A continuous high-resolution transient cavitation morphology capturing device and method

Abstract

The present application relates to the technical field of transient cavitation morphology capturing, and provides a continuous high-resolution transient cavitation morphology capturing device and method, which comprises a firing laser, an illumination laser, a CCD camera, a synchronous controller, a hydrophone, a water tank, an oscilloscope, a PC terminal and a control unit; the firing laser generates pulse energy exceeding the liquid breakdown threshold in water, thereby breaking through the liquid to form plasma and grow to form a cavitation bubble; the illumination laser serves as a light source of the CCD camera; the synchronous controller controls the coordinated work of the firing laser, the illumination laser and the CCD camera; the hydrophone is used for calibrating the repeatability of cavitation bubble growth and collapse; the oscilloscope monitors the sound signal of the cavitation bubble in the water tank; the PC terminal records the cavitation bubble morphology images captured by the CCD camera; and the control unit records the development morphology of the cavitation bubble at a preset observation time point, so as to obtain a group of cavitation bubble morphology image sequences through the recorded development morphology changes of the cavitation bubble in the whole growth and collapse cycle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transient cavitation morphology capturing, in particular to a continuous high-resolution transient cavitation morphology capturing device and method. BACKGROUND

[0002] Cavitation phenomenon is a common problem in actual production and life, and exploring the development process of cavitation bubbles in cavitation helps us understand the application or prevention of cavitation in the fields of ultrasonic cleaning, hydraulic machinery, etc. However, the growth and collapse process of cavitation bubbles is on the order of several hundred microseconds or even smaller, and now high-speed cameras or CCD cameras are commonly used to capture them.

[0003] Although high-speed cameras can capture a continuous development image sequence of the same cavitation bubble, due to the limitations of bandwidth and resolution, the higher the frame rate of the camera, the fewer pictures it can store, and the lower the image resolution, which is far from being able to clearly and completely capture the continuous growth and collapse morphology of the same cavitation bubble in the ns level exposure time. SUMMARY

[0004] The present application provides a continuous high-resolution transient cavitation morphology capturing device and method to solve the defect that the existing technology cannot completely capture the growth and collapse morphology of cavitation bubbles under the same period.

[0005] The present application provides a continuous high-resolution transient cavitation morphology capturing device, comprising: a firing laser, an illumination laser, a CCD camera, a synchronous controller, a hydrophone, a water tank, an oscilloscope, a PC end and a control unit, the firing laser, the illumination laser, the CCD camera and the synchronous controller are connected, the hydrophone is placed in the water tank and connected with the oscilloscope, and the CCD camera is connected with the PC end; wherein:

[0006] The firing laser is used to generate pulse energy exceeding the liquid breakdown threshold in water, thereby breaking down the liquid to form plasma and growing to form a cavitation bubble;

[0007] The illumination laser is used as a light source for the CCD camera to enable the CCD camera to capture cavitation bubble morphology images under ns level exposure time;

[0008] The synchronous controller is used to control the coordinated work of the firing laser, the illumination laser and the CCD camera;

[0009] The hydrophone is used to calibrate the repeatability of cavitation bubble growth and collapse, so that a group of selected cavitation bubble morphology image sequences can represent the occurrence process of the same cavitation bubble;

[0010] The oscilloscope is used to display the sound signal of the cavitation bubble captured by the hydrophone in the water tank in the form of voltage.

[0011] The PC end is used for recording the cavity shape image photographed by the CCD camera.

[0012] The control unit is used for recording the development shape of the cavity at the preset observation time point, so as to obtain a group of cavity shape image sequences by recording the development shape change of the cavity in the whole growth and collapse cycle, wherein the development shapes of the cavity at different preset observation time points are different.

[0013] According to the continuous high-resolution instantaneous cavity shape capturing device, the control unit records the development shape of the cavity at the preset observation time point by the following way:

[0014] According to the preset observation time point, the trigger time interval of the ignition laser and the illumination laser is adjusted; and,

[0015] The synchronization controller is triggered to control the ignition laser and the illumination laser to work coordinately at the trigger time interval; and,

[0016] The cavity shape image at the trigger time is photographed by the CCD camera, and the numerical size and time interval of the initial peak value and the collapse peak value of the cavity in a growth and collapse cycle are recorded by the oscilloscope; and,

[0017] The cavity shape images at different development time points are screened according to the hydrophone signal.

[0018] According to the continuous high-resolution instantaneous cavity shape capturing device, the synchronization controller is connected with the CCD camera through a synchronization signal line, so as to control the shutter switch of the CCD camera through the synchronization signal line.

[0019] The laser cavity of the single-cavity pulse laser comprises a first lamp trigger signal line and a first Q switch trigger signal line connected with the synchronization controller.

[0020] The laser cavity of the illumination laser comprises a second lamp trigger signal line and a second Q switch trigger signal line connected with the synchronization controller, and the signal line length of the illumination laser is the same as that of the ignition laser.

[0021] According to the continuous high-resolution instantaneous cavity shape capturing device, the lamp signal sent by the lamp trigger signal line of the synchronization controller is used for sending a preheating signal, the Q signal sent by the Q switch trigger signal line of the synchronization controller represents that the preheating is completed and energy can be emitted, and the optimal trigger time interval of the lamp signal and the Q signal is 193 μs.

