Air lift system with variable air volume and control method

Abstract

The invention relates to the technical field of multiphase flow testing, in particular to a variable-air-volume pneumatic lifting system and a control method.The variable-air-volume pneumatic lifting system comprises an air supply module, a material supply module, a vertically-arranged lifting stand pipe, an air flow control module and a testing module, and the air flow control module comprises a laminar flow measuring unit and an electromagnetic proportional valve; the laminar flow measuring unit is arranged on a gas conveying pipeline between the gas supply module and the lifting riser and measures the gas volume flow by detecting the laminar flow pressure difference at the two ends of the laminar flow measuring unit, and the electromagnetic proportional valve is located on the gas inlet side of the laminar flow measuring unit and electrically connected with the gas inlet side of the laminar flow measuring unit. The opening degree can be automatically adjusted according to the comparison result of the gas volume measurement value and the preset flow value sent by the upper computer, closed-loop control is formed, and the upper computer of the testing module is used for sending the preset flow value and recording the gas volume flow in real time. Through laminar flow measurement and electromagnetic proportional valve closed-loop control, high-precision dynamic programmed adjustment of the air inflow of the pneumatic lifting system is achieved, and the limitation that a traditional device is single in working condition is overcome.

Description

Technical Field

[0001] This invention belongs to the field of multiphase flow testing technology, specifically relating to a variable gas volume pneumatic boosting system and control method. Background Technology

[0002] Pneumatic booster pumps, as important multiphase flow conveying and testing equipment, are widely used in mining, environmental protection, chemical engineering, and marine engineering. They are primarily used to lift and mix solid, liquid, and gaseous media in vertical or inclined pipelines. Their basic working principle utilizes compressed air as a power source, injecting a high-speed airflow into the bottom of the booster pipe through a gas nozzle. This causes the liquid or solid-liquid mixture within the pipe to rise due to density differences and momentum exchange, thereby achieving material conveying or fluid circulation. In experimental research and engineering testing, the performance evaluation of pneumatic booster pumps often relies on the measurement and analysis of parameters such as flow rate, pressure, lifting efficiency, and multiphase flow pattern under different inlet conditions.

[0003] Currently, common pneumatic booster pump air supply systems typically operate by continuously injecting compressed air into the booster pipe through nozzles at a basically constant flow rate after the pressure is stabilized by a pressure regulating valve. Although this constant flow air supply method is simple in structure and easy to control, it has gradually revealed the following limitations in practical applications and experimental tests: (1) The constant air intake mode cannot truly simulate complex and variable actual engineering conditions. In actual industrial scenarios, pneumatic booster pumps often face operating conditions with fluctuating air intake, such as unstable air source pressure, changes in the characteristics of the conveyed materials, and fluctuations in pipeline resistance. These factors will all lead to natural changes in air intake. The performance parameters (such as boosting efficiency, critical submersion rate, pulsation frequency, etc.) measured by the pneumatic booster pump under constant flow conditions often deviate from the actual situation under variable conditions, which limits the guiding value of experimental data for engineering design; (2) Due to the strong nonlinear and transient characteristics of the gas-liquid-solid multiphase flow in the booster pipe, the system is prone to enter steady-state or quasi-steady-state flow under constant air intake conditions, which masks the generation and evolution of certain transient flow phenomena (such as intermittent flow, slug flow, strong pulsation, etc.). These transient phenomena often have a significant impact on the pump's operational stability, vibration noise, wear life, and energy efficiency. The lack of experimental research methods under variable intake conditions limits a deeper understanding and optimization of the dynamic characteristics of pneumatic booster pumps.

[0004] Therefore, existing pneumatic booster pump experimental devices generally suffer from problems such as single operating conditions and insufficient dynamic simulation capabilities in terms of air intake control, which restricts their further application in multiphase flow mechanism research, pump type optimization design, and complex operating condition adaptability assessment. Summary of the Invention

[0005] This invention provides a variable air volume pneumatic boosting system and control method to solve the problem that the air intake conditions of existing pneumatic boosting pumps are singular and cannot simulate dynamic changes.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a variable air volume pneumatic lifting system, comprising: The air supply module provides and delivers compressed air; The feeding module provides and conveys a multiphase medium containing particles and liquids; A vertically arranged lifting riser is provided, with its bottom connected to the air supply module and the material supply module, respectively, so that the multiphase medium is lifted inside the lifting riser under the drive of compressed air. The airflow control module includes a laminar flow measurement unit and an electromagnetic proportional valve. The laminar flow measurement unit is installed on the gas supply pipeline connecting the gas supply module and the lift riser, and measures the volumetric flow rate of the gas flowing through it by detecting the laminar flow pressure difference at both ends of the laminar flow measurement unit. The electromagnetic proportional valve is electrically connected to the laminar flow measurement unit and is located on the gas inlet side of the laminar flow measurement unit. It is used by the laminar flow measurement unit to adjust the opening of the electromagnetic proportional valve according to the comparison between the gas volume measurement value and the preset flow rate value. The testing module includes a host computer electrically connected to the laminar flow measurement unit, used to send a preset flow rate value to the laminar flow measurement unit and to receive and record the gas volume flow rate transmitted by the laminar flow measurement unit in real time.

[0007] Optionally, the laminar flow measurement unit includes a measurement housing, a laminar flow assembly disposed within the measurement housing, a differential pressure sensor disposed outside the measurement housing, and a lower-level computer; One end of the measuring housing is provided with an air inlet port, which is connected to the air supply module. The other end of the measuring housing is provided with an air outlet port, which is connected to the bottom of the lifting riser. The laminar flow assembly includes multiple laminar flow channels that are separated and distributed in parallel along the vertical direction within the measuring housing. An upstream pressure tap is provided on the top wall of the measuring housing near the air inlet port, and the multiple laminar flow channels are connected vertically to the upstream pressure tap. A downstream pressure tap is provided on the top wall of the measuring housing near the air outlet port, and the multiple laminar flow channels are connected vertically to the downstream pressure tap. The differential pressure sensor is located above the measuring housing, with one end of the differential pressure sensor connected to the upstream pressure tap and the other end of the differential pressure sensor connected to the downstream pressure tap. The lower-level computer is electrically connected to the differential pressure sensor and is used to receive the differential pressure signal to calculate the gas volume flow rate.

[0008] Optionally, the lower-level machine includes a first display screen with an interactive interface for setting and generating different flow condition commands, and the upper-level machine includes a second display screen with an interactive interface for setting and generating preset flow commands. The lower-level machine and the upper-level machine are electrically connected, and the lower-level machine receives the preset flow commands sent by the upper-level machine and generates valve opening adjustment commands based on the comparison result of the gas volume measurement value and the preset flow value.

[0009] Optionally, the testing module further includes a particle image velocity measurement component and a pressure detection component. A gas injection port is provided on the pipe wall near the bottom of the lifting riser. The gas injection port is connected to the gas supply module. The particle image velocity measurement component includes an illumination light source and an image acquisition device disposed on one side of the lifting riser. The working direction of the illumination light source and the image acquisition device are both towards the middle section of the lifting riser. The host computer is electrically connected to the image acquisition device. The pressure detection assembly includes a first pressure sensor disposed at the gas injection port and a second pressure sensor disposed at the gas outlet side at the top of the lifting riser. The host computer is electrically connected to the first pressure sensor and the second pressure sensor respectively.

[0010] Optionally, the gas supply module includes an air compressor, a refrigerated dryer, and a gas storage tank connected in sequence. The gas storage tank is connected to the air inlet port, and a first control valve is provided on the gas supply pipeline connecting the air compressor and the refrigerated dryer, and a second control valve is provided on the gas supply pipeline connecting the gas storage tank and the air inlet port. A gas injector is provided between the measuring housing and the lifting riser. One end of the gas injector is connected to the gas outlet port, and the other end of the gas injector forms a tapered nozzle. The nozzle is inserted into and fixed in the gas inlet. A check valve is provided on the gas supply pipeline connecting the gas injector and the gas outlet port.

[0011] Optionally, the pneumatic lifting system further includes a media separation unit, which includes a gas separation chamber and a solid-liquid separator; The bottom wall of the gas separation chamber is inclined. The top end of the lifting riser is located at the bottom wall of the high side of the gas separation chamber and is connected to the gas separation chamber. The second pressure sensor is fixed on the top inner wall of the gas separation chamber at the position corresponding to the top end of the lifting riser. A vertical medium discharge pipe is provided below the gas separation chamber. The medium discharge pipe is located at the bottom wall of the low side of the gas separation chamber and is connected to the gas separation chamber. A gas outlet is opened on the top wall of the gas separation chamber at the position corresponding to the medium discharge pipe. The solid-liquid separator includes a separation container and a filter assembly disposed within the separation container. The separation container is located below the media discharge pipe, and the top of the separation container has an open structure facing the media discharge pipe.

