Device for simulating gas-liquid slug flow in multiphase mixed-flow pump and testing method thereof

Abstract

The application discloses a device for simulating gas-liquid slug flow of a multiphase mixed delivery pump and a testing method thereof, and belongs to the technical field of multiphase flow mixed delivery, and solves the problem that the prior art cannot effectively study the operation characteristics of a spiral blade type mixed delivery pump under a slug flow condition; the device comprises a liquid storage tank, a multiphase mixed delivery pump, a gas-liquid separation tank and a control assembly. The multiphase mixed delivery pump, the liquid storage tank, the gas-liquid separation tank and a back mixing pipeline and other assemblies are integrated in a test platform, so that the pump operation characteristics under a high gas rate or a slug flow condition can be simulated. The gas-liquid storage tank inputs gas and liquid into the gas-liquid separation tank through the multiphase mixed delivery pump, the gas-liquid separation tank can realize gas-liquid separation, the liquid part and the gas part are returned to the inlet of the pump through the back mixing pipeline and the gas return pipeline respectively, so that the device can realize accurate control of the gas-liquid ratio according to different working condition requirements in cooperation with the control assembly.

Description

Technical Field

[0001] This invention relates to the field of multiphase flow mixing technology, specifically to a device and testing method for simulating gas-liquid slug flow in a multiphase flow mixing pump. Background Technology

[0002] Helical vane mixed-transfer pumps must meet the requirements of different gas content conditions, meaning they must guarantee the outlet oil and gas pressure within the specified flow range under any given condition. Experimental studies show that when the gas content exceeds 50%, the pressurization capacity generated by the helical vane structure weakens, preventing gas from exiting the first-stage impeller and entering the second-stage impeller. This results in a large accumulation of gas within the pump chamber, creating a slugging effect and causing a sharp drop in pump pressure and efficiency. Slug flow is a common flow pattern in oil-gas mixed-transfer pipelines. Due to the interphase nature of the gas and liquid phases, it causes drastic fluctuations in liquid content and pressure within the pipeline, requiring pipelines operating under this flow pattern to withstand pulse stress impacts. Under slug flow conditions, the pump is entirely composed of gas, leading to decreased pump compressibility and reduced pressurization performance. Current technology is inconvenient for controlling the gas content, lacking a device to realistically simulate the impact of slug flow changes on helical vane mixed-transfer pumps under high gas content conditions. This hinders effective research into the operating characteristics of helical vane mixed-transfer pumps at high gas content. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides a device and testing method for simulating gas-liquid slug flow using a multiphase mixed-transfer pump, thus solving the problem that the prior art cannot effectively study the operating characteristics of a helical vane mixed-transfer pump under slug flow conditions.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] On one hand, a device for simulating gas-liquid slug flow using a multiphase mixed-transfer pump is provided, comprising a storage tank, a multiphase mixed-transfer pump, a gas-liquid separator, and a control component. The liquid outlet and gas outlet of the storage tank are connected to one end of a main liquid pipeline and a main gas pipeline, respectively; the inlet of the multiphase mixed-transfer pump is connected to the other end of the main liquid pipeline and the main gas pipeline via a homogenizer; the inlet of the gas-liquid separator is connected to the outlet of the multiphase mixed-transfer pump via an outlet pipeline, and the liquid outlet of the gas-liquid separator is connected to both the main liquid pipeline and the storage tank via a return mixing pipeline; the gas outlet of the gas-liquid separator is connected to the main gas pipeline via a return gas pipeline; the control component includes a valve assembly, a sensor assembly, and a host computer. The valve assembly and sensor assembly are used to adjust and monitor the flow rate or gas pressure of the storage tank, the main liquid pipeline, the main gas pipeline, the outlet pipeline, the return mixing pipeline, and the return gas pipeline, respectively; the host computer is used to adjust the valve assembly based on the monitoring data fed back by the sensor assembly.

[0006] Furthermore, the remixing pipeline includes a first remixing branch and a second remixing branch, which are respectively connected to the main liquid pipeline and the storage tank.

[0007] Furthermore, the sensor assembly includes a pressure sensor, a main liquid pipeline flow meter, a re-mixing liquid flow meter, and a gas turbine flow meter, which are respectively installed on the storage tank, the main liquid pipeline, the first re-mixing branch, and the main gas pipeline.

[0008] Furthermore, the sensor assembly also includes a pump inlet pressure sensor and a pump outlet pressure sensor for detecting the inlet and outlet pressures of the multiphase mixed-transfer pump, respectively.

[0009] Furthermore, the valve assembly includes a storage tank valve, a main liquid pipeline valve, a main gas pipeline valve, an outlet pipeline valve, a remixing pipeline valve, and a return gas pipeline valve; the storage tank valve includes a gas-liquid inlet valve, a safety valve, and an electrically operated relief valve installed on the storage tank; the main liquid pipeline valve includes a main liquid pipeline ball valve, a check valve, and a main liquid pipeline electric valve installed on the main liquid pipeline; the main gas pipeline valve includes an inlet electric valve installed on the main gas pipeline; the outlet pipeline valve includes a pump outlet electric valve installed on the outlet pipeline; the remixing pipeline valve includes a remixing electric valve and a pressure regulating valve installed on the first remixing branch, and a return liquid valve installed on the second remixing branch; the return gas pipeline valve includes a return gas valve installed on the return gas pipeline.

