Experimental device for generating sub-hemispherical bubbles, experimental method and experimental system

Abstract

The present invention provides an experimental device for generating sub-hemispherical bubbles, an experimental method and an experimental system thereof. A transparent glass water tank (1) is used to generate sub-hemispherical bubbles in cooperation with a thin aluminum plate (6) under the action of a shock wave; a tracer particle (2) is used to display the sub-hemispherical bubbles under the irradiation of a laser source (3); a host computer (4) is used to display data obtained by a mechanical sensor (5) and to control the laser source (3), a high-speed camera (7) and a shock wave source (8); the mechanical sensor (5) is used to monitor the pressure data applied by the shock wave source (8) to the thin aluminum plate (6); the thin aluminum plate (6) is used to obtain sub-hemispherical bubbles in cooperation with the shock wave source (8); and the shock wave source (8) is used to shock the thin aluminum plate (6) to obtain shock waves, tensile waves and compression waves. The present invention is used to fill the gap in the experiment of generating sub-hemispherical bubbles and lay a foundation for the popularization of sub-hemispherical bubble experiments in the future.

Description

Technical Field

[0001] The invention belongs to the field of bubble dynamics, and in particular relates to an experimental device for generating sub-hemispherical bubbles, an experimental method and an experimental system thereof. Background Art

[0002] Bubbles are ubiquitous in nature and are of great significance in many scientific and engineering fields, including marine science, marine engineering, mechanical and material engineering, environmental and chemical engineering, medicine and life sciences. Bubble dynamics is a fundamental scientific issue that has attracted widespread attention. For example, some acoustic and laser cavitation bubbles, usually millimeter or micron-sized oscillating bubbles, can be used for ultrasonic cleaning, ultrasound therapy, drug / gene delivery, inkjet printing, and bubble propulsion.

[0003] Whether it is natural bubbles or artificial bubbles, the existence of different scales, different boundaries and multiple oscillation periods makes the bubble dynamics complicated, which brings great challenges to theoretical, numerical and experimental research. Experimental research is the key to understanding the physical properties of bubbles under different conditions, and is the basis for making full use of bubbles and avoiding bubble hazards. For experimental research on the movement of bubbles near the wall, it is first necessary to determine the bubble source, that is, how the bubbles are generated. Currently, commonly used bubbles mainly include electric spark bubbles, laser bubbles and underwater explosion bubbles.

[0004] Spark bubbles are formed by electrolyzing water by quickly passing electricity through positive and negative electrodes in water. They are favored by laboratories for their simplicity. Laser bubbles are formed by ionizing local liquid by applying strong laser pulses to a certain point in the water. Laser bubbles can accurately control the time and position of bubble generation and have good spherical symmetry. Compared with spark bubbles, laser bubbles are more complex to control and more expensive. Underwater explosion bubbles are one of the most commonly used bubble sources in engineering. It is generally believed that underwater explosions will produce two loads, shock waves and bubbles. The peak value of shock waves is large but the duration is short, while the bubble load lasts long and has a load equivalent to the shock wave, which cannot be ignored. At present, at the laboratory scale, the main bubble sources used are spark bubbles and laser bubbles.

[0005] In conventional laboratory scale, the bubbles generated near the surface by electric spark and laser are mainly large hemispherical or spherical bubbles, such as the invention patents with patent numbers CN116832743A and CN114292741A. The dynamic characteristics of bubbles have been studied in depth, and the jet and flow field disturbances generated by their collapse are no different from traditional research. However, there are very few studies on the dynamics of sub-hemispherical bubbles, and the jet and flow field disturbances generated by their collapse are different from the traditional bubble collapse mode. Therefore, it is necessary to study the formation and collapse mechanism of sub-hemispherical bubbles.

[0006] In existing research, there is no experimental method for producing sub-hemispherical bubbles. Summary of the invention

[0007] The invention provides an experimental method for generating sub-hemispherical bubbles, which is used to fill the blank of the experiment for generating sub-hemispherical bubbles and lay a foundation for popularizing the experiment of sub-hemispherical bubbles in the future.

[0008] The invention also provides an experimental device for generating sub-hemispherical bubbles, which is used to realize the experimental method for generating sub-hemispherical bubbles.

[0009] The invention also provides an experimental system for generating sub-hemispherical bubbles, which is used to realize the experimental method for generating sub-hemispherical bubbles.

