Aeration cavitation reduction test method for low-pressure environment

Abstract

The invention provides an air entrainment and erosion reduction test device and method for a low-pressure environment, and relates to the technical field of cavitation erosion resistance of hydraulic engineering materials, the device comprises a pressure reduction tank, a water tank is arranged in the pressure reduction tank, the water tank is connected with a filter through a centrifugal pump, and an air entrainment device is further arranged on the centrifugal pump; the filter is arranged in the water tank, a vibration container is further arranged in the water tank, a concrete test piece is placed in the vibration container, and a water outlet is formed in the bottom of the vibration container and connected with the water tank; a vibration cavitation erosion instrument is arranged on the vibration container and is connected with an ultrasonic generator; a vacuumizing device is further arranged on the pressure reducing tank; a pressure gauge is further arranged in the pressure reduction box. According to the invention, the inhibition effect of the bubble-doped group on cavitation bubble development in a low-pressure environment can be systematically studied, and the relationship between the bubble concentration and the cavitation erosion damage rate under different pressure conditions can be determined.

Description

Technical Field

[0001] This invention relates to the field of cavitation erosion resistance technology for hydraulic engineering materials, and in particular to an aeration-entrained erosion reduction test device and method for use in low-pressure environments. Background Technology

[0002] Traditional air-incorporation cavitation reduction tests are mostly conducted in atmospheric pressure environments. However, the reduced air pressure at high altitudes significantly alters the dynamic behavior of cavitation bubbles, making it difficult for existing test methods to accurately simulate actual engineering conditions. In particular, the inhibitory effect of air-incorporation on cavitation damage under low-pressure environments lacks systematic research.

[0003] While existing vibration cavitation testing devices can simulate cavitation phenomena, they lack precise control over the air pressure environment. Furthermore, the design of the gas-entraining system is relatively simple, making it difficult to achieve stable adjustment of bubble size and concentration, and thus difficult to quantify the relationship between air pressure changes and the cavitation reduction effect. In addition, conventional testing methods do not consider the unique interaction between bubbles and cavitation bubbles under low-pressure conditions, leading to deviations between test results and actual engineering conditions. Therefore, there is an urgent need to invent a gas-entraining cavitation reduction testing method suitable for low-pressure environments. Summary of the Invention

[0004] This invention provides an air-entraining corrosion reduction test device and method for low-pressure environments, aiming to solve at least one of the technical problems of the prior art mentioned in the background section.

[0005] The present invention provides the following technical solution to achieve the above objectives: An aeration-entraining erosion reduction test device for low-pressure environments includes a pressure-reducing chamber containing a water tank connected to a filter via a centrifugal pump. The centrifugal pump is also equipped with an aeration device. The filter is located within a water tank containing a vibrating container holding a concrete specimen. The bottom of the vibrating container has a drain outlet connected to the water tank. A vibration cavitation meter is mounted on the vibrating container and connected to an ultrasonic generator. The pressure-reducing chamber also includes a vacuum device and a pressure gauge.

[0006] Furthermore, the decompression chamber is equipped with an observation window.

[0007] A method for air-entrained corrosion reduction testing in low-pressure environments, specifically comprising the following steps: Step 1: Fix the concrete specimen in the vibrating container inside the pressure reducing chamber, ensuring that the concrete specimen is tightly connected to the vibration mechanism of the vibration cavitation apparatus; turn on the centrifugal pump to inject clean water into the water tank and the vibrating container, and control the clean water to completely submerge the surface of the concrete specimen to be tested. Step 2: Start the air mixing device, use a filter to control the air intake flow rate, and evenly disperse the air in the form of microbubbles in the clean water, and continuously monitor the system pressure changes through a pressure gauge; Step 3: After gas mixing is completed, start the vacuum pump and gradually adjust the air pressure inside the pressure reducing chamber to the target value to simulate the low-pressure environment under different altitude conditions. Step 4: After the air pressure stabilizes, simultaneously turn on the vibration cavitation apparatus and the ultrasonic generator, adjust the parameters of the ultrasonic generator, and make the vibration cavitation apparatus drive the specimen to vibrate at high frequency to induce cavitation in the liquid. Step 5: After the test, first turn off the vibration cavitation instrument, then restore the air pressure in the decompression chamber, and take out the concrete specimen for three-dimensional morphology scanning and microstructure analysis; Step Six: Repeat steps one to five by changing the air pressure parameters and air entrainment conditions, compare and analyze the cavitation damage characteristics under different working conditions, and establish a relationship model between the air entrainment cavitation reduction effect and the air pressure environment.