[0010] On the other hand, a test method for a device that provides a multiphase mixed-transfer pump to simulate gas-liquid slug flow includes the following steps:

[0011] S1. Determine the target operating condition for testing the operating characteristics of the multiphase mixed-transfer pump, and obtain the target input flow rate setpoint and target gas content setpoint of the multiphase mixed-transfer pump under the target operating condition.

[0012] S2. Monitor the flow and pressure data fed back from the sensor assembly through the host computer, and use multiple PID controllers in the host computer to adjust the opening degree of each valve in the valve assembly so that the liquid flow rate in the main liquid pipeline and the back mixing pipeline and the gas flow rate in the back mixing pipeline are equal to the target input flow rate setting value and the target gas content setting value, respectively.

[0013] S3. Test the operating characteristics of the multiphase mixed-transfer pump under the current target operating conditions.

[0014] Furthermore, the expression for the valve opening adjustment value in each PID controller is as follows:

[0015]

[0016] in, For the corresponding PID controller in the valve assembly The valve opening adjustment value corresponding to the given time; This is the deviation between the measured flow rate and the target input flow rate setpoint. , and These are all PID control parameters, namely proportional gain coefficient, integral time constant, and derivative time constant.

[0017] Furthermore, the calculation method for the PID control parameters in each PID controller is as follows:

[0018] S21. Predefine various typical operating conditions for multiphase mixed-transfer pumps. Each typical operating condition is divided according to different combinations of the input flow rate and gas content of the multiphase mixed-transfer pump.

[0019] S22. Based on the target input flow rate setpoint and the target gas content setpoint, calculate the membership degree of the current working condition under each typical working condition using their respective predefined membership degree functions, and calculate the normalized weight under each typical working condition through the membership degree.

[0020] S23. Using the PID control parameters of each PID controller as the initial population, and using the normalized weights of each typical working condition to determine the population structure of the sparrow algorithm, and performing variable update and mutation operations of the sparrow algorithm according to the normalized weights of each typical working condition to optimize the solution, and output the optimal combination of PID control parameters.

[0021] Furthermore, step S23 specifically includes,

[0022] S231. Randomly generate an initial population of N sparrows. The position of each sparrow represents a set of candidate PID control parameter combinations. The expression for the position of the i-th sparrow is:

[0023]

[0024] in, A random number within the range [0,1]; and These are the lower and upper limits of the PID control parameter combination, respectively;

[0025] S232. Divide the initial population into discoverers and followers, with the number of discoverers and followers being respectively... and , The expression is:

[0026]

[0027] in, For the proportion of mixed discoverers, Let x be the normalized weight of the xth typical working condition; X is the total number of typical working conditions. The proportion of those who discovered the xth typical working condition;

[0028] S233, Update the discoverer's location:

[0029]

[0030]

[0031] in, Let be the value of the j-th PID control parameter for the i-th sparrow at the (t+1)-th iteration. Let be the value of the j-th PID control parameter for the i-th sparrow at time t during the t-th iteration; It is the maximum number of iterations. Let x be the step size threshold for the xth typical working condition. This is a warning value; Let L be a random number that follows a standard normal distribution; L is a matrix with row i and column j, and all elements are 1. Mixed alert thresholds; Let x be the warning threshold under the xth typical working condition;

[0032] S234, Update follower positions:

[0033]

[0034] in, This represents the worst position in the current j-dimensional global dimension. Let A be the optimal position of the discoverer in the current iteration; A is a matrix of all ones.

[0035] S235, Update the location of the Vigilant:

[0036]

[0037] in, It is the current global best position; These are step size control parameters. A random number between -1 and 1; This is the current fitness value of the sparrow. This represents the globally optimal fitness value. It is the worst fitness value globally; It is a constant;

[0038] S236. Randomly perturb the positions of some sparrows using mixed mutation probabilities:

[0039]

[0040]

[0041] in, With a mean of 0 and a standard deviation of Normally distributed random numbers; For mixed mutation probability; Let x be the variation probability of the xth typical working condition;

[0042] S237. Calculate the fitness function. Its expression is:

[0043]

[0044] Where T is the time window;

[0045] S238. Repeat steps S233 to S237 until completion. The maximum number of iterations is used to obtain the sparrow corresponding to the minimum fitness function. The PID control parameter combination corresponding to this sparrow is the optimal PID control parameter combination.

[0046] This invention discloses a device and testing method for simulating gas-liquid slug flow in a multiphase mixed-transport pump, the beneficial effects of which are:

[0047] 1. This invention addresses the issue that traditional spiral vane multiphase mixed-transfer pumps typically have a gas-liquid separator at the inlet. This separator performs initial gas-liquid separation on the oil and gas delivered from the wellhead. The separated liquid flows through a pipeline to the inlet of the multiphase mixed-transfer pump, while the gas flows through the gas path into the liquid path, forming a gas-liquid mixture. When high gas content occurs, or even slug flow, the liquid in the gas-liquid separator is rapidly consumed, while gas becomes the dominant component. At this point, the multiphase mixed-transfer pump is almost entirely composed of gas, leading to decreased compressibility and reduced pressurization performance, ultimately halting oil and gas transport. When high gas content or even slug flow occurs, timely replenishment of liquid from the outlet pipeline to the inlet ensures that the multiphase mixed-transfer pump operates at a stable gas content, preventing any decrease in its pressurization capacity. Therefore, this invention, based on the inlet gas-liquid separator, adds a return mixing pipeline and a return gas pipeline. Combined with the control components, high gas content conditions are applied to the surrounding environment during the experiment, realistically simulating the impact of slug flow changes on the helical vane multiphase mixed-transfer pump. The control components enable real-time monitoring and adjustment, dynamically adjusting valve opening, reducing manual intervention, avoiding overshoot and oscillation, and improving the accuracy and repeatability of test data.

