Method and device for testing gas content of water delivery pipeline in regions with different altitudes

Abstract

The invention discloses a method and a device for testing the gas content of a water conveying pipeline in different altitude areas, and relates to the technical field of water conservancy projects. The invention discloses a method and a device for testing the gas content of a water conveying pipeline in different altitude areas, and the device comprises a transparent organic glass pipeline, a temperature control water tank, an air compressor, a water pump, a pressure sensor, a temperature sensor and a high-precision stainless steel graduated scale, and the transparent organic glass pipeline is arranged in the middle of the device. According to the invention, the gas content of the water delivery pipeline system in different altitudes of areas can be tested by regulating the water temperature and pressure conditions, the gas content can still be tested by regulating the water temperature and other conditions for water delivery projects in areas with large temperature changes all the year round, acquisition and testing on the project site are not needed, and the test efficiency is greatly improved. Therefore, the device and the method have the advantages of high efficiency and convenience, and can provide a certain reference for water hammer and vaporization analysis of water delivery pipelines in different altitudes due to different gas contents, so that corresponding protective measures can be taken to ensure safe operation of a water delivery system.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, specifically to a method and apparatus for testing the air content of water pipelines at different altitudes. Background Technology

[0002] Due to the different temperatures and air pressures at different altitudes, there are differences in water temperature and dissolved gas content in various pipeline water transmission systems such as long-distance water diversion projects, hydropower stations, and pumping stations. Temperature, air pressure, and pressure head during pressurized water transport all affect the air content in the water of the pipeline. Furthermore, the start-up and shutdown of the pipeline system, due to the presence of air or dissolved gases in the water at the pipeline's front end, leads to varying air content within the pipeline, thus having different impacts on the water transport system. These impacts include: ① Influencing the water hammer pressure in the pipeline when operating valves under the conditions of system operation control and water supply requirements (e.g., the peak water hammer pressure increases as the air content decreases); ② When the pipeline contains air bubbles, air pockets, and air masses, changes in air content affect the cross-sectional area and friction coefficient, thus affecting the pipeline's water transport capacity; ③ When the pipeline experiences fluctuations and transient flow accompanied by air entrainment, differences in temperature and pressure affect its saturated vapor pressure, causing cavitation erosion in the water transport system, resulting in structural vibration and noise, and even surface erosion; ④ Changes in air content also affect the effective bulk modulus of the water, impacting buffering and shock protection.

[0003] To ensure the safe operation of the water transmission system, it is necessary to conduct experiments and research on the air content of water in pipelines at different altitudes under varying temperature and air pressure conditions. Therefore, a testing device was designed to simulate the air content of water pipelines at different altitudes. First, based on the altitude and hydrological data of the water transmission project location, the air pressure, water temperature, and design pressure head of the pipeline were determined. The designed testing device simulated these conditions, collected experimental data, and calculated the air content. This provides a reference for analyzing water hammer and vaporization phenomena occurring in water pipelines at different altitudes due to varying air content, enabling the implementation of appropriate protective measures to ensure the safe operation of the water transmission system.

[0004] Existing cross-sectional gas content testing methods primarily focus on heating pipelines and the chemical and petroleum industries. These methods involve testing vertical risers on high-temperature, high-pressure test benches and using gamma-ray methods to measure vertical risers at normal temperature and pressure. However, the parameters (density, viscosity coefficient) of the fluids tested differ from those of water, as do the environmental conditions. Furthermore, long-distance water pipeline systems are mainly laid out at small inclination angles. Tomography can also be used to measure cross-sectional gas content, offering high accuracy but requiring complex operation and processing signals from the gas-liquid two-phase interface, which demands advanced technology. Therefore, these existing technologies cannot be used to test the gas content in two-phase flow (water and gas) in water pipelines, and they cannot adequately consider the effects of air pressure, temperature, and pressure head at different altitudes. In addition, while the gamma-ray method is unaffected by flow patterns, it is radioactive and harmful to human health, and its maintenance and operating costs are relatively high. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for testing the air content of water pipelines at different altitudes, solving the problems of existing technologies being complex to operate, posing a radioactive hazard, having high maintenance and usage costs, and failing to fully consider the air content under the influence of air pressure, temperature, and pressure head at different altitudes.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for testing the air content of water pipelines at different altitudes includes the following steps:

[0008] S1: Based on the location of the pipeline water transmission project, find the altitude, hydrological data and design information, determine the corresponding water temperature and pressure conditions during water transmission, check the connection sequence of the entire testing device, and check the reliability of the flanges at both ends of the transparent plexiglass pipe and the connecting pipes for air and water transmission to ensure good sealing and no water or air leakage.