[0012] Optionally, the filter assembly includes a multi-stage filter screen detachably connected within the separation container, wherein the multi-stage filter screens are distributed vertically and the pore size of the multi-stage filter screens decreases sequentially along the vertical direction. The testing module also includes a first weighing device and a weighing water tank. The first weighing device is used to weigh the filtered solid particles. The weighing water tank includes a weighing box body and a second weighing device disposed at the bottom of the weighing box body. The weighing box body is located below the separation container and connected to the bottom of the separation container. A regulating water tank is provided between the weighing box and the separation container, and an electrically controlled three-way valve is provided on the infusion pipeline connecting the weighing box and the separation container. The electrically controlled three-way valve is connected to the regulating water tank.

[0013] Optionally, the feeding module includes a mixing tank, a pellet supply component, and a mobile water supply component; The mixing tank includes a mixing tank body located below the lifting riser, and a material container plate fixed inside the mixing tank body. The material container plate surrounds an upward-opening solid-liquid mixing zone inside the mixing tank body, and the top of the mixing tank body has an open structure. The bottom end of the lifting riser has a gradually expanding medium inlet located within the solid-liquid mixing zone. The particle supply assembly includes a particle supply chamber and a vertically arranged particle conveying pipe. One end of the particle conveying pipe is connected to the bottom of the particle supply chamber, and the other end of the particle conveying pipe is positioned above the mixing chamber corresponding to the position of the solid-liquid mixing zone. A third control valve is provided on the particle conveying pipe. The mobile water supply assembly includes a lifting platform, a mobile water tank, a storage tank, and a water pump. The mobile water tank is fixed on the lifting platform and connected to the mixing tank. A fourth control valve is provided on the infusion pipeline connecting the mobile water tank and the mixing tank. The storage tank, the water pump, and the mobile water tank are connected in sequence. An overflow pipe connected to the mobile water tank is also provided on the storage tank.

[0014] Optionally, the material container includes a first vertical plate and a second vertical plate arranged opposite to each other, and an arc-shaped plate horizontally connecting the first vertical plate and the second vertical plate. The top of the first vertical plate extends to the top opening of the mixing box, which is used to separate the solid-liquid mixing area from the internal space of the mixing box. A liquid inlet is provided on the side wall of the mixing box adjacent to the first vertical plate, and the liquid inlet is connected to the mobile water tank. The top of the second vertical plate is lower than that of the first vertical plate, and is used to connect the solid-liquid mixing zone and the internal space of the mixing box.

[0015] This invention discloses a control method using the aforementioned variable gas volume pneumatic lifting system, the control method comprising: The host computer receives waveform parameters defined based on the target operating condition and generates a preset flow command containing a continuous time-flow correspondence based on the waveform parameters. The waveform parameters include any one of sine wave, sawtooth wave, or gradient wave. The host computer sends the preset flow rate instruction to the laminar flow measurement unit, and in response to the laminar flow measurement unit receiving the preset flow rate instruction, the gas supply module starts to provide gas flow to the riser according to the waveform parameters contained in the preset flow rate instruction; The laminar pressure difference between its two ends is obtained in real time through the laminar flow measurement unit, and the obtained laminar pressure difference is calculated based on the Hagen-Poiseuille law to obtain the gas volume measurement value flowing through the laminar flow measurement unit. The gas volume measurement value is compared with the target flow value at the current moment in the preset flow command to obtain the instantaneous flow deviation. The instantaneous flow deviation is then calculated based on the preset PID control algorithm to obtain the valve opening adjustment amount. An opening control signal is generated based on the valve opening adjustment amount, and the electromagnetic proportional valve is driven to adjust the opening based on the opening control signal. In response to the opening adjustment of the electromagnetic proportional valve, the particle supply rate and liquid supply height supplied to the lifting riser are adjusted by the feeding module to simulate different solid-liquid mixing ratios and submersion rates. The host computer acquires and records the gas volume measurement value, the pressure value in the lift riser, and the particle flow state. Based on the acquired gas volume measurement value, pressure value, and particle flow state, the dynamic performance and multiphase flow pattern evolution law of the pneumatic lifting system under variable intake conditions are analyzed and determined.

[0016] Compared with the prior art, the variable gas volume pneumatic lifting system and control method provided in this embodiment of the invention have the following advantages: The laminar flow measurement unit of the airflow control module measures the gas volumetric flow rate delivered by the gas supply module in real time. The host computer sends a preset flow rate value to the laminar flow measurement unit, which drives the electromagnetic proportional valve to adjust the opening based on the comparison between the measured value and the preset value, thereby precisely controlling the amount of air entering the lift riser. This dynamic control allows the gas supply module to simulate various changing air intake conditions. Under the drive of variable air intake, the lift riser lifts the multiphase medium provided by the supply module. The test module records the gas volumetric flow rate data in real time through the host computer, which helps to achieve a comprehensive analysis of the system's performance improvement under different dynamic conditions, thus overcoming the limitations of the traditional constant air intake mode. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the overall structure of the pneumatic lifting system provided by the present invention; Figure 2 This is a schematic diagram of the structure of the laminar flow measurement unit provided by the present invention; Figure 3 This is a schematic diagram of the material container plate provided by the present invention.

[0019] The markings in the attached diagram are as follows: 1. Air supply module; 11. Air compressor; 111. First control valve; 12. Refrigerated dryer; 13. Air storage tank; 131. Second control valve; 2. Material supply module; 21. Mixing box; 22. Material receiving plate; 221. First vertical plate; 222. Second vertical plate; 223. Arc plate; 23. Pellet supply bin; 24. Pellet conveying pipe; 241. Third control valve; 25. Lifting platform; 26. Mobile water tank; 27. Water storage tank; 28. Water pump; 29. ​​Overflow pipe; 3. Lifting 31. Lifting pipe; 32. Gas injector; 4. Medium inlet; 4. Laminar flow measurement unit; 41. Measuring housing; 42. Differential pressure sensor; 43. Laminar flow channel; 5. Electromagnetic proportional valve; 6. Test module; 61. Image acquisition unit; 62. Weighing box; 63. Second weighing device; 64. Regulating water tank; 641. Electrically controlled three-way valve; 7. Medium separation unit; 71. Gas separation chamber; 72. Medium discharge pipe; 73. Gas discharge outlet; 74. Separation container; 75. Filter screen. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and 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, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 the present invention according to the specific circumstances. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] This invention provides a variable air volume pneumatic lifting system, such as... Figure 1 As shown, it includes: Air supply module 1 provides and delivers compressed air; Feeding module 2 provides and conveys a multiphase medium containing particles and liquids; The vertically arranged lifting riser 3 is connected at its bottom to the air supply module 1 and the material supply module 2, so that the multiphase medium is lifted inside the lifting riser 3 under the drive of compressed air. The airflow control module includes a laminar flow measurement unit 4 and an electromagnetic proportional valve 5. The laminar flow measurement unit 4 is installed on the gas supply pipeline connecting the gas supply module 1 and the lifting riser 3. It measures the volumetric flow rate of the gas flowing through by detecting the laminar flow pressure difference at both ends of the laminar flow measurement unit 4. The electromagnetic proportional valve 5 is electrically connected to the laminar flow measurement unit 4 and is located on the gas inlet side of the laminar flow measurement unit 4. It is used by the laminar flow measurement unit 4 to adjust the opening of the electromagnetic proportional valve 5 according to the comparison between the gas volume measurement value and the preset flow rate value. The test module 6 includes a host computer electrically connected to the laminar flow measurement unit 4, which is used to send preset flow values ​​to the laminar flow measurement unit 4 and to receive and record the gas volume flow rate transmitted by the laminar flow measurement unit 4 in real time.

[0027] Through the implementation of the above-described pneumatic lifting system embodiment, the airflow control module is introduced, which mainly consists of a laminar flow measurement unit 4 and an electromagnetic proportional valve 5. The laminar flow measurement unit 4 is directly installed on the gas supply pipeline connected to the gas supply module 1 and the lifting riser 3. Based on the laminar flow pressure difference measurement principle, that is, when the gas flows through the flow channel inside the laminar flow measurement unit 4, the pressure difference at both ends of it has a stable linear relationship with the gas volume flow rate. Therefore, by detecting the laminar flow pressure difference, the gas volume flow rate can be calculated in real time and accurately.

