Method for capturing cavitation evolution characteristics of pump turbine

Abstract

The invention belongs to the technical field of hydraulic model research and development tests, and particularly relates to a method for capturing cavitation evolution characteristics of a pump turbine, which comprises the following steps of: arranging an image acquisition system in a working space of the pump turbine, and connecting the image acquisition system with a central control system of a workstation in a communication way; the workstation central control system generates a stroboscopic control signal and a shooting control signal based on working parameters of the pump turbine, and sends the stroboscopic control signal and the shooting control signal to a stroboscope, a high-speed camera I and a miniature high-speed camera of the image acquisition system respectively; the high-speed camera I and the miniature high-speed camera capture cavitation image data of the back and the front of the pump turbine runner based on the shooting control signal; and the image processing equipment processes and analyzes the cavitation image data to obtain cavitation evolution characteristic information of the pump turbine. According to the technical scheme, the miniature high-speed camera is additionally arranged to cooperate with the height camera to capture the cavitation image of the pump turbine, and the problem that blade front cavitation observation is difficult is effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic model development and testing, and in particular relates to a method for capturing the cavitation evolution characteristics of a water pump turbine. Background Art

[0002] With the large-scale development of pumped storage power stations, a large number of pumped storage power stations with ultra-large head / lift amplitude have been born. Usually, the operating flow amplitude of these power stations is also large, which puts forward strict requirements on the cavitation performance of pump turbines. At present, the industry's evaluation standard for the initial cavitation of pump turbines is that the initial cavitation of two or more blades is considered to be primary cavitation.

[0003] There are three types of conventional methods for judging incipient cavitation: The first type is also the most commonly used cavitation observation method. The incipient cavitation is judged by subjective observation of test personnel. This method requires extremely high professionalism of test personnel and there are subjective differences, making it difficult to achieve standard unification; in addition, after the test personnel determine the characteristic operating point of incipient cavitation, it is necessary to capture photos of two or more blade incipient cavitations as a basis. Since the incipient cavitation is fleeting and does not necessarily occur on adjacent blades, it is extremely difficult to capture the true characteristic operating point of incipient cavitation. The second type is the image recognition method. The biggest problem with this type of method is that it is suitable for obtaining cavitation images on the back of the blade, that is, the high-lift and low-flow operation area; while for the low-lift and high-flow operation area, the cavitation position is generated on the front of the blade. Due to the overlapping perspectives between adjacent blades of the pump turbine, this method is not easy to obtain the cavitation characteristics on the front of the blade. At the same time, this method uses a high-definition photography system to judge cavitation by taking multiple sets of impeller flow characteristic pictures at the same photography frequency as the impeller rotation frequency. Since the shooting frequency is the same as the impeller rotation frequency, the impeller area / local blade position photographed is the same, and the problem of failing to capture the images of primary cavitation bubbles on two or more blades may occur. The third type uses a hydrophone to obtain the special sound frequency of the impeller cavitation condition, and judges cavitation after analysis. The hydrophone used in this method is generally inserted into the flow field through a hole punched in the tailwater cone observation window. The sensor and auxiliary equipment will destroy the original flow state and cause unpredictable effects on the cavitation characteristics. If a conventional sound field sensor is used and does not extend into the flow field, it will be affected by the test environment, and the sound field of the fan and dynamometer motor will even cover the sound field of the cavitation itself.

[0004] Therefore, in order to solve the above problems and realize accurate and objective evaluation of the initial cavitation characteristics of pump-turbines, there is an urgent need for a precise capture method that can be applied to different runner shapes, all operating conditions, and the cavitation information on the front and back sides of blades. Summary of the invention

[0005] In order to overcome the defects and shortcomings of the above-mentioned prior art solutions, the present application provides a method for capturing the cavitation evolution characteristics of a pump-turbine. The present invention aims to solve the problems of difficulty in capturing the initial cavitation characteristics of a pump-turbine, difficulty in observing cavitation on the front of the blades, and the acoustic field observation method being easily disturbed by the flow field or susceptible to environmental interference.

