Visualization device and method for measuring evaporation of electrostatic spraying liquid drops

Abstract

The invention discloses a visual device and method for measuring evaporation of electrostatic spraying liquid drops, and belongs to the field of multiphase flow thermophysics. The device comprises a visual heating system and a transparent electrostatic spraying system, wherein the visual heating system comprises a double-layer ITO (Indium Tin Oxide) coating plate, a Joule direct current heating system, a transparent wind shield and a transparent base; the double-layer ITO plating layer plate can realize visual heating, the transparent electrode and effective isolation of heat dissipation to surrounding air due to power-on heating of the ITO plating layer; the transparent electrostatic spraying system comprises a high-voltage electrostatic generator, a valve, a displacement system, a constant liquid level system, a peristaltic pump, a double-layer water tank, an electronic balance and a nozzle; the constant liquid level system can achieve precise control and measurement of the working medium flow of electrostatic spraying. The double-layer water tank is mainly used for providing constant liquid level height and reducing unstable electrostatic spraying caused by pressure fluctuation. Through the visual heating system and the transparent electrostatic spraying system, the effect of cooling a high-temperature wall surface by electrostatic spraying can be visually detected.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of multiphase flow thermophysics, and particularly relates to a visual device for measuring evaporation of electrostatic spray droplets and a method thereof. BACKGROUND

[0002] The electrostatic spray method is to apply high-voltage static electricity to the sprayed droplets to form a high-voltage electrostatic field between the nozzle electrode, the charged mist cloud and the crops, so that the charged droplets move directionally under the action of the electrostatic field force and are adsorbed to the solid surface to form a thin liquid film. The electrostatic spray technology is currently widely applied to the spraying of automobile appearance, pesticide spraying and the solution of high heat flux density heat dissipation problems of high-power electronic components. In this method, the size and deposition distribution of the charged microdroplets are two key factors affecting the cooling and heat dissipation performance of the electrostatic spray.

[0003] Therefore, it is necessary to design a device and a method for visualizing and measuring the evaporation process of electrostatic spray droplets. SUMMARY

[0004] The purpose of the application is to provide a device for visualizing and measuring the evaporation process of electrostatic spray droplets in the field of multiphase flow thermophysics. The ITO coating has good light transmission performance. The Joule direct current heating method is used to realize the visual measurement and research of the evaporation of electrostatic spray droplets, thereby improving the detection and research efficiency of heat transfer and fluid mechanics.

[0005] The technical scheme of the visual device for measuring the evaporation of electrostatic spray droplets and the method thereof is as follows: a visual device for measuring the evaporation of electrostatic spray droplets, comprising a visual heating system and a transparent electrostatic spray system.

[0006] The visual heating system comprises a double-layer ITO coating plate, a Joule direct current heating system, a transparent wind shield and a transparent base. The double-layer ITO coating plate can realize visual heating, transparent electrode and effective isolation of heat dissipation from the ITO coating to the surrounding air. The transparent wind shield is located around the double-layer ITO coating plate, and the transparent base is located below the double-layer ITO coating plate. The end of the copper plate is fixedly connected with the Joule direct current heating system to realize high-precision heat flow control.

[0007] The transparent electrostatic spraying system comprises a high-voltage electrostatic generator, a valve, a displacement system, a constant liquid level system, a peristaltic pump, a double-layer water tank, an electronic balance and a nozzle.

[0008] In the above scheme, the transparent electrostatic spraying system mainly applies a non-uniform electric field and provides a working medium for atomization, adjusts the electric field intensity through the high-voltage electrostatic generator, adjusts the distance between the nozzle and the double-layer ITO coating plate through the displacement system, and adjusts the working medium flow through the valve and the electronic balance.

[0009] In the above scheme, the double-layer ITO coating plate has a uniform distribution of translucent ITO coating in the middle interlayer and the bottom layer, and the size and thickness of the glass plate of the double-layer ITO coating plate are determined according to actual needs, which helps to enhance the visualization effect of the visualization heating system.

[0010] In the above scheme, the transparent base is determined according to actual needs, so that the visualization heating system realizes the visualization of the heating surface.

[0011] In the above scheme, the transparent wind deflector is made of transparent heat preservation material, which plays a role in visualizing the evaporation of liquid droplets.