[0022] The water listener is arranged at the center of the needle, and the center of the needle is opposite to the center of the bubble in the water tank.

[0023] The continuous high-resolution instantaneous bubble shape capturing device provided by the application is used for capturing the bubble shape image at different time points by adjusting the trigger time interval of the ignition laser and the illumination laser.

[0024] The continuous high-resolution instantaneous bubble shape capturing device provided by the application is used for screening the bubble shape images at different development time points of the same bubble evolution sequence by using the peak signals of the water listener at the initial time and the collapse time of the bubble.

[0025] The continuous high-resolution instantaneous bubble shape capturing device provided by the application is used for screening the bubble shape images at different development time points of the same bubble evolution sequence by using the peak signals of the water listener at the initial time and the collapse time of the bubble.

[0026] The continuous high-resolution instantaneous bubble shape capturing device provided by the application is used for screening the bubble shape images at different development time points of the same bubble evolution sequence by using the peak signals of the water listener at the initial time and the collapse time of the bubble.

[0027] The application further provides a continuous high-resolution instantaneous bubble shape capturing method based on the continuous high-resolution instantaneous bubble shape capturing device.

[0028] The ignition laser, the illumination laser and the CCD camera are connected with the synchronous controller, so that the synchronous controller controls the ignition laser, the illumination laser and the CCD camera to work coordinately.

[0029] The water listener is arranged in the water tank and connected with the oscilloscope, so that the oscilloscope monitors the sound signals of the bubble in the water tank and screens the bubble development repeatedly.

[0030] The CCD camera is connected with the PC terminal, so that the PC terminal records the bubble shape images captured by the CCD camera.

[0031] The development form of the cavitation bubble at a preset observation time point is recorded, so as to obtain a group of cavitation bubble form image sequences by recording the development form change of the cavitation bubble in the whole growth and collapse cycle, wherein the development forms of the cavitation bubble at different preset observation time points are different.

[0032] The application further provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the continuous high-resolution instantaneous cavitation bubble form capturing method according to any one of the preceding aspects when executing the program.

[0033] The application further provides a non-transitory computer readable storage medium, which stores a computer program, wherein the computer program is executable on a processor to implement the continuous high-resolution instantaneous cavitation bubble form capturing method according to any one of the preceding aspects.

[0034] The application further provides a computer program product, which includes a computer program, wherein the computer program is executable on a processor to implement the continuous high-resolution instantaneous cavitation bubble form capturing method according to any one of the preceding aspects.

[0035] The application provides a continuous high-resolution instantaneous cavitation bubble form capturing device and method, which includes a firing laser, an illumination laser, a CCD camera, a synchronous controller, a hydrophone, a water tank, an oscilloscope, a PC terminal and a control unit, the firing laser, the illumination laser and the CCD camera are connected with the synchronous controller, the hydrophone is arranged in the water tank and connected with the oscilloscope, and the CCD camera is connected with the PC terminal; wherein: the firing laser is used to generate pulse energy exceeding a liquid breakdown threshold in water, so as to break through the liquid to form a plasma and grow to form a cavitation bubble; the illumination laser is used as a light source of the CCD camera, so that the CCD camera can capture a cavitation bubble form image under a ns-level exposure time; the synchronous controller is used to control the firing laser, the illumination laser and the CCD camera to work coordinately; the hydrophone is used to calibrate the repeatability of the cavitation bubble growth and collapse, so that a group of selected cavitation bubble form image sequences can represent the occurrence process of the same cavitation bubble; the oscilloscope is used to display the sound signal of the cavitation bubble captured by the hydrophone in the water tank in the form of voltage; the PC terminal is used to record the cavitation bubble form image captured by the CCD camera; and the control unit is used to record the development form of the cavitation bubble at a preset observation time point, so as to obtain a group of cavitation bubble form image sequences by recording the development form change of the cavitation bubble in the whole growth and collapse cycle, wherein the development forms of the cavitation bubble at different preset observation time points are different. The application utilizes the advantages of high resolution and small exposure time of the CCD camera, and uses the hydrophone to observe the proximity of the cavitation bubble development time interval induced by the laser, to judge the proximity of the cavitation bubble form change in the growth and collapse process of the cavitation bubble, to select the extremely similar cavitation bubble form changes at different time points with the same cavitation bubble development time interval, and to obtain an extremely continuous, high-resolution instantaneous cavitation bubble development sequence. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the present application or the prior art, the drawings required to be used in the following embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0037] Figure 1 is one of the structural schematic diagrams of the continuous high-resolution instantaneous bubble morphology capturing device provided by the present application;

[0038] Figure 2 is the second structural schematic diagram of the continuous high-resolution instantaneous bubble morphology capturing device provided by the present application;

[0039] Figure 3 is the oscilloscope display signal peak schematic diagram provided by the embodiment of the present application;

[0040] Figure 4 is the flow schematic diagram of the continuous high-resolution instantaneous bubble morphology capturing method provided by the embodiment of the present application;

[0041] Figure 5 is the structural schematic diagram of the electronic device provided by the present application;

[0042] IDENTIFICATION OF DRAWINGS

[0043] 1: synchronization controller; 2: ignition laser; 3: illumination laser; 4: beam expander; 5: oscilloscope; 6: PC end; 7: CCD camera; 8: lens; 9: hydrophone; 10: water tank; 11: signal line. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the present application will be described clearly and completely in the following with reference to the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0045] The current method for capturing bubble morphology images is to use a CCD industrial camera to cooperate with a short pulse width laser (illumination laser) to shoot. Under normal circumstances, the exposure time can reach the order of ns, and more instantaneous bubble morphology images can be captured, but only single frame by single frame can be captured, and a complete sequence cannot be formed. Since the laser emits strong energy instantaneously, there is a certain instability, and the repeatability of each set of experiments cannot be guaranteed, so a continuous bubble morphology sequence cannot be obtained.