[0048] 2. This invention divides the recirculation pipeline into a first recirculation branch and a second recirculation branch. The first recirculation branch can precisely regulate the liquid recirculated to the multiphase mixed-transfer pump, while the second recirculation branch returns excess liquid to the storage tank. Specifically, when the gas content is high, the system can switch to the first recirculation branch for active liquid replenishment, while the second recirculation branch is used for conventional recirculation. This avoids the risk of insufficient or excessive liquid replenishment in a single pipeline under slug flow conditions, ensuring precise control of the gas content at the pump inlet.

[0049] 3. The coordinated operation of the pressure sensor, main liquid pipeline flow meter, refluxing liquid flow meter, and gas turbine flow meter in this invention can accurately measure the total liquid flow, refluxing liquid flow, and gas flow in the system, providing an accurate data basis for the host computer to calculate and monitor the inlet gas content in real time. This ensures the accuracy of the feedback signal of the entire control system and is a prerequisite for achieving high-precision operating condition simulation and stable control.

[0050] 4. The pump inlet pressure sensor and pump outlet pressure sensor in this invention can directly and in real-time monitor the operating status and performance changes of the multiphase mixed-transfer pump itself. The pressure difference between the pump inlet and outlet directly reflects the pump's pressurization capacity. Under high gas content conditions such as slug flow, this pressure data is a key indicator for judging whether the pump is about to experience gas lock and whether its performance has dropped sharply. It provides the most direct decision-making basis for the control system to promptly initiate intervention measures such as liquid replenishment, effectively preventing pump failure and improving the safety and success rate of testing.

[0051] 5. The valve assembly of the present invention has multiple valves that can cover a variety of test modes. The host computer can precisely adjust specific valves for different test conditions, thereby improving the system's adaptability and control efficiency to different test requirements.

[0052] 6. This invention transforms the testing process from relying on manual experience to automatic control based on precise data feedback by setting target operating conditions via a host computer, monitoring real-time data, and dynamically adjusting valve opening using a PID controller. This method efficiently and reliably stabilizes system flow rate and gas content at the target setpoints, thereby accurately capturing the true operating characteristics of multiphase mixed-transfer pumps under specific transient or steady-state conditions, and improving the accuracy and repeatability of test data.

[0053] 7. In each PID controller of this invention, the proportional gain coefficient determines the response speed, the integral time constant eliminates steady-state error, and the overshoot and oscillation are suppressed. The combination of these three factors ensures the accuracy of valve opening adjustment, enabling the system to quickly recover stability from disturbances, and significantly improving the dynamic quality of control and the robustness of the overall system.

[0054] 8. This invention considers that different operating conditions affect the dynamic characteristics of the system. The system's requirements for PID control parameters vary under different operating conditions. For example, in high-flow-rate, low-gas-content conditions, rapid response is crucial, while in high-gas-content, slug flow conditions, higher robustness and stability are required. Therefore, the entire operating range is divided into several representative typical operating conditions. By calculating the membership degree of each operating condition, the host computer can identify the current operating condition type. For each typical operating condition, a relatively optimal set of PID control parameters can be optimized. However, when the operating conditions change, directly switching the PID control parameters will induce system oscillations. To ensure a smooth transition and avoid oscillations, this invention abandons the traditional practice of setting fixed or randomly selected sparrow parameters (such as the discoverer ratio and mutation probability) during initialization in cumbersome optimization algorithms. Instead, it uses normalized weights to weight and mix the preset sparrow algorithm parameters for different typical operating conditions, generating a set of initial parameters that conform to the current target operating condition. This ensures that the sparrow algorithm is in a high-potential search region from the beginning. For example, when the target operating condition is identified as a "high flow rate and high gas content" condition prone to oscillation, the hybrid algorithm parameters will inherently possess stronger global exploration capabilities and a tendency to mutate, thus more effectively avoiding local optima, accelerating convergence, and reducing the number of iterations and computation time required to find the optimal PID parameter combination. Furthermore, since the normalized weights are dynamically calculated based on the target operating condition, they change continuously and smoothly with variations in the target operating condition. Therefore, the hybrid sparrow algorithm parameters also change continuously and gradually, rather than abruptly, thereby avoiding system oscillations caused by jumps in PID control parameters and ensuring control stability.

[0055] 9. This invention provides the implementation steps of the sparrow algorithm. By weighted fusion of parameters from different typical working conditions, the algorithm can adaptively optimize the proportional gain coefficient, integral time constant, and derivative time constant of the PID controller. This allows the sparrow algorithm to automatically adjust the search strategy according to real-time requirements, combining adaptability, global optimization, and real-time performance. Ultimately, this ensures that the multiphase mixed-transfer pump can operate accurately and stably under the target working conditions. Attached Figure Description

[0056] Figure 1 A schematic diagram of the device and its testing method for simulating gas-liquid slug flow in a multiphase mixed-transfer pump;

[0057] Figure 2 This is a flowchart illustrating the process of adjusting PID control parameters using the sparrow algorithm.

