Experimental device and measuring method for measuring plug-wall friction in vertical pipe hydraulic transportation

Abstract

The application discloses an experimental device and a measuring method for measuring the friction force between an embolus and a pipe wall in vertical pipe hydraulic transportation, comprising a water circulation pipeline module, an embolus of different particle size groups and a measuring module. The application can verify the friction force between the embolus and the pipe wall under different particle size group combinations, provide important data support for designing and optimizing the vertical hydraulic transportation system, and especially analyze the pipe wall friction force under different sediment combinations; the modular design ensures the flexible adjustment and repeated use of the experimental device, improves the reliability and consistency of the experimental results; through in-depth study on the friction force of different sediment embolus, the vertical hydraulic transportation system is optimized, the risk of pipeline blockage caused by embolus formation in the transportation process is reduced, and the efficiency and safety of the overall system are improved. The application has wide application prospect, provides important experimental data and theoretical support for the development and practical application of related technologies, and hopes to promote the industry technology progress.

Description

Technical Field

[0001] This invention belongs to the field of measurement, specifically relating to an experimental apparatus and measurement method for measuring the frictional force between a plug and the pipe wall in a vertical pipe hydraulic transport process. Background Technology

[0002] Vertical pipe hydraulic transport is a highly efficient method for transporting solid bulk materials, widely used in various industrial sectors, including dredging, onshore mining, and deep-sea mining. In these applications, transporting suspended sediments and ores via vertical pipes is particularly important. However, during long-distance vertical hydraulic transport, the formation of solid sediment emboli can lead to pipe blockage, affecting transport efficiency and safety. Therefore, an experimental apparatus is needed to measure and analyze the wall friction forces of sediment emboli during vertical hydraulic transport in detail, in order to optimize the design and operation of vertical transport systems and avoid vertical pipe blockage caused by sediment emboli formation. However, research in this area is still very limited. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an experimental apparatus and measurement method for measuring the frictional force between emboli and pipe walls in vertical pipe hydraulic transport, thereby optimizing the design and operation of vertical transport systems and preventing vertical pipe blockage caused by sediment embolism.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An experimental apparatus for measuring the frictional force between a plug and the pipe wall in a vertical pipe hydraulic transport process includes a water circulation pipeline module, a plug module, and a measurement module. The water circulation pipeline module provides the water flow dynamics and circulating water environment required for the experiment, ensuring continuous water circulation during the experiment. The plug module includes sediment particle groups of different sizes, and by controlling the layered combination of sediments, it simulates the formation of sediment plugs under actual working conditions. The measurement module is used to accurately measure and record the frictional force and related parameters between the sediment plug and the pipe wall during the experiment.

[0006] Furthermore, the water circulation pipeline module includes an ascending pipe and a descending pipe, each with an inner diameter of 100 mm and a length of 2 m, and is made of transparent PVC.

[0007] Furthermore, the sediment particle group is uniformly injected in layers from the particle inlet of the water circulation pipe module, consisting of two layers of particle groups with different particle sizes stacked in layers. The bottom layer of sediment particles is placed above the closed valve and at the bottom of the riser pipe.

[0008] Furthermore, the sediment particle group includes coarse sand and gravel.

[0009] Furthermore, the coarse sand has a particle size of 2 mm and a density of 2600 kg / m³.3 The gravel has a particle size of 7 mm and a density of 2600 kg / m³. 3 .

[0010] Furthermore, the measurement system includes a first pressure sensor, a second pressure sensor, a flow meter, and a high-speed camera; the first and second pressure sensors are used to measure the pressure changes of the sediment plug during its movement, and are respectively installed 60 cm and 300 cm above the valve; the flow meter is installed between the water tank and the centrifugal pump to measure the changes in water flow in the system; the high-speed camera is used to record the movement of the sediment plug and is installed outside the riser pipe.

[0011] The present invention also provides a method for measuring the frictional force between a plug and the pipe wall in a vertical pipe hydraulic transport process, comprising the following steps:

[0012] Step 1: Place a batch of sediment particles evenly above the closed valve and at the bottom of the riser pipe;

[0013] Step 2: Start the centrifugal pump and gradually increase the water pressure below the valve; ensure there is no flow in the system to form an initial static pressure difference; at this time, the difference between the first pressure sensor and the second pressure sensor records the hydrostatic pressure difference of the water column and the gravity of a portion of the sediment plug.

