Study device for electric spark bubbles at any position in long and narrow pipe

Abstract

The invention provides a research device for electric spark bubbles at any position in a long and narrow pipe, and relates to the field of underwater explosion. The water tank is arranged on the water tank support, the circular pipe support is arranged in the water tank, and fixing hoops are arranged at the two ends of the support and used for clamping the tail end of the circular pipe to achieve the supporting effect. And the connecting part of the two circular tubes is connected with the circular tube connecting piece through a flange and a discharging device. The discharging device extends into two holes in the two sides of the circular tube connecting piece and then makes contact with the two holes to generate bubbles, and the other ends of the two electrodes are externally connected with a control electric box. A light source and a high-speed camera are arranged on the two sides of the water tank support, and the water tank and the high-speed camera are arranged opposite to the water tank. The in-pipe electric spark bubble experiment device can achieve the purpose of generating multiple times of secondary cavitation in a long and narrow pipeline, is simple in structure, high in repeatability and obvious in experiment effect, meets more complex and fine experiment requirements, and can be used for carrying out experiments in common laboratories.

Description

Technical Field

[0001] An electric spark bubble research device for arbitrary positions inside a narrow tube belongs to the field of underwater explosion research experimental devices. Background Technology

[0002] Secondary cavitation in pipelines is quite common in engineering practice, including the multi-cavitation effect generated in hydraulic pipelines, hydraulic pumps, and valve passages. This plays a decisive role in the operation of hydraulic pumps and valves, and the removal of gas inside pipes can also be driven by cavitation jets. Research on cavitation in flexible pipes is of great significance for biomedicine, drug delivery, and vascular rupture.

[0003] Cavitation has been studied for over a century, including research on cavitation dynamics in different liquids and the behavior of cavitation near different confined areas (including rigid flat walls, rigid curved walls, elastic walls, and free liquid surfaces). Cavitation motion in pipes is less frequently discussed in the literature due to the numerous influencing factors, experimental difficulties, and complex analysis. The main focus is on simulations rather than experiments.

[0004] Due to the varying confinement domains surrounding cavitation bubbles, particularly their geometry and physical properties, the behavior of cavitation bubbles differs considerably. With advancements in high-speed imaging technology and improvements in numerical calculation methods, research on cavitation bubbles within confinement domains is increasing. Studies of the growth and collapse behavior of single cavitation bubbles within pipes have revealed that the expansion and contraction deformation of cavitation bubbles triggers secondary cavitation during formation and collapse, which interferes with primary cavitation. This is similar to secondary cavitation induced near the liquid surface, but more intense and pronounced. Studies of cavitation oscillation behavior in different types of pipes (different cross-sectional shapes, different diameter variations, different bifurcation forms, different elastic moduli, etc.) have also revealed secondary cavitation phenomena.

[0005] In-tube spark emission experimental devices are commonly used experimental equipment with significant application value in scientific research, engineering testing, and medical diagnosis. By adjusting factors such as pipe structure, electrode position, and voltage pulses, different forms of bubbles can be generated, allowing for in-depth research into bubble generation and motion patterns. Current research on secondary cavitation within pipes is limited to cases with relatively short pipe dimensions. However, our preliminary experimental investigations have revealed multiple instances of secondary cavitation within pipes with relatively long bubble dimensions, presenting a novel research topic with significant engineering practical implications. Due to existing issues such as spark emitter instability and poor flow visualization, traditional in-tube spark emission experimental devices struggle to meet more complex and detailed experimental requirements. Placing the spark device at the center of a relatively long pipe initially involves drilling a hole in the pipe; however, the internal air pressure during device startup causes liquid jetting, affecting the accuracy of experimental data. Placing the spark device at the end of the pipe to reduce liquid jetting would limit the length of the experimental pipeline, hindering the observation of multiple secondary cavitation events within the pipe.