[0006] This application achieves the above purpose through the following technical solutions:

[0007] A method for capturing the cavitation evolution characteristics of a pump-turbine comprises the following steps:

[0008] S1, arranging a stroboscope, a high-speed camera I and a micro high-speed camera in the working space of the pump-turbine, and connecting the stroboscope, the high-speed camera I and the micro high-speed camera to the central control system of the workstation of the pump-turbine respectively;

[0009] S2, the workstation central control system obtains the working parameters of the water pump turbine, and generates a strobe control signal and a shooting control signal based on the working parameters of the water pump turbine;

[0010] S3, the central control system of the workstation sends a stroboscopic control signal to the stroboscope, and sends a shooting control signal to the high-speed camera I and the micro high-speed camera respectively;

[0011] S4, in cooperation with the stroboscope, the high-speed camera I captures cavitation image data on the back of the pump-turbine runner based on the shooting control signal, and the micro high-speed camera captures cavitation image data on the front of the pump-turbine runner based on the shooting control signal;

[0012] S5, uploading the cavitation image data of the front and back sides of the pump-turbine runner to the workstation central control system, and using image processing equipment to process and analyze the cavitation image data to obtain the cavitation evolution characteristic information of the pump-turbine.

[0013] Preferably, in step S1, the miniature high-speed camera is installed on the top cover of the pump turbine runner, that is, an observation hole is opened through the top cover directly above the runner flow channel, and the miniature high-speed camera is installed in the observation hole through a fixing device, so that the bottom of the miniature high-speed camera and the fixing device as a whole is flush with the bottom of the top cover.

[0014] Preferably, the fixing device includes a main body component, a camera mounting part and a transparent cover; the main body component is hollow and through-set, and includes a coaxially integrally formed locking part and a connecting part; a first threaded structure and a second threaded structure are provided on the outer wall of the connecting part, and a is provided on the inner wall of the connecting part; the transparent cover is threadedly fastened to the main body component through the second threaded structure; the first threaded structure cooperates with the observation hole, so that the main body component is threadedly fastened to the top cover; the camera mounting part axially penetrates the main body component and is connected to the inner wall of the main body component; the miniature high-speed camera is located inside the transparent cover and fixedly connected to the end of the camera mounting part.

[0015] Preferably, the bottom of the transparent cover is a planar structure.

[0016] Preferably, the camera mounting part includes an adjusting rod and a rotating connecting piece, the end of the adjusting rod is provided with an inclined surface for mounting a miniature high-speed camera; the rotating connecting piece is sleeved on the outside of the adjusting rod and fixedly connected to the adjusting rod; a locking structure is provided on the inner wall of the connecting part, and the rotating connecting piece cooperates with the locking structure so that the camera mounting part and the main body component can be rotatably adjusted and connected.

[0017] Preferably, in the step S1, the process of deploying the micro high-speed camera also includes adjusting the shooting angle of the micro high-speed camera, that is: after fixing the main body component on the top cover, the shooting angle of the micro high-speed camera meets the requirements by rotating the adjustment rod, and finally fixing the adjustment rod.

[0018] Preferably, in step S1, before installing the main body component on the top cover, a gasket needs to be sleeved on the main body component according to the thickness of the top cover, so that after the main body component is fixed on the top cover, the bottom of the transparent cover is flush with the bottom of the top cover.

[0019] Preferably, in step S2, the stroboscopic control signal is expressed as T=1 / (N+ΔN)=T1+T2; wherein: T represents a single stroboscopic cycle of the stroboscope; N represents the rotational speed of the pump turbine impeller; ΔN represents visual compensation; T1 represents the high pulse triggering cycle of the stroboscope, and T2 represents the low pulse triggering cycle of the stroboscope.