[0014] Step 3: Quickly open the valve to allow the sediment plug to begin moving under the pressure differential; at this time, water flows through the sediment plug, causing it to move upwards along the riser pipe; calculate the sediment plug movement time. ;

[0015] Step 4: Record the pressure difference The pressure change of the deposit plug during its movement is recorded by the difference between the first and second pressure sensors. The first and second pressure sensors are installed 60 cm and 300 cm above the valve, respectively, and the distance between the first and second pressure sensors is denoted as [missing information]. The flow meter records the change in water flow rate Q. f The movement of the sediment plug was filmed using a high-speed camera, which was installed outside the riser pipe to record the movement of the sediment plug in detail.

[0016] Step 5: After the experiment, save all measurement data and import them into the computer for analysis; use pressure data, flow data and motion video to analyze the motion behavior and friction of sediment embolism.

[0017] Furthermore, step 4 also includes:

[0018] At the start of the experiment, the hydrostatic pressure difference of the water column and a portion of the weight of the sediment plug were recorded using the difference between the first and second pressure sensors. After the valve was opened, the difference between the first and second pressure sensors recorded the total pressure required for the initial movement of the sediment plug. The excess pressure generated by the sediment plug due to fluid acceleration was calculated. The formula is as follows:

[0019] ;

[0020] in, This represents the time it takes for a sediment embolism to travel between two sensors, i.e., the time required for the sediment embolism to move from one sensor location to another, calculated from the time captured by the high-speed camera. This indicates the cross-sectional area of ​​the pipe. Indicates the mass of sediment embolism, This indicates the distance between the two pressure sensors.

[0021] Further, step 5 includes:

[0022] The frictional force is obtained by subtracting the static gravity of the deposit plug and the pressure drop caused by acceleration from the differential pressure data measured by the difference between the first and second pressure sensors, as shown in the following formula:

[0023] ;

[0024] in, This indicates the measured pressure difference. The density of sediment emboli indicates the density of the sediment plug. Indicates fluid density, Indicates the volume fraction of sediments. Indicates the total length of the sediment embolism. Indicates the length of the sediment embolism layer. Indicates the length of the upper sediment embolism, Indicates the pipe diameter. This indicates the pressure drop caused by accelerated sediment embolism.

[0025] Beneficial effects:

[0026] This invention can verify the pipe wall friction force of sediment emboli under different particle size combinations, providing important data support for the design and optimization of vertical hydraulic transport systems, especially for analyzing the friction force under different sediment combinations. The modular design ensures flexible adjustment and reusability of the experimental apparatus, improving the reliability and consistency of experimental results. By deeply studying the friction force of different sediment emboli, the vertical hydraulic transport system can be optimized, reducing the risk of pipe blockage caused by embolism during transportation and improving the overall system efficiency and safety. This invention has broad application prospects, providing important experimental data and theoretical support for the development and practical application of related technologies, and is expected to promote technological progress in the industry. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the experimental apparatus for measuring the frictional force between the plug and the pipe wall in vertical pipe hydraulic transport according to the present invention.

[0028] The attached diagram is labeled as follows: 1. Ascending pipe; 2. Descending pipe; 3. Centrifugal pump; 4. Water tank; 5. Valve; 6. First pressure sensor; 7. Second pressure sensor; 8. Flow meter; 9. High-speed camera; 10. Particle inlet. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] like Figure 1 As shown, the experimental apparatus of the present invention for measuring the frictional force between the plug and the pipe wall in vertical pipe hydraulic transport includes a water circulation pipe module, a plug module, and a measurement module.

[0031] The water circulation pipeline module includes an ascending pipe 1 and a descending pipe 2, each with an inner diameter of 100 mm and a length of 2 m, made of transparent PVC. A centrifugal pump 3 is installed on one side of the loop, with a maximum flow rate of 20 m³ / h. 3 The pump has a flow rate of / h and a maximum head of 50 m, providing water flow power. Water tank 4 has a capacity of 60 L and is used to provide circulating water. Valve 5, made of stainless steel and installed at the bottom of riser pipe 1, is used to release sediment at the start of the experiment.

[0032] The embolization module comprises sediment particle groups of different sizes, which are uniformly injected in layers from the particle inlet 10 of the riser pipe 1. The layers consist of two stratified layers of particle groups of different sizes, with the bottom layer positioned above the closed valve 5 at the bottom of the riser pipe 1. The sediment particle groups include coarse sand and gravel, with the coarse sand having a particle size of 2 mm and a density of 2600 kg / m³. 3 The gravel has a particle size of 7 mm and a density of 2600 kg / m³. 3 The assemblage of sediment particles can be adjusted according to experimental requirements, such as coarse sand on top and gravel at the bottom, or vice versa.

