CN-122016553-A - Method and device for testing air content of water pipeline aiming at different altitude areas

Abstract

The invention discloses a method and a device for testing the air content of water pipelines in different altitude areas, and relates to the technical field of hydraulic engineering. The utility model provides a method and device for testing the air content of water pipelines in different altitude areas, which 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, wherein the middle part of the device is provided with the transparent organic glass pipeline. The invention can test the air content of the water pipe system in different elevation areas by regulating and controlling the water temperature and pressure conditions, and can test the air content by regulating the water temperature and other conditions for water delivery projects in areas with larger temperature change all the year round without collecting and testing on the project site, so 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 the water pipe system in different elevation areas due to different air content, so as to take corresponding protective measures to ensure the safe operation of the water delivery system.

Inventors

• YANG XULIANG
• GU SHENGLONG
• HOU QINGZHI
• Ma Pingcheng
• WU HAITAO
• BAI WENWEN
• ZHAO QINXIA

Assignees

• 青海大学
• 青海民族大学

Dates

Publication Date

20260512

Application Date

20260205

Claims (9)

1. 1. The method for testing the air content of the water pipeline aiming at different altitude areas is characterized by comprising the following steps of: S1, searching altitude, hydrologic data and design data according to a pipeline water delivery project place, determining corresponding water temperature and pressure conditions during water delivery, checking the connection sequence of the whole testing device, checking the reliability of flanges (5) at two ends of a transparent organic glass pipeline (1) and a connecting pipe for ventilation and water supply, and ensuring good sealing performance, no water leakage and no air leakage; S2, closing an air compressor valve (61), a left valve (62) and a right valve (63) of a transparent organic glass pipeline, opening a temperature control water tank (7) until the water temperature is regulated to a preset temperature, opening the right valve (63) to enable the transparent organic glass pipeline (1) to be filled with water to a certain height, then closing the right valve (63), sequentially opening the air compressor valve (61) and the air compressor (8), pressurizing the transparent organic glass pipeline (1), closing the air compressor valve (61) after the preset pressure is reached, respectively reading a high-precision stainless steel graduated scale (4) to perform initial readings h g0 and h l0 after the water surface in the pipeline is stable, reading P 0 of a pressure sensor (2), and reading T 0 of a temperature sensor (3), thereby determining initial parameters in the pipeline; S3, closing an air compressor valve (61), opening a left valve (62) and a right valve (63) of an organic glass pipeline, starting a water pump (10), regulating and controlling the opening of the left valve (62) and the right valve (63) according to the data of an electromagnetic flowmeter (11) to enable the water-gas two-phase flow circulation to fully consider dissolved gas in water, controlling a water tank (7) to ensure preset water temperature in the whole circulation process, closing the left valve (62) and the right valve (63) after the readings of a pressure sensor and a temperature sensor are stable, sequentially opening the air compressor valve (61) and an air compressor (8), pressurizing the transparent organic glass pipeline (1), closing the air compressor valve (61) after the preset pressure is reached, respectively reading high-precision stainless steel scales (4) for test readings h g1 and h l1 after the water surface of the pipeline is stable, reading P 1 of a pressure sensor (2), and reading T 1 of the temperature sensor (3), so as to determine the parameters tested in the pipeline; And S4, calculating the section air content alpha according to the tested data, repeating the step S2 and the step S3, comparing and checking the data, taking an average value, and determining the section air content alpha.
2. 2. The method for testing the air content of the water conveying pipeline aiming at different altitude areas according to claim 1, wherein the steps S1-S4 are repeated for the pipeline water conveying projects of the different altitude areas, and the air content of the water conveying pipeline systems of the different altitude areas can be tested by regulating water temperature and pressure conditions.
3. 3. The method for testing the air content of the water pipeline aiming at different altitude areas as set forth in claim 1, wherein the calculation formula of the section air content alpha is as follows: , Wherein A g is the gas phase sectional area, A l is the liquid phase sectional area, A is the total sectional area, A=A g +A l , wherein A g 、A l is calculated by the data r and h g1 、h l1 corresponding to the pipeline cross section and the gas-liquid interface distribution diagram; Referring to the ideal gas state equation: , Where P is the pressure of the ideal gas, V is the volume of the ideal gas, n is the amount of the gaseous substance, T is the thermodynamic temperature of the ideal gas, and R is the ideal gas constant. With a constant volume, the pressure is proportional to the temperature: , relates to the relation between the vaporization pressure of water body and the altitude , Wherein z is the elevation m of the engineering site, According to the above, the altitude, hydrologic data, design data and conditions (z, P 1 ,T 1 ,T 2 ) of the region where the testing device is located are searched according to the water delivery engineering location, and then the water delivery pressure P 2 and the temperature condition T 2 required to be set in the experiment are calculated.
4. 4. The method for testing the air content of the water transmission pipeline aiming at different altitude areas according to claim 1, wherein the water transmission project of the pipeline is pressurized water transmission, the pressure head applied by conversion can be carried out according to Bernoulli equation, , Wherein ρ is density, g is gravitational acceleration, v is flow velocity, P is pressure, h is height of the point, and C is constant.
5. 5. The device of the water pipe air content testing method for different altitude areas according to claim 1, comprising a transparent organic glass pipe (1), a water control tank (7), an air compressor (8) and a water pump (10), wherein the transparent organic glass pipe (1) is arranged in the middle of the device, embedded flanges (5) are arranged at two ends of the transparent organic glass pipe (1), the left flange (5) is connected to the right upper part of the water control tank (7) through a connecting pipe, a left valve (62), the water pump (10) and an electromagnetic flowmeter (11) are sequentially arranged on the connecting pipe connected to the right upper part of the water control tank (7) from left to right, the flange (5) on the right side is connected to the left lower part of the water control tank (7) through a connecting pipe, a right valve (63) is arranged on the connecting pipe connected to the left lower part of the water control tank (7), and the left upper wall of the transparent organic glass pipe (1) is connected with the air compressor (8) through the air compressor (8) on the connecting pipe connected with the left air compressor (1).
6. 6. The device of the water pipe air content testing method for different altitude areas according to claim 5, wherein the pressure sensor (2) and the temperature sensor (3) are installed in the transparent organic glass pipe (1), and the high-precision stainless steel graduated scale (4) is installed at the center of the right end flange (5) of the transparent organic glass pipe (1).
7. 7. The device of the water pipe air content testing method for different altitude areas according to claim 6, wherein the right end flange (5) of the transparent organic glass pipe (1) is a pre-opening transparent blind flange, and is connected with the right connecting pipe, and the high-precision stainless steel graduated scale (4) can be observed to measure the water depth through the pre-opening transparent blind flange.
8. 8. The device of the water pipe gas content testing method for different altitude areas according to claim 5, wherein the bottom of the transparent organic glass pipe (1) and the bottom of the water tank (7) are fixedly connected with a bracket (9) in a threaded manner.
9. 9. The device of the method for testing the air content of the water pipe in different altitude areas according to claim 5, wherein the length of the transparent organic glass pipe (1) is L, the wall thickness is delta, the inner diameter is r, and the calculation formula of the inner diameter is: 。