[0008] Furthermore, step two involves uniformly dispersing air in the form of microbubbles in clean water, including real-time observation of the bubble formation process and adjustment of the air mixing pressure and time.

[0009] Furthermore, step three also includes verifying the actual value with a pressure gauge after each change in air pressure to ensure that the air pressure control accuracy is within the accuracy range required by the test.

[0010] Furthermore, step four, inducing cavitation in the liquid, includes image acquisition of the concrete specimen and maintaining liquid circulation through a centrifugal pump to ensure uniform gas incorporation.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The experimental method of this invention can be used to systematically study the inhibitory effect of air bubble swarms on cavitation bubble development under low pressure conditions, clarify the relationship between bubble concentration and cavitation damage rate under different pressure conditions, and provide theoretical basis and technical support for the air-entrained erosion reduction design of water conservancy projects in high-altitude areas.

[0012] The precise matching of bubble parameters and gas pressure environment is achieved through the linkage control of the gas mixing device and the vacuum pumping device; the observation window design of the decompression chamber, together with the vibration cavitation instrument, allows direct observation of the interaction process between cavitation bubbles and mixed bubbles. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the gas-infused corrosion reduction test device of the present invention; Figure reference numerals: 1-Pressure relief chamber; 2-Water tank; 3-Water; 4-Vacuum pump; 5-Vibration cavitation meter; 6-Ultrasonic generator; 7-Centrifugal pump; 8-Air; 9-Aeration device; 10-Pressure gauge; 11-Filter; 12-Container; 13-Concrete specimen. Detailed Implementation

[0014] To facilitate understanding of the present invention, a more complete description of this application will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of the present invention.

[0015] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] Example. An apparatus and method for gas-infused corrosion reduction testing in low-pressure environments, structural reference. Figure 1 A gas-entraining cavitation reduction test device for low-pressure environments includes a pressure-reducing chamber 1, a water tank 2 inside the pressure-reducing chamber 1, the water tank 2 being connected to a filter 11 via a centrifugal pump 7, and a gas-entraining device 9 on the centrifugal pump 7; the filter 11 being placed inside a water tank, and a vibrating container 12 inside the water tank, containing a concrete specimen 13, with a drain outlet at the bottom of the vibrating container 12 connected to the water tank 2; a vibration cavitation meter 5 on the vibrating container 12, connected to an ultrasonic generator 6; a vacuum device 4 on the pressure-reducing chamber 1; a pressure gauge 10 inside the pressure-reducing chamber 1; and an observation window on the pressure-reducing chamber 1 for convenient observation of the cavitation process of the concrete specimen 13. A gas-entrained corrosion reduction test method for low-pressure environments, performed using the aforementioned gas-entrained corrosion reduction test apparatus, specifically includes the following steps: Step 1: Fix the concrete specimen 13 in the vibration container 12 inside the pressure reduction chamber 1, and ensure that the concrete specimen 13 is tightly connected to the vibration mechanism of the vibration cavitation instrument 5; turn on the centrifugal pump 7 to inject clean water 3 into the water tank and the vibration container 12, and control the clean water 3 to completely submerge the surface of the concrete specimen 13 to be tested. Step 2: Start the air mixing device 9, use the filter 11 to control the air intake flow rate, and uniformly disperse the air 8 in the water 3 in the form of microbubbles. Continuously monitor the system pressure changes using the pressure gauge 10. This process includes real-time observation of the bubble formation process and adjustment of the air mixing pressure and time. The observation window allows for real-time monitoring of the bubble formation process, and adjustments to the air mixing pressure and time to ensure that the bubble size distribution meets technical requirements. During this process, the pressure gauge 10 continuously monitors system pressure changes, providing reference data for subsequent air pressure adjustments. Step 3: After gas mixing is completed, start the vacuum pumping device 4 and gradually adjust the internal air pressure of the pressure reducing chamber 1 to the target value to simulate the low air pressure environment under different altitude conditions; after each air pressure change, the actual value is checked by the pressure gauge 10 to ensure that the air pressure control accuracy is within the accuracy range required by the test. Step 4: After the air pressure stabilizes, simultaneously turn on the vibration cavitation instrument 5 and the ultrasonic generator 6, adjust the parameters of the ultrasonic generator 6, and make the vibration cavitation instrument 5 drive the specimen to vibrate at high frequency to induce cavitation in the liquid; during the process of inducing cavitation in the liquid, the concrete specimen 13 is image acquired, and the liquid is kept circulating by the centrifugal pump 7 to ensure uniform air mixing. Step 5: After the test, first turn off the vibration cavitation instrument 5, then restore the air pressure in the decompression chamber 1, and take out the concrete specimen 13 for three-dimensional morphology scanning and microstructure analysis. Step Six: Repeat steps one to five by changing the air pressure parameters and air entrainment conditions, compare and analyze the cavitation damage characteristics under different working conditions, and establish a relationship model between the air entrainment cavitation reduction effect and the air pressure environment.