[0009] S2: Close the air compressor valve, the left valve and the right valve of the acrylic pipe. Open the temperature-controlled water tank and wait for the water temperature to reach the preset temperature. Open the right valve to fill the transparent acrylic pipe with water to a certain height, then close the right valve. Next, open the air compressor valve and the air compressor in sequence to pressurize the transparent acrylic pipe. After reaching the preset pressure, close the air compressor valve. Once the water level in the pipe stabilizes, take the initial reading h using a high-precision stainless steel ruler. g0 and h l0 The readings P0 from the pressure sensor and T0 from the temperature sensor are used to determine the initial parameters inside the pipeline.

[0010] S3: Close the air compressor valve, open the left and right valves of the acrylic pipe, start the water pump, and adjust the opening of the left and right valves according to the data of the electromagnetic flowmeter to ensure that the water-air two-phase flow circulation fully takes into account the dissolved gases in the water. During the entire circulation process, the temperature-controlled water tank can maintain the preset water temperature. After the pressure sensor and temperature sensor readings stabilize, close the left and right valves, and then open the air compressor valve and air compressor in sequence to pressurize the transparent acrylic pipe. After reaching the preset pressure, close the air compressor valve. After the water level in the pipe stabilizes, read the test reading h using a high-precision stainless steel ruler. g1 and h l1 The readings P1 from the pressure sensor and T1 from the temperature sensor are used to determine the parameters for testing inside the pipeline.

[0011] S4: Calculate the cross-sectional gas content α based on the tested data, and repeat steps S2 and S3 above. After verifying that the data is correct, take the average value to determine the cross-sectional gas content α.

[0012] Furthermore, for water pipeline projects at different altitudes, the above steps S1 to S4 are repeated. By adjusting the water temperature and pressure conditions, the air content of the water pipeline system at different altitudes can be tested.

[0013] Furthermore, the formula for calculating the gas content α of the cross section is:

[0014] ,

[0015] In the formula, A g A is the cross-sectional area of ​​the gas phase; l A is the liquid phase cross-sectional area; A is the total cross-sectional area. A = A g +A l A g A l Data r and h corresponding to the pipe cross-section and gas-liquid interface distribution diagram g1 h l1 Perform calculations;

[0016] Refer to the ideal gas law: ,

[0017] In the formula, P represents the pressure of the ideal gas, V represents the volume of the ideal gas, n represents the amount of substance of the gas, T represents the thermodynamic temperature of the ideal gas, and R is the ideal gas constant. Under constant volume, pressure is directly proportional to temperature:

[0018] ,

[0019] The relationship between water vaporization pressure and altitude ,

[0020] In the formula, z is the elevation (m) of the project site.

[0021] Furthermore, since pipeline water transmission projects involve pressurized water transmission, the applied pressure head can be calculated using Bernoulli's equation.

[0022] ,

[0023] In the formula, ρ is density; g is gravitational acceleration; v is flow velocity; P is pressure; h is the height of the point; and C is a constant.

[0024] Based on the above formula, the elevation, hydrological data, design information, and conditions (z, P1, T1, T2) of the area where the test device is located are found according to the location of the water conveyance project. Then, the water conveyance pressure P2 and temperature conditions T2 that need to be set for the experiment are calculated.

[0025] This invention also provides the following technical solutions:

[0026] An apparatus for testing the air content of water pipelines at different altitudes is characterized by comprising a transparent plexiglass pipe, a temperature-controlled water tank, an air compressor, and a water pump. The transparent plexiglass pipe is located in the middle of the apparatus, and both ends of the transparent plexiglass pipe are fitted with flanges. The flange on the left is connected to the upper right part of the temperature-controlled water tank via a connecting pipe. From left to right, a left valve, a water pump, and an electromagnetic flow meter are sequentially installed on the connecting pipe connected to the upper right part of the temperature-controlled water tank. The flange on the right is connected to the lower left part of the temperature-controlled water tank via a connecting pipe. A right valve is installed on the connecting pipe connected to the lower left part of the temperature-controlled water tank. The upper left wall of the transparent plexiglass pipe is connected to the left side of the air compressor via a connecting pipe. An air compressor valve is installed on the connecting pipe connecting the transparent plexiglass pipe and the air compressor.