[0028] The electromagnetic proportional valve 5, acting as the actuator, is located on the inlet side of the laminar flow measurement unit 4 and is electrically connected to it, forming a closed-loop control circuit. During operation, the host computer in the test module 6 (typically an industrial control computer or high-performance industrial PC, such as a model equipped with an Intel Core i5 / i7 processor running Windows or Linux) first sends a preset flow rate value to the laminar flow measurement unit 4. This value can be a constant or a function sequence that dynamically changes over time (such as a sine wave, sawtooth wave, gradient wave, or a custom waveform). The preset flow rate value can be set via the host computer software interface (preferably a graphical programming environment such as National Instruments' LabVIEW or a general programming language such as Python combined with a control library) through input or script programming. After receiving the preset flow rate value, the laminar flow measurement unit 4 continuously measures the actual gas volume flow rate and compares the measured value with the preset value in real time. Based on the difference signal obtained from the comparison, the electromagnetic proportional valve 5 is preferably adjusted to change its opening degree via a built-in microcontroller.

[0029] If the measured value is lower than the preset value, the opening of the electromagnetic proportional valve 5 is increased to increase air intake; if the measured value is higher than the preset value, the opening is decreased to limit air intake. This closed-loop regulation mechanism based on laminar pressure differential feedback enables the gas volume flow rate to quickly and stably track the preset flow rate value, achieving precise and continuous control of the compressed air flow rate delivered from the air supply module 1 to the riser 3. Therefore, the air supply is no longer a constant output, but can be flexibly changed according to the preset mode, thereby simulating various dynamic air intake conditions in actual engineering. At the same time, the material supply module 2 continuously supplies multiphase medium to the bottom of the riser 3, making the riser 3, as the core conveying component, simultaneously receive the controlled airflow from the air supply module 1 and the multiphase medium from the material supply module 2 at its bottom. Driven by the variable air intake, a complex and adjustable multiphase flow is formed inside the pipe, which allows the system to realistically reproduce dynamic flow patterns such as pulsating flow and intermittent flow.

[0030] Preferably, the host computer is not only responsible for sending control commands, but also for receiving and recording the gas volumetric flow rate data transmitted by the laminar flow measurement unit 4 in real time (usually stored in Excel or TDMS format with a high sampling rate). The entire system enables researchers to accurately set any intake mode, thereby systematically studying the impact of changes in intake volume on the multiphase flow mechanism, lifting efficiency, pulsation characteristics, and energy consumption within the lift riser 3. This overcomes the shortcomings of traditional constant intake systems, such as limited operating conditions and insufficient dynamic simulation capabilities, and provides a highly flexible and comprehensive experimental platform for the optimized design, operating condition adaptability assessment, and fundamental research on multiphase flow of pneumatic lift pumps.

[0031] Furthermore, combined Figure 2As shown, the laminar flow measurement unit 4 includes a measurement housing 41, a laminar flow assembly disposed inside the measurement housing 41, a differential pressure sensor 42 disposed outside the measurement housing 41, and a lower-level computer; One end of the measuring housing 41 is provided with an air inlet port, which is connected to the air supply module 1. The other end of the measuring housing 41 is provided with an air outlet port, which is connected to the bottom of the lifting riser 3. The laminar flow assembly includes multiple laminar flow channels 43 that are separated and distributed in parallel along the vertical direction within the measuring housing 41. An upstream pressure tap is provided on the top wall of the measuring housing 41 near the air inlet port, and the multiple laminar flow channels 43 are connected vertically to the positions of the upstream pressure taps. A downstream pressure tap is provided on the top wall of the measuring housing 41 near the air outlet port, and the multiple laminar flow channels 43 are connected vertically to the positions of the downstream pressure taps. The differential pressure sensor 42 is located above the measuring housing 41. One end of the differential pressure sensor 42 is connected to the upstream pressure tap, and the other end of the differential pressure sensor 42 is connected to the downstream pressure tap. The lower-level computer is electrically connected to the differential pressure sensor 42 to receive differential pressure signals and calculate gas volume flow rate.

[0032] In the implementation of the above-described pneumatic lifting system embodiment, the measuring housing 41 adopts an integral design and is typically made of pressure-resistant and corrosion-resistant aluminum alloy or stainless steel (such as 304 or 316L stainless steel) through precision machining to ensure structural stability and sealing under high-pressure airflow. Its air inlet and outlet ports can be connected to the air supply pipeline of the air supply module 1 and the bottom of the lifting riser 3 respectively through standard flanges or quick-connect fittings. Sealing rings (such as nitrile rubber or fluororubber) can be configured at the interfaces to prevent leakage.

[0033] The laminar flow assembly within the measuring housing 41 is a key measuring element. It consists of multiple laminar flow channels 43 arranged in parallel along the vertical direction, ensuring that the gas remains in a laminar state as it flows through the measuring housing 41. This satisfies the applicability conditions of the Hagen-Poiseuille law, i.e., the pressure difference and flow rate are linearly related. The parallel distribution of multiple channels not only increases the overall flow capacity but also reduces the flow velocity of individual channels through flow diversion, further ensuring the stability of the laminar flow and improving the measurement range and contamination resistance.

[0034] On the top wall of the measuring housing 41, an upstream pressure tap is provided near the air inlet port, and a downstream pressure tap is provided near the air outlet port. These two pressure taps are vertically connected to the corresponding positions of all laminar flow channels 43 through internal channels, enabling the pressure taps to accurately and evenly collect the static pressure at the inlet and outlet of the flow channel group, avoiding measurement errors caused by local eddies or pressure fluctuations. The differential pressure sensor 42 is preferably a high-precision, low-drift silicon piezoresistive or capacitive sensor, such as Honeywell's TruStability series or Siemens' Sitrans P series, with a measurement accuracy of ±0.1% of full scale. The two pressure interfaces of the differential pressure sensor 42 are connected to the upstream and downstream pressure taps respectively through pressure guide tubes or direct sealed docking, to detect the laminar flow pressure difference across the laminar flow assembly in real time, and convert the pressure difference signal into an electrical signal (usually a 4-20mA analog signal or a digital signal such as I2C / SPI) for output. The lower-level device (often an embedded microcontroller, such as the STMicroelectronics STM32 series or the Texas Instruments MSP430 series based on the ARM Cortex-M4 core, with an integrated ADC module for signal acquisition) is electrically connected to the differential pressure sensor 42 and receives the differential pressure signal transmitted by the differential pressure sensor 42.

[0035] As described above, the control and operation of the lower-level machine and the upper-level machine are illustrated with an example: The lower-level machine can run embedded firmware, which uses a pre-programmed algorithm (based on the Hagen-Poiseuille law for flow calculation) to convert the pressure difference signal into an uncorrected gas volumetric flow rate value. It can also integrate inputs from temperature sensors (such as Pt100) and pressure sensors (such as absolute pressure sensors) to perform real-time temperature and pressure corrections on the gas volumetric flow rate, thus obtaining the volumetric flow rate under standard conditions. The correction algorithm is typically based on the ideal gas law and can incorporate lookup tables or polynomial fitting formulas to improve calculation speed and accuracy.

[0036] The lower-level computer is also responsible for communicating with the upper-level computer. The preferred communication interface is RS-485, Ethernet, or CAN bus to support long-distance reliable data transmission in industrial environments. The upper-level computer sends a preset flow rate value (which can be a constant value or a dynamic waveform parameter) to the lower-level computer. The lower-level computer can compare the calculated actual gas volume flow rate with the preset value, and generate a control command based on the difference using a PID control algorithm (proportional-integral-derivative control, parameters of which can be set by the upper-level computer software or self-tuned). This command drives the electromagnetic proportional valve 5 to adjust its opening degree through PWM or analog output, thus forming a closed-loop control system.

[0037] Furthermore, the lower-level computer includes a first display screen with an interactive interface for setting and generating different flow condition commands, and the upper-level computer includes a second display screen with an interactive interface for setting and generating preset flow commands. The lower-level computer and the upper-level computer are electrically connected so that the lower-level computer receives the preset flow commands sent by the upper-level computer and generates valve opening adjustment commands based on the comparison results of the gas volume measurement value and the preset flow value.