[0018] Obviously, the above description is only a part of the embodiments of the present invention, and not all of the embodiments. The above embodiments are not intended to limit the present invention, and various modifications and variations can be made to the present invention by those skilled in the art. Any combination, modification, equivalent substitution, improvement, and all other embodiments that can be made by those skilled in the art within the spirit and principles of the present invention should be within the protection scope of the present invention.

Claims

1. A gas-entraining corrosion reduction test device for low-pressure environments, characterized in that: The system includes a pressure reducing chamber (1), a water tank (2) inside the pressure reducing chamber (1), a water tank (2) connected to a filter (11) via a centrifugal pump (7), and an aeration device (9) on the centrifugal pump (7); the filter (11) is located in a water tank, and a vibrating container (12) is located in the water tank, a concrete specimen (13) is placed inside the vibrating container (12), a drain outlet is located at the bottom of the vibrating container (12), and the drain outlet is connected to the water tank (2); a vibration cavitation meter (5) is located on the vibrating container (12), and the vibration cavitation meter (5) is connected to an ultrasonic generator (6); a vacuum pumping device (4) is located on the pressure reducing chamber (1); and a pressure gauge (10) is located inside the pressure reducing chamber (1).

2. The gas-entraining corrosion reduction test apparatus for low-pressure environments according to claim 1, characterized in that: The pressure relief chamber (1) is equipped with an observation window.

3. A method for gas-entrained corrosion reduction testing in low-pressure environments, performed using the gas-entrained corrosion reduction testing apparatus described in claim 1, characterized in that... Specifically, the steps include the following: Step 1: Fix the concrete specimen (13) in the vibration container (12) inside the pressure reducing chamber (1), and ensure that the concrete specimen (13) is tightly connected to the vibration mechanism of the vibration cavitation instrument (5); turn on the centrifugal pump (7) to inject clean water (3) into the water tank and vibration container (12), and control the clean water (3) to completely submerge the surface of the concrete specimen (13) to be tested; Step 2: Start the air mixing device (9), use the filter (11) to control the air intake flow rate, and evenly disperse the air (8) in the water (3) in the form of microbubbles, and continuously monitor the system pressure change through the pressure gauge (10); Step 3: After the gas mixing is completed, start the vacuum pump (4) and gradually adjust the internal air pressure of the pressure reducing box (1) to the target value to simulate the low air pressure environment under different altitude conditions. Step 4: After the air pressure stabilizes, turn on the vibration cavitation instrument (5) and the ultrasonic generator (6) simultaneously, adjust the parameters of the ultrasonic generator (6) so that the vibration cavitation instrument (5) drives the specimen to vibrate at high frequency, inducing cavitation in the liquid. Step 5: After the test, first turn off the vibration cavitation instrument (5), then restore the air pressure in the decompression chamber (1), and take out the concrete specimen (13) for three-dimensional morphology scanning and microstructure analysis; Step Six: Repeat steps one to five by changing the air pressure parameters and air entrainment conditions, compare and analyze the cavitation damage characteristics under different working conditions, and establish a relationship model between the air entrainment cavitation reduction effect and the air pressure environment.

4. The gas-entraining corrosion reduction test method for low-pressure environments according to claim 3, characterized in that: Step two involves uniformly dispersing air (8) in the form of microbubbles in clean water (3), including real-time observation of the bubble formation process and adjustment of the gas mixing pressure and time.

5. The gas-entraining corrosion reduction test method for low-pressure environments according to claim 3, characterized in that: Step three also includes verifying the actual value using a pressure gauge (10) after each change in air pressure to ensure that the air pressure control accuracy is within the accuracy range required by the test.

6. The gas-entraining corrosion reduction test method for low-pressure environments according to claim 3, characterized in that: Step four involves inducing cavitation in the liquid by acquiring images of the concrete specimen (13) and maintaining the liquid circulation flow through a centrifugal pump (7) to ensure uniform gas mixing.

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