[0046] Therefore, aiming at the above technical problems, a continuous high-resolution instantaneous air bubble shape capturing device is provided.

[0047] The continuous high-resolution instantaneous air bubble shape capturing device provided by the present application will be described in detail below in combination with embodiments.

[0048] Figure 1 The structure diagram of the continuous high-resolution instantaneous air bubble shape capturing device provided by the present application includes but is not limited to: an ignition laser 2, an illumination laser 3, a CCD camera 7, a synchronous controller 1, a hydrophone 9, a water tank 10, an oscilloscope 5, a PC end 6, and a control unit.

[0049] The ignition laser 2, the illumination laser 3, and the CCD camera 7 are connected to the synchronous controller 1, the hydrophone 9 is placed in the water tank 10 and connected to the oscilloscope 5, and the CCD camera 7 is connected to the PC end 6; wherein:

[0050] The ignition laser 2 is used to generate pulse energy exceeding the liquid breakdown threshold in water, thereby breaking down the liquid to form plasma and growing to form an air bubble;

[0051] The illumination laser 3 is used as a light source for the CCD camera 7, so that the CCD camera 7 can capture air bubble shape images under ns-level exposure time;

[0052] The synchronous controller 1 is used to control the ignition laser 2, the illumination laser 3, and the CCD camera 7 to work in coordination;

[0053] The hydrophone 9 is used to calibrate the repeatability of air bubble growth and collapse, so that a group of screened air bubble shape image sequences can represent the occurrence process of the same air bubble;

[0054] The oscilloscope 5 is used to monitor the sound signal of the air bubble in the water tank 10;

[0055] The PC end 6 is used to record the air bubble shape images taken by the CCD camera 7;

[0056] The control unit is used to record the development shape of the air bubble at a preset observation time point, so as to obtain a group of air bubble shape image sequences by recording the development shape changes of the air bubble in the entire growth and collapse period, wherein the development shapes of the air bubble at different preset observation time points are different.

[0057] In this embodiment, the ignition laser 2 is used to generate pulse energy exceeding the liquid breakdown threshold in water. When the ignition laser 2 is triggered, it will generate a high-energy pulse laser beam, break down the liquid to form plasma, and start to form an air bubble.

[0058] The illumination laser 3 acts as a light source for the CCD camera 7, providing sufficient light conditions for the CCD camera 7 to capture the morphological images of the cavitation bubble at a ns-level exposure time. The CCD camera 7 is always in an exposure state, and the exposure time of its imaging is determined by the illumination laser 3.

[0059] The illumination laser 3 emits light before the CCD camera 7 takes a picture. The CCD camera 7 is connected to the synchronization controller 1 and takes a picture through the light source provided by the illumination laser 3. The CCD camera 7 records the morphological changes of the cavitation bubble in a high-speed image acquisition mode. Due to its high sensitivity and fast response characteristics, the CCD camera 7 can capture the morphology of the cavitation bubble at a ns-level exposure time.

[0060] The synchronization controller 1 is used to coordinate the operation of the ignition laser 2, the illumination laser 3 and the CCD camera 7. It ensures that the ignition laser 2 and the illumination laser 3 are triggered at the right time, and is synchronized with the shooting of the CCD camera 7 to ensure accurate recording of the morphology of the cavitation bubble.

[0061] The hydrophone 9 is used to monitor the growth and disappearance of the cavitation bubble in water. Through multiple experiments on the growth and disappearance of the cavitation bubble by devices such as the hydrophone 9, a set of cavitation bubble morphological image sequences can be selected, which can accurately reflect the growth and disappearance process of the same cavitation bubble.

[0062] The oscilloscope 5 is connected to the hydrophone 9 in the water tank 10 and displays the sound signals captured by the hydrophone 9 in the water tank in the form of voltage. These sound signals can provide additional information about the growth and collapse of the cavitation bubble.

[0063] The PC terminal 6 is connected to the CCD camera 7 to receive and record the cavitation bubble morphological images taken by the CCD camera 7. The PC terminal 6 can obtain the development morphology of the cavitation bubble by storing and processing these images.

[0064] The control unit is used to record the development morphology of the cavitation bubble at the preset observation time point. By recording the development morphology of the cavitation bubble throughout its growth and collapse cycle, the control unit can generate a set of cavitation bubble morphological image sequences, thereby capturing the growth and collapse morphology of the cavitation bubble in the same cycle.