[0038] In the implementation of the above-described pneumatic lifting system embodiment, the lower-level computer acts as a field control unit. Its first display screen, featuring an interactive interface, is typically an embedded integrated touchscreen, such as a Weintek or Siemens simplified series panel. This first display screen is directly connected to the core microcontroller of the lower-level computer, forming an independent local operation and display terminal. The interactive interface of the first display screen can be developed based on an embedded real-time operating system (such as FreeRTOS), providing a simple and intuitive menu and parameter input area. This allows operators to directly set and generate different flow condition commands on-site: for example, inputting a fixed flow setting value via the touchscreen, or selecting several preset basic waveform modes (such as constant and step). This local interactive capability makes equipment debugging, emergency intervention, and independent operation without the upper-level computer possible, improving the system's operational redundancy and on-site adaptability.

[0039] The host computer serves as the system's monitoring and high-level command generation center. Its second display screen, typically an industrial computer monitor, features an interactive interface. The host computer's software can be built upon an NI data acquisition system (such as the NI LabVIEW development environment). Therefore, the second display screen is essentially the human-machine interface for running NI control programs. Through this interactive interface, researchers can utilize LabVIEW's graphical programming capabilities or script nodes to flexibly set and generate complex preset flow commands. For example, they can edit mathematical functions for sine waves, sawtooth waves, or custom "bow"-shaped waves, and set parameters such as amplitude, frequency, and offset to accurately describe the desired intake dynamics curve.

[0040] The lower-level computer communicates with the upper-level computer via an electrical connection, preferably using a high-speed serial bus such as Ethernet (TCP / IP protocol) or USB to ensure efficient and stable transmission of commands and data. The upper-level computer sends the generated preset flow command (usually in the form of a data array or function parameters) to the lower-level computer in real time through this electrical connection. After receiving the preset flow command, the lower-level computer's core control program begins to work: the lower-level computer continuously acquires signals from the differential pressure sensor 42 of the laminar flow measurement unit 4 and calculates the gas volume measurement value in real time. Then, it quickly compares this measurement value with the preset flow value corresponding to the current moment (derived from the received preset flow command) to calculate the instantaneous flow deviation. Based on this deviation, the control algorithm embedded in the lower-level computer (such as a digital PID controller) immediately calculates and generates a corresponding valve opening adjustment command. This command is converted into a drive signal (such as an analog voltage or PWM wave) that directly acts on the electromagnetic proportional valve 5, thereby achieving precise and rapid closed-loop regulation of the gas supply flow.

[0041] Therefore, this control structure, which integrates the first and second displays and constructs a collaborative electrical connection, enables the system to perform complex and varied intake condition programming and macroscopic experimental management through the host computer, and to achieve stable and precise local real-time closed-loop control through the slave computer. This not only makes the operation more user-friendly and flexible, but more importantly, it ensures high precision and rapid response of dynamic flow control, providing strong and reliable technical support for in-depth research on improving the multiphase flow mechanism and pump performance of riser 3 under various preset dynamic intake conditions.

[0042] Furthermore, looking back Figure 1 The test module 6 also includes a particle image velocity measurement component and a pressure detection component. A gas injection port is provided on the pipe wall near the bottom of the lifting riser 3. The gas injection port is connected to the gas supply module 1. The particle image velocity measurement component includes an illumination light source and an image acquisition device 61 set on one side of the lifting riser 3. The working direction of the illumination light source and the image acquisition device 61 is towards the middle section of the lifting riser 3. The host computer is electrically connected to the image acquisition device 61. The pressure detection assembly includes a first pressure sensor located at the gas injection port and a second pressure sensor located at the gas outlet side of the top of the lifting riser 3. The host computer is electrically connected to the first pressure sensor and the second pressure sensor respectively.

[0043] Through the implementation of the above-described pneumatic lifting system embodiment, the gas injection port on the lifting riser 3 is connected to the air supply module 1 to ensure that controlled compressed air is injected into the lifting riser 3. The particle image velocimetry component, as a key component for flow field visualization and quantitative measurement, has its illumination light source (usually preferably a continuous laser or a high-brightness LED surface light source, such as a 532nm semiconductor solid-state laser) and image acquisition device 61 (usually a high-frame-rate, high-resolution CMOS or CCD high-speed camera, such as the Photron SA-Z series) respectively positioned on one side of the lifting riser 3. Their working directions are precisely oriented towards the middle section of the lifting riser 3, which is a crucial observation section for gas-liquid-solid multiphase mixing and flow development. Simultaneously, to obtain clear particle images, the observation section of the lifting riser 3 needs to be made of transparent materials (such as plexiglass or borosilicate glass).

[0044] The illumination source projects sheet light or light of a specific wavelength onto the measurement plane, illuminating solid particles (i.e., tracer particles, such as hollow glass microspheres) in the flow field. The image acquisition unit 61 then continuously captures images of particle motion at high speed in a direction perpendicular to the light plane, thereby recording the transient structure of the flow field. The pressure detection component is responsible for acquiring pressure parameters at key locations. Its first pressure sensor (preferably a piezoresistive or ceramic capacitive pressure transmitter, such as a measurement range of 0-1 MPa and an accuracy of 0.1%) is directly installed at the gas injection port or on the pipeline near it to measure the inlet pressure when compressed air is injected. The second pressure sensor (the model can be the same as the first sensor or selected according to the outlet pressure range) is set on the outlet side at the top of the lifting riser 3 to measure the outlet pressure when the fluid is discharged after lifting.

[0045] The host computer serves as the data collection and processing center for the entire test module 6. It is electrically connected to the image acquisition unit 61, the first pressure sensor, and the second pressure sensor via a BNC or D-Sub interface cable using an NI data acquisition card. During operation, the host computer uses its software (e.g., NI LabVIEW with the Vision Development Module and DAQmx driver) to synchronously trigger and control each component. For the particle image velocimetry component, the host computer software controls the activation of the illumination light source and the acquisition frequency of the image acquisition unit 61, and receives high-speed sequential images transmitted by the image acquisition unit 61. Subsequently, the software analyzes the continuous images using built-in PIV (particle image velocimetry) processing algorithms (such as cross-correlation algorithms) to calculate the instantaneous velocity vector distribution, vorticity field, and other flow information within the observation plane. For the pressure detection component, the host computer software synchronously acquires the electrical signals from the first and second pressure sensors in real time via the data acquisition card and converts them into precise pressure values. This ensures that each frame of image acquired by the particle image velocimetry component has a precise temporal correspondence with each pressure data point acquired by the pressure detection component.

[0046] As described above, the entire system can not only actively change the intake conditions through the airflow control module, but also intuitively and quantitatively capture the complex transient flow pattern evolution (such as the transformation from slug flow to annular flow, and the generation and disappearance of local recirculation zones) caused by the variable intake volume inside the lift riser 3 through the particle image velocimetry component. At the same time, the pressure detection component synchronously acquires the dynamic pressure changes at the gas injection port and the top of the lift riser 3. By integrating and processing these synchronous flow field image data and pressure data, the host computer can deeply reveal the intrinsic causal relationship between the dynamic changes in intake volume, inlet / outlet pressure fluctuations, and the internal multiphase flow structure. This provides unprecedented multi-dimensional, high spatiotemporal resolution experimental data support for optimizing the design of the pneumatic lift pump and evaluating its operational stability and efficiency under different dynamic conditions.

[0047] Furthermore, the gas supply module 1 includes an air compressor 11, a refrigerated dryer 12 and a gas storage tank 13 connected in sequence. The gas storage tank 13 is connected to the air inlet port, and a first control valve 111 is provided on the gas transmission pipeline connecting the air compressor 11 and the refrigerated dryer 12, and a second control valve 131 is provided on the gas transmission pipeline connecting the gas storage tank 13 and the air inlet port. A gas injector 31 is provided between the measuring housing 41 and the lifting riser 3. One end of the gas injector 31 is connected to the gas outlet port, and the other end of the gas injector 31 forms a tapered nozzle. The nozzle is inserted into and fixed in the gas inlet. A check valve is provided on the gas supply pipeline connected to the gas injector 31 and the gas outlet port.

[0048] In the implementation of the above-described pneumatic booster system embodiment, the air compressor 11 typically uses a screw or piston industrial air compressor as the air source generating device. The compressed air output from the compressor first enters the refrigerated dryer 12. The refrigerated dryer 12 is a refrigerated dryer, whose core includes a refrigeration compressor and a heat exchanger to remove moisture and some oil mist from the air, ensuring that dry and clean gas enters the subsequent pipelines and preventing moisture from condensing or causing corrosion in precision components such as the laminar flow measurement unit 4 and the electromagnetic proportional valve 5. The dried compressed air is then transported to the air receiver 13, which is typically a carbon steel or stainless steel pressure vessel. The air receiver 13 acts as a buffer and pressure stabilizing unit, effectively suppressing pressure fluctuations that may be generated by the air compressor 11 and providing the system with instantaneous high-flow-rate supply capacity, ensuring the stability of the air source.