[0010] The present invention is achieved through the following technical solutions:

[0011] An experimental device for generating sub-hemispherical bubbles, the experimental device comprising a transparent glass water tank 1, tracer particles 2, a host computer 4, a mechanical sensor 5, a thin aluminum plate 6, and a shock wave source 8;

[0012] The transparent glass water tank 1 is used to load the tracer particles 2, the mechanical sensor 5, the thin aluminum plate 6 and water, and the thin aluminum plate 6 generates sub-hemispherical bubbles under the action of the shock wave;

[0013] The tracer particles 2 are used to display sub-hemispherical bubbles under the irradiation of the laser source 3;

[0014] The host computer 4 is used to display the data obtained by the mechanical sensor 5 and control the laser source 3, the high-speed camera 7 and the shock wave source 8;

[0015] The mechanical sensor 5 is used to monitor the pressure data applied by the shock wave source 8 to the thin aluminum plate 6;

[0016] The thin aluminum plate 6 is used to cooperate with the shock wave source 8 to obtain a sub-hemispherical bubble;

[0017] The shock wave source 8 is used to impact the thin aluminum plate 6 to obtain shock waves, tensile waves and compression waves.

[0018] An experimental device for generating sub-hemispherical bubbles, the experimental device further comprising a laser source 3, a high-speed camera 7

[0019] The laser source 3 is used to display the tracer particles 2;

[0020] The high-speed camera 7 is used to shoot the experimental process and the obtained sub-hemispherical bubbles.

[0021] An experimental device for generating sub-hemispherical bubbles, wherein the transparent glass water tank 1 is rigidly fixedly connected to a thin aluminum plate 6, the upper ends of the transparent glass water tank 1 and the thin aluminum plate 6 are filled with water, a mechanical sensor 5 is arranged on the thin aluminum plate 6, and a shock wave source 8 is arranged between the bottom of the transparent glass water tank 1 and the thin aluminum plate 6;

[0022] The mechanical sensor 5 displays the collected signal on the host computer 4.

[0023] An experimental device for generating sub-hemispherical bubbles, wherein the laser source 3 is vertically arranged directly above the transparent glass water tank 1;

[0024] The high-speed camera 7 is arranged outside the transparent glass water tank 1 and facing the thin aluminum plate 6;

[0025] The laser source 3 and the shock wave source 8 are both controlled by a host computer 4;

[0026] The high-speed camera 7 displays the collected signals on the host computer 4 .

[0027] An experimental device for generating sub-hemispherical bubbles, wherein the tracer particles 2 are mixed with water.

[0028] An experimental device for generating sub-hemispherical bubbles, wherein there is no object obstructing between the shock wave source 8 and the thin aluminum plate 6.

[0029] An experimental method for generating sub-hemispherical bubbles, the experimental method uses the experimental device for generating sub-hemispherical bubbles as described above, and the experimental method specifically comprises:

[0030] Assemble the experimental device and ensure that there are no objects blocking the transmission of the shock wave;

[0031] Start and debug to the experimental state, activate the shock wave source, and release the shock wave;

[0032] The shock wave source releases shock waves to impact the thin aluminum plate;

[0033] The shock wave is transmitted into the thin aluminum plate and then transmitted upward through the thin aluminum plate;

[0034] After the shock wave touches the thin aluminum plate to the upper surface of the thin aluminum plate, the thin aluminum plate vibrates repeatedly at a high frequency;

[0035] Due to the surface tension of the thin aluminum plate and the effect of the tensile wave, the internal pressure is less than the surrounding pressure, so cavitation occurs and a large number of tiny bubbles appear.

[0036] Due to the tension on the bubble surface, a large number of tiny bubbles will gather into one bubble, which has a sub-hemispherical shape.

[0037] An experimental method for producing sub-hemispherical bubbles, the experimental method further comprising:

[0038] The impact distance h from the shock wave source to the thin aluminum plate and the thickness t of the thin aluminum plate are adjusted to control the energy loss ratio of the shock wave;

[0039] By adjusting the initial energy of the shock wave source and controlling the pulse peak of the initial shock wave, the number of tiny cavitation bubbles generated above the aluminum plate can be adjusted, and ultimately the size of the sub-hemispherical bubbles can be controlled.

[0040] An experimental method for generating sub-hemispherical bubbles. The liquid at the aluminum-water interface has a certain velocity, which is calculated according to the Bernoulli equation.

[0041] p+1 / 2ρv 2 +ρgh=c

[0042] Among them, p is the pressure at a certain point in the fluid, ρ is the fluid density, v is the flow velocity of the fluid at that point, g is the acceleration due to gravity, h is the height of the point, and c is a constant.

[0043] The invention discloses an experimental system for generating sub-hemispherical bubbles. The experimental system is used to realize the sub-hemispherical bubbles.

