Doppler flow measurement system suitable for runway type culture pond

Abstract

The invention provides a Doppler flow measurement system suitable for a runway type culture pond, and solves the problems that the flow velocity distribution in an open water body of the runway type culture pond is complicated, and the precision of a traditional flow measurement means is insufficient. According to the Doppler flow measurement system, a synchronous trigger signal is generated through the main control system, the ultrasonic transducer array is driven to obtain the flow speeds of different water area positions, and basic data is provided for flow field measurement of an open water body; and the continuous calculation and abnormal state detection of the flow velocity distribution are realized by combining a signal processing and interpolation reconstruction algorithm, and the operation state of the water pushing equipment is automatically adjusted according to a monitoring result, so that the closed-loop control and self-adaptive adjustment of the flow velocity are realized. The Doppler flow measurement system is compact in structure, easy and convenient to install and excellent in anti-interference performance, continuous, real-time and high-precision monitoring of the flow speed can be achieved in the complex breeding environment, and technical support is provided for hydrodynamic regulation and control and environment management of the runway type breeding pond.

Description

Technical Field

[0001] This application belongs to the field of aquaculture flow velocity monitoring and intelligent control technology, specifically involving a Doppler flow measurement system suitable for racetrack-type aquaculture ponds. Background Technology

[0002] Raceway-style aquaculture ponds are a widely used structural form in recirculating aquaculture systems, primarily for the cultivation of economically important fish species that require high flow rates. These ponds utilize aeration devices to create a stable, directional water flow, providing fish with a swimming environment similar to natural water bodies. This helps promote growth, improve feed utilization, and enhance water circulation and self-purification. However, raceway-style aquaculture ponds are open water bodies, and their flow patterns are influenced by various factors such as flow rate, pond structure, and fish activity. The flow velocity distribution is complex and frequently changes, posing a significant challenge to accurate monitoring.

[0003] Existing flow velocity measurement methods are mostly used in closed pipes or regular channels, such as electromagnetic flowmeters and ultrasonic time-of-flight flowmeters, which are difficult to maintain accuracy in open water bodies. Simple flow measurement methods such as mechanical rotors and floating flowmeters are easily affected by water surface fluctuations, suspended particles, and air bubbles, making it impossible to obtain stable and reliable data. With the intelligent and refined development of aquaculture, real-time monitoring of flow velocity distribution within aquaculture ponds has become a crucial requirement for flow field control and environmental management. Therefore, there is an urgent need for a high-precision flow measurement technology suitable for open water bodies. Doppler flow measurement technology analyzes the frequency shift effect generated by the interaction of ultrasonic waves with suspended particles or air bubbles in the water, achieving non-contact, real-time, and continuous flow velocity measurement. It has high accuracy and environmental adaptability, making it particularly suitable for flow velocity monitoring in open water bodies. However, when applied in racetrack-style aquaculture ponds, problems still exist, such as complex signal reflection, uneven flow velocity distribution, limited installation space, and susceptibility of measurement data to noise.

[0004] Therefore, there is an urgent need to develop a Doppler flow measurement system suitable for racetrack-type aquaculture ponds, which should be optimized for the flow field characteristics of open water bodies to achieve accurate, stable, and real-time monitoring of flow velocity, and provide reliable technical support for flow velocity monitoring and intelligent control in aquaculture. Summary of the Invention

[0005] To address the technical problems of low measurement accuracy and real-time control in existing technologies for use in open water bodies such as racetrack aquaculture ponds, this application provides a Doppler flow measurement system suitable for racetrack aquaculture ponds. The technical problem to be solved by this application is achieved through the following technical solution: A Doppler flow measurement system suitable for racetrack-type aquaculture ponds includes: an ultrasonic transducer array, a submersible sliding rail device, a system integration chassis, a main control system, a water-pushing and oxygenating device, and a display terminal; the main control system is connected to the ultrasonic transducer array and the display terminal; the main control system is housed within the system integration chassis, which is installed on the wall of the aquaculture pond; The ultrasonic transducer array includes multiple ultrasonic transducers. A pair of ultrasonic transducers are respectively arranged in the inlet area, the core area of ​​the aquaculture area and the outlet area of ​​the aquaculture pond. Each pair of ultrasonic transducers adopts a through-beam method. The submersible slide rail device is used to fix the ultrasonic transducer at a predetermined water depth position in the aquaculture pond and to adjust the measuring angle of the ultrasonic transducer. The main control system is used to synchronously acquire the fluid velocity obtained by each ultrasonic transducer and output control signals based on the fluid velocity. The water-pushing and oxygenating equipment is used to adjust its own operating power according to the control signal; The display terminal is used to display fluid flow rate and alarm information.