[0065] Specifically, several key observation time points are selected during the growth and collapse cycle of the cavitation bubble, which correspond to important stages in the morphological changes of the cavitation bubble, such as bubble formation, growth, deformation, and collapse. At each preset observation time point, the morphological image of the cavitation bubble is captured by the CCD camera 7. These images record the morphological characteristics of the cavitation bubble at different stages, including size, shape, position, and any other relevant features. Through the coordination of the control unit, the work of each component is ensured to continuously monitor the morphological changes of the cavitation bubble throughout the growth and collapse cycle. In this way, a series of cavitation bubble morphological image sequences covering the entire life cycle of the cavitation bubble can be obtained. By processing and analyzing the recorded cavitation bubble morphological images and comparing the morphological changes at different time points, the details and rules of the cavitation bubble growth and collapse process can be revealed. This helps to understand the behavior characteristics, development rules, and influencing factors of the cavitation bubble.

[0066] The continuous high-resolution instantaneous cavitation bubble morphology capturing device provided by the present application applies the advantages of high resolution and small exposure time of the CCD camera, and uses the hydrophone to observe the proximity of the cavitation bubble development time interval induced by the laser, to judge the proximity of the morphological changes of the cavitation bubble during the growth and collapse process of the cavitation bubble, to select the extremely similar morphological changes of the cavitation bubble at different time points with the same cavitation bubble development time interval, and to obtain an extremely continuous, high-resolution instantaneous cavitation bubble development sequence.

[0067] Based on the above embodiment, the control unit records the development morphology of the cavitation bubble at the preset observation time points by the following method:

[0068] According to the preset observation time points, the trigger time interval of the ignition laser 2 and the illumination laser 3 is adjusted; and,

[0069] The synchronization controller 1 is triggered to control the ignition laser 2 and the illumination laser 3 to work coordinately at the trigger time interval; and,

[0070] The CCD camera 7 is used to shoot the morphological image of the cavitation bubble at the trigger time, and the oscilloscope 5 is used to record the numerical value and time interval of the initial peak value and the collapse peak value of the cavitation bubble within one growth and collapse cycle; and,

[0071] According to the hydrophone signal, the cavitation bubble morphological images at different development time points are selected.

[0072] First, according to the preset observation time points, the control unit calculates and adjusts the trigger time interval of the ignition laser 2 and the illumination laser 3 to ensure that they are triggered at specific time points, thereby forming cavitation bubbles and enabling the CCD camera 7 to capture the morphology of the cavitation bubbles.

[0073] The control unit triggers the synchronization controller 1 to ensure that the ignition laser 2 and the illumination laser 3 work in coordination at the adjusted trigger time interval. In this way, the ignition laser 2 can generate a cavitation bubble at a preset time point, and the illumination laser 3 and the CCD camera 7 can take a picture within an appropriate time to capture the cavitation bubble image.

[0074] By triggering the synchronization controller 1, the CCD camera 7 takes a picture at the same time when the ignition laser 2 generates a cavitation bubble, recording the cavitation bubble image at the trigger time. These cavitation bubble images will be transmitted to the PC 6 for recording and analysis. At the same time, the hydrophone 9 records the sound signal generated by the cavitation bubble to obtain information about the cavitation bubble shape change. According to the signal provided by the hydrophone, the development time of the cavitation bubble can be inferred, and then the cavitation bubble image associated with the specific development time is selected. The oscilloscope 5 records the numerical value and time interval of the initial peak value and the collapse peak value of the cavitation bubble in a growth and collapse cycle. These numerical values and time intervals can provide important information about the growth and collapse process of the cavitation bubble, which helps to record the development of the cavitation bubble.

[0075] The continuous high-resolution instantaneous cavitation bubble shape capturing device provided by the application realizes the recording and capturing of the development of the cavitation bubble at the preset observation time point by accurately adjusting the trigger time interval, triggering the synchronization controller, taking the cavitation bubble image, and recording the peak time interval of the growth and collapse cycle.

[0076] Based on the above embodiment, the synchronization controller 1 is connected to the CCD camera 7 through a synchronization signal line to control the shutter switch of the CCD camera 7 through the synchronization signal line.

[0077] In this embodiment, the synchronization controller 1 is connected to the CCD camera 7 through a synchronization signal line to control the shutter switch of the CCD camera 7. When the ignition laser 2 and the illumination laser 3 start to form a cavitation bubble, the synchronization controller 1 sends a signal to the CCD camera 7 to instruct it to start the shutter at the appropriate time to capture the cavitation bubble image. In this way, the CCD camera 7 can take a picture at the correct time point to record the shape change of the cavitation bubble.

[0078] Based on the above embodiment, the ignition laser is a single-cavity pulse laser, and the laser cavity of the single-cavity pulse laser includes a first lamp trigger signal line and a first Q switch trigger signal line connected to the synchronization controller.

[0079] The first lamp trigger signal line is connected to a lamp trigger device in the laser cavity of the single-cavity pulsed laser. When the synchronization controller 1 sends a trigger signal, the lamp trigger device in the laser cavity receives the signal through the first lamp trigger signal line and discharges after receiving the signal, thereby causing the laser to generate pulsed laser.

[0080] The first Q-switch trigger signal line is connected to a Q-switch in the laser cavity. The Q-switch is a device for controlling the energy release in the laser cavity, which receives a trigger signal from the synchronization controller 1 and opens or closes after receiving the signal, thereby controlling the energy release in the laser cavity.