[0058] The components include: 1. Storage tank; 2. Gas-liquid feed valve; 3. Safety valve; 4. Electric relief valve; 5. Pressure sensor; 6. Level gauge; 7. Return valve; 8. Main liquid pipeline ball valve; 9. Check valve; 10. Recirculation electric valve; 11. Pressure regulating valve; 12. Recirculation liquid flow meter; 13. Main liquid pipeline electric valve; 14. Main liquid pipeline flow meter; 15. Inlet electric valve; 16. Gas turbine flow meter; 17. Mixer; 18. Pump inlet pressure sensor; 19. Multiphase mixing pump; 20. Pump outlet pressure sensor; 21. Return gas valve; 22. Pump outlet electric valve; 23. Separator; 24. PLC controller; 25. Computer. Detailed Implementation

[0059] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0060] Example 1

[0061] refer to Figure 1 This embodiment provides a device for simulating gas-liquid slug flow using a multiphase mixed-transfer pump. Its purpose is to address the problem that existing technologies cannot effectively study the operating characteristics of helical vane mixed-transfer pumps under slug flow conditions. The device includes a liquid storage tank 1, a multiphase mixed-transfer pump 19, a gas-liquid separator 23, and control components, which are described in detail below.

[0062] The liquid outlet and gas outlet of the storage tank 1 are connected to one end of the main liquid pipeline and the main gas pipeline, respectively.

[0063] The inlet of the multiphase mixing pump 19 is connected to the other end of the main liquid pipeline and the main gas pipeline through the homogenizer 17.

[0064] The inlet of the gas-liquid separator 23 is connected to the outlet of the multiphase mixing pump 19 via an outlet pipeline. The liquid outlet of the gas-liquid separator 23 is connected to the main liquid pipeline and the storage tank 1 via a return mixing pipeline. The gas outlet of the gas-liquid separator 23 is connected to the main gas pipeline via a return gas pipeline. The return mixing pipeline includes a first return mixing branch and a second return mixing branch, which are connected to the main liquid pipeline and the storage tank 1 respectively.

[0065] The control components include valve components, sensor components, and a host computer. The valve components and sensor components are used to regulate and monitor the flow rate or air pressure of the storage tank 1, main liquid pipeline, main gas pipeline, outlet pipeline, remixing pipeline, and return gas pipeline, respectively. The host computer is used to regulate the valve components based on the monitoring data fed back by the sensor components. In this embodiment, the host computer is preferably a computer 25 and a PLC controller 24.

[0066] In this embodiment, the sensor assembly includes a pressure sensor 5, a main liquid pipeline flow meter 14, a re-mixing liquid flow meter 12, and a gas turbine flow meter 16, respectively installed on the storage tank 1, the main liquid pipeline, the first re-mixing branch, and the main gas pipeline. The pressure sensor 5 is used to monitor the pressure inside the storage tank 1 in real time; the level gauge 6 is used to control the liquid level in the tank during water addition; the main liquid pipeline flow meter 14 and the re-mixing liquid flow meter 12 are used to measure the total flow rate of the liquid at the inlet; and the gas turbine flow meter 16 is used to measure the total flow rate of the gas entering the multiphase mixing pump 19.

[0067] As a further embodiment, the sensor assembly also includes a pump inlet pressure sensor 18 and a pump outlet pressure sensor 20 for detecting the inlet pressure and outlet pressure of the multiphase mixed pump 19, respectively.

[0068] In this embodiment, the valve assembly includes a liquid storage tank valve, a main liquid pipeline valve, a main gas pipeline valve, an outlet pipeline valve, a remixing pipeline valve, and a return gas pipeline valve.

[0069] The storage tank valves include a gas-liquid feed valve 2, a safety valve 3, and an electrically operated relief valve 4, all installed on the storage tank 1. The gas-liquid feed valve 2 serves as the main feed valve for the system, controlling the entry of compressed air and clean water into the storage tank 1. During the test preparation phase, opening this valve allows gas and liquid to be injected into the storage tank 1, establishing the initial system pressure and gas-liquid ratio. During the test, closing this valve maintains the stability of the closed system and prevents external interference. The safety valve 3 is a safety measure to prevent excessive system pressure. The electrically operated relief valve 4 is used to promptly release pressure within the storage tank 1.

[0070] The main liquid pipeline valves include a main liquid pipeline ball valve 8, a check valve 9, and a main liquid pipeline electric valve 13, all installed on the main liquid pipeline. The main liquid pipeline ball valve 8 serves as a manual or electric shut-off valve, controlling the opening and closing of the main liquid pipeline. During testing, it allows normal liquid flow when fully open; in slug flow tests, it can be partially or completely closed to switch to the recirculation pipeline, simulating operating conditions. The check valve 9 ensures that liquid in the storage tank 1 can only flow from its outlet to the pump inlet. The main liquid pipeline electric valve 13, controlled by a PLC controller 24, is an adjustable valve used to precisely control the liquid flow rate in the main liquid pipeline. Under PID control, it dynamically adjusts its opening based on flow meter feedback, stabilizing the flow rate at the set value, playing a crucial role, especially in extreme gas content tests.

[0071] The main gas pipeline valves include an intake electric valve 15 installed on the main gas pipeline. The intake electric valve 15 is used to dynamically control the intake volume based on the data from the gas turbine flow meter 16 and the gas content setpoint, in order to simulate different gas content conditions, such as high gas content or slug flow.