Description

Method and device for testing air content of water pipeline aiming at different altitude areas Technical Field The invention relates to the technical field of hydraulic engineering, in particular to a method and a device for testing the air content of water pipelines in different altitude areas. Background The temperature and the air pressure corresponding to different elevation areas are different, so that the water temperature and the dissolved gas content in water in various pipeline water delivery systems of long-distance water guiding and regulating engineering, hydropower stations, pump stations and the like are different. The temperature, the air pressure and the pressure water head during pressurized water delivery can influence the change of the air content in water in the water delivery pipeline, and the air content in the water delivery pipeline is different due to the fact that the front end of the pipeline is filled with air or dissolved gas in water in the start-stop process of the pipeline water delivery system, so that different influences are generated on the water delivery system, namely ① influences the pressure of a pipeline water hammer when a valve is operated under the conditions of operation regulation and control of the water delivery system and water supply requirements (such as the decrease of the air content and the increase of the peak value of the pressure of the pipeline water hammer), ② influences the area of an overflow section and an on-way resistance coefficient due to the change of the air content when the water delivery pipeline contains bubbles, air bags and air clusters, so that the water delivery capacity of the pipeline is influenced, ③ influences the saturated steam pressure of the water delivery system due to the difference of the temperature and the pressure when the fluctuation and the transient flow of the water delivery pipeline are accompanied by the air entrainment, so that cavitation of the water delivery system occurs, and vibration and noise of a water delivery structure are caused, and even the surface degradation of the structure is caused, and the effective volume modulus is influenced due to the change of the air content when ④ influences on buffering and protection. In order to ensure the safe operation of the water delivery system, it is necessary to develop test experiments and researches on the air content of the water delivery pipeline under different conditions of temperature and air pressure in different elevation areas, so that a set of test device capable of simulating and testing the air content of the water delivery pipeline under different elevation conditions is designed. Firstly, according to the altitude and hydrologic data of a water delivery engineering place, the design pressure water head of the air pressure, the water temperature and the water delivery pipeline is known, the conditions are simulated by a designed testing device, and experimental data are collected to calculate the air content, so that a certain reference is provided for the water hammer and vaporization analysis of the water delivery pipeline in different altitude areas due to different air content, and corresponding protective measures are taken to ensure the safe operation of the water delivery system. The existing section gas content test is mainly concentrated in the fields of heat supply pipelines, chemical industry and petroleum, and is characterized in that a vertical rising pipe is tested on a high-temperature high-pressure test bench, a normal-temperature normal-pressure vertical rising pipe is tested by adopting a gamma ray method, the tested fluid and water have different parameters (density and viscosity coefficient), environment working conditions are different, a long-distance water conveying pipeline system is mainly distributed at a small inclination angle, a chromatographic imaging method can be used for measuring section gas content, the accuracy is higher, the operation is complex, signals of a gas-liquid two-phase contact interface are required to be processed, and the technical requirement is higher. Therefore, the prior art cannot be used for testing the gas content in the water-gas two-phase flow in the water pipeline, and the gas content under the influence of air pressure, temperature and pressure water heads in different altitude areas cannot be fully considered. In addition, the gamma ray method is not affected by the flow pattern, but is harmful to the human body due to radioactivity, and has relatively high maintenance and use costs. Disclosure of Invention The invention aims to provide a method and a device for testing the air content of a water pipeline aiming at different altitude areas, and solves the problems that the operation is complex, the radioactivity is dangerous, the maintenance and use costs are relatively high, and the air content under the influence of air pressure, temperature and pressure water heads in different altitu