[0081] The continuous high-resolution transient cavitation morphology capturing device provided by the present application can accurately control the laser output of the single-cavity pulsed laser by sending trigger signals to the first lamp trigger signal line and the first Q-switch trigger signal line through the synchronization controller, thereby generating pulsed laser at a specific time point, forming a cavitation bubble, and allowing the CCD camera to capture the morphology image of the cavitation bubble.

[0082] Based on the above embodiment, the laser cavity of the illumination laser 3 includes a second lamp trigger signal line and a second Q-switch trigger signal line connected to the synchronization controller 1, and the signal line length of the illumination laser 3 is the same as that of the ignition laser 2.

[0083] Like the single-cavity pulsed laser above, the laser cavity of the illumination laser 3 also includes a second lamp trigger signal line and a second Q-switch trigger signal line connected to the synchronization controller 1. Specifically, the illumination laser can be a double-cavity pulsed laser of a standard PIV system, which has two independent laser cavities, each of which includes a second lamp trigger signal line and a second Q-switch trigger signal line connected to the synchronization controller 1.

[0084] In this embodiment, by making the signal line lengths of the ignition laser 2 and the illumination laser 3 the same, the trigger time difference caused by signal transmission delay can be avoided, thereby ensuring that they act at the same time point, form a cavitation bubble, and allow the CCD camera 7 to capture the morphology image of the cavitation bubble.

[0085] Based on the above embodiment, the lamp signal sent by the lamp trigger signal line of the synchronization controller 1 is used to send a preheating signal, the Q signal sent by the Q-switch trigger signal line of the synchronization controller 1 indicates that the preheating is complete and energy can be emitted, and the optimal trigger time interval of the lamp signal and the Q signal is 193 μs.

[0086] It should be noted that the illumination laser 3 and the ignition laser 2 in the embodiment need to be preheated to emit a large amount of stable energy at a moment. Therefore, before the laser works, preheating is performed by sending a lamp trigger signal to make the laser medium reach an appropriate working state. Once the preheating is completed, the synchronization controller 1 sends a Q signal to inform that the Q switch can be opened and the energy in the laser cavity can be released.

[0087] The optimal trigger time interval of the lamp signal and the Q signal is 193 μs. That is, the Q switch is triggered within a specific time window after the preheating is completed. The selection of the time window can be adjusted based on experimental requirements, laser characteristics, system optimization and other factors. By accurately controlling the trigger time interval, the laser energy can be released at an appropriate time point after the preheating is completed, so that the desired experimental effect can be achieved.

[0088] Based on the above embodiment, the center of the needle of the hydrophone is directly opposite the center of the cavity in the water tank, and the distance between the hydrophone and the center of the cavity in the water tank is 4.9 mm to 5.1 mm.

[0089] It should be noted that the hydrophone 9 is used for high-energy ultrasonic measurement and underwater shock wave. The hydrophone 9 has a hemispherical head, a small sensitive diameter (less than 0.5 mm) and an extremely short rise time (about 50 ns). Generally, the selected model of the hydrophone 9 is 100-100-1 (Müller-Platte Needle Probe), the measurable pressure range is -100 ~ 1500 bar, the rise time interval of the typical signal is at least 50 ns, the sensitivity diameter is much smaller than 0.5 mm, the sensitivity is 1 mV / bar, the maximum temperature adapted is 60℃, the bandwidth is 0.3-11 MHz ± 3.0 dB, the material is stainless steel, and the tip diameter is 1.2 mm.

[0090] Since the hydrophone 9 is a precision instrument, if the force received is too large, the probe will be damaged. Therefore, in the embodiment, as shown in FIG. 9, the center of the needle of the hydrophone 9 is directly opposite the center of the cavity in the water tank 10, and the distance between the hydrophone 9 and the center of the cavity in the water tank 10 is 4.9 mm to 5.1 mm. Preferably, the optimal placement position of the hydrophone 9 is about 5 mm away from the center of the cavity. Figure 2

[0091] Based on the above embodiment, when the trigger time interval of the ignition laser 2 and the illumination laser 3 is 0, the cavity shape image captured by the CCD camera 7 is a cavity nascent shape image. By adjusting the trigger time interval of the ignition laser 2 and the illumination laser 3, cavity shape images at different time points can be obtained.

[0092] ​When two lasers are triggered simultaneously, the resulting cavitation bubbles form at the same time point, thus the captured images show the nascent stage of the cavitation bubbles. However, by changing the time interval between the two lasers on the synchronization controller 1, the development morphology of the cavitation bubbles at different time points can be obtained. By adjusting the time interval between the ignition laser 2 and the illumination laser 3, the development process of the cavitation bubbles can be controlled, allowing observation of their morphology and characteristics at different stages.

[0093] When the trigger button on the synchronization controller 1 is pressed, the ignition laser 2 stores energy and emits energy to the water tank 10, the illumination laser 3 stores energy and emits energy to the CCD camera 7 to provide an exposure light source, the PC terminal 6 obtains the image captured by the CCD camera 7 and saves it automatically, the hydrophone 9 captures the energy emitted by cavitation bubbles during their growth and collapse, and the oscilloscope 5 is used to display the voltage signal waveform captured by the hydrophone (reference). Figure 3 As shown in the figure, these waveforms reflect the energy signals released during the growth and collapse of cavitation bubbles. By analyzing these signals, we can understand the formation, evolution, and disappearance of cavitation bubbles.