[0006] Therefore, there is an urgent need for an experimental device for generating bubbles through electric spark explosions inside pipes, aiming to produce multiple secondary cavitation phenomena within the pipe, improve its performance and stability, and meet more complex and precise experimental requirements. Summary of the Invention

[0007] The purpose of this invention is to provide a device for studying electric spark bubbles at any position inside a long and narrow tube. Its main features are reusability, high reproducibility, simple structure, improved performance and stability of exploding bubbles inside long tubes, significant experimental results, and the ability to meet more complex and precise experimental requirements. It is an electric spark bubble experimental device for tubes that can be used in ordinary laboratories.

[0008] The objective of this invention is achieved as follows: It includes a water tank support, a water tank mounted on the support, and a circular tube support placed inside the water tank. Fixed clamps are connected to both ends of the support, and these clamps connect to the ends of the circular tubes. The connection between the two circular tubes is achieved using a flange and a discharge device connected to a circular tube connector. The length and diameter of the two circular tubes are adjustable, thereby changing the location and size of different bubble generation points. The bubble generation device, i.e., the contact electrodes, is inserted into two holes on both sides of the circular tube connector via the discharge device and then makes contact to generate the bubble. The other end of the two electrodes is externally connected to a control box, and the size of the generated bubble is adjusted by regulating the voltage. A light source and a high-speed camera are arranged on both sides of the water tank support, with the water tank and high-speed camera positioned relative to the water tank to achieve better exposure at high frame rates. At the beginning of the experiment, it is essential to ensure that the added water completely covers the cylinder. The connection points of the circular tubes are treated with waterproof glue or waterproof material. Furthermore, it is crucial to ensure that there are no air bubbles inside the circular tubes to prevent air bubbles and water pressure from affecting the experimental results.

[0009] The present invention also includes the following structural features: 1. The location of the explosion bubble can be easily adjusted by adjusting the length of the two sections of the circular tube; the inner diameter of the flange, the inner diameter of the discharge device and the inner diameter of the connecting parts of the circular tube are consistent with the inner diameter of the circular tube.

[0010] 2. The connection between the discharge device and the round tube has two small through holes on both sides.

[0011] 3. The fixing clamp features a butterfly nut and bolt combination at the bottom, and the switch uses a threaded fastening design. The diameter of the fixing clamp needs to be determined according to the diameter of the selected experimental tube, and theoretically should be 2-3 mm larger than the diameter of the experimental tube.

[0012] Compared with existing technologies, the advantages of this invention are: This invention achieves arbitrary bubble generation location and good repeatability by using a two-section circular tube connection. A fixing clamp is designed at the end of the cylinder, and a butterfly nut and bolt combination is used at the bottom for quick disassembly under conditions of high water resistance. The switch adopts a threaded fastening design, which can better facilitate disassembly and fixation under conditions of high electric spark discharge impact force. This patent is safe to use, has good experimental results, is reusable, and has a simple structure. It improves the performance and stability of exploding bubbles in narrow tubes, meets more complex and precise experimental requirements, and can provide an effective experimental device for the study of the mechanism of electric spark bubbles in narrow tubes in ordinary laboratories. Attached Figure Description

[0013] Figure 1 is a partial schematic diagram of the pipe connection installation and internal discharge of the present invention; Figure 2 is a schematic diagram of the connection between the discharge device and the circular tube of the present invention; Figure 3 is a schematic diagram of the connecting flange of the pipe of the present invention; Figure 4 is a schematic diagram of the discharge needle of the present invention; Figure 5 is a schematic diagram of the pipe fixing clamp of the present invention; Figure 6 is an overall schematic diagram of the present invention; Figure Descriptions: 1. Discharge device; 2. Connection between discharge device and round tube; 3. Fixing clamp; 4. Round tube; 5. Flange; 6. Round tube support; 7. Power supply box; 8. Butterfly-shaped fixing bolt; 9. Fastening bolt; 10. Clamp switch; 11. High-speed camera; 12. Water tank; 13. Water tank support; 14. Light source; 15. Equipment support. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] Results attached Figure 1-6 This invention is mainly used for an experimental device for generating spark-explosion bubbles inside pipes, especially for spark-explosion bubbles inside narrow pipes, providing an experimental device for studying the cavitation state at different diameters and bubble generation locations. The device includes: 1. a discharge device; 2. a connection between the discharge device and the circular pipe; 3. a fixing clamp; 4. a circular pipe; 5. a flange; 6. a circular pipe support; 7. a power supply box; 8. butterfly-shaped fixing bolts; 9. fastening bolts; 10. a clamp switch; 11. a high-speed camera; 12. a water tank; 13. a water tank support; 14. a light source; and 15. an equipment support.