[0006] This application addresses the challenges of complex velocity distribution and insufficient accuracy of traditional flow measurement methods in open water bodies of racetrack-type aquaculture ponds. It proposes a Doppler flow measurement system suitable for these ponds. The system generates a synchronous trigger signal through a main control system, driving an ultrasonic transducer array to acquire flow velocities at different locations within the water body, providing fundamental data for flow field measurement in open water bodies. Combined with signal processing and interpolation reconstruction algorithms, it achieves continuous calculation of velocity distribution and anomaly detection. Based on the monitoring results, it automatically adjusts the operation of the water-pushing equipment, thus realizing closed-loop control and adaptive adjustment of the flow velocity. This system features a compact structure, easy installation, and excellent anti-interference performance, enabling continuous, real-time, and high-precision flow velocity monitoring in complex aquaculture environments, providing technical support for hydrodynamic control and environmental management in racetrack-type aquaculture ponds.

[0007] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0008] Figure 1 This application provides a schematic diagram of the overall structure of a Doppler flow measurement system suitable for racetrack-type aquaculture ponds; Figure 2 This is a schematic diagram of the submersible slide rail device provided in this application; Figure 3 The hardware architecture diagram of the main control system provided in this application; Figure 4 The system workflow diagram provided for this application; Figure 5A schematic diagram of the system integration chassis provided in this application. Detailed Implementation

[0009] The present application will be described in further detail below with reference to specific embodiments, but the implementation of the present application is not limited thereto.

[0010] like Figure 1 As shown, this application provides a Doppler flow measurement system suitable for racetrack-type aquaculture ponds, comprising: an ultrasonic transducer array 1, an immersion sliding rail device 2, a system integration chassis 3, a main control system 4, a water-pushing and aeration device 5, and a display terminal 6. The main control system 4 is connected to the ultrasonic transducer array 1 and the display terminal 6; the main control system 4 is housed within the system integration chassis 3, which is installed on the wall of the aquaculture pond. The ultrasonic transducer array 1 includes multiple ultrasonic transducers. A pair of ultrasonic transducers are respectively arranged in the inlet area 7, the aquaculture core area 8, and the outlet area 9 of the aquaculture pond. Each pair of ultrasonic transducers adopts a through-beam method. The ultrasonic transducers are piezoelectric ceramic transducers with a working frequency f_t=110kHz, and the ultrasonic beams propagate in the horizontal direction.

[0011] refer to Figure 1 The submersible slide rail device is used to fix the ultrasonic transducer at a predetermined water depth in the aquaculture pond and to adjust the measurement angle of the ultrasonic transducer; the main control system is used to synchronously collect the fluid flow rate obtained by each ultrasonic transducer and output a control signal based on the fluid flow rate; the water pushing and oxygenating device is used to adjust its own operating power according to the control signal; the display terminal is used to display the fluid flow rate and alarm information.

[0012] Combination Figure 1 and Figure 2 The Doppler flow measurement system applicable to racetrack-type aquaculture ponds in this application has a workflow that includes six stages: synchronous triggering and signal acquisition, Doppler frequency shift extraction, flow velocity inverse calculation and data averaging, flow velocity distribution function reconstruction, uniformity assessment and anomaly detection, and power adjustment and closed-loop control.

[0013] The immersion slide rail device 2 of this application fixes the ultrasonic transducer array at a preset water depth position and provides depth and angle adjustment functions.

[0014] like Figure 3As shown, the immersion slide rail device of this application includes: a vertical slide rail 10, a locking mechanism 11, an angle adjustment mechanism 12, and a sliding seat 13; wherein, the vertical slide rail is fixed to the wall of the aquaculture pond; the sliding seat can move along the vertical slide rail to adjust the installation depth of the ultrasonic transducer; the angle adjustment mechanism is used to adjust the measurement angle of the ultrasonic transducer probe; and the locking mechanism is used to lock the sliding seat and the angle adjustment mechanism.