[0072] The outlet pipeline valve includes a pump outlet electric valve 22 installed on the outlet pipeline. The pump outlet electric valve 22 is used to control the flow of fluid at the pump outlet. During testing, it is fully open to ensure normal flow; in maintenance or emergency situations, it is closed to isolate the pump body for convenient safety inspection or maintenance.

[0073] The remixing pipeline valves include a remixing electric valve 10 and a pressure regulating valve 11 installed on the first remixing branch, and a return liquid valve 7 installed on the second remixing branch. The remixing electric valve 10 is controlled by a PLC controller 24 based on gas content feedback to dynamically adjust the amount of liquid remixed from the separator 23 to the pump inlet. When a high gas content is detected, this valve opens to replenish the liquid, reducing the inlet gas content and preventing pump performance degradation. The pressure regulating valve 11 is used to regulate the pressure of the remixed liquid, keeping it consistent with the pump inlet pressure. It automatically adjusts according to changes in pump outlet pressure, avoiding flow instability caused by pressure imbalance and ensuring a smooth replenishment process. The return liquid valve 7 controls the return of liquid from the separator 23 to the storage tank 1. It is open during normal operation to achieve liquid recycling; in specific tests, its opening can be adjusted to help maintain system liquid level balance.

[0074] The return gas pipeline valve includes a return gas valve 21 installed on the return gas pipeline. The return gas valve 21 is used to control the gas return from the outlet of the separator 23 to the main gas pipeline. When open, it allows gas to re-enter the main circulation, maintaining the gas volume balance of the system; when closed, it can isolate the gas path for specific test modes.

[0075] In this embodiment, the PLC controller 24 has a built-in PID controller, which is connected to the pressure regulating valve 11, the main liquid pipeline electric valve 13, and the air inlet electric valve 15. The pressure sensor 5 collects the internal pressure signal of the storage tank 1, the gas turbine flow meter 16 collects the flow signal in the main gas pipeline, the main liquid pipeline flow meter 14 collects the flow signal in the main liquid pipeline, the pump inlet pressure sensor 18 collects the pump inlet pressure signal, and the backflushing liquid flow meter 12 collects the flow signal in the backflushing pipeline. All of the above signals are transmitted to the PLC controller 24. When it is necessary to simulate a certain working condition, the specified working condition can be simulated by adjusting the pressure regulating valve 11, the main liquid pipeline electric valve 13, and the air inlet electric valve 15.

[0076] The test preparation process in this embodiment includes:

[0077] Calibration process: Calibrate pressure sensor 5, level gauge 6, backflushing electric valve 10, pressure regulating valve 11, backflushing liquid flow meter 12, main liquid pipeline electric valve 13, main liquid pipeline flow meter 14, inlet electric valve 15, gas turbine flow meter 16, pump inlet pressure sensor 18, pump outlet pressure sensor 20, and pump outlet electric valve 22.

[0078] Perform an airtightness test on the test bench: Set all valves in the circuit to full open, and allow compressed air to enter the storage tank 1 through the gas-liquid feed valve 2. After half an hour, close the gas-liquid feed valve 2. After the system has stabilized for half an hour, observe the pressure in the pressure sensor 5, gas turbine flow meter 16, and pump inlet pressure sensor 18. If there is no change in pressure and the values ​​are the same, it indicates that the airtightness test has passed.

[0079] A water pressure test was conducted on the test bench: Following the results of the airtightness test, clean water was introduced into the storage tank 1 through the gas-liquid inlet valve 2. The level gauge 6 was observed; once the water level in storage tank 1 exceeded the center line of the main liquid pipeline, the gas-liquid inlet valve 2 was closed. The system was allowed to stabilize for half an hour, during which time no leaks were observed in any pipelines, valves, or equipment, indicating that the water pressure test was passed. The system's test conditions were met, and the test can proceed.

[0080] The test process in this embodiment is as follows: depending on the product's operating conditions, it can be divided into two types: extreme gas content test and slug flow test.

[0081] 1. Limiting gas content test

[0082] Compressed air and clean water enter the storage tank 1 through the gas-liquid feed valve 2. The return valve 7, main liquid line ball valve 8, main liquid line electric valve 13, return air valve 21, and pump outlet electric valve 22 in the circuit are fully opened, while the remaining valves are set to fully closed. Once the pressure sensor 5 and level gauge 6 readings reach the required levels for the test, the gas-liquid feed valve 2 is closed. The multiphase mixed-transfer pump 19 is started, and the frequency is adjusted to the design requirements. After the system stabilizes, the model in the operating condition setting module is invoked according to the required operating conditions. Based on the identification results and other parameters, the valve opening variation range is calculated, and a flow rate setpoint is given within the allowable pressure range. A PID controller is used to control the inlet electric valve 15 and the main liquid pipeline electric valve 13. The measured flow rate after the system stabilizes is compared with the actual flow rate measured by the flow meter. The difference ΔQ is used by the PID controller to perform PID logic calculation to calculate the opening degree of the corresponding inlet electric valve 15 and the main liquid pipeline electric valve 13. The change in valve opening will affect the flow state. When ΔQ approaches 0, the system reaches a stable state. The flow rate of clean water in the main liquid pipeline flow meter 14, the gas flow rate and gas pressure in the gas turbine flow meter 16, the pressure in the pump inlet pressure sensor 18 and the pressure in the pump outlet pressure sensor 20 are recorded when the valves are opened and closed. The gas content is calculated and the gas-liquid ratio in the regulating loop system is greater than 5.