[0044] The beneficial effects of the present invention are:

[0045] The invention adopts shock wave induction to generate sub-hemispherical bubbles, which is very safe in the laboratory.

[0046] The method of the invention is simple, has accurate effect and is easy to be implemented under laboratory conditions.

[0047] Schematic diagram of the evolution process of near-wall spherical, large hemispherical and sub-hemispherical bubbles. At the laboratory scale, near-wall spherical and large hemispherical bubbles can be produced by existing technology, but there is still a gap in the method for producing sub-hemispherical bubbles. The present invention fills this gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the experimental device of the present invention.

[0049] Figure 2 This is the schematic diagram A of the sub-hemispherical bubble generation process of the present invention.

[0050] Figure 3This is the schematic diagram B of the sub-hemispherical bubble generation process of the present invention.

[0051] Figure 4 It is a simplified mechanism diagram of the sub-hemispherical bubble generation process of the present invention.

[0052] Figure 5 Schematic diagram A of the sub-hemispherical bubble generation process of the present invention.

[0053] Figure 6 Schematic diagram B of the sub-hemispherical bubble generation process of the present invention.

[0054] Figure 7 It is a schematic diagram of the evolution process of a spherical bubble near the wall.

[0055] Figure 8 This is a schematic diagram of the evolution process of a large hemispherical bubble near the wall.

[0056] Fig. 9 It is a schematic diagram of the evolution process of the near-wall sub-hemispherical bubble of the present invention. DETAILED DESCRIPTION

[0057] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0058] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0059] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0060] The following is attached to this application specification Figure 1-9 , the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0061] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0062] Embodiment 1

[0063] This embodiment provides an experimental device for generating sub-hemispherical bubbles, the experimental device comprising a transparent glass water tank 1, tracer particles 2, a host computer 4, a mechanical sensor 5, a thin aluminum plate 6, and a shock wave source 8;

[0064] The transparent glass water tank 1 is used to load the tracer particles 2, the mechanical sensor 5, the thin aluminum plate 6 and water, and the thin aluminum plate 6 generates sub-hemispherical bubbles under the action of the shock wave;

[0065] The tracer particles 2 are used to display sub-hemispherical bubbles under the irradiation of the laser source 3;

[0066] The host computer 4 is used to display the data obtained by the mechanical sensor 5 and control the laser source 3, the high-speed camera 7 and the shock wave source 8;

[0067] The mechanical sensor 5 is used to monitor the pressure data applied by the shock wave source 8 to the thin aluminum plate 6;

[0068] The thin aluminum plate 6 is used to cooperate with the shock wave source 8 to obtain a sub-hemispherical bubble;

[0069] The shock wave source 8 is used to impact the thin aluminum plate 6 to obtain shock waves, tensile waves and compression waves.

[0070] An experimental device for generating sub-hemispherical bubbles, the experimental device further comprising a laser source 3, a high-speed camera 7

[0071] The laser source 3 is used to display the tracer particles 2;

[0072] The high-speed camera 7 is used to shoot the experimental process and the obtained sub-hemispherical bubbles.

[0073] This embodiment also provides an experimental device for generating sub-hemispherical bubbles, the experimental device comprising a transparent glass water tank 1, tracer particles 2, a laser source 3, a host computer 4, a mechanical sensor 5, a thin aluminum plate 6, a high-speed camera 7 and a shock wave source 8;

[0074] The transparent glass water tank 1 is rigidly fixedly connected to the thin aluminum plate 6, the upper ends of the transparent glass water tank 1 and the thin aluminum plate 6 are filled with water, a mechanical sensor 5 is arranged on the thin aluminum plate 6, and a shock wave source 8 is arranged between the bottom of the transparent glass water tank 1 and the thin aluminum plate 6;

[0075] The mechanical sensor 5 displays the collected signal on the host computer 4.

[0076] An experimental device for generating sub-hemispherical bubbles, wherein the laser source 3 is vertically arranged directly above the transparent glass water tank 1;

[0077] The high-speed camera 7 is arranged outside the transparent glass water tank 1 and facing the thin aluminum plate 6;

[0078] The laser source 3 and the shock wave source 8 are both controlled by a host computer 4;

[0079] The high-speed camera 7 displays the collected signals on the host computer 4 .

[0080] An experimental device for generating sub-hemispherical bubbles, wherein the tracer particles 2 are mixed with water.

[0081] An experimental device for generating sub-hemispherical bubbles, wherein there is no object obstructing between the shock wave source 8 and the thin aluminum plate 6.