[0033] The measurement module includes a first pressure sensor 6, a second pressure sensor 7, a flow meter 8, and a high-speed camera 9. The first pressure sensor 6 and the second pressure sensor 7 are used to measure pressure changes during the movement of the sediment plug. The first pressure sensor 6 and the second pressure sensor 7 are installed 60 cm and 300 cm above the valve 5, respectively, with a measurement range of 0-10 kPa and an accuracy of ±0.04%. The flow meter 8 is located between the water tank 4 and the centrifugal pump 3 to measure changes in water flow in the system, with a measurement range of 0-20 m³ / s. 3 / h, with an accuracy of ±0.5%. High-speed camera 9 is used to record the movement of sediment plugs at a frame rate of 500 frames per second and a resolution of 1920×1080 pixels. It is installed next to riser pipe 1.

[0034] The measurement method of the present invention includes:

[0035] Step 1, Preparations, including:

[0036] (1) Placement of sediment: Place a batch of sediment (such as coarse sand or gravel) evenly at the bottom of the riser pipe 1 above the closed valve 5. Adjust the layering of sediments according to experimental requirements (e.g., coarse sand on top, gravel on the bottom, or vice versa).

[0037] (2) System check: Check all connecting pipes and equipment to ensure there are no leaks or damage. Ensure that there is enough water in tank 4 for experimental circulation.

[0038] Step 2: Start the centrifugal pump, including:

[0039] (1) Start the centrifugal pump and gradually increase the water pressure below the valve;

[0040] (2) Ensure there is no flow within the system to create an initial static pressure difference. At this time, the difference between the first pressure sensor 6 and the second pressure sensor 7 records the hydrostatic pressure difference of the water column and the gravity of a portion of the sediment plug. ,in, The density of sediment emboli indicates the density of the sediment plug. Indicates fluid density, Indicates the volume fraction of sediments. (This represents the length of the sediment plug, and g is the acceleration due to gravity).

[0041] Step 3: Open valve 5 to release the sediment, including:

[0042] (1) Quickly open the valve to allow the sediment plug to start moving under the pressure difference. At this time, water flows through the sediment plug, causing it to move upward along the riser pipe.

[0043] (2) Calculate the sediment embolism time The time it takes for the sediment embolism to pass between the first pressure sensor 6 and the second pressure sensor 7.

[0044] Step 4: Collect data, including:

[0045] (1) Record the pressure difference The pressure difference between the first pressure sensor 6 and the second pressure sensor 7 records the pressure change of the deposit plug during its movement. The first pressure sensor 6 and the second pressure sensor 7 are installed 60 cm and 300 cm above the valve, respectively, and the distance between the two pressure sensors is denoted as... .

[0046] (2) Flow meter 8 records the change in water flow rate Q f The measurement range is 0-20 m. 3 / h, with an accuracy of ±0.5%.

[0047] (3) The movement of the sediment plug is filmed using a high-speed camera 9. The frame rate of the high-speed camera 9 is 500 frames per second. The high-speed camera 9 is installed next to the riser pipe 1 to record the movement of the sediment plug in detail.

[0048] Step 5: Data Saving and Processing: After the experiment, all measurement data were saved and imported into a computer for analysis. Pressure data, flow data, and motion videos were used to analyze the motion behavior and friction of the sediment embolism.

[0049] Specifically, step 4 further includes:

[0050] At the start of the experiment, the hydrostatic pressure difference of the water column and a portion of the gravity of the sediment plug were recorded using the difference between the first pressure sensor 6 and the second pressure sensor 7. After the valve was opened, the difference between the first pressure sensor 6 and the second pressure sensor 7 recorded the total pressure required for the initial movement of the sediment plug; the excess pressure generated by the sediment plug due to fluid acceleration was calculated using the following formula:

[0051] ;

[0052] in, This indicates the distance between the two pressure sensors. This represents the time it takes for a sediment embolism to travel between two sensors. It is the time required for the sediment embolism to move from one sensor location to the other, calculated from the time captured by the high-speed camera. This indicates the cross-sectional area of ​​the pipe. Indicates the mass of sediment embolism, This indicates the distance between the two pressure sensors.

[0053] Specifically, step 5 includes:

[0054] The frictional force is obtained by measuring the pressure difference using pressure sensor 1 and pressure sensor 2, subtracting the static weight of the deposit plug and the pressure drop caused by acceleration, as shown in the following formula:

[0055] ;

[0056] in, This indicates the measured pressure difference. The density of sediment emboli indicates the density of the sediment plug. Indicates fluid density, Indicates the volume fraction of sediments. Indicates the total length of the sediment embolism. Indicates the length of the sediment embolism layer. Indicates the length of the upper sediment embolism, Indicates the pipe diameter. This indicates the pressure drop caused by accelerated sediment embolism.