[0083] 2. Slug Flow Test

[0084] Under the extreme gas content test, after the main liquid pipeline electric valve 13 is adjusted to close to 10%, the opening of the inlet electric valve 15 remains unchanged. The return mixing pipeline is then opened, i.e., the return mixing electric valve 10 is fully opened, and then the main liquid pipeline electric valve 13 is completely closed. The opening of the return liquid valve 7 and the return mixing electric valve 10 are adjusted using a PID controller to ensure normal pump operation. The liquid flow rate in the return mixing flow meter, the gas flow rate and gas pressure in the gas turbine flow meter 16, the pressure in the pump inlet pressure sensor 18, and the pressure in the pump outlet pressure sensor 20 are recorded to calculate the gas content.

[0085] Example 2

[0086] This embodiment is a further limitation based on Embodiment 1, and its purpose is to provide a test method for a device simulating gas-liquid slug flow using a multiphase mixed-transfer pump. (Refer to...) Figure 2 This includes the following steps:

[0087] S1. Determine the target operating condition for testing the multiphase mixed-transfer pump's operating characteristics, and obtain the target input flow rate setpoint and target gas content setpoint for the multiphase mixed-transfer pump under the target operating condition.

[0088] S2. Monitor the flow and pressure data fed back from the sensor components through the host computer, and use multiple PID controllers in the host computer to adjust the opening degree of each valve in the valve assembly so that the liquid flow rate in the main liquid pipeline and the back mixing pipeline and the gas flow rate in the back mixing pipeline are equal to the target input flow rate set value and the target gas content set value, respectively.

[0089] If the re-doping loop is not opened, the flow rate can be calculated using the following formula:

[0090]

[0091]

[0092] in, For total flow, Main fluid pipeline flow rate, For air intake flow rate, Let P1 be the gas flow rate at the pump inlet, P2 be the absolute pressure at the pump inlet, and P3 be the absolute pressure of the gas entering the system. For the gas content, we have:

[0093]

[0094] Where M is the gas content; if the re-mixing loop is opened and the main liquid pipeline is closed, the flow rate can be calculated using the following formula:

[0095]

[0096] in The flow rate of the re-mixing loop; for gas content, we have:

[0097]

[0098] Preferably, the expression for the valve opening adjustment value in each PID controller is:

[0099]

[0100] in, For the corresponding PID controller in the valve assembly The valve opening adjustment value corresponding to the given time; This is the deviation between the measured flow rate and the target input flow rate setpoint. , and These are all PID control parameters, namely proportional gain coefficient, integral time constant, and derivative time constant.

[0101] As a further embodiment, the calculation method for the PID control parameters in each PID controller is as follows:

[0102] S21. Predefine various typical operating conditions for multiphase mixed-transfer pumps. Each typical operating condition is divided according to different combinations of the input flow rate and gas content of the multiphase mixed-transfer pump.

[0103] S22. Based on the target input flow rate setpoint and the target gas content setpoint, calculate the membership degree of the current working condition under each typical working condition using their respective predefined membership degree functions, and calculate the normalized weight under each typical working condition through the membership degree.

[0104] S23. Using the PID control parameters of each PID controller as the initial population, and using the normalized weights of each typical working condition to determine the population structure of the sparrow algorithm, and performing variable update and mutation operations of the sparrow algorithm according to the normalized weights of each typical working condition to optimize the solution, and output the optimal combination of PID control parameters.

[0105] As a further aspect of this embodiment, step S23 specifically includes,

[0106] S231. Randomly generate an initial population of N sparrows. The position of each sparrow represents a set of candidate PID control parameter combinations. The expression for the position of the i-th sparrow is:

[0107]

[0108] in, A random number within the range [0,1]; and These are the lower and upper limits of the PID control parameter combination, respectively.

[0109] S232. Divide the initial population into discoverers and followers, with the number of discoverers and followers being respectively... and , The expression is:

[0110]

[0111] in, For the proportion of mixed discoverers, Let x be the normalized weight of the xth typical working condition; X is the total number of typical working conditions. The proportion of discoverers of the xth typical working condition.

[0112] S233, Update the discoverer's location:

[0113]

[0114]

[0115] in, Let be the value of the j-th PID control parameter for the i-th sparrow at the (t+1)-th iteration. Let be the value of the j-th PID control parameter for the i-th sparrow at time t during the t-th iteration; It is the maximum number of iterations. Let x be the step size threshold for the xth typical working condition. This is a warning value; Let L be a random number that follows a standard normal distribution; L is a matrix with row i and column j, and all elements are 1. Mixed alert thresholds; is the warning threshold under the xth typical working condition.

[0116] S234, Update follower positions:

[0117]

[0118] in, This represents the worst position in the current j-dimensional global dimension. Let A be the optimal position of the discoverer in the current iteration; A is a matrix of all ones.

[0119] S235, Update the location of the Vigilant:

[0120]

[0121] in, It is the current global best position; These are step size control parameters. A random number between -1 and 1; This is the current fitness value of the sparrow. This represents the globally optimal fitness value. It is the worst fitness value globally; It is a constant.