[0094] like Figure 3 As shown, the energy signals released by a cavitation bubble at its initial formation and collapse have distinct peaks. The peak on the left represents the peak of the initial formation signal, and the peak on the right represents the peak of the collapse signal. Therefore, the time interval of one development cycle of the cavitation bubble is displayed on oscilloscope 5, allowing observation and measurement of the complete process of the cavitation bubble from its initial formation to collapse and then to the formation of the next cycle. The waveforms displayed on oscilloscope 5 clearly show the changes in the energy signals released by the cavitation bubble at different stages, including the energy wave at initial formation, the energy wave at collapse, and the periodic energy signals. By measuring the time intervals between these waveforms, the duration of one complete development cycle of the cavitation bubble can be determined.

[0095] Based on the above embodiments, the peak signals of the hydrophone 9 at the initial and collapse times of the cavitation bubble are used to filter out cavitation morphology images at different development times that can form the same cavitation bubble evolution sequence.

[0096] In this embodiment, the sound signals generated by cavitation bubbles at their initial formation and collapse are recorded using a hydrophone 9, and the peak signals at these two moments are determined. Based on the peak signals at these two moments, cavitation morphology images at different moments that can form the same cavitation evolution sequence are selected.

[0097] In one example, at different triggering time intervals of the ignition laser 2 and the illumination laser 3, the errors in the magnitude and time interval of the initial peak and collapse peak of the cavitation bubble detected by the hydrophone 9 are all less than 1%, which indicates that they are different developmental stages of the same cavitation bubble.

[0098] Specifically, the step of monitoring the cavitation bubble by the hydrophone is repeatedly performed at different trigger time intervals until the error of the numerical value and time interval of the initial peak value and the collapse peak value of the cavitation bubble monitored by the hydrophone is less than 1%, and the corresponding cavitation bubble morphology image is screened out.

[0099] In the embodiment, in each experiment, different trigger time intervals are set by slight adjustment. After setting different trigger time intervals, repeated experiments are performed, and the hydrophone signal and the corresponding cavitation bubble morphology image are recorded until the hydrophone signal in which the error of the numerical value and time interval of the initial peak value and the collapse peak value of the cavitation bubble is less than 1% is screened out even at different trigger time intervals.

[0100] In this case, it can be considered that the development morphology of different development moments of the same cavitation bubble. Then, the cavitation bubble morphology images under the group of experiments are screened out. The cavitation bubble morphology images screened out at different development moments are arranged in time sequence, and a continuous and high-resolution cavitation bubble morphology image sequence of the growth and collapse process of the same cavitation bubble is formed.

[0101] In the embodiment, generally, the cavitation bubbles in several groups of experiments with the same cavitation bubble growth and collapse time interval have the same cavitation bubble morphology at each moment, and the capture of the cavitation bubble development morphology at different moments will be a large number of repeated experiments. Therefore, the experimental group with the same cavitation bubble development time interval at each moment can be selected to form a continuous and high-resolution instantaneous image sequence of the extremely short process of the growth and collapse of the same cavitation bubble.

[0102] Based on the above embodiment, the embodiment of the present application also provides a continuous high-resolution instantaneous cavitation bubble morphology capture method in the above embodiment, Figure 4 The flowchart of the continuous high-resolution instantaneous cavitation bubble morphology capture method provided by the embodiment of the present application comprises the following steps:

[0103] Step 401, connecting the ignition laser, the illumination laser, and the CCD camera to the synchronous controller to control the ignition laser, the illumination laser, and the CCD camera to work coordinately through the synchronous controller;

[0104] Step 402, placing the hydrophone in the water tank and connecting it to the oscilloscope to monitor the sound signal of the cavitation bubble in the water tank through the oscilloscope to perform repeated screening of the cavitation bubble development;

[0105] Step 403, connecting the CCD camera to the PC end to record the cavitation bubble morphology image photographed by the CCD camera through the PC end;

[0106] At step 404, the development morphology of the cavitation bubble at the preset observation time point is recorded to obtain a group of cavitation bubble morphology image sequences by recording the development morphology of the cavitation bubble in the entire growth and collapse cycle, wherein the development morphologies of the cavitation bubble at different preset observation time points are different.

[0107] In this embodiment, the work of the ignition laser, the illumination laser and the CCD camera is coordinated by the synchronization controller, so that they can operate coordinately at a specific time point, thereby capturing the morphology change of the same cavitation bubble. The hydrophone is connected with the oscilloscope and can be used for monitoring the sound signal of the cavitation bubble in the water tank, thereby providing another way for researchers to observe the growth and collapse process of the cavitation bubble.

[0108] The CCD camera is connected with the PC terminal, so that the real-time recording and saving of the cavitation bubble morphology image can be realized, thereby providing convenience for subsequent data analysis and processing. By recording the development morphology of the cavitation bubble at different preset observation time points, a group of cavitation bubble morphology image sequences can be obtained, thereby obtaining the development morphology change of the cavitation bubble in the entire growth and collapse cycle.

[0109] Specifically, the development morphology of the cavitation bubble at the preset observation time point is recorded in the following manner:

[0110] According to the preset observation time point, the trigger time interval of the ignition laser and the illumination laser is adjusted; and

[0111] The synchronization controller is triggered to control the ignition laser and the illumination laser to work coordinately at the trigger time interval; and

[0112] The cavitation bubble morphology image at the trigger time is captured by the CCD camera, and the size and time interval of the initial peak value and the collapse peak value of the cavitation bubble in one growth and collapse cycle are recorded by the oscilloscope; and

[0113] According to the error standard of the hydrophone signal, the cavitation bubble morphology images at different development times are screened out.