[0027] Furthermore, pressure and temperature sensors are installed inside the transparent acrylic pipe, and a high-precision stainless steel ruler is installed at the center of the flange on the right end of the transparent acrylic pipe.

[0028] Furthermore, the flange at the right end of the transparent acrylic pipe is a pre-drilled transparent blind flange, which is connected to the connecting pipe on the right side. The water depth can be measured by observing a high-precision stainless steel ruler through the pre-drilled transparent blind flange.

[0029] Furthermore, the transparent plexiglass pipe is screwed to the bottom of the temperature-controlled water tank and fixed with a bracket.

[0030] Furthermore, the transparent acrylic pipe has a length of L, a wall thickness of δ, and an inner diameter of r. The formula for calculating the inner diameter is:

[0031]

[0032] The beneficial effects of this invention are as follows: This application utilizes the gas content testing device and method to determine the corresponding water temperature and pressure conditions during water transmission by searching hydrological data and design information based on the altitude of various pipeline water transmission projects such as long-distance water diversion projects, hydropower stations, and pumping stations. By adjusting the water temperature and pressure conditions, the gas content of water transmission pipeline systems at different altitudes can be tested. For water transmission projects in areas with large temperature variations throughout the year, the gas content can still be tested by adjusting water temperature and other conditions without having to collect data at the project site. Therefore, this testing device and method have the advantages of high efficiency and convenience, and can provide a certain reference for the analysis of water hammer and vaporization that occur in water transmission pipelines at different altitudes due to different gas contents, so as to take corresponding protective measures to ensure the safe operation of the water transmission system.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0035] Figure 2 This is a diagram showing the cross-section of the pipe and the distribution of the gas-liquid interface as illustrated in this invention.

[0036] Explanation of reference numerals in the attached diagram: 1. Transparent acrylic pipe; 2. Pressure sensor; 3. Temperature sensor; 4. High-precision stainless steel ruler; 5. Flange; 7. Temperature-controlled water tank; 8. Air compressor; 9. Support bracket; 10. Water pump; 11. Electromagnetic flow meter; 61. Air compressor valve; 62. Left valve; 63. Right valve. Detailed Implementation

[0037] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0040] A method for testing the air content of water pipelines at different altitudes includes the following steps:

[0041] S1: Based on the location of the pipeline water transmission project, find the altitude, hydrological data and design information, determine the corresponding water temperature and pressure conditions during water transmission, check the connection sequence of the entire test device, and check the reliability of the flanges 5 at both ends of the transparent plexiglass pipe 1 and the air and water connection pipe 12 to ensure good sealing and no water or air leakage.

[0042] S2: Close air compressor valve 61, left valve 62 and right valve 63 of the acrylic pipe, open the temperature-controlled water tank 7 and wait for the water temperature to reach the preset temperature. Open right valve 63 to fill the transparent acrylic pipe 1 with water to a certain height, then close right valve 63. Open air compressor valve 61 and air compressor 8 in sequence to pressurize the transparent acrylic pipe 1. After reaching the preset pressure, close air compressor valve 61. After the water level in the pipe stabilizes, take the initial reading h from the high-precision stainless steel ruler 4. g0 and h l0 The readings P0 of pressure sensor 2 and T0 of temperature sensor 3 are used to determine the initial parameters inside the pipeline.