[0020] Preferably, when 750r / min<N≤1000r / min, ΔN takes a value of 1r / min; when 1000r / min<N≤1200r / min, ΔN takes a value of 1.5r / min; when 1200r / min<N, ΔN takes a value of 2r / min.

[0021] Preferably, in step S2, the shooting control signal is expressed as T1=n×T n , T n =T n1 +T n2Where: n represents the number of photographs within the time period T1, and the n value is adjusted to ensure that the cavitation image data of each runner blade is captured; T n Represents the photography period; T n1 Indicates the capture time of a single image; T n2 Indicates the silent time of the photography cycle; by adjusting T n1 Value and T n2 value to adjust the imaging effect.

[0022] Beneficial effects of the present invention:

[0023] The present invention proposes a method for capturing the cavitation evolution characteristics of a pump-turbine, which effectively solves the problem of difficult observation of cavitation on the front side of the blade by adding a miniature high-speed camera to cooperate with a high-speed camera to capture the cavitation image of the pump-turbine.

[0024] This technical solution generates a stroboscopic control signal and a shooting control signal based on the working parameters of the pump-turbine runner, adds visual compensation to the stroboscopic control signal, and specifically plans the photography cycle in the shooting control signal, which has an extremely superior cavitation image capture effect. Specifically, this technical solution controls the photography interval and the stroboscopic interval through the pump-turbine runner rotation frequency signal to ensure that the cavitation information images of all runner blades with high quality can be captured. The video signal generated in this way can realize the observation and analysis of the cavitation evolution characteristics, solving the problem that conventional observation methods are difficult to capture the initial cavitation information of two or more blades.

[0025] During the implementation of this technical solution, a special fixing device is used to install a micro high-speed camera, which can adjust the camera angle by 360°. After the main body is fixed on the top cover, the shooting angle of the micro high-speed camera is made to meet the requirements by rotating the adjustment rod, and finally the adjustment rod is fixed. By adjusting the angle of the micro high-speed camera, the full-space area information of the pump turbine runner blades can be captured. In addition, the bottom of the transparent cover of the fixing device is a flat structure, which is flush with the bottom of the top cover after installation, and will not interfere with the flow field of the pump turbine runner. It can be applicable to pump turbine runners of different forms. After the fixing device is installed, it can be applied to different runner tests, and there is no need to disassemble and assemble when replacing the runner. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the basic implementation flow chart of this technical solution;

[0027] Figure 2 This is a schematic diagram of the layout structure of the image acquisition system of this technical solution;

[0028] Figure 3 This is a schematic diagram of the cross-sectional structure of the fixing device of the present technical solution;

[0029] Figure 4 It is a schematic diagram of the relationship between the strobe control signal and the shooting control signal.

[0030] In the figure:

[0031] 1. Strobe; 2. High-speed camera I; 3. Mini high-speed camera; 4. Pump turbine runner; 4.1. Top cover; 4.2. Runner blades; 5. Fixing device; 5.1. Clamping part; 5.2. Connecting part; 5.3. First thread structure; 5.4. Second thread structure; 5.5. Adjusting rod; 5.6. Rotating connector; 5.7. Clamping structure; 5.8. Transparent cover; 6. Tailwater cone observation window. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0033] Therefore, the following detailed description of the invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment discloses a method for capturing the cavitation evolution characteristics of a pump-turbine, which, as a preferred implementation of the present invention, comprises the following steps:

[0036] S1, design an image acquisition system that can capture both the back cavitation and the front cavitation of the blade. Specifically, the image acquisition system includes a stroboscope 1, a high-speed camera I2 and a micro high-speed camera 3, which are respectively connected to the central control system of the workstation of the pump-turbine, and the stroboscope 1, the high-speed camera I2 and the micro high-speed camera 3 are arranged in the working space of the pump-turbine through corresponding mounting brackets.