[0114] Firstly, according to the preset observation time point, the control unit calculates and adjusts the trigger time interval of the ignition laser and the illumination laser, so as to ensure that they are triggered at a specific time point, thereby forming the cavitation bubble and enabling the CCD camera to capture the morphology of the cavitation bubble.

[0115] The control unit triggers the synchronization controller to ensure that the ignition laser and the illumination laser work coordinately at the adjusted trigger time interval. In this way, the ignition laser can generate the cavitation bubble at the preset time point, and the illumination laser and the CCD camera can capture the cavitation bubble morphology image at the appropriate time.

[0116] By triggering the synchronization controller, the CCD camera captures images simultaneously with the cavitation bubble generated by the ignition laser, recording the cavitation bubble morphology at the trigger moment. These images are then transmitted to a PC for recording and analysis. Simultaneously, a hydrophone records the sound signals generated by the cavitation bubble to obtain information about its morphological changes. Based on the signals provided by the hydrophone, the development time of the cavitation bubble can be inferred, allowing for the selection of cavitation morphology images associated with specific development times. An oscilloscope records the magnitude and time interval of the initial and collapse peak values ​​within a growth-collapse cycle of the cavitation bubble. These magnitudes and time intervals provide crucial information about the cavitation bubble growth and collapse process, contributing to a complete record of the cavitation bubble's development morphology.

[0117] The continuous high-resolution instantaneous cavitation morphology capture method provided by this invention utilizes the advantages of high resolution and short exposure time of CCD cameras, and uses hydrophones to observe the similarity of the time intervals of cavitation development induced by lasers, judges the similarity of cavitation morphology changes during the growth and collapse of cavitation, selects cavitation morphology changes at different times with the same cavitation development time interval, and obtains an extremely continuous, high-resolution instantaneous cavitation development sequence.

[0118] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include: a processor 510, a communications interface 520, a memory 530, and a communications bus 540, wherein the processor 510, the communications interface 520, and the memory 530 communicate with each other through the communications bus 540. The processor 510 can call logic instructions in the memory 530 to execute a continuous high-resolution transient cavitation morphology capture method. This method includes: connecting an ignition laser, an illumination laser, a CCD camera, and a synchronization controller to coordinate the operation of the ignition laser, the illumination laser, and the CCD camera; placing a hydrophone in a water tank and connecting it to an oscilloscope to monitor the sound signals of cavitation bubbles in the water tank and screen for cavitation development repeatability; connecting the CCD camera to a PC to record cavitation morphology images captured by the CCD camera; and recording the development morphology of cavitation bubbles at preset observation time points to obtain a sequence of cavitation morphology images based on the recorded changes in cavitation morphology throughout the growth and collapse cycle, wherein the development morphology of cavitation bubbles differs at different preset observation time points.

[0119] In addition, the logic instructions in the memory 530 described above can be implemented in the form of software functional units and sold or used as independent products, and can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for making a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0120] In another aspect, the present application also provides a computer program product, which comprises a computer program, the computer program can be stored on a non-transitory computer readable storage medium, and the computer program can be executed by a processor to enable a computer to perform the continuous high-resolution instantaneous bubble morphology capturing method provided by the above-mentioned methods. The method comprises: connecting a firing laser, an illumination laser, and a CCD camera with a synchronous controller to control the firing laser, the illumination laser, and the CCD camera to work in coordination through the synchronous controller; placing a hydrophone in a water tank and connecting it with an oscilloscope to monitor the sound signal of the bubble in the water tank through the oscilloscope to screen the repeatability of the bubble development; connecting the CCD camera with a PC end to record the bubble morphology image photographed by the CCD camera through the PC end; recording the development morphology of the bubble at a preset observation time point to obtain a group of bubble morphology image sequences by recording the development morphology change of the bubble in the entire growth and collapse cycle, wherein the development morphology of the bubble at different preset observation time points is different.

[0121] In yet another aspect, the application also provides a non-transitory computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements a continuous high-resolution instantaneous bubble morphology capturing method provided by each of the above methods, the method comprising: connecting a firing laser, an illumination laser, a CCD camera and a synchronous controller, so as to control the firing laser, the illumination laser and the CCD camera to work in coordination through the synchronous controller; placing a hydrophone in a water tank and connecting the hydrophone with an oscilloscope, so as to monitor a sound signal of a bubble in the water tank through the oscilloscope to screen the bubble development for repeatability; connecting the CCD camera with a PC end, so as to record bubble morphology images photographed by the CCD camera through the PC end; recording a development morphology of the bubble at a preset observation time point, so as to obtain a group of bubble morphology image sequences through the recorded development morphology changes of the bubble in an entire growth and collapse cycle, wherein the development morphologies of the bubble at different preset observation time points are different.