[0043] S3: Close the air compressor valve 61, open the left valve 62 and right valve 63 of the plexiglass pipe, start the water pump 10, and adjust the opening of the left valve 62 and right valve 63 according to the data of the electromagnetic flowmeter 11 to ensure that the water-air two-phase flow circulation fully takes into account the dissolved gas in the water. During the entire circulation process, the temperature-controlled water tank 7 can ensure the preset water temperature. After the pressure sensor and temperature sensor readings stabilize, close the left valve 62 and right valve 63, and then open the air compressor valve 61 and air compressor 8 in sequence to pressurize the transparent plexiglass pipe 1. After reaching the preset pressure, close the air compressor valve 61. After the water level in the pipe stabilizes, read the test reading h from the high-precision stainless steel scale 4. g1 and h l1 The readings P1 of pressure sensor 2 and T1 of temperature sensor 3 are used to determine the parameters of the test inside the pipeline.

[0044] S4: Calculate the cross-sectional gas content α based on the tested data, and repeat steps S2 and S3 above. After verifying that the data is correct, take the average value to determine the cross-sectional gas content α.

[0045] For water pipeline projects at different altitudes, repeat steps S1 to S4 as described above. By adjusting the water temperature and pressure conditions, the air content of the water pipeline system at different altitudes can be tested.

[0046] In addition, the above results can be verified by using volumetric gas content measurement.

[0047] An apparatus for testing the air content of water pipelines at different altitudes includes a transparent plexiglass pipe 1, a temperature-controlled water tank 7, an air compressor 8, and a water pump 10. The transparent plexiglass pipe 1 is located in the middle of the apparatus, and flanges 5 are fitted at both ends of the transparent plexiglass pipe 1. The flange 5 on the left is connected to the upper right of the temperature-controlled water tank 7 through a connecting pipe. A left valve 62, a water pump 10, and an electromagnetic flow meter 11 are installed on the connecting pipe connected to the upper right of the temperature-controlled water tank 7 from left to right. The flange 5 on the right is connected to the lower left of the temperature-controlled water tank 7 through a connecting pipe. A right valve 63 is installed on the connecting pipe connected to the lower left of the temperature-controlled water tank 7. The upper left wall of the transparent plexiglass pipe 1 is connected to the air compressor 8 on the left through a connecting pipe. An air compressor valve 61 is installed on the connecting pipe connecting the transparent plexiglass pipe 1 and the air compressor 8.

[0048] The transparent plexiglass pipe 1 is equipped with a pressure sensor 2 and a temperature sensor 3. A high-precision stainless steel ruler 4 is installed at the center of the flange 5 at the right end of the transparent plexiglass pipe 1.

[0049] The right end flange 5 of the transparent plexiglass pipe 1 is a transparent blind flange, which is connected to the connecting pipe on the right side. The water depth can be measured by observing the high-precision stainless steel scale 4 through the pre-drilled transparent blind flange.

[0050] A bracket 9 is screwed to the bottom of the transparent plexiglass pipe 1 and the temperature-controlled water tank 7.

[0051] This invention primarily simulates the water temperature and pressure conditions of water pipelines at different altitudes by adjusting water temperature and pressure, collecting data such as pressure, temperature, and water level, and then calculating the gas content of the gas-liquid two-phase flow in the water pipeline. The testing device mainly includes a transparent acrylic pipe, a pressure sensor, a temperature sensor, a high-precision stainless steel ruler, flanges, valves, a (integrated digital display) temperature-controlled water tank, an air compressor, a support frame, a water pump (vertical pipeline centrifugal pump), an electromagnetic flowmeter, and connecting pipes. A schematic diagram of the testing device is shown below. Figure 1 To minimize the size effect of the test tube section and to withstand a certain air pressure, the diameter, length, and wall thickness of the plexiglass pipe should not be too small. Recommended pipe dimensions: outer diameter D = 200mm, length L = 2m, wall thickness δ = 5mm, inner diameter... (See the diagram for the pipe cross-section and gas-liquid interface distribution.) Figure 2 .

[0052] Test principle:

[0053] The temperature of the water entering the transparent plexiglass pipe in the test section is regulated by a temperature-controlled water tank, the air pressure inside the transparent plexiglass pipe in the test section is regulated by an air compressor, and the water pump is started to circulate the water in the pipe to simulate the water temperature and dissolved gas situation of the water supply system. Then, the test is carried out and the gas content is calculated.

[0054] cross-sectional gas content α:

[0055]

[0056] In the formula, A g A is the cross-sectional area of ​​the gas phase; l A is the liquid phase cross-sectional area; A is the total cross-sectional area, A = A g +A l A g A l Available Figure 2 Data r and h corresponding to the cross-section and gas-liquid interface distribution diagram of the pipeline g1 h l1 Perform the calculation.