[0016] The water tank 12 is placed on the water tank support 13, and the circular tube support 6 is placed inside the water tank 12. A fixing clamp 3 is connected to the support 6, and the circular tube 4 is coaxial with the fixing clamp 3, with the clamp 3 placed at the end of the circular tube 4. The other ends of the two circular tubes 4 are connected to the circular tube 4 via flanges 5 and the discharge device 1. The connection between the circular tube 4, flanges 5, and the discharge device 1 needs to be treated with waterproof material, and the inner diameter of flange 5 must be consistent with the inner diameter of the circular tube 4 to avoid affecting the shape of the bubble and thus the experiment. The electrodes extend through two holes on both sides of the connection between the discharge device 1 and flange 5, again requiring waterproofing. The electrode endpoints are welded to allow for faster removal of damaged tips, improving experimental efficiency and minimizing changes to the intersection point, thus enhancing reproducibility and accuracy. The other ends of the two electrodes are connected to an external control box, and the initial bubble size is adjusted by regulating the voltage. A high-speed camera 11 and a light source 14 are placed on either side of the water tank, with their positions opposite each other. The distance between them is adjusted according to the experimental conditions and requirements to ensure that the high-speed camera 11 achieves good exposure while maintaining the required frame rate. During and at the start of the experiment, the entire experiment must be conducted underwater, meaning the water in the tank must completely submerge the circular tube 4. Furthermore, it is crucial to ensure that there are no air bubbles inside the circular tube 4; large air bubbles will severely affect the experimental results, while numerous small air bubbles will negatively impact the image capture.

[0017] The experimental environment, specific structure, and experimental process of this invention are as follows:

[0018] 1. Experimental Environment The experimental environment of this invention is shown in Figure 6. In addition to the device of this invention, the following equipment should also be provided: light source 14, high-speed camera 11, discharge device 1, experimental table, data acquisition system, etc.

[0019] The experimental water tank 12 is made of plexiglass; the discharge device 1, the circular tube connector 2, and the connecting flange 5 are 3D printed. To ensure observation by the high-speed camera 11, a custom-shaped transparent acrylic material can also be used. During the experiment, the water tank 12 is placed on the water tank support 13. The circular tube 4 is connected via connector 2 and then fixed to the circular tube support 6 via fixing clamps 3. The high-speed camera 11 is located to one side of the experimental water tank 12, and the light source is located to the opposite side of the water tank 12. The distance is adjusted according to the experimental shooting requirements, and the center of the light source is at the same height as the high-speed camera 11. The experimental table is placed approximately 3 meters away from the experimental water tank, and the data acquisition system is placed on the experimental table.

[0020] 2. Specific structure of the experimental setup The water tank 12 is placed on the water tank support 13, and the circular tube support 6 is placed inside the water tank 12. A fixing clamp 3 is connected to the support 6, and the circular tube 4 is coaxial with the fixing clamp 3, with the clamp 3 placed at the end of the circular tube 4. The other ends of the two circular tubes 4 are connected to the circular tube 4 connector using flanges 5 and discharge device 1. The connectors between the circular tube 4 and the flanges 5 and discharge device 1 need to be treated with waterproof material, and the inner diameter of the flanges 5 and the inner diameter of the circular tubes 4 must be consistent. Electrodes extend into the discharge device 1 through two holes on both sides of the connector between the flanges 5 and discharge device 1. The other ends of the two electrodes are externally connected to a control box. A high-speed camera 11 and a light source 14 are placed on both sides of the water tank, positioned opposite each other.