[0122] S236. Randomly perturb the positions of some sparrows using mixed mutation probabilities:

[0123]

[0124]

[0125] in, With a mean of 0 and a standard deviation of Normally distributed random numbers; For mixed mutation probability; Let x be the variation probability of the xth typical working condition.

[0126] S237. Calculate the fitness function. Its expression is:

[0127]

[0128] Where T is the time window.

[0129] S238. Repeat steps S233 to S237 until completion. The maximum number of iterations is used to obtain the sparrow corresponding to the minimum fitness function. The PID control parameter combination corresponding to this sparrow is the optimal PID control parameter combination.

[0130] Preferably, in this embodiment, X is 4, meaning that typical operating conditions are divided into four categories. Input flow rate and gas content thresholds are set, resulting in low flow rate, high flow rate, low gas content, and high gas content. These are combined in pairs to obtain low flow rate with low gas content (energy-saving condition), low flow rate with high gas content (accuracy-sensitive characteristic), high flow rate with low gas content (stable condition), and high flow rate with high gas content (easily oscillating condition). The extreme gas content test and slug flow test in Example 1 are both under the "high flow rate with high gas content" condition. Each operating condition has preset key parameters for the sparrow algorithm. For example, for the easily oscillating condition under high flow rate and high gas content, the proportion of discoverers and the probability of mutation are increased to enhance the ability to escape local optima.

[0131] Membership function for input flow rate or gas content The general form is:

[0132]

[0133] In this example, for the input flow rate or gas content, a, b, c, and d represent the four vertices of the trapezoid. a represents the starting point; below this point, the membership degree is 0. b is the end point of the ascending segment, with the membership degree increasing linearly from 0 to 1. c is the starting point of the descending segment; from b to c, the membership degree is 1. d is the end point of the ascending segment, with the membership degree increasing linearly from 1 to 0. Specific parameter values ​​are set according to the operating condition. In this embodiment, the membership degrees for low flow rate, high flow rate, low gas content, and high gas content are respectively... , , and Multiplying the membership degrees pairwise, we can obtain the weights for a single working condition:

[0134]

[0135] , , and The weights are respectively for low flow rate and low gas content, low flow rate and high gas content, high flow rate and low gas content, and high flow rate and high gas content. , , and Each weight is normalized to obtain a normalized weight. , .

[0136] In summary, the beneficial effects of this embodiment are as follows:

[0137] This invention takes into account that different operating conditions affect the dynamic characteristics of the system. Under different operating conditions, the system has different requirements for PID control parameters. For example, in operating conditions with high flow rate and low gas content, fast response is key, while in operating conditions with high gas content and slug flow, higher robustness and stability are required. Therefore, the entire operating range is divided into several representative typical operating conditions. By calculating the membership degree of each operating condition, the host computer can identify the current operating condition type. For each typical operating condition, a set of relatively optimal PID control parameters can be optimized.

[0138] However, when operating conditions change, directly switching the PID control parameters will induce system oscillations. To ensure a smooth transition and avoid oscillations, this invention abandons the traditional practice of setting fixed or randomly selected sparrow parameters (such as the discoverer ratio and mutation probability) during initialization in cumbersome optimization algorithms. Instead, it uses normalized weights to weighted mix the preset sparrow algorithm parameters for different typical operating conditions, generating a set of initial parameters that conform to the current target operating condition. This ensures that the sparrow algorithm is in a high-potential search region from the outset. For example, when the target operating condition is identified as a oscillating "high flow rate and high gas content" condition, the mixed algorithm parameters will have stronger global exploration capabilities and mutation tendencies, thus more effectively avoiding local optima, accelerating convergence, and reducing the number of iterations and computation time required to find the optimal PID parameter combination.

[0139] Furthermore, since the normalized weights are dynamically calculated based on the target operating conditions, they change continuously and smoothly as the target operating conditions change. Therefore, the parameters of the hybrid sparrow algorithm also change continuously and gradually, rather than abruptly, thus avoiding system oscillations caused by jumps in PID control parameters and ensuring control stability.

[0140] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this invention. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this invention.

Claims

1. A device for simulating gas-liquid slug flow using a multiphase mixed-transfer pump, characterized in that, include: The liquid storage tank (1) has its liquid outlet and gas outlet connected to one end of the main liquid pipeline and the main gas pipeline, respectively. A multiphase mixing pump (19) is connected at its inlet to the other end of the main liquid pipeline and the main gas pipeline via a homogenizer (17). A gas-liquid separator (23) is provided. The inlet of the gas-liquid separator (23) is connected to the outlet of the multiphase mixing pump (19) through an outlet pipeline. The outlet of the gas-liquid separator (23) is connected to the main liquid pipeline and the storage tank (1) through a return mixing pipeline. The outlet of the gas-liquid separator (23) is connected to the main gas pipeline through a return gas pipeline. The control component includes a valve assembly, a sensor assembly, and a host computer, which is equipped with multiple PID controllers. The valve assembly and the sensor assembly are used to adjust and monitor the flow rate or gas pressure of the liquid storage tank (1), the main liquid pipeline, the main gas pipeline, the outlet pipeline, the remixing pipeline, and the return gas pipeline, respectively. The host computer is used to adjust the valve assembly based on the monitoring data fed back by the sensor assembly. The calculation method for the PID control parameters in each PID controller in the host computer is as follows: S21. Predefined multiphase mixed-transfer pump (19) has multiple typical operating conditions, each of which is divided according to different combinations of input flow rate and gas content of multiphase mixed-transfer pump (19); S22. Based on the target input flow rate setpoint and the target gas content setpoint, calculate the membership degree of the current working condition under each typical working condition using their respective predefined membership degree functions, and calculate the normalized weight under each typical working condition through the membership degree. S23. Using the PID control parameters of each PID controller as the initial population, and using the normalized weights of each typical working condition to determine the population structure of the sparrow algorithm, and performing variable update and mutation operations of the sparrow algorithm according to the normalized weights of each typical working condition to optimize the solution, and output the optimal combination of PID control parameters.