[0082] Specifically, the present invention intends to generate sub-hemispherical bubbles near the thin aluminum plate, and to generate cavitation inside the water droplets attached below the thin aluminum plate by focusing the laser. The resulting shock wave penetrates the thin aluminum plate and is transmitted to the fluid medium above the thin aluminum plate, so that a large number of tiny bubbles are generated above the thin aluminum plate, and finally converge into sub-hemispherical bubbles.

[0083] This paper provides a methodological reference for studying the dynamic characteristics of the sub-hemispherical bubble collapse process adsorbed on the wall, as well as the jet and flow field disturbance generated after the collapse.

[0084] Embodiment 2

[0085] This embodiment provides an experimental method for generating sub-hemispherical bubbles based on the experimental device of embodiment 1. The experimental method uses the experimental device for generating sub-hemispherical bubbles as described above. The experimental method is specifically as follows:

[0086] Assemble the experimental device and ensure that there are no objects blocking the transmission of the shock wave;

[0087] Start and debug to the experimental state, activate the shock wave source, and release the shock wave;

[0088] The shock wave source releases shock waves to impact the thin aluminum plate;

[0089] The shock wave is transmitted to the inside of the thin aluminum plate and transmitted upward through the thin aluminum plate; because the thin aluminum plate material has strong elasticity, the aluminum plate bends upward in a middle arch state; such as the principle of the sub-hemispherical bubble generation process Figure 1 shown.

[0090] After the shock wave touches the thin aluminum plate to the upper surface of the thin aluminum plate (the surface touching the water), due to the different sound propagation speeds of water and aluminum materials, a tensile wave will be formed that propagates downward from the surface touching the water; at the same time, due to the good elasticity of the thin aluminum plate, after being in the middle arch state, it will quickly return to the middle droop state. The combination of these two effects causes the thin aluminum plate to vibrate repeatedly at high frequency; such as the principle of the process of sub-hemispherical bubble generation Figure 2 As shown;

[0091] Due to the surface tension of the thin aluminum plate and the effect of the tensile wave, the liquid at the aluminum-water interface has a certain velocity. According to the Bernoulli equation (p+1 / 2ρv 2 +ρgh=c) As the internal pressure is lower than the surrounding pressure, cavitation occurs and a large number of tiny bubbles appear, such as the schematic diagram of the sub-hemispherical bubble generation process. Figure 1 shown.

[0092] Due to the tension on the bubble surface, a large number of tiny bubbles will gather into a bubble, forming a sub-hemispherical shape, as shown in the schematic diagram of the sub-hemispherical bubble generation process Figure 2 shown.

[0093] An experimental method for producing sub-hemispherical bubbles, the experimental method further comprising:

[0094] The impact distance h from the shock wave source to the thin aluminum plate and the thickness t of the thin aluminum plate are adjusted to control the energy loss ratio of the shock wave;

[0095] By adjusting the initial energy of the shock wave source and controlling the pulse peak of the initial shock wave, the number of tiny cavitation bubbles generated above the aluminum plate can be adjusted, and ultimately the size of the sub-hemispherical bubbles can be controlled.

[0096] An experimental method for generating sub-hemispherical bubbles. The liquid at the aluminum-water interface has a certain velocity, which is calculated according to the Bernoulli equation.

[0097] p+1 / 2ρv 2 +ρgh=c

[0098] Among them, p is the pressure at a certain point in the fluid, ρ is the fluid density, v is the flow velocity of the fluid at that point, g is the acceleration due to gravity, h is the height of the point, and c is a constant.

[0099] Specifically, the present invention intends to generate sub-hemispherical bubbles near a thin aluminum plate, and generate cavitation inside the water droplets attached to the bottom of the thin aluminum plate by focusing a laser. The resulting shock wave penetrates the thin aluminum plate and is transmitted to the fluid medium above the thin aluminum plate, causing a large number of tiny bubbles to be generated above the thin aluminum plate, which eventually converge into sub-hemispherical bubbles. This provides a new method for experimental research on tiny bubbles in biology, medicine, fluid mechanics, etc.

[0100] Embodiment 3

[0101] This embodiment also provides an experimental system for generating sub-hemispherical bubbles, and the experimental system is used to realize sub-hemispherical bubbles.

[0102] This paper provides a methodological reference for studying the dynamic characteristics of the sub-hemispherical bubble collapse process adsorbed on the wall, as well as the jet and flow field disturbance generated after the collapse.