[0057] And referencing the ideal gas law:

[0058] In the formula, P represents the pressure of the ideal gas, V represents the volume of the ideal gas, n represents the amount of substance of the gas, T represents the thermodynamic temperature of the ideal gas, and R is the ideal gas constant. Under constant volume, pressure is directly proportional to temperature:

[0059]

[0060] It also involves the relationship between water vaporization pressure and altitude.

[0061] In the formula, z is the elevation (m) of the project site.

[0062] Based on the above relationship, given the known air pressure and temperature at different altitudes, if we want to measure the gas content in a water pipeline at another altitude, we only need to apply the converted water temperature and air pressure. First, we need to find the altitude, hydrological data, design information, and conditions (z, P1, T1, T2) of the area where the test device is located based on the location of the water transmission project. Then, we need to calculate the water pressure P2 and temperature conditions T2 required for the experiment. Finally, we need to test the data and calculate the gas content of the cross section.

[0063] When the pipeline water conveyance project is pressurized, the applied pressure head can also be calculated according to Bernoulli's equation.

[0064]

[0065] In the formula, ρ is density; g is gravitational acceleration; v is flow velocity; P is pressure; h is the height of the point; and C is a constant.

[0066] In summary, this invention provides a method and apparatus for testing the gas content of water pipelines at different altitudes. This method utilizes the gas content testing apparatus and method to determine the corresponding water temperature and pressure conditions during water transmission by consulting hydrological data and design documents based on the altitude of various water transmission pipeline projects such as long-distance water diversion projects, hydropower stations, and pumping stations. By adjusting the water temperature and pressure conditions, the gas content of water transmission pipeline systems at different altitudes can be tested. For water transmission projects in areas with significant temperature variations throughout the year, the gas content can still be tested by adjusting water temperature and other conditions without needing to collect data at the project site. Therefore, this testing apparatus and method have the advantages of high efficiency and convenience, and can provide a certain reference for the analysis of water hammer and vaporization occurring in water transmission pipelines at different altitudes due to varying gas content, so as to take corresponding protective measures to ensure the safe operation of the water transmission system.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for testing the air content of water pipelines at different altitudes, characterized in that, Includes the following steps: S1: Based on the location of the pipeline water conveyance project, find the altitude, hydrological data and design information, determine the corresponding water temperature and pressure conditions during water conveyance, check the connection sequence of the entire test device, and check the reliability of the flanges (5) at both ends of the transparent plexiglass pipe (1) and the air and water connection pipes to ensure good sealing and no water or air leakage. S2: Close the air compressor valve (61), the left valve (62) and the right valve (63) of the transparent plexiglass pipe, open the temperature-controlled water tank (7) and wait for the water temperature to be adjusted to the preset temperature. Open the right valve (63) to fill the transparent plexiglass pipe (1) with water to a certain height, and then close the right valve (63). Open the air compressor valve (61) and the air compressor (8) in sequence to pressurize the transparent plexiglass pipe (1). After reaching the preset pressure, close the air compressor valve (61). After the water level in the pipe stabilizes, read the initial reading h using the high-precision stainless steel ruler (4). g0 and h l0 The readings P0 of the pressure sensor (2) and T0 of the temperature sensor (3) are used to determine the initial parameters in the pipeline. S3: Close the air compressor valve (61), open the left valve (62) and right valve (63) of the plexiglass pipe, start the water pump (10), and adjust the opening of the left valve (62) and right valve (63) according to the data of the electromagnetic flowmeter (11) so that the water-air two-phase flow circulation fully considers the dissolved gas in the water. During the entire circulation process, the temperature control tank (7) can ensure the preset water temperature. After the pressure sensor and temperature sensor readings are stable, close the left valve (62) and right valve (63), and then open the air compressor valve (61) and air compressor (8) in sequence to pressurize the transparent plexiglass pipe (1). After reaching the preset pressure, close the air compressor valve (61). After the water level in the pipe is stable, read the high-precision stainless steel scale (4) to test the reading h. g1 and h l1 The readings P1 of the pressure sensor (2) and T1 of the temperature sensor (3) are used to determine the parameters of the test inside the pipeline. S4: Calculate the cross-sectional gas content α based on the tested data, and repeat steps S2 and S3 above. After verifying that the data is correct, take the average value to determine the cross-sectional gas content α.