2. The apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 1, characterized in that, The remixing pipeline includes a first remixing branch and a second remixing branch that are respectively connected to the main liquid pipeline and the storage tank (1).

3. The apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 2, characterized in that, The sensor assembly includes a pressure sensor (5), a main liquid pipeline flow meter (14), a remixed liquid flow meter (12), and a gas turbine flow meter (16) respectively disposed on the liquid storage tank (1), the main liquid pipeline, the first remixing branch, and the main gas pipeline.

4. The apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 3, characterized in that, The sensor assembly also includes a pump inlet pressure sensor (18) and a pump outlet pressure sensor (20) for detecting the inlet and outlet pressures of the multiphase mixed-transport pump (19), respectively.

5. The apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 1, characterized in that, The valve assembly includes a storage tank valve, a main liquid pipeline valve, a main gas pipeline valve, an outlet pipeline valve, a remixing pipeline valve, and a return gas pipeline valve. The storage tank valves include a gas-liquid feed valve (2), a safety valve (3), and an electric relief valve (4) installed on the storage tank (1). The main liquid pipeline valves include a main liquid pipeline ball valve (8), a check valve (9), and a main liquid pipeline electric valve (13) installed on the main liquid pipeline. The main gas pipeline valve includes an intake electric valve (15) installed on the main gas pipeline. The outlet pipeline valve includes a pump outlet electric valve (22) installed on the outlet pipeline. The return pipeline valves include a return electric valve (10) and a pressure regulating valve (11) installed on the first return branch, and a return liquid valve (7) installed on the second return branch. The return gas pipeline valve includes a return gas valve (21) installed on the return gas pipeline.

6. The apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 1, characterized in that, Step S23 specifically includes, S231. Randomly generate an initial population of N sparrows. The position of each sparrow represents a set of candidate PID control parameter combinations. The expression for the position of the i-th sparrow is: in, A random number in the range [0,1]; and These are the lower and upper limits of the PID control parameter combination, respectively; S232. Divide the initial population into discoverers and followers, with the number of discoverers and followers being respectively... and , The expression is: in, For the proportion of mixed discoverers, Let x be the normalized weight of the xth typical working condition; X is the total number of typical working conditions. The proportion of those who discovered the xth typical working condition; S233, Update the discoverer's location: in, Let be the value of the j-th PID control parameter for the i-th sparrow at the (t+1)-th iteration. Let be the value of the j-th PID control parameter for the i-th sparrow at time t during the t-th iteration; It is the maximum number of iterations. Let x be the step size threshold for the xth typical working condition. This is a warning value; Let L be a random number that follows a standard normal distribution; L is a matrix with row i and column j, and all elements are 1. Mixed alert thresholds; Let x be the warning threshold under the xth typical working condition; S234, Update follower positions: in, This represents the worst position in the current j-dimensional global dimension. Let A be the optimal position of the discoverer in the current iteration; A is a matrix of all ones. S235, Update the location of the Vigilant: in, It is the current global best position; These are step size control parameters. A random number in the range of -1 to 1; This is the current fitness value of the sparrow. This represents the globally optimal fitness value. It is the worst fitness value globally; It is a constant; S236. Randomly perturb the positions of some sparrows using mixed mutation probabilities: in, With a mean of 0 and a standard deviation of Normally distributed random numbers; For mixed mutation probability; Let x be the variation probability of the xth typical working condition; S237. Calculate the fitness function. Its expression is: Where T is the time window; S238. Repeat steps S233 to S237 until completion. The maximum number of iterations is used to obtain the sparrow corresponding to the minimum fitness function. The PID control parameter combination corresponding to this sparrow is the optimal PID control parameter combination.

7. The test method for the apparatus for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Determine the target operating condition for testing the operating characteristics of the multiphase mixed-transfer pump (19), and obtain the target input flow rate setting value and target gas content setting value of the multiphase mixed-transfer pump (19) under the target operating condition. S2. Monitor the flow and pressure data fed back from the sensor assembly through the host computer, and use multiple PID controllers in the host computer to adjust the opening degree of each valve in the valve assembly so that the liquid flow rate in the main liquid pipeline and the back mixing pipeline and the gas flow rate in the back mixing pipeline are equal to the target input flow rate setting value and the target gas content setting value, respectively. S3. Test the operating characteristics of the multiphase mixed pump (19) under the current target operating conditions.

8. The test method for the device for simulating gas-liquid slug flow using a multiphase mixed-transport pump according to claim 7, characterized in that, The expression for the valve opening adjustment value in each PID controller is: in, For the corresponding PID controller in the valve assembly The valve opening adjustment value corresponding to the given time; This is the deviation between the measured flow rate and the target input flow rate setpoint. , and These are all PID control parameters, namely proportional gain coefficient, integral time constant, and derivative time constant.

Images