[0015] Specifically, the vertical slide rail 10 of this application is designed with a "U"-shaped groove in the sliding seat 13. It is fixed to the slide rail on the wall of the aquaculture pond by the locking mechanism 11 and can move freely up and down along the slide rail to adjust the water depth of the ultrasonic transducer array 1. The angle adjustment mechanism 12 includes a rotating shaft, an angle scale, and a fixed bracket. The fixed bracket is used to install the ultrasonic transducer probe, and the angle θ between the ultrasonic beam emitted by the ultrasonic transducer array 1 and the water flow direction can be adjusted by the rotating shaft.

[0016] refer to Figure 4 As shown, the main control system 4 of this application is installed inside the system integration chassis 3 and is connected to each ultrasonic transducer through waterproof wiring terminals. The main control system 4 includes: a pulse generator, a signal receiving and processing module, a data storage module, a communication interface module, and a power management module. The signal receiving and processing module includes a low-noise preamplifier, time gain control, bandpass filter, analog-to-digital converter, and microprocessor. The communication interface module includes an RS485 interface and an Ethernet interface. The pulse generator generates synchronous trigger high-voltage pulse signals to drive each ultrasonic transducer to emit ultrasonic waves. The signal receiving and processing module receives each echo signal and extracts the Doppler frequency shift from it. Based on the Doppler frequency shift, it calculates the fluid velocity and generates a control signal based on the fluid velocity. The echo signal is the signal reflected when the ultrasonic waves emitted by each ultrasonic transducer encounter scattering particles moving with the fluid. The data storage module stores historical fluid velocity, system parameters, and alarm records. The communication interface module exchanges data with the display terminal and the water-pushing and oxygenating equipment. The power management module provides 24V and 5V DC power to power the various modules within the system.

[0017] Specifically, the pulse generator described in this application uses a high-voltage pulse generation circuit, which can generate a 200Vpp, 110kHz pulse signal. The pulse generator has three independent output channels, which are connected to three ultrasonic transducers respectively. Synchronous triggering is achieved through a microcontroller. In this embodiment, it is set to 100ms, that is, 10 flow rate data are collected per second. The signal receiving and processing module adopts a multi-channel parallel processing architecture, including three independent signal processing channels. Each channel includes a low-noise preamplifier, a time gain control circuit, a bandpass filter, an analog-to-digital converter, and a microprocessor. The low-noise preamplifier uses an AD8065 operational amplifier chip, with an adjustable gain range of 40dB to 80dB (60dB in this embodiment), and a noise figure of less than 3dB, used to amplify the weak echo signal received by the transducer. The time gain control circuit uses a VCA810 variable gain amplifier chip, with the gain increasing linearly with time to compensate for the attenuation loss of sound waves propagating in water. The gain adjustment range is 0dB to 40dB, and the adjustment rate is 200dB / ms. The bandpass filter adopts a fourth-order Butterworth filter structure with a center frequency of... The bandwidth is 20kHz, used to filter out power frequency interference and high-frequency noise, improving the signal-to-noise ratio. The analog-to-digital converter uses a 12-bit high-speed ADC chip ADS7861 with a sampling rate of 10MHz to convert analog signals into digital signals. The microprocessor uses an STM32F407VG chip with a main frequency of 168MHz, featuring a floating-point arithmetic unit and DSP instruction set, used for digital signal processing and Doppler frequency shift extraction. The data storage module uses a 32GB SD card storage scheme, storing data in CSV format. Each record includes a timestamp, flow rate value, flow rate variation coefficient (CV) value, and system status flag. The communication interface module includes an RS485 interface and an Ethernet interface for real-time data interaction with the display terminal 5; the Ethernet interface is used for data communication with a host computer or remote monitoring platform. The power management module has an input voltage of AC220V, which is converted to DC24V and DC5V outputs by a switching power supply to power the main control system 4, the water-pushing and oxygenating equipment 5 and the display terminal 6. The power module has overvoltage, overcurrent and short-circuit protection functions and is equipped with a backup power interface.