2. The method for testing the air content of water pipelines at different altitudes as described in claim 1, characterized in that, For water pipeline projects at different altitudes, repeat steps S1 to S4 as described above. By adjusting the water temperature and pressure conditions, the air content of the water pipeline system at different altitudes can be tested.

3. The method for testing the air content of water pipelines at different altitudes as described in claim 1, characterized in that, The formula for calculating the gas content α of the cross section is: ， In the formula, A g A is the cross-sectional area of ​​the gas phase; l A is the liquid phase cross-sectional area; A is the total cross-sectional area, A = A g +A l A g A l Data r and h corresponding to the pipe cross-section and gas-liquid interface distribution diagram g1 h l1 Perform calculations; Refer to the ideal gas law: , In the formula, P represents the pressure of the ideal gas, V represents the volume of the ideal gas, n represents the amount of substance of the gas, T represents the thermodynamic temperature of the ideal gas, and R is the ideal gas constant. Under constant volume, pressure is directly proportional to temperature: ， The relationship between water vaporization pressure and altitude , In the formula, z is the elevation (m) of the project site. Based on the above formula, the elevation, hydrological data, design information, and conditions (z, P1, T1, T2) of the area where the test device is located are found according to the location of the water conveyance project. Then, the water conveyance pressure P2 and temperature conditions T2 that need to be set for the experiment are calculated.

4. The method for testing the air content of water pipelines at different altitudes as described in claim 1, characterized in that, Pipeline water transmission projects involve pressurized water transmission, and the applied pressure head can be calculated using Bernoulli's equation. ， In the formula, ρ is density; g is gravitational acceleration; v is flow velocity; P is pressure; h is the height of the point; and C is a constant.

5. The apparatus for testing the air content of water pipelines at different altitudes as described in claim 1, characterized in that, The device includes a transparent plexiglass pipe (1), a temperature-controlled water tank (7), an air compressor (8), and a water pump (10). The transparent plexiglass pipe (1) is located in the middle of the device. Both ends of the transparent plexiglass pipe (1) are fitted with flanges (5). The flange (5) on the left side is connected to the upper right of the temperature-controlled water tank (7) through a connecting pipe. From left to right, the connecting pipe connected to the upper right of the temperature-controlled water tank (7) is equipped with a left valve (62), a water pump (10), and an electromagnetic flow meter (11). The flange (5) on the right side is connected to the lower left of the temperature-controlled water tank (7) through a connecting pipe. The connecting pipe connected to the lower left of the temperature-controlled water tank (7) is equipped with a right valve (63). The upper left wall of the transparent plexiglass pipe (1) is connected to the air compressor (8) on the left side through a connecting pipe. The connecting pipe connecting the transparent plexiglass pipe (1) and the air compressor (8) is equipped with an air compressor valve (61).

6. The apparatus for testing the air content of water pipelines at different altitudes as described in claim 5, characterized in that, A pressure sensor (2) and a temperature sensor (3) are installed inside the transparent plexiglass pipe (1), and a high-precision stainless steel ruler (4) is installed at the center of the flange (5) on the right end of the transparent plexiglass pipe (1).

7. The apparatus for testing the air content of water pipelines at different altitudes as described in claim 6, characterized in that, The right end flange (5) of the transparent plexiglass pipe (1) is a pre-drilled transparent blind flange, which is connected to the connecting pipe on the right side. The high-precision stainless steel ruler (4) can be observed through the pre-drilled transparent blind flange to measure the water depth.

8. The apparatus for testing the air content of water pipelines at different altitudes as described in claim 5, characterized in that, A bracket (9) is screwed to the bottom of the transparent plexiglass pipe (1) and the temperature-controlled water tank (7).

9. The apparatus for testing the air content of water pipelines at different altitudes as described in claim 5, characterized in that, The transparent acrylic pipe (1) has a length of L, a wall thickness of δ, and an inner diameter of r. The formula for calculating the inner diameter is: 。

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