devices (403) are used to shoot the velocity of the liquid droplets during the process of impacting the metal plate from the top and the right side. Two infrared cameras (404) are used to shoot the temperature of the liquid droplets during the process of impacting the metal plate from the top and the left side. The high-speed camera (402), the particle image velocimetry device (403) and the infrared camera (404) are connected to a computer (405) via a data cable.

2. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The syringe (102) is replaceable and can produce droplets with controllable diameters.

3. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The metal plate (201) is fixed on the base (203) by a clamp (202) and is easy to replace to study the effects of different surface types on droplet dynamics and evaporation characteristics.

4. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The inclination angle of the metal plate (201) is measured using a protractor.

5. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The droplet generation system (1) is installed on a height-adjustable lifting platform (301), and gravity causes the droplets to have an initial velocity set in the experiment when they collide with the metal flat plate (201).

6. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The metal plate (201) is heated by using a heating electrode, so that before the droplet hits the metal plate (201), the temperature of the metal plate (201) is adjusted according to experimental requirements.

7. The experimental device for studying droplet dynamics and evaporation characteristics according to claim 1, characterized in that: The lifting platform (301) moves along the guide rail (302), ensuring the stability of the lifting platform (301) when it moves up and down.

8. The experimental method of any one of claims 1 to 7, wherein: Before the experiment begins, the preset syringe (102) and metal plate (201) are replaced, and an appropriate amount of water is sucked into the syringe (102); the height of the lifting platform (301) and the tilt angle of the metal plate (201) are adjusted; the height and distance of the high-speed camera (402), the infrared camera (404) and the particle image velocimetry device (403) are adjusted so that the position where the droplet hits the metal plate (201) is within the optimal field of view; Turn on the LED light background board and adjust the light brightness so that the high-speed camera (402) captures the image with moderate brightness; When conducting a study on the dynamic characteristics of a droplet impacting an inclined metal plate, a high-speed camera (402) and a particle image velocimetry device (403) are turned on; a push-pull injection pump (101) is connected to push the syringe (102) to generate a droplet; the experiment is stopped when the droplet falls onto the metal plate and stops or slides onto the edge of the metal plate; the high-speed camera (402) and the particle image velocimetry device (403) are turned off, and the LED light (401) is turned off; and the dynamic characteristics of the droplet impacting the metal plate are studied by photographing the morphological evolution and velocity change of the droplet impacting the heated metal plate. When conducting a study on the evaporation characteristics of a droplet impacting a heated metal plate, a heating electrode is used to heat the metal plate (201) to a temperature required for the experiment; a high-speed camera (402), an infrared camera (404), and a particle image velocimetry device (403) are turned on; a push-pull injection pump (101) is connected to push the syringe (102) to generate droplets; the experiment is stopped when the droplet falls onto the metal plate and stops or slides onto the edge of the metal plate; the high-speed camera (402), the infrared camera (404), and the particle image velocimetry device (403) are turned off; and an LED light (401) is turned off; and the evaporation characteristics of the droplet impacting the metal plate are studied by photographing the morphological evolution, velocity, and temperature changes of the droplet impacting the heated metal plate.

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