[0018] In one specific embodiment of this application, the signal receiving and processing module is specifically used for: a. Collect echo signals reflected when ultrasonic waves emitted by ultrasonic transducers at different locations encounter scattering particles moving with the fluid. refer to Figure 2 In the synchronization triggering and signal acquisition phase, the main control system 4 sends synchronization trigger signals to the ultrasonic transducer array installed in the inlet area, core area, and outlet area of ​​the aquaculture pond, with a transmission frequency of [frequency missing]. When an ultrasonic beam encounters scattering particles moving with the fluid, the frequency of the reflected signal shifts, and the reflected signal is received by the ultrasonic transducer.

[0019] b. Extract the Doppler frequency offset from the echo signal and use the Doppler frequency offset to calculate the fluid velocity in different regions; for each region, average the fluid velocity obtained from multiple measurements to obtain the average velocity. refer to Figure 2 In the Doppler frequency shift extraction stage, the signal receiving and processing module of this application, i.e., the microprocessor, can perform a Fast Fourier Transform (FFT) on the acquired echo signal to obtain the signal's spectral distribution and identify the dominant frequency of the echo signal. Fluid velocity was calculated using the Doppler frequency shift method:

[0020] refer to Figure 2 In the flow velocity inverse calculation and data averaging process, this application uses the measured Doppler frequency shift... The fluid velocity is calculated by back-calculating the fluid velocity using the formula: ; In the formula, The velocity coefficient is... For Doppler frequency shift, The frequency of the echo signal, This is the emission frequency of the ultrasonic wave. For fluid velocity, The angle between the ultrasonic beam and the fluid flow direction. The speed at which ultrasound propagates in the medium.

[0021] The main control system 4 receives the flow velocity values ​​{V1, V2, V3} measured by each ultrasonic transducer at the same time; it averages the multiple measurements from two transducers in each region to obtain the average flow velocity of that region. , , The average flow rate is transmitted to the display terminal for display and stored in the data storage module.

[0022] c. Calculate the local velocity gradient based on the average velocity of adjacent areas, and establish the velocity distribution function of the aquaculture area based on the local velocity gradient; refer to Figure 2 In the velocity distribution function reconstruction stage, to reconstruct the continuous velocity distribution of the entire aquaculture pond from the velocity data of three discrete measuring points, the system employs a piecewise cubic Hermite interpolation algorithm. The local velocity gradient is calculated based on the representative velocity values ​​of adjacent regions, and this local velocity gradient is expressed by the formula: ; ; In the formula, and These represent the local velocity gradients in the inlet and outlet regions, respectively. , , The coordinates of the center positions of the inlet area, the aquaculture core area, and the outlet area are respectively, and a local velocity gradient is set in the aquaculture core area. ; , , This indicates the average flow velocity in the inlet area, the core aquaculture area, and the outlet area.

[0023] This application divides the aquaculture pond into two sub-sections; the coordinates of the two sub-sections are represented as follows: , Using the local velocity gradients in the inlet and outlet regions, and through cubic polynomial interpolation, the velocity distribution functions for the two sub-sections are established, expressed as:

[0024]

[0025] In the formula, , , This is the normalized position parameter, with a value range of [0, 1]. , , , The cubic Hermite basis functions are defined as follows:

[0026] The above method enables a smooth reconstruction of discrete measurement point data into a continuous velocity function V(x), making the velocity function and its first derivative continuous throughout the entire watershed.

[0027] d. Calculate the velocity variation coefficient based on the velocity distribution function, and determine the velocity state of the aquaculture pond based on the velocity variation coefficient; refer to Figure 2 In the uniformity assessment and outlier detection phase, for each area within the aquaculture pond, the velocity variation coefficient is calculated based on the average flow velocity of that area, expressed as: In the formula, The standard deviation of the flow rate. The average flow velocity of the region; for each region in the aquaculture pond, if the coefficient of variation of the flow velocity in that region is less than 15%, the flow velocity in that region is judged to be uniform; otherwise, the region enters the adjustment mode; in the adjustment mode, the flow velocity status of each sub-segment is determined to be abrupt abnormal, dead zone abnormal, or excessively high flow velocity according to the flow velocity distribution function.