[0037] Among them, since the pump turbine runner 4 is in a completely closed space, the high-speed camera Ⅰ2 can only use the transparent tailwater cone observation window 6 to shoot the runner blade 4.2 information at an oblique upward angle. Despite this, there is still a problem that the high-speed camera Ⅰ2 can only capture the cavitation information on the back of the runner due to the partial mechanical structure blocking and the overlap of the runner blade 4.2 viewing angle. Based on this, since the micro high-speed camera 3 has an extremely small structure size and can be inserted into the device to observe the cavitation of the runner blade 4.2, the cavitation characteristics of the front of the runner blade 4.2 are captured with the help of the micro high-speed camera 3.

[0038] Considering the installation problem of the micro high-speed camera 3, that is, the structure of the micro high-speed camera 3 is not compatible with the pump-turbine runner 4 and its flow channel structure, it is necessary to extend the micro high-speed camera 3 from the top cover 4.1 to capture the cavitation information of the front face of the runner with the help of a special fixing device 5. Specifically: the micro high-speed camera 3 is installed on the top cover 4.1 of the pump-turbine runner 4, that is, an observation hole is opened on the top cover 4.1 directly above the runner flow channel, and the micro high-speed camera 3 is installed in the observation hole through the fixing device 5, so that the bottom of the micro high-speed camera 3 and the fixing device 5 as a whole is flush with the bottom of the top cover 4.1.

[0039] S2, the workstation central control system obtains the working parameters of the water pump turbine, and generates a strobe control signal and a shooting control signal based on the working parameters of the water pump turbine.

[0040] S3, the workstation central control system sends a stroboscopic control signal to the stroboscope 1, and sends a shooting control signal to the high-speed camera Ⅰ2 and the micro high-speed camera 3 respectively;

[0041] S4, in cooperation with the stroboscope 1, the high-speed camera I2 captures the cavitation image data on the back of the pump-turbine runner 4 based on the shooting control signal, and the micro high-speed camera 3 captures the cavitation image data on the front of the pump-turbine runner 4 based on the shooting control signal;

[0042] S5, uploading the cavitation image data of the front and back sides of the pump-turbine runner 4 to the workstation central control system, and using image processing equipment to process and analyze the cavitation image data to obtain the cavitation evolution characteristic information of the pump-turbine.

[0043] Example 2

[0044] This embodiment discloses a method for capturing the cavitation evolution characteristics of a water pump turbine, as a basic implementation method of the present invention, that is, based on Example 1, in step S1, the fixing device 5 includes a main body component, a camera mounting portion and a transparent cover 5.8; the main body component is hollow and through-set, including a coaxial integrally formed clamping portion 5.1 and a connecting portion 5.2; the outer wall of the connecting portion 5.2 is provided with a first threaded structure 5.3 and a second threaded structure 5.4, and the inner wall of the connecting portion 5.2 is provided with; the transparent cover 5.8 is threadedly fastened to the main body component through the second threaded structure 5.4; the first threaded structure 5.3 cooperates with the observation hole, so that the main body component is threadedly fastened to the top cover 4.1, and the camera mounting portion axially penetrates the main body component and is connected to the inner wall of the main body component; the micro high-speed camera 3 is inside the transparent cover 5.8 and is fixedly connected to the end of the camera mounting portion. Among them, the transparent cover 5.8 has the function of protecting the micro high-speed camera 3. Furthermore, the bottom of the transparent cover 5.8 is a planar structure. After the fixing device 5 is installed, the clamping portion 5.1 of the main body is in close contact with the upper plane of the top cover 4.1 to achieve pre-tightening. The bottom of the transparent cover 5.8 is flush with the bottom of the top cover 4.1, so as to achieve the effect of not interfering with the flow field of the pump turbine runner 4. In order to adapt to the top cover 4.1 of different thicknesses, a gasket of corresponding thickness can be set on the connecting portion 5.2 during the installation process, so that after the main body is pre-tightened on the top cover 4.1, the gasket is between the top cover 4.1 and the clamping portion 5.1, and the bottom of the transparent cover 5.8 is just flush with the bottom of the top cover 4.1.