[0049] A first control valve 111, typically a ball valve or butterfly valve, is installed on the gas supply pipeline connecting the air compressor 11 and the refrigerated dryer 12. This valve serves as a manual or pneumatic switch to control the opening, closing, or isolation of the entire gas supply path, facilitating equipment maintenance and safe operation. A second control valve 131, also a ball valve, is installed on the gas supply pipeline connecting the gas storage tank 13 and the inlet port of the laminar flow measurement unit 4. This valve is located upstream of the airflow control module and is used to cut off the main gas supply to the measurement and control system before experiments or in emergencies.

[0050] The gas injector 31 between the measuring housing 41 and the lifting riser 3 is a key gas injection component. The tapered nozzle structure significantly increases the velocity of the high-pressure gas from the outlet port at the nozzle, allowing it to be injected into the bottom of the lifting riser 3 with higher kinetic energy and a smaller diameter jet. This enhances the momentum exchange efficiency between the gas and the multiphase medium provided by the feeding module 2, promoting more thorough gas-liquid-solid mixing and lifting start-up. A spring-loaded swing or lift check valve is used to prevent liquid or solid particles in the lifting riser 3 from flowing back into the airflow control module during system shutdown or pressure fluctuations, thus protecting these valuable and precise instruments from contamination and damage.

[0051] When starting the system, firstly, the first control valve 111 is opened, and the air compressor 11 and refrigerated dryer 12 are run to fill the air tank 13 with dry compressed air to the set pressure (e.g., 0.8 MPa). When preparing for the experiment, the second control valve 131 is opened, and the gas enters the airflow control module. The host computer or slave computer drives the electromagnetic proportional valve 5 to adjust the opening according to preset instructions. After the gas flows through the laminar flow measurement unit 4 and is accurately measured, it enters the gas injector 31 through the outlet port and check valve, and finally is injected at high speed into the lift riser 3 through the converging nozzle. The automatic opening and closing characteristic of the check valve requires no additional control signal and relies entirely on the forward and reverse pressure difference in the pipeline. Therefore, these structures work together to make the entire gas supply path, from gas source preparation and accurate measurement to efficient injection, more complete, safe, and efficient, providing crucial hardware support for the stable and accurate operation of the variable volume pneumatic lift system under various complex dynamic conditions and for the high reliability of experimental data acquisition.

[0052] Furthermore, the pneumatic lifting system also includes a media separation unit 7, which includes a gas separation chamber 71 and a solid-liquid separator; The bottom wall of the gas separation chamber 71 is inclined. The top end of the lifting riser 3 is located at the bottom wall of the high side of the gas separation chamber 71 and is connected to the gas separation chamber 71. The second pressure sensor is fixed on the top inner wall of the gas separation chamber 71 at the position corresponding to the top end of the lifting riser 3. A vertical medium discharge pipe 72 is provided below the gas separation chamber 71. The medium discharge pipe 72 is located at the bottom wall of the low side of the gas separation chamber 71 and is connected to the gas separation chamber 71. A gas outlet 73 is opened on the top wall of the gas separation chamber 71 at the position corresponding to the medium discharge pipe 72. The solid-liquid separator includes a separation container 74 and a filter assembly disposed within the separation container 74. The separation container 74 is located below the media discharge pipe 72, and the top of the separation container 74 has an open structure facing the media discharge pipe 72.

[0053] Through the implementation of the above-described pneumatic lifting system embodiment, the media separation unit 7 consists of two stages: a gas separation chamber 71 and a solid-liquid separator. The gas separation chamber 71, as the primary separation device, has an inclined bottom wall that allows the gas-liquid-solid mixture discharged from the top of the lifting riser 3 to enter the gas separation chamber 71. The denser liquid and solid phases naturally converge and flow towards the lower side of the inclined surface under gravity, effectively promoting the initial separation of the gas and liquid-solid phases.

[0054] The top end of the lifting riser 3 is positioned and connected to the bottom wall of the gas separation chamber 71 on the high side, ensuring that the discharged medium can smoothly enter the separation chamber without stagnation or backflow. The second pressure sensor is fixed to the top inner wall of the gas separation chamber 71 at the position corresponding to the top end of the lifting riser 3. This installation position allows the sensor to directly and accurately measure the pressure of the medium discharged from the lifting riser 3 but not yet fully diffused. This pressure value is crucial for evaluating the outlet back pressure and overall lifting efficiency of the lifting system, avoiding inaccurate pressure signals caused by measurements in open spaces.

[0055] A vertical media discharge pipe 72 is installed and connected to the bottom wall of the gas separation chamber 71 on the lower side, allowing the liquid-solid mixture collected thereto to be discharged downwards through this pipe. Simultaneously, a gas outlet 73 is provided on the top wall of the gas separation chamber 71 at the position corresponding to the media discharge pipe 72, enabling the pre-separated gas to be guided to subsequent processing or directly discharged. This effectively prevents gas accumulation within the chamber from affecting the smooth discharge of the liquid-solid phase and maintains relative pressure stability within the chamber.

[0056] The solid-liquid separator, as a secondary separation device, includes a separation container 74 and a filter assembly disposed within the separation container 74. The separation container 74 is located directly below the media discharge pipe 72, allowing the liquid-solid mixture flowing out of the media discharge pipe 72 to directly fall into the separation container 74. The filter assembly is used to intercept solid particles, achieving the final separation of the liquid and solid phases, thereby facilitating the separate collection and weighing analysis of solid particles, as well as the metering of the discharged clarified liquid.

[0057] Overall, the medium separation unit 7 is seamlessly connected with the air supply module 1, airflow control module and lifting riser 3 at the front end of the pneumatic lifting system, forming a complete, efficient and data-traceable experimental loop from medium lifting and dynamic process monitoring to terminal separation and recovery. This provides a strong terminal guarantee for in-depth research on the comprehensive performance and multiphase separation characteristics of the pneumatic lifting system under variable air intake conditions.

[0058] Furthermore, the filter assembly includes a multi-stage filter screen 75 detachably connected to the separation container 74. The multi-stage filter screen 75 is distributed in the vertical direction, and the filter pore size of the multi-stage filter screen 75 decreases sequentially in the vertical direction. The test module 6 also includes a first weighing device and a weighing water tank. The first weighing device is used to weigh the filtered solid particles. The weighing water tank includes a weighing box body 62 and a second weighing device 63 disposed at the bottom of the weighing box body 62. The weighing box body 62 is located below the separation container 74 and connected to the bottom of the separation container 74. A regulating water tank 64 is provided between the weighing box 62 and the separation container 74, and an electrically controlled three-way valve 641 is provided on the infusion pipeline connecting the weighing box 62 and the separation container 74. The electrically controlled three-way valve 641 is connected to the regulating water tank 64.

[0059] Through the implementation of the above-described pneumatic lifting system embodiment, the filter assembly adopts a multi-stage filter screen 75 that is detachably connected to the separation container 74. This allows the liquid-solid mixture falling into the separation container 74 from the media discharge pipe 72 to first pass through the upper filter screen 75 with a larger pore size, intercepting larger solid particles. Subsequently, the liquid carries finer particles through the lower filter screen 75 with a smaller pore size, achieving effective graded interception and collection of solid particles with different particle sizes. This not only improves the overall filtration efficiency and reduces the clogging speed of a single-layer filter screen, but also facilitates subsequent independent analysis and research of particles with different particle sizes.

[0060] The detachable connection of the multi-stage filter 75 (such as using snap-fit ​​or flange connections) also makes cleaning and replacement extremely convenient. The first weighing device (usually a high-precision electronic balance) added to the test module 6 is specifically used to accurately weigh the solid particles collected from the multi-stage filter 75, thereby directly obtaining the mass of the solid material being lifted and conveyed, which is key data for evaluating the system's solid conveying capacity.

[0061] The weighing tank system includes a weighing tank 62 and a second weighing device 63 (usually a weighing sensor or platform scale) located at the bottom of the weighing tank 62. The weighing tank 62 is located below the separation container 74 and is connected to the bottom of the separation container 74 through a liquid infusion line, and is used to collect and weigh the filtered liquid medium.