[0028] The main control system detects the following three abnormal states based on the reconstructed velocity distribution curve V(x): If This is determined to be an abnormal change in flow rate; if If the flow rate dead zone is abnormal; The flow rate was determined to be abnormally high.

[0029] e. Calculate the power adjustment amount of the water-pushing and oxygenating equipment based on the deviation between the average flow velocity and the target flow velocity in the core aquaculture area; refer to Figure 2 In the power regulation and closed-loop control stage, this application calculates the deviation between the average flow velocity and the target flow velocity in the core aquaculture area, expressed as: Based on the aforementioned deviation, the power adjustment of the water-pushing and oxygenating equipment, expressed through a PID control algorithm, is as follows: ; In the formula, , , These are the proportional, integral, and differential coefficients, respectively. This is the error from the previous cycle. For the sampling period, when At that time, increase the power of the water-push aeration equipment to increase the flow rate; when At this time, reduce the power of the water-pushing and aeration equipment to maintain a stable flow.

[0030] f, generates a control signal based on the power adjustment amount.

[0031] In one specific embodiment of this application, the display terminal provides a parameter setting interface, a historical data query interface, and a real-time display interface; the target flow rate is set in the parameter setting interface. The system includes anomaly detection thresholds, PID control parameters, and data acquisition cycles; it displays the flow velocity distribution curve, average flow velocity at each measuring point, flow velocity variation coefficient, and alarm information in real time on the real-time display interface; and it allows querying and exporting flow velocity data curves by time period on the historical data query interface.

[0032] The display terminal 6 of this application is connected to the main control system 4 via an RS485 interface, using Modbus RTU as the communication protocol and a baud rate of 115200bps. The touchscreen display is a 7-inch LCD screen. The display terminal software interface includes: a real-time monitoring interface: displaying the flow velocity distribution function V(x) as a coordinate curve graph, with the X-axis representing the position coordinates and the Y-axis representing the flow velocity value. The interface simultaneously displays the flow velocity values ​​at the measuring points, CV values, the power of the water-pushing equipment, and the system status. When an anomaly is detected, the interface displays alarm information and triggers a buzzer. A parameter setting interface: providing the target flow velocity. The system includes settings for anomaly detection thresholds, PID parameters, and data acquisition cycle. Modified parameters are transmitted to the main control system via RS485. The historical data query interface allows selection of the query time range using a date and time selector. The system information interface displays hardware information, software version, network configuration, and operational statistics. The display terminal 6 is powered by a DC24V input from the main control system 4.

[0033] In one specific embodiment of this application, reference is made to Figure 5 As shown, the system integration chassis 3 of this application is used to install and house the main control system 4. The system integration chassis 3 is made of 304 stainless steel, with external dimensions of 400mm×300mm×200mm, wall thickness of 2mm, and protection rating of IP65. The upper layer inside the chassis is the main control circuit board mounting area 14, which is fixed by copper pillars 15 and has ventilation openings 16; the middle layer is the power module 17 mounting area, outputting DC24V and DC5V; the lower layer is the terminal block 18, which has three rows of waterproof terminals, respectively connecting to the transducer signal line 19, power line 20, and DC5V line 21. The backup power interface 22 supports UPS uninterruptible power supply access to ensure that data is not lost during power outages.

[0034] In one specific embodiment of this application, the water-pushing and oxygenating device employs vector control variable frequency speed regulation technology to adjust its operating power within a power adjustment range according to the control signal; wherein, the power adjustment range is 30% to 120% of the rated power. The water-pushing and oxygenating device of this application has a smooth acceleration and deceleration function and can automatically adjust its operating state according to the flow rate detection results.

[0035] It is worth noting that the terms "first" and "second" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of this application, and all such modifications or substitutions should be considered within the scope of protection of this application.