[0045] Example 3

[0046] This embodiment discloses a method for capturing the cavitation evolution characteristics of a pump-turbine, which, as a basic implementation of the present invention, comprises the following steps:

[0047] S1, a stroboscope 1, a high-speed camera I2 and a micro high-speed camera 3 are arranged in the working space of the pump-turbine, and the stroboscope 1, the high-speed camera I2 and the micro high-speed camera 3 are respectively connected to the central control system of the workstation of the pump-turbine for communication.

[0048] The high-speed camera Ⅰ2 uses the transparent tailwater cone observation window 6 to shoot the information of the runner blade 4.2 at an oblique upward angle. An observation hole is provided on the top cover 4.1 directly above the runner flow channel, and the micro high-speed camera 3 is installed in the observation hole through the fixing device 5, so that the bottom of the micro high-speed camera 3 and the fixing device 5 as a whole is flush with the bottom of the top cover 4.1.

[0049] More specifically, the fixing device 5 includes a main body part, a camera mounting part and a transparent cover 5.8; the main body part is hollow and through-set, and includes a coaxially integrally formed locking part 5.1 and a connecting part 5.2; a first threaded structure 5.3 and a second threaded structure 5.4 are provided on the outer wall of the connecting part 5.2, and a transparent cover 5.8 is provided on the inner wall of the connecting part 5.2; the first threaded structure 5.3 cooperates with the observation hole, so that the main body part is threadedly fastened to the top cover 4.1; the camera mounting part axially penetrates the main body part and is connected to the inner wall of the main body part; the miniature high-speed camera 3 is inside the transparent cover 5.8 and is fixedly connected to the end of the camera mounting part.

[0050] Furthermore, the camera mounting part includes an adjusting rod 5.5 and a rotating connector 5.6, the end of the adjusting rod 5.5 is provided with an inclined surface for mounting the micro high-speed camera 3; the rotating connector 5.6 is sleeved on the outside of the adjusting rod 5.5 and fixedly connected to the adjusting rod 5.5; a latching structure 5.7 is provided on the inner wall of the connecting part 5.2, and the rotating connector 5.6 cooperates with the latching structure 5.7 so that the camera mounting part and the main body can be rotatably adjusted. In this technical solution, the micro high-speed camera 3 can be rotated within a range of 360° by the adjusting rod 5.5, and the process of arranging the micro high-speed camera 3 also includes adjusting the shooting angle of the micro high-speed camera 3, that is: after the main body is fixed on the top cover 4.1, the shooting angle of the micro high-speed camera 3 is made to meet the requirements by rotating the adjusting rod 5.5, and finally the adjusting rod 5.5 can be fixed, and the full space area information of the blades of the runner 4 of the water pump turbine can be captured by adjusting the angle of the micro high-speed camera 3.

[0051] Furthermore, before installing the main body component on the top cover 4.1, a gasket needs to be mounted on the main body component according to the thickness of the top cover 4.1, so that after the main body component is fixed on the top cover 4.1, the bottom of the transparent cover 5.8 is flush with the bottom of the top cover 4.1.

[0052] S2, the workstation central control system obtains the working parameters of the water pump turbine, and generates a strobe control signal and a shooting control signal based on the working parameters of the water pump turbine.