[0122] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e., can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0123] From the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and a necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0124] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A continuous, high-resolution, transient cavitation morphology capture device, characterized in that, include: The system includes an ignition laser, an illumination laser, a CCD camera, a synchronization controller, a hydrophone, a water tank, an oscilloscope, a PC, and a control unit. The ignition laser, the illumination laser, and the CCD camera are connected to the synchronization controller. The hydrophone is placed in the water tank and connected to the oscilloscope. The CCD camera is connected to the PC. Wherein: The ignition laser is used to generate pulse energy in water that exceeds the liquid breakdown threshold, thereby breaking down the liquid to form plasma and growing cavitation bubbles. The illumination laser is used as a light source for the CCD camera, enabling the CCD camera to capture images of cavitation morphology at nanosecond-level exposure times. The synchronization controller is used to control the ignition laser, the illumination laser and the CCD camera to work in coordination. The hydrophone is used to calibrate the repeatability of cavitation growth and collapse so that a selected set of cavitation morphology image sequences can characterize the occurrence process of the same cavitation. The oscilloscope is used to display the sound signal of cavitation captured by the hydrophone in the water tank in the form of voltage. The PC is used to record images of cavitation morphology captured by the CCD camera. The control unit is used to record the development morphology of cavitation bubbles at preset observation time points, so as to obtain a set of cavitation bubble morphology image sequences by recording the development morphology changes of cavitation bubbles throughout the entire growth and collapse cycle, wherein the development morphology of cavitation bubbles is different at different preset observation time points.

2. The continuous high-resolution transient cavitation morphology capture device according to claim 1, characterized in that, The control unit records the development morphology of cavitation bubbles at preset observation time points in the following manner: Adjust the trigger time interval between the ignition laser and the illumination laser according to the preset observation time point; and, The synchronization controller is triggered to control the ignition laser and the illumination laser to operate in coordination during the triggering time interval; and, The image of the cavitation morphology at the trigger moment is captured by the CCD camera, and the magnitudes and time intervals of the initial peak and collapse peak values ​​of the cavitation bubble within one growth-collapse cycle are recorded by the oscilloscope; and, Images of cavitation morphology at different development stages were selected based on hydrophone signals.

3. The continuous high-resolution transient cavitation morphology capture device according to claim 1, characterized in that, The synchronization controller is connected to the CCD camera via a synchronization signal line to control the shutter switch of the CCD camera via the synchronization signal line; The laser cavity of the ignition laser includes a first lamp trigger signal line and a first Q switch trigger signal line connected to the synchronization controller. The laser cavity of the illumination laser includes a second lamp trigger signal line and a second Q switch trigger signal line connected to the synchronization controller, and the signal line length of the illumination laser is the same as the signal line length of the ignition laser.

4. The continuous high-resolution transient cavitation morphology capture device according to claim 3, characterized in that, The lamp signal sent by the lamp trigger signal line of the synchronization controller is used to send a preheating signal. The Q signal sent by the Q switch trigger signal line of the synchronization controller indicates that the preheating is complete and energy can be emitted. The optimal trigger time interval between the lamp signal and the Q signal is 193μs.

5. The continuous high-resolution transient cavitation morphology capture device according to claim 1, characterized in that, The tip of the hydrophone is aligned with the center of the cavitation bubble in the water tank, and the distance between the hydrophone and the center of the cavitation bubble in the water tank is 4.9mm to 5.1mm.

6. The continuous high-resolution transient cavitation morphology capture device according to claim 1, characterized in that, When the trigger time interval between the ignition laser and the illumination laser is 0, the cavitation morphology image captured by the CCD camera is the cavitation initial morphology image. By adjusting the trigger time interval between the ignition laser and the illumination laser, cavitation morphology images at different time points can be obtained.

7. The continuous high-resolution transient cavitation morphology capture device according to claim 1, characterized in that, By using the peak signals from the hydrophone at the inception and collapse of cavitation bubbles, cavitation morphology images at different development stages that can form the same cavitation evolution sequence are selected.

8. The continuous high-resolution transient cavitation morphology capturing device according to claim 7, characterized in that, At different triggering time intervals of the ignition laser and the illumination laser, the errors in the magnitude and time interval of the initial peak value and collapse peak value of the cavitation bubble detected by the hydrophone are all less than 1%, which indicates that they are different developmental forms of the same cavitation bubble at different developmental moments.

9. The continuous high-resolution transient cavitation morphology capture device according to claim 8, characterized in that, The step of monitoring cavitation using the hydrophone is repeated at different trigger time intervals until the error in the magnitude and time interval of the initial peak and collapse peak of the cavitation detected by the hydrophone is less than 1%, and the corresponding cavitation morphology image is selected.

10. A method for capturing continuous high-resolution transient cavitation morphology based on the continuous high-resolution transient cavitation morphology capturing device according to claim 1, characterized in that, include: The ignition laser, illumination laser, and CCD camera are connected to a synchronization controller so that the synchronization controller can control the ignition laser, illumination laser, and CCD camera to work in coordination. A hydrophone is placed in a water tank and connected to an oscilloscope to monitor the sound signal of cavitation bubbles in the water tank and screen for the repeatability of cavitation development. Connect the CCD camera to the PC to record the cavitation morphology images captured by the CCD camera through the PC. The development morphology of cavitation bubbles is recorded at preset observation time points to obtain a set of cavitation bubble morphology image sequences through the recorded changes in the development morphology of cavitation bubbles throughout the entire growth and collapse cycle. The development morphology of cavitation bubbles is different at different preset observation time points.

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