[0012] In the above scheme, the displacement system is a reciprocating mechanism adjusting valve, which helps to realize the purpose of adjusting the position of the nozzle.

[0013] Compared with the prior art, the present application has the following advantages:

[0014] 1. By means of the double-layer ITO coating plate mode structure design, the transparent heating and transparent electrode are combined to realize the visualization measurement and scientific research of electrostatic spraying liquid droplet evaporation, and the cooling and heat dissipation performance of electrostatic spraying is detected.

[0015] 2. The displacement system can effectively control the distance between the nozzle and the double-layer ITO coating plate, and improve the stability of the non-uniform electric field.

[0016] 3. The transparent wind deflector can prevent the influence of surrounding flowing air on the evaporation of liquid droplets, which is conducive to improving the experimental accuracy.

[0017] 4. The transparent base can realize the visualization of the heating surface of the electrostatic spraying liquid droplet evaporation.

[0018] 5、The device structure is simple, and only needs to be simply modified from the existing electrostatic spraying experimental equipment to realize the visual measurement and scientific research of the evaporation of electrostatic spraying droplets.

[0019] 6、The double-layer ITO plated board with a scale ruler is adopted to realize the visual measurement of the size and distribution of the electrostatic spraying droplets. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a visual device and method for measuring the evaporation of electrostatic spraying droplets according to an embodiment of the present application.

[0021] Figure 2 is a double-layer ITO plated board structure in the visual device and method for measuring the evaporation of electrostatic spraying droplets according to an embodiment of the present application.

[0022] Figure 3 is a droplet evaporation side experimental diagram in the visual device and method for measuring the evaporation of electrostatic spraying droplets according to an embodiment of the present application.

[0023] Figure 4 is a droplet evaporation bottom experimental diagram in the visual device and method for measuring the evaporation of electrostatic spraying droplets according to an embodiment of the present application.

[0024] Figure 5 is a double-layer ITO plated board temperature distribution experimental diagram in the visual device and method for measuring the evaporation of electrostatic spraying droplets according to an embodiment of the present application.

[0025] In the figure, 1 is a double-layer ITO plated board, 2 is a transparent base, 3 is a valve, 4 is a transparent wind shield, 5 is a high-voltage electrostatic generator, 6 is a displacement system, 7 is an electronic balance, 8 is a peristaltic pump, 9 is a double-layer water tank, 10 is a flow outlet, 11 is a constant liquid level system, 12 is a Joule direct-current heating system, 14 is a camera A, 15 is a camera B, 16 is an infrared camera, 17 is a nozzle, 18 is a copper plate, 19 is a transparent glass plate, and ITO is a plated layer. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below with reference to the specific embodiments and the accompanying drawings, but the protection scope of the present application is not limited thereto.

[0027] Figure 1The visualization device for measuring evaporation of electrostatic spray droplets and the method thereof according to the present application is shown in one embodiment, which comprises a visualization heating system and a transparent electrostatic spray system. The visualization heating system horizontally fixes the double-layer ITO-coated plate 1 at the bottom, and the middle ITO-coated layer 19 of the double-layer ITO-coated plate 1 serves as a heating element to realize transparent heating. The ITO-coated layer 19 at the bottom of the double-layer ITO-coated plate 1 serves as a transparent electrode to realize visualization of electrostatic application.

[0028] The visualization heating system comprises the double-layer ITO-coated plate 1, the Joule direct-current heating system 12, the transparent wind shield 4, and the transparent base 2. The transparent wind shield 4 is located around the double-layer ITO-coated plate 1, and the transparent base 2 is located below the double-layer ITO-coated plate 1. The glass plate 18 at the bottom of the double-layer ITO-coated plate 1 and the transparent base 2 are used to prevent the middle ITO-coated layer 19 of the double-layer ITO-coated plate 1 from dissipating heat to the surrounding air, which helps to realize high-precision heat measurement.