[0021] 3. Experimental Procedure The experimental procedure of this invention is as follows: (1) Assemble the experimental apparatus according to the experimental content and the specific structure of the experimental apparatus, and in conjunction with Figures 1 to 6. Arrange the experimental environment according to the experimental environment description and Figure 6.

[0022] The device includes: 1. Discharge device; 2. Discharge device and round tube connector; 3. Fixing clamp; 4. Round tube; 5. Flange; 6. Round tube support; 7. Power supply box; 8. Butterfly-type fixing bolt; 9. Fastening bolt; 10. Clamp switch; 11. High-speed camera; 12. Water tank; 13. Water tank support; 14. Light source; 15. Equipment support.

[0023] Adjust the light intensity of light source 14 according to the required illumination intensity for the experiment. Change the length and diameter of the tube to meet the experimental requirements, and assemble the matching round tube, discharge device connector 2, and flange 5. Adjust the height of light source 14 and high-speed camera 11 to align their intersection points with discharge device 1. Connect the required data cables, power cables, control cables, etc.

[0024] (2) Turn on the power and test all control devices, test devices and data acquisition devices to the experimental state.

[0025] (3) Adjust the power supply discharge voltage to the required voltage and complete the charging, and set the experimental trigger controller to the triggerable state.

[0026] (4) The trigger controller is activated, and the light source 14, high-speed camera 11, and data acquisition equipment begin to operate. After a delay, the discharge needle discharges, causing an underwater explosion. The underwater explosion process will be recorded by the high-speed camera 11.

[0027] In summary, this invention relates to an experimental apparatus for generating electric spark explosion bubbles in a narrow tube. It is mainly designed to generate multiple secondary cavitations at any position within a narrow tube. It features high repeatability and reproducibility, a simple structure, and improves the performance and stability of the explosion bubbles in the long tube. The experimental effect is significant, meeting the requirements of more complex and precise experiments. It is an experimental apparatus for generating electric spark bubbles in a narrow tube that can be used in ordinary laboratories.

Claims

1. An experimental apparatus for in-tube electrospark explosion bubble, characterized in that, It includes the water tank arranged on the water tank support, the assembled pipe in the water tank, the two ends of the assembled pipe are fixed on the pipe support by the fixed clamp, and the middle part is connected by the flange and the connecting piece of the discharge device and the pipe; the high-speed camera and the power supply are arranged on the two sides of the water tank respectively, and the water in the water tank covers the whole assembled pipe.

2. The pipe internal electric spark explosion bubble experiment device according to claim 1, wherein the assembled pipe is characterized in that the occurrence position of the explosion bubble can be easily adjusted by adjusting the length of the two pipe sections; the inner diameter of the flange, the inner diameter of the connecting piece of the discharge device and the pipe, and the inner diameter of the pipe are consistent.

3. The pipe internal electric spark explosion bubble experiment device according to claims 1 and 2, wherein the two sides of the connecting piece of the discharge device and the pipe are provided with two small through holes, so that the discharge device can be directly and better installed on the connecting piece, and the tail of the discharge device can be welded with a discharge needle which can be disassembled after being broken.

4. The pipe internal electric spark explosion bubble experiment device according to claim 1, wherein the fixed clamp is characterized in that the bottom is combined with a butterfly nut and a bolt, so that it can be quickly disassembled under the condition of greater resistance in water; the switch is designed in a threaded fastening type, so that it can be better disassembled and fixed under the condition of greater electric spark discharge impact force; the diameter of the fixed clamp needs to be determined according to the diameter of the selected experimental pipe, and in theory, it should be greater than 2-3 mm of the diameter of the experimental pipe.

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