Claims

1. An experimental apparatus for measuring the frictional force between a plug and the pipe wall in a vertical pipe hydraulic transport process, characterized in that, The system includes a water circulation pipeline module, an embolization module, and a measurement module. The water circulation pipeline module provides the water flow dynamics and circulating water environment required for the experiment, ensuring continuous water circulation during the experiment. The embolization module includes sediment particle groups of different sizes, and by controlling the layered combination of sediments, it simulates the formation of sediment emboli under actual working conditions. The measurement module is used to accurately measure and record the frictional force and related parameters between the sediment emboli and the pipe wall during the experiment. The water circulation pipeline module includes an ascending pipeline and a descending pipeline, and the material is transparent PVC. The sediment particle group is uniformly injected in layers from the particle inlet of the water circulation pipeline module, and consists of two layers of particle groups with different particle sizes stacked in layers. The sediment particle group includes coarse sand and gravel; The measurement module includes a first pressure sensor, a second pressure sensor, a flow meter, and a high-speed camera. The first and second pressure sensors are used to measure the pressure changes of the sediment plug during its movement. The first and second pressure sensors are installed 60 cm and 300 cm above the valve, respectively. The flow meter is placed between the water tank and the centrifugal pump to measure the changes in water flow in the module. The high-speed camera is used to record the movement of the sediment plug and is installed outside the riser pipe.

2. The experimental apparatus for measuring the frictional force between the plug and the pipe wall in vertical pipe hydraulic transport according to claim 1, characterized in that, The water circulation pipe module has an inner diameter of 100 mm and a length of 2 m.

3. The experimental apparatus for measuring the frictional force between the plug and the pipe wall in vertical pipe hydraulic transport according to claim 1, characterized in that, The bottom layer of sediment particles is placed above the closed valve and at the bottom of the riser pipe.

4. The experimental apparatus for measuring the frictional force between the plug and the pipe wall in vertical pipe hydraulic transport according to claim 1, characterized in that, The coarse sand has a particle size of 2 mm and a density of 2600 kg / m³. 3 The gravel has a particle size of 7 mm and a density of 2600 kg / m³. 3 .

5. A method for measuring the frictional force between a plug and the pipe wall in a vertical pipe hydraulic transport process, characterized in that, Includes the following steps: Step 1: Place a batch of sediment particles evenly above the closed valve and at the bottom of the riser pipe; Step 2: Start the centrifugal pump and gradually increase the water pressure below the valve; ensure there is no flow in the system to form an initial static pressure difference; at this time, the difference between the first pressure sensor and the second pressure sensor records the hydrostatic pressure difference of the water column and the gravity of a portion of the sediment plug. Step 3: Quickly open the valve to allow the sediment plug to begin moving under the pressure differential; at this time, water flows through the sediment plug, causing it to move upwards along the riser pipe; calculate the sediment plug movement time. ; Step 4: Record the pressure difference The pressure change of the deposit plug during its movement is recorded by the difference between the first and second pressure sensors. The first and second pressure sensors are installed 60 cm and 300 cm above the valve, respectively, and the distance between the first and second pressure sensors is denoted as [missing information]. The flow meter records the change in water flow rate Q. f The movement of the sediment plug was filmed using a high-speed camera, which was installed outside the riser pipe to record the movement of the sediment plug in detail. Step 5: After the experiment, save all measurement data and import them into the computer for analysis; use pressure data, flow data and motion video to analyze the motion behavior and friction of sediment embolism.

6. The measurement method according to claim 5, characterized in that, Step 4 also includes: At the start of the experiment, the hydrostatic pressure difference of the water column and a portion of the weight of the sediment plug were recorded using the difference between the first and second pressure sensors. After the valve was opened, the difference between the first and second pressure sensors recorded the total pressure required for the initial movement of the sediment plug. The excess pressure generated by the sediment plug due to fluid acceleration was calculated. The formula is as follows: ； in, This represents the time it takes for a sediment embolism to travel between two sensors, i.e., the time required for the sediment embolism to move from one sensor location to another, calculated from the time captured by the high-speed camera. This indicates the cross-sectional area of ​​the pipe. Indicates the mass of sediment embolism, This indicates the distance between the two pressure sensors.

7. The measurement method according to claim 5, characterized in that, Step 5 includes: The frictional force is obtained by subtracting the static gravity of the deposit plug and the pressure drop caused by acceleration from the differential pressure data measured by the difference between the first and second pressure sensors, as shown in the following formula: ； in, This indicates the measured pressure difference. The density of sediment emboli indicates the density of the sediment plug. Indicates fluid density, Indicates the volume fraction of sediments. Indicates the total length of the sediment embolism. Indicates the length of the sediment embolism layer. Indicates the length of the upper sediment embolism, Indicates the pipe diameter. This indicates the pressure drop caused by accelerated sediment embolism.

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