[0062] A regulating water tank 64 and an electrically controlled three-way valve 641 are added to the liquid delivery pipeline between the weighing tank 62 and the separation container 74. The three ports of the electrically controlled three-way valve 641 are connected to the bottom outlet of the separation container 74, the regulating water tank 64, and the weighing tank 62, respectively. This structure allows for controllable flow of the liquid medium: during the experiment, to avoid affecting the stability of the liquid level in the separation container 74 and the continuity of the filtration process, the host computer or slave computer can send a control signal to the electrically controlled three-way valve 641 to connect the pipeline between the bottom of the separation container 74 and the regulating water tank 64, allowing the filtered liquid to temporarily flow into the regulating water tank 64 for storage. When it is necessary to perform phased liquid collection and measurement, the electrically controlled three-way valve 641 is controlled to switch to the pipeline connecting the separation container 74 and the weighing tank 62, and the liquid temporarily stored in the regulating water tank 64 is also introduced into the weighing tank 62, thereby achieving accurate and batch weighing of the total liquid output within a specific time period.

[0063] Preferably, the electrically controlled three-way valve 641 can be an electromagnetically driven or electrically actuated three-way ball valve, controlled by a digital output module of the host computer or the I / O port of the slave computer via a relay to send a switching signal. Its switching logic can be triggered based on a time-programmed signal. The output signal of the second weighing device 63 can be connected to the data acquisition system of the host computer through an analog input module to realize the automatic and synchronous recording and storage of weighing data. Overall, these structural components work together, enabling the medium separation unit 7 to not only efficiently complete the physical separation of the gas-liquid-solid three phases, but also to simultaneously output the two key experimental data of solid particle mass and liquid medium mass. Moreover, the entire process can be programmed and data synchronously acquired through the host computer, which greatly enhances the experimental data acquisition capability, repeatability, and analytical depth. This provides crucial hardware support and data foundation for comprehensively and quantitatively evaluating the overall conveying performance of the variable gas volume pneumatic lifting system (such as the solid-liquid conveying ratio and the dynamic change of lifting efficiency with the intake gas).

[0064] Furthermore, combined Figure 3 As shown, the feeding module 2 includes a mixing tank, a pellet supply component, and a mobile water supply component; The mixing tank includes a mixing tank body 21 located below the lifting riser 3, and a material receiving plate 22 fixed inside the mixing tank body 21. The material receiving plate 22 surrounds the mixing tank body 21 to form an upward-opening solid-liquid mixing zone. The top of the mixing tank body 21 is an open structure, and the bottom end of the lifting riser 3 forms a gradually expanding medium inlet 32 ​​placed in the solid-liquid mixing zone. The particle supply assembly includes a particle supply chamber 23 and a vertically arranged particle conveying pipe 24. One end of the particle conveying pipe 24 is connected to the bottom of the particle supply chamber 23, and the other end of the particle conveying pipe 24 is positioned above the mixing box 21 corresponding to the position of the solid-liquid mixing zone. A third control valve 241 is provided on the particle conveying pipe 24. The mobile water supply assembly includes a lifting platform 25, a mobile water tank 26, a storage tank 27, and a water pump 28. The mobile water tank 26 is fixed on the lifting platform 25 and connected to the mixing tank 21. A fourth control valve is installed on the infusion pipeline connecting the mobile water tank 26 and the mixing tank 21. The storage tank 27, the water pump 28, and the mobile water tank 26 are connected in sequence. The storage tank 27 is also equipped with an overflow pipe 29 connected to the mobile water tank 26.

[0065] By implementing the above-described pneumatic lifting system embodiment, a solid-liquid mixing zone with an upward opening is formed by using the material container plate 22 fixed inside the mixing tank, so that solid particles and liquid can be pre-mixed in this zone, providing a uniform multiphase medium source for the lifting process.

[0066] The open structure at the top of the mixing tank 21 facilitates the input of particles and the lifting of the multiphase medium. The bottom of the lifting riser 3 features a gradually expanding medium inlet 32, which widens downwards (towards the solid-liquid mixing zone) like a funnel. On one hand, when the medium in the solid-liquid mixing zone flows upwards under pressure, it flows from a funnel-shaped inlet with a larger cross-sectional area to the lifting riser 3 with a smaller cross-sectional area. This structure provides a streamlined, smooth transition, avoiding sharp contractions and eddies that occur when the multiphase medium suddenly enters the lifting riser 3 from the open solid-liquid mixing zone, thus reducing local resistance losses at the medium inlet 32 ​​and making the flow smoother. On the other hand, the medium inlet 32 ​​significantly increases the "capturing area" for the multiphase medium, more effectively collecting solid particles that may settle or be distributed within the solid-liquid mixing zone, preventing particle accumulation in areas far from the central inlet, and ensuring that the solid phase is reliably entrained in the lifting process. This facilitates more complete momentum exchange and mixing of the gas-liquid-solid three phases in the initial lifting section.

[0067] The particle supply chamber 23 is used to store solid particles. The particles are transported to the solid-liquid mixing zone in the mixing chamber 21 through the vertically arranged particle conveying pipe 24. The third control valve 241 (which can be a precision ball valve or a solenoid valve) on the particle conveying pipe 24 allows the supply rate of solid particles to be turned on or off or roughly adjusted, so as to realize the controllable addition of the solid phase.

[0068] The mobile water supply assembly provides an adjustable supply method for the liquid medium. Its lifting platform 25 (usually composed of an electric actuator or a lead screw slide) can move vertically, and the mobile water tank 26 fixed on it rises and falls accordingly, thereby changing the liquid potential energy relative to the mixing tank. The mobile water tank 26 is connected to the mixing tank through a delivery pipeline with a fourth control valve (also optionally a solenoid valve or a regulating valve). By controlling the opening and closing of this valve and the height of the lifting platform 25, the flow rate and pressure of the liquid injected into the mixing tank can be precisely adjusted, thereby controlling the liquid level height in the solid-liquid mixing zone, i.e., the submersion rate, which is a key parameter affecting the performance of the pneumatic booster pump. Thus, initial experimental conditions with different solid-liquid ratios and different submersion rates can be automatically configured according to a preset experimental program. For example, when simulating low submersion rate conditions or requiring a higher liquid delivery rate, the driving head is increased by raising the mobile water tank 26 to ensure that the liquid can overcome resistance and be supplied stably. In conjunction with the particle supply assembly, it can accurately prepare multiphase media with different solid-liquid mixing ratios and different inlet hydraulic conditions.

[0069] Meanwhile, the water storage tank 27, serving as both the main water source and a buffer container, provides ample water reserves for long-term continuous experiments, eliminating the need for manual water replenishment during interruptions. The water pump 28 (preferably a corrosion-resistant centrifugal pump or magnetically driven pump), acting as the power unit, is connected to the bottom of the water storage tank 27. It can send start / stop signals or frequency conversion control signals via a host computer or independent controller (such as a PLC) to automatically pump water to the mobile water tank 26 as needed, ensuring that the mobile water tank 26 does not run out of water during continuous supply to the mixing tank. Furthermore, an overflow pipe 29, connected to the mobile water tank 26, is additionally installed on the water storage tank 27. When the rate at which the water pump 28 supplies water to the mobile water tank 26 exceeds the rate at which the mobile water tank 26 supplies water to the mixing tank, the excess water in the mobile water tank 26 will automatically flow back to the water storage tank 27 through the overflow pipe 29, thereby maintaining the water level in the mobile water tank 26 at a level comparable to the inlet height of the overflow pipe 29.

[0070] Regardless of fluctuations in the water supply of pump 28, the working water level of mobile water tank 26 (i.e., the static pressure potential energy it generates) remains absolutely constant. This fundamentally ensures that the pressure head height (i.e., the height difference set by lifting platform 25) driving the liquid into the mixing tank is the only and stable driving force, eliminating pressure interference caused by changes in the water level of mobile water tank 26 itself, thus maximizing the control accuracy of the submersion rate of the mixing tank. At the same time, overflow pipe 29 effectively "hydraulically isolates" the power system (pressure pulsation, vibration) of pump 28 from the static pressure water supply system of mobile water tank 26. The fluctuations generated by pump 28 are dissipated in water storage tank 27 through overflow circuit, and will not be transmitted to mobile water tank 26 and downstream experimental pipelines, ensuring that the liquid supplied to the mixing tank flows smoothly without pulsation.

[0071] In summary, the material supply module 2, through its modular and controllable structural design, enables the system to conveniently and accurately configure the initial state and supply parameters of the multiphase medium. This lays a reliable and flexible material supply foundation for the downstream pneumatic lifting process to study the effects of different solid-liquid mixing characteristics and different submersion rates on lifting performance, flow pattern evolution, and efficiency under various variable air intake conditions.