[0029] The transparent electrostatic spray system comprises the high-voltage electrostatic generator 5, the valve 3, the displacement system 6, the constant liquid level system 11, the peristaltic pump 8, the double-layer water tank 9, the electronic balance 7, and the nozzle 16. The constant liquid level system 11 realizes high-precision visualization constant liquid level control through the double-layer water tank 9, the peristaltic pump 8, and the drain port 10, and then realizes high-precision flow control through the nozzle 16. The electronic balance 7 is used to accurately measure the mass of the working medium in the double-layer water tank 9 in real time. The double-layer water tank 9 mainly provides a constant liquid level height to reduce pressure fluctuations caused by the peristaltic pump. The ITO-coated layer 19 at the bottom of the double-layer ITO-coated plate 1 and the nozzle 16 are connected to both ends of the high-voltage electrostatic generator 5 through wires. The nozzle 16 realizes spacing control with the double-layer ITO-coated plate 1 through the displacement system 6. The high-voltage electrostatic generator 5 realizes non-uniform electric field application through the nozzle 16 and the double-layer ITO-coated plate 1.

[0030] In specific use, for example, in a detection experiment, the double-layer ITO coated plate 1 is connected to the Joule direct current heating system 12 through the copper plate 17, the nozzle 16 and the ITO coating 19 on the bottom surface of the double-layer ITO coated plate 1 are connected to both ends of the high-voltage electrostatic generator 5 through a wire, the valve 3 of the transparent electrostatic spraying system and the switch of the Joule direct current heating system 12 are opened in sequence, the evaporation process of the liquid droplets on the double-layer ITO coated plate 1 is observed through the camera A 13 and the camera B 14, the wall surface temperature distribution of the double-layer ITO coated plate 1 is observed through the infrared camera 15, the operation of the device is stopped, the switch of the Joule direct current heating system 12 and the valve 3 of the transparent electrostatic spraying system are closed in sequence, and the operation is thus completed. According to the above use mode, the electrostatic spraying liquid droplet evaporation visualization device and method can also be used in the measurement of the wetting characteristics of a working medium, and the application range is wide.

[0031] The examples are preferred embodiments of the present application, but the present application is not limited to the above embodiments, and any obvious improvements, replacements or modifications made by those skilled in the art without departing from the essential content of the present application shall fall within the protection scope of the present application.

Claims

1. A visualization device and method of measuring evaporation of electrostatically sprayed droplets, characterized by, It includes: Double ITO coating plate (1), transparent base (2), valve (3), transparent wind deflector (4), high-voltage static generator (5), displacement system (6), electronic balance (7), peristaltic pump (8), double-layer water tank (9), drain (10), constant liquid level system (11), joule direct current heating system (12), camera A (13), camera B (14), infrared camera (15), nozzle (16), copper plate (17), transparent glass plate (18), ITO coating (19) and so on.

2. A device for visualizing the evaporation of electrostatically sprayed droplets and a method thereof according to claim 1, characterized in that: The double ITO coating plate (1) is fixedly connected with the joule direct current heating system (12) through the copper plate (17), so that high-precision visual heat flow control is realized; the bottom ITO coating (19) of the double ITO coating plate (1) is grounded to realize the function of transparent electrode; the bottom transparent glass plate (18) of the double ITO coating plate (1) and the transparent base (2) effectively isolate the heat dissipation of ITO coating from the surrounding air.

3. A device for visualizing the evaporation of electrostatically sprayed droplets and a method thereof according to claim 1, characterized in that: The constant liquid level system (11) realizes high-precision visual constant liquid level control through the double-layer water tank (9), peristaltic pump (8) and drain (10), and then realizes high-precision static spray flow control through the nozzle (16); the electronic balance (7) is used for real-time accurate measurement of the working medium mass in the double-layer water tank (9); the double-layer water tank (9) mainly provides constant liquid level height, and reduces the pressure fluctuation caused by the peristaltic pump.

4. A device for visualizing the evaporation of electrostatically sprayed droplets and a method thereof according to claim 1, characterized in that: The camera A (13) records the deformation process of droplet evaporation from the side; the camera B (14) records the wall wetting process of droplet evaporation from the bottom; the camera (15) records the wall temperature distribution change process from the top. The camera A (13), the camera B (14) and the camera (15) are started at the same time, and the relationship between droplet evaporation and wall temperature is recorded in real time, and the static spray cooling and heat dissipation performance is measured.

5. A device for visualizing the evaporation of electrostatically sprayed droplets and a method thereof according to claim 1, characterized in that: The double ITO coating plate (1) has a scale ruler, which realizes visual measurement of the size and distribution of the electrostatic spray droplets.

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