[0053] In actual use, the stroboscopic frequency of the stroboscope 1 cannot be the same as the rotation frequency of the pump-turbine runner 4, but should be slightly greater than or less than the rotation frequency of the pump-turbine runner 4. The purpose is to ensure that the pump-turbine runner 4 has a visual rotation effect relative to the stroboscope 1, and avoid the problem that the position area of ​​the runner blade 4.2 photographed by the high-speed camera Ⅰ2 is not comprehensive. Therefore, the stroboscopic control signal can be expressed as T = 1 / (N + ΔN). Where: T represents a single stroboscopic cycle of the stroboscope 1; N represents the rotation speed of the pump-turbine runner 4; ΔN represents visual compensation. After long-term debugging, it is found that: when 750r / min<N≤1000r / min, ΔN takes a value of 1r / min; when 1000r / min<N≤1200r / min, ΔN takes a value of 1.5r / min; when 1200r / min<N, ΔN takes a value of 2r / min. This has a better visual effect.

[0054] The working parameters of the pump turbine runner 4 are determined by the workstation central control system, and then the pulse cycle of the stroboscope 1 is controlled. A single stroboscope cycle can be divided into a high pulse trigger period (i.e., the time period when the light of the stroboscope 1 flashes) and a low pulse trigger period (i.e., the time period when the light of the stroboscope 1 is off). Therefore, the stroboscopic control signal can be expressed as T=T1+T2, i.e., T=1 / (N+ΔN)=T1+T2. Among them, T1 represents the high pulse trigger period of the stroboscope 1, and T2 represents the low pulse trigger period of the stroboscope 1.

[0055] The driving mode of the high-speed camera I2 and the micro high-speed camera 3 is as follows: a single photography cycle of the high-speed camera I2 and the micro high-speed camera 3 can be divided into a high-speed photography period and a photography stop period, and a single high-speed photography period can be further divided into a single photo capture period and a high-speed photography silent period. Therefore, the shooting control signal can be expressed as T1=n×T n , T n =T n1 +T n2 Where: n represents the number of photographs within the time period T1, and the n value is adjusted to ensure that the cavitation image data of each runner blade 4.2 is captured; T n Represents the photography period; T n1 Indicates the capture time of a single image; T n2 Indicates the silent time of the photography cycle; by adjusting T n1 Value and T n2 value to adjust the imaging effect.

[0056] S3, the workstation central control system sends a stroboscopic control signal to the stroboscope 1, and sends a shooting control signal to the high-speed camera I2 and the micro high-speed camera 3 respectively.

[0057] S4, in cooperation with the stroboscope 1, the high-speed camera I2 captures the cavitation image data on the back side of the pump-turbine impeller 4 based on the shooting control signal, and the micro high-speed camera 3 captures the cavitation image data on the front side of the pump-turbine impeller 4 based on the shooting control signal.

[0058] S5, uploading the cavitation image data of the front and back sides of the pump-turbine runner 4 to the workstation central control system, and using image processing equipment to process and analyze the cavitation image data to obtain the cavitation evolution characteristic information of the pump-turbine.

Claims

1. A method for capturing the cavitation evolution characteristics of a pump-turbine, characterized in that: The following steps are involved: S1, arranging a stroboscope (1), a high-speed camera I (2) and a micro high-speed camera (3) in the working space of the water pump turbine, and connecting the stroboscope (1), the high-speed camera I (2) and the micro high-speed camera (3) to the central control system of the workstation of the water pump turbine for communication respectively; S2, the workstation central control system obtains the working parameters of the water pump turbine, and generates a strobe control signal and a shooting control signal based on the working parameters of the water pump turbine; S3, the workstation central control system sends a stroboscopic control signal to the stroboscope (1), and sends a shooting control signal to the high-speed camera I (2) and the micro high-speed camera (3) respectively; S4, in cooperation with the stroboscope (1), the high-speed camera I (2) captures cavitation image data on the back side of the pump-turbine runner (4) based on the shooting control signal, and the micro high-speed camera (3) captures cavitation image data on the front side of the pump-turbine runner (4) based on the shooting control signal; S5, uploading the cavitation image data of the front and back sides of the pump-turbine runner (4) to the workstation central control system, and using image processing equipment to process and analyze the cavitation image data to obtain the cavitation evolution characteristic information of the pump-turbine.

2. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 1, characterized in that: In the step S1, the micro high-speed camera (3) is installed on the top cover (4.1) of the pump turbine runner (4), that is, an observation hole is provided through the top cover (4.1) directly above the runner flow channel, and the micro high-speed camera (3) is installed in the observation hole through the fixing device (5), so that the bottom of the micro high-speed camera and the fixing device (5) as a whole are flush with the bottom of the top cover (4.1).

3. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 2, characterized in that: The fixing device (5) comprises a main body component, a camera mounting portion and a transparent cover (5.8); The main body component is hollow and through-set, and comprises a coaxially integrally formed clamping portion (5.1) and a connecting portion (5.2); a first thread structure (5.3) and a second thread structure (5.4) are arranged on the outer wall of the connecting portion (5.2); and a thread structure (5.3) and a second thread structure (5.4) are arranged on the inner wall of the connecting portion (5.2); The transparent cover (5.8) is threadedly fastened to the main body component via the second threaded structure (5.4); the first threaded structure (5.3) cooperates with the observation hole so that the main body component is threadedly fastened to the top cover (4.1) The camera mounting part axially penetrates the main body component and is connected to the inner wall of the main body component; the micro high-speed camera (3) is located inside the transparent cover (5.8) and is fixedly connected to the end of the camera mounting part.

4. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 3, characterized in that: The bottom of the transparent cover (5.8) is a planar structure.

5. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 3, characterized in that: The camera mounting portion comprises an adjusting rod (5.5) and a rotating connecting piece (5.6); the end of the adjusting rod (5.5) is provided with an inclined surface for mounting a micro high-speed camera (3); the rotating connecting piece (5.6) is sleeved on the outside of the adjusting rod (5.5) and is fixedly connected to the adjusting rod (5.5); a locking structure (5.7) is provided on the inner wall of the connecting portion (5.2); the rotating connecting piece (5.6) cooperates with the locking structure (5.7) so that the camera mounting portion and the main body component can be rotatably and adjustable connected.

6. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 5, characterized in that: In the step S1, the process of arranging the micro high-speed camera (3) also includes adjusting the shooting angle of the micro high-speed camera (3), that is, after the main body component is fixed on the top cover (4.1), the adjustment rod (5.5) is rotated so that the shooting angle of the micro high-speed camera (3) meets the requirements, and finally the adjustment rod (5.5) is fixed.

7. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 6, characterized in that: In the step S1, before the main body component is installed on the top cover (4.1), a gasket needs to be sleeved on the main body component according to the thickness of the top cover (4.1), so that after the main body component is fixed on the top cover (4.1), the bottom of the transparent cover (5.8) is flush with the bottom of the top cover (4.1).

8. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 1, characterized in that: In step S2, the stroboscopic control signal is expressed as T=1 / (N+ΔN)=T1+T2; wherein: T represents a single stroboscopic cycle of the stroboscope (1); N represents the rotation speed of the pump turbine runner (4); ΔN represents visual compensation; T1 represents a high pulse triggering cycle of the stroboscope (1), and T2 represents a low pulse triggering cycle of the stroboscope (1).

9. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 8, characterized in that: When 750r / min<N≤1000r / min, ΔN takes 1r / min; when 1000r / min<N≤1200r / min, ΔN takes 1.5r / min; when 1200r / min<N, ΔN takes 2r / min.

10. A method for capturing the cavitation evolution characteristics of a pump-turbine as claimed in claim 8, characterized in that: In step S2, the shooting control signal is expressed as T1=n×T n , T n =T n1 +T n2 Wherein: n represents the number of photographs within the time period T1, and the n value is adjusted to ensure that the cavitation image data of each rotor blade (4.2) is captured; T n Represents the photography period; T n1 Indicates the capture time of a single image; T n2 Indicates the silent time of the photography cycle; by adjusting T n1 Value and T n2 value to adjust the imaging effect.

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