[0072] Furthermore, the material container 22 includes a first vertical plate 221 and a second vertical plate 222 arranged opposite to each other, and an arc-shaped plate 223 that horizontally connects the first vertical plate 221 and the second vertical plate 222. The top of the first vertical plate 221 extends to the top opening of the mixing box 21 to separate the solid-liquid mixing area from the internal space of the mixing box 21. A liquid inlet is provided on the side wall of the mixing box 21 adjacent to the first vertical plate 221, and the liquid inlet is connected to the movable water tank 26. The top of the second vertical plate 222 is lower than the first vertical plate 221, and is used to connect the solid-liquid mixing zone and the internal space of the mixing box 21.

[0073] Through the implementation of the above-described pneumatic lifting system embodiment, the top of the first vertical plate 221 extends to the top opening of the mixing tank 21, separating the solid-liquid mixing zone from the internal space of the mixing tank 21. On the separating side, a liquid inlet is provided on the side wall of the mixing tank 21 adjacent to the first vertical plate 221. This liquid inlet is connected to the mobile water tank 26 of the mobile water supply assembly via a pipeline. When the liquid flows in from the liquid inlet through the pipeline controlled by the fourth control valve, driven by the potential energy provided by the mobile water tank 26, the liquid first enters the area separated by the first vertical plate 221, rather than directly rushing into the solid-liquid mixing zone.

[0074] The top of the second vertical plate 222 is lower than that of the first vertical plate 221, ensuring that the space separated on one side of the mixing chamber 21 remains connected to the solid-liquid mixing zone at the top of the second vertical plate 222. This means the liquid first fills the separated space and then smoothly overflows from the top of the second vertical plate 222 into the solid-liquid mixing zone. On one hand, this eliminates the violent scouring and disturbance caused by direct liquid injection from the inlet to the already deposited or mixing solid particles in the solid-liquid mixing zone, preventing the initial mixing state from being unstable due to the dispersion or uplift of solid particles. On the other hand, the gentle overflow from the top helps maintain a relatively stable distribution or settling layer of solid particles at the bottom of the solid-liquid mixing zone (especially in the concave area of ​​the arc-shaped plate 223), which is crucial for studying the lifting characteristics of solid particles at specific concentrations. The arc-shaped plate 223 also helps reduce dead zones in the flow, preventing particle accumulation.

[0075] Preferably, the container plate 22 and the mixing box 21 can be made of transparent acrylic or stainless steel for easy observation.

[0076] This invention discloses a control method using the aforementioned variable gas volume pneumatic lifting system. The control method includes: The host computer receives waveform parameters defined based on the target operating condition and generates a preset flow command containing a continuous time-flow correspondence based on the waveform parameters. The waveform parameters include any one of sine wave, sawtooth wave or gradient wave. The host computer sends the preset flow rate command to the laminar flow measurement unit 4. In response to the laminar flow measurement unit 4 receiving the preset flow rate command, the gas supply module 1 starts to supply gas flow to the riser pipe 3 according to the waveform parameters contained in the preset flow rate command. The laminar pressure difference between its two ends is obtained in real time through laminar flow measurement unit 4, and the obtained laminar pressure difference is calculated based on Hagen-Poiseuille law to obtain the gas volume measurement value flowing through laminar flow measurement unit 4. The gas volume measurement value is compared with the target flow value at the current moment in the preset flow command to obtain the instantaneous flow deviation. The instantaneous flow deviation is then calculated based on the preset PID control algorithm to obtain the valve opening adjustment amount. An opening control signal is generated based on the valve opening adjustment amount, and the electromagnetic proportional valve 5 is driven to adjust the opening based on the opening control signal; In response to the opening adjustment of the electromagnetic proportional valve 5, the particle supply rate and liquid supply height of the supply riser 3 are adjusted through the feeding module 2 to simulate different solid-liquid mixing ratios and submersion rates. The host computer acquires and records the gas volume measurement value, the pressure value in the riser 3 and the particle flow state. Based on the acquired gas volume measurement value, pressure value and particle flow state, the dynamic performance and multiphase flow pattern evolution law of the gas lifting system under variable intake conditions are analyzed and determined.

[0077] By implementing the above control method embodiment, a host computer (which may be an industrial computer running NI LabVIEW software) is used as the central control unit. It first receives waveform parameters (such as the amplitude, period, and offset of a sine wave) defined based on the target operating condition, and generates a preset flow command containing a continuous time-flow correspondence. This command is then sent to the slave computer of the laminar flow measurement unit 4 via a communication interface (such as Ethernet).

[0078] Upon receiving the command, the system sequentially activates the gas supply module 1 (including air compressor 11, refrigerated dryer 12, and gas storage tank 13) to ensure the gas flow rate follows the command. The laminar flow measurement unit 4, as a key sensing and calculation node, uses its internal differential pressure sensor 42 to acquire the laminar flow pressure difference across its terminals in real time. The processor within its lower-level unit performs calculations and temperature / pressure compensation on this raw signal based on the Hagen-Poiseuille law to obtain the measured gas volume flowing through the laminar flow measurement unit 4.

[0079] A control closed loop is then established: the system continuously compares the measured gas volume with the target flow rate value at the current moment in the preset flow command to obtain the instantaneous flow deviation. This deviation is fed into a preset PID control algorithm (proportional-integral-derivative algorithm, whose parameters such as Kp, Ki, and Kd can be tuned in the host computer interface based on the system response) for calculation to obtain the valve opening adjustment amount. Based on this adjustment amount, the lower-level controller generates an opening control signal (usually an analog voltage or PWM signal) and drives the electromagnetic proportional valve 5 (preferably a high-response servo proportional valve, such as the Festo MPYE series) to adjust the opening, thereby accurately correcting the airflow and enabling the actual flow rate to dynamically track the preset complex waveform.

[0080] This dynamic air intake control process is not carried out in isolation. The method responds synchronously to the opening adjustment of the electromagnetic proportional valve 5. By controlling the feeding module 2 (specifically involving the third control valve 241 of the particle supply component and the lifting platform 25 and the fourth control valve of the moving water supply component), the particle supply rate and liquid supply height of the supply riser 3 are adjusted, thereby simulating different solid-liquid mixing ratios and submersion rates. This achieves programmed coordinated changes in air intake conditions and medium supply conditions, and can accurately reproduce various actual or hypothetical composite conditions.

[0081] At the testing and analysis level, the host computer synchronously acquires and records the gas volume measurement values ​​continuously transmitted from the laminar flow measurement unit 4, the pressure values ​​in the lift riser 3 transmitted from the pressure detection components (first and second pressure sensors), and the particle flow state image sequence captured by the particle image velocimetry component (high-speed camera and laser sheet light) through its data acquisition system (such as the NI USB-6000 series DAQ card). The host computer software (such as LabVIEW combined with the Vision module) processes and fuses these time-synchronized data streams to analyze and determine the dynamic performance (such as instantaneous lift efficiency and pressure pulsation spectrum) and multiphase flow pattern evolution law (such as flow pattern transition boundary and particle concentration distribution response to intake fluctuations) of the pneumatic lift system under variable intake conditions.

[0082] The entire control method integrates dynamic intake generation, real-time closed-loop feedback control (based on PID algorithm), multiphase medium supply coordination, and multi-dimensional data synchronous acquisition and analysis through the aforementioned hardware and software collaboration. It achieves precise programmed control of the intake volume with arbitrary waveforms, while also actively configuring and associating other key boundary conditions. This greatly expands the dimensions and depth of experimental research, providing an unprecedented and powerful methodological tool for exploring the dynamic characteristics of pneumatic booster pumps under real and transient operating conditions, optimizing their operating parameters, and gaining a deeper understanding of multiphase flow mechanisms.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A variable air volume pneumatic lifting system, characterized in that, The variable air volume pneumatic lifting system includes: The air supply module provides and delivers compressed air; The feeding module provides and conveys a multiphase medium containing particles and liquids; A vertically arranged lifting riser is provided, with its bottom connected to the air supply module and the material supply module, respectively, so that the multiphase medium is lifted inside the lifting riser under the drive of compressed air. The airflow control module includes a laminar flow measurement unit and an electromagnetic proportional valve. The laminar flow measurement unit is installed on the gas supply pipeline connecting the gas supply module and the lift riser, and measures the volumetric flow rate of the gas flowing through it by detecting the laminar flow pressure difference at both ends of the laminar flow measurement unit. The electromagnetic proportional valve is electrically connected to the laminar flow measurement unit and is located on the gas inlet side of the laminar flow measurement unit. It is used by the laminar flow measurement unit to adjust the opening of the electromagnetic proportional valve according to the comparison between the gas volume measurement value and the preset flow rate value. The testing module includes a host computer electrically connected to the laminar flow measurement unit, used to send a preset flow rate value to the laminar flow measurement unit and to receive and record the gas volume flow rate transmitted by the laminar flow measurement unit in real time.