Claims

1. An experimental device for generating sub-hemispherical bubbles, characterized in that: The experimental device comprises a transparent glass water tank (1), tracer particles (2), a host computer (4), a mechanical sensor (5), a thin aluminum plate (6), and a shock wave source (8); The transparent glass water tank (1) is used to contain tracer particles (2), mechanical sensors (5), thin aluminum plates (6) and water, and the thin aluminum plates (6) generate sub-hemispherical bubbles under the action of shock waves; The tracer particles (2) are used to display sub-hemispherical bubbles under the irradiation of the laser source (3); The host computer (4) is used to display the data obtained by the mechanical sensor (5) and control the laser source (3), the high-speed camera (7) and the shock wave source (8); The mechanical sensor (5) is used to monitor the pressure data applied by the shock wave source (8) to the thin aluminum plate (6); The thin aluminum plate (6) is used to cooperate with the shock wave source (8) to obtain a sub-hemispherical bubble; The shock wave source (8) is used to impact the thin aluminum plate (6) to obtain shock waves, tension waves and compression waves.

2. An experimental device for generating sub-hemispherical bubbles according to claim 1, characterized in that: The experimental device also includes a laser source (3), a high-speed camera (7) The laser source (3) is used to display the tracer particles (2); The high-speed camera (7) is used to shoot the experimental process and the obtained sub-hemispherical bubbles.

3. The experimental device for generating sub-hemispherical bubbles according to claim 1, characterized in that: The transparent glass water tank (1) is rigidly fixedly connected to the thin aluminum plate (6), the upper ends of the transparent glass water tank (1) and the thin aluminum plate (6) are filled with water, a mechanical sensor (5) is arranged on the thin aluminum plate (6), and a shock wave source (8) is arranged between the bottom of the transparent glass water tank (1) and the thin aluminum plate (6); The mechanical sensor (5) displays the collected signal on the host computer (4).

4. An experimental device for generating sub-hemispherical bubbles according to claim 3, characterized in that: The laser source (3) is vertically arranged above the transparent glass water tank (1); The high-speed camera (7) is arranged on the outside of the transparent glass water tank (1) at a position directly facing the thin aluminum plate (6); The laser source (3) and the shock wave source (8) are both controlled by a host computer (4); The high-speed camera (7) displays the collected signals on the host computer (4).

5. The experimental device for generating sub-hemispherical bubbles according to claim 3, characterized in that: The tracer particles (2) are mixed with water.

6. The experimental device for generating sub-hemispherical bubbles according to claim 3, characterized in that: There is no object obstructing the shock wave source (8) and the thin aluminum plate (6).

7. An experimental method for producing sub-hemispherical bubbles, characterized in that: The experimental method uses the experimental device for generating sub-hemispherical bubbles as described in claim 1 or 2, and the experimental method is specifically as follows: Assemble the experimental device and ensure that there are no objects blocking the transmission of the shock wave; Start and debug to the experimental state, activate the shock wave source, and release the shock wave; The shock wave source releases a shock wave to impact the thin aluminum plate; The shock wave is transmitted into the thin aluminum plate and then transmitted upward through the thin aluminum plate; After the shock wave touches the thin aluminum plate to the upper surface of the thin aluminum plate, the thin aluminum plate vibrates repeatedly at a high frequency; Due to the surface tension of the thin aluminum plate and the effect of the tensile wave, the internal pressure is less than the surrounding pressure, so cavitation occurs and a large number of tiny bubbles appear. Due to the tension on the bubble surface, a large number of tiny bubbles will gather into one bubble, which has a sub-hemispherical shape.

8. An experimental method for producing sub-hemispherical bubbles according to claim 7, characterized in that: The experimental method also includes: The impact distance h from the shock wave source to the thin aluminum plate and the thickness t of the thin aluminum plate are adjusted to control the energy loss ratio of the shock wave; By adjusting the initial energy of the shock wave source and controlling the pulse peak of the initial shock wave, the number of tiny cavitation bubbles generated above the thin aluminum plate can be adjusted, and ultimately the size of the sub-hemispherical bubbles can be controlled.

9. An experimental method for producing sub-hemispherical bubbles according to claim 7, characterized in that: The liquid at the aluminum-water interface has a certain velocity, which is calculated according to the Bernoulli equation p+1 / 2ρv 2 +ρgh=c Among them, p is the pressure at a certain point in the fluid, ρ is the fluid density, v is the flow velocity of the fluid at that point, g is the acceleration due to gravity, h is the height of the point, and c is a constant.

10. An experimental system for generating sub-hemispherical bubbles, characterized in that: The experimental system realizes sub-hemispherical bubbles by using an experimental method for generating sub-hemispherical bubbles as described in claim 7.

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