2. The variable air volume pneumatic lifting system according to claim 1, characterized in that: The laminar flow measurement unit includes a measurement housing, a laminar flow assembly disposed within the measurement housing, a differential pressure sensor disposed outside the measurement housing, and a lower-level computer. One end of the measuring housing is provided with an air inlet port, which is connected to the air supply module. The other end of the measuring housing is provided with an air outlet port, which is connected to the bottom of the lifting riser. The laminar flow assembly includes multiple laminar flow channels that are separated and distributed in parallel along the vertical direction within the measuring housing. An upstream pressure tap is provided on the top wall of the measuring housing near the air inlet port, and the multiple laminar flow channels are connected vertically to the upstream pressure tap. A downstream pressure tap is provided on the top wall of the measuring housing near the air outlet port, and the multiple laminar flow channels are connected vertically to the downstream pressure tap. The differential pressure sensor is located above the measuring housing, with one end of the differential pressure sensor connected to the upstream pressure tap and the other end of the differential pressure sensor connected to the downstream pressure tap. The lower-level computer is electrically connected to the differential pressure sensor and is used to receive differential pressure signals to calculate gas volume flow rate.

3. The variable air volume pneumatic lifting system according to claim 2, characterized in that: The lower-level machine includes a first display screen with an interactive interface for setting and generating different flow condition commands. The upper-level machine includes a second display screen with an interactive interface for setting and generating preset flow commands. The lower-level machine and the upper-level machine are electrically connected, and the lower-level machine receives the preset flow commands sent by the upper-level machine and generates valve opening adjustment commands based on the comparison result of the gas volume measurement value and the preset flow value.

4. The variable air volume pneumatic lifting system according to claim 2, characterized in that: The testing module also includes a particle image velocity measurement component and a pressure detection component. A gas injection port is provided on the pipe wall near the bottom of the lifting riser. The gas injection port is connected to the gas supply module. The particle image velocity measurement component includes an illumination light source and an image acquisition device disposed on one side of the lifting riser. The working direction of the illumination light source and the image acquisition device are both facing the middle section of the lifting riser. The host computer is electrically connected to the image acquisition device. The pressure detection assembly includes a first pressure sensor disposed at the gas injection port and a second pressure sensor disposed at the gas outlet side at the top of the lifting riser. The host computer is electrically connected to the first pressure sensor and the second pressure sensor respectively.

5. A variable air volume pneumatic lifting system according to claim 2, characterized in that: The gas supply module includes an air compressor, a refrigerated dryer, and a gas storage tank connected in sequence. The gas storage tank is connected to the air inlet port, and a first control valve is provided on the gas supply pipeline connecting the air compressor and the refrigerated dryer. A second control valve is provided on the gas supply pipeline connecting the gas storage tank and the air inlet port. A gas injector is provided between the measuring housing and the lifting riser. One end of the gas injector is connected to the gas outlet port, and the other end of the gas injector forms a tapered nozzle. The nozzle is inserted into and fixed in the gas inlet. A check valve is provided on the gas supply pipeline connecting the gas injector and the gas outlet port.

6. The variable air volume pneumatic lifting system according to claim 4, characterized in that: The pneumatic lifting system also includes a media separation unit, which includes a gas separation chamber and a solid-liquid separator. The bottom wall of the gas separation chamber is inclined. The top end of the lifting riser is located at the bottom wall of the high side of the gas separation chamber and is connected to the gas separation chamber. The second pressure sensor is fixed on the top inner wall of the gas separation chamber at the position corresponding to the top end of the lifting riser. A vertical medium discharge pipe is provided below the gas separation chamber. The medium discharge pipe is located at the bottom wall of the low side of the gas separation chamber and is connected to the gas separation chamber. A gas outlet is opened on the top wall of the gas separation chamber at the position corresponding to the medium discharge pipe. The solid-liquid separator includes a separation container and a filter assembly disposed within the separation container. The separation container is located below the media discharge pipe, and the top of the separation container has an open structure facing the media discharge pipe.

7. A variable air volume pneumatic lifting system according to claim 6, characterized in that: The filter assembly includes a multi-stage filter screen detachably connected to the separation container. The multi-stage filter screens are distributed vertically, and the pore size of the multi-stage filter screens decreases sequentially in the vertical direction. The testing module also includes a first weighing device and a weighing water tank. The first weighing device is used to weigh the filtered solid particles. The weighing water tank includes a weighing box body and a second weighing device disposed at the bottom of the weighing box body. The weighing box body is located below the separation container and connected to the bottom of the separation container. A regulating water tank is provided between the weighing box and the separation container, and an electrically controlled three-way valve is provided on the infusion pipeline connecting the weighing box and the separation container. The electrically controlled three-way valve is connected to the regulating water tank.

8. The variable air volume pneumatic lifting system according to claim 1, characterized in that: The feeding module includes a mixing tank, a pellet supply component, and a mobile water supply component; The mixing tank includes a mixing tank body located below the lifting riser, and a material container plate fixed inside the mixing tank body. The material container plate surrounds an upward-opening solid-liquid mixing zone inside the mixing tank body, and the top of the mixing tank body has an open structure. The bottom end of the lifting riser has a gradually expanding medium inlet located within the solid-liquid mixing zone. The particle supply assembly includes a particle supply chamber and a vertically arranged particle conveying pipe. One end of the particle conveying pipe is connected to the bottom of the particle supply chamber, and the other end of the particle conveying pipe is positioned above the mixing chamber corresponding to the position of the solid-liquid mixing zone. A third control valve is provided on the particle conveying pipe. The mobile water supply assembly includes a lifting platform, a mobile water tank, a storage tank, and a water pump. The mobile water tank is fixed on the lifting platform and connected to the mixing tank. A fourth control valve is provided on the infusion pipeline connecting the mobile water tank and the mixing tank. The storage tank, the water pump, and the mobile water tank are connected in sequence. An overflow pipe connected to the mobile water tank is also provided on the storage tank.

9. A variable air volume pneumatic lifting system according to claim 8, characterized in that: The material container includes a first vertical plate and a second vertical plate arranged opposite to each other, and an arc-shaped plate that horizontally connects the first vertical plate and the second vertical plate. The top of the first vertical plate extends to the top opening of the mixing box, which is used to separate the solid-liquid mixing area from the internal space of the mixing box. A liquid inlet is provided on the side wall of the mixing box adjacent to the first vertical plate, and the liquid inlet is connected to the mobile water tank. The top of the second vertical plate is lower than that of the first vertical plate, and is used to connect the solid-liquid mixing zone and the internal space of the mixing box.

10. A control method employing a variable air volume pneumatic lifting system according to any one of claims 1-9, characterized in that, The control method includes: The host computer receives waveform parameters defined based on the target operating condition and generates a preset flow command containing a continuous time-flow correspondence based on the waveform parameters. The waveform parameters include any one of sine wave, sawtooth wave, or gradient wave. The host computer sends the preset flow rate instruction to the laminar flow measurement unit, and in response to the laminar flow measurement unit receiving the preset flow rate instruction, the gas supply module starts to provide gas flow to the riser according to the waveform parameters contained in the preset flow rate instruction; The laminar pressure difference between its two ends is obtained in real time through the laminar flow measurement unit, and the obtained laminar pressure difference is calculated based on the Hagen-Poiseuille law to obtain the gas volume measurement value flowing through the laminar flow measurement unit. The gas volume measurement value is compared with the target flow value at the current moment in the preset flow command to obtain the instantaneous flow deviation. The instantaneous flow deviation is then calculated based on the preset PID control algorithm to obtain the valve opening adjustment amount. An opening control signal is generated based on the valve opening adjustment amount, and the electromagnetic proportional valve is driven to adjust the opening based on the opening control signal. In response to the opening adjustment of the electromagnetic proportional valve, the particle supply rate and liquid supply height supplied to the lifting riser are adjusted by the feeding module to simulate different solid-liquid mixing ratios and submersion rates. The host computer acquires and records the gas volume measurement value, the pressure value in the lift riser, and the particle flow state. Based on the acquired gas volume measurement value, pressure value, and particle flow state, the dynamic performance and multiphase flow pattern evolution law of the pneumatic lifting system under variable intake conditions are analyzed and determined.

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