Claims

1. A Doppler flow measurement system suitable for racetrack-type aquaculture ponds, characterized in that, include: The system includes an ultrasonic transducer array, an immersion slide rail device, a system integration chassis, a main control system, a water-pushing and oxygenating device, and a display terminal; the main control system is connected to the ultrasonic transducer array and the display terminal; the main control system is housed within the system integration chassis, which is installed on the wall of the aquaculture pond; The ultrasonic transducer array includes multiple ultrasonic transducers. A pair of ultrasonic transducers are respectively arranged in the inlet area, the core area of ​​the aquaculture area and the outlet area of ​​the aquaculture pond. Each pair of ultrasonic transducers adopts a through-beam method. The submersible slide rail device is used to fix the ultrasonic transducer at a predetermined water depth position in the aquaculture pond and to adjust the measuring angle of the ultrasonic transducer. The main control system is used to synchronously acquire the fluid velocity obtained by each ultrasonic transducer and output control signals based on the fluid velocity. The water-pushing and oxygenating equipment is used to adjust its own operating power according to the control signal; The display terminal is used to display fluid flow rate and alarm information.

2. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 1, characterized in that, The immersion slide rail device includes: a vertical slide rail, a locking mechanism, an angle adjustment mechanism, and a sliding seat; wherein, the vertical slide rail is fixed to the wall of the aquaculture pond; the sliding seat can move along the vertical slide rail to adjust the installation depth of the ultrasonic transducer; the angle adjustment mechanism is used to adjust the measurement angle of the ultrasonic transducer probe; and the locking mechanism is used to lock the sliding seat and the angle adjustment mechanism.

3. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 1, characterized in that, The main control system includes: a pulse generator, a signal receiving and processing module, a data storage module, a communication interface module, and a power management module; the signal receiving and processing module includes a low-noise preamplifier, time gain control, a bandpass filter, an analog-to-digital converter, and a microprocessor; the communication interface module includes an RS485 interface and an Ethernet interface. The pulse generator is used to generate a synchronous trigger high-voltage pulse signal to drive each ultrasonic transducer to emit ultrasonic waves. The signal receiving and processing module is used to receive each echo signal and extract the Doppler frequency shift from it; calculate the fluid flow velocity based on the Doppler frequency shift, and generate a control signal based on the fluid flow velocity; wherein, the echo signal is the signal reflected when the ultrasonic waves emitted by each ultrasonic transducer encounter scattering particles moving with the fluid. The data storage module is used to store historical fluid flow rates, system parameters, and alarm records; The communication interface module is used to exchange data with the display terminal and the water-pushing and oxygenating equipment; The power management module is used to provide 24V and 5V DC power to power the various modules in the system.

4. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 3, characterized in that, The signal receiving and processing module is specifically used for: Collect echo signals of ultrasonic waves emitted by ultrasonic transducers at different locations when they encounter scattering particles moving with the fluid. The Doppler frequency offset is extracted from the echo signal, and the fluid velocity in different regions is calculated using the Doppler frequency offset; for each region, the average velocity is obtained by averaging the fluid velocity measured multiple times. Calculate the local velocity gradient based on the average velocity of adjacent areas, and establish the velocity distribution function of the aquaculture area based on the local velocity gradient; The velocity variation coefficient is calculated based on the velocity distribution function, and the velocity state of the aquaculture pond is determined based on the velocity variation coefficient. The power adjustment of the water-pushing and oxygenating equipment is calculated based on the deviation between the average flow velocity and the target flow velocity in the core aquaculture area. A control signal is generated based on the power adjustment amount.

5. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 4, characterized in that, The fluid velocity is expressed by the formula: ； In the formula, The velocity coefficient is... For Doppler frequency shift, The frequency of the echo signal, This is the emission frequency of the ultrasound wave. For fluid velocity, The angle between the ultrasonic beam and the fluid flow direction. The speed at which ultrasound propagates in the medium; The local velocity gradient is expressed by the formula: ； ； In the formula, and These represent the local velocity gradients in the inlet and outlet regions, respectively. , , The coordinates of the center positions of the inlet area, the aquaculture core area, and the outlet area are respectively, and a local velocity gradient is set in the aquaculture core area. ; , , This indicates the average flow velocity in the inlet area, the core aquaculture area, and the outlet area.

6. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 5, characterized in that, The flow velocity distribution function for establishing the aquaculture core area based on the local flow velocity gradient includes: The aquaculture pond is divided into two sub-sections; the coordinates of the two sub-sections are represented as follows: , ; Using the local velocity gradients in the inlet and outlet regions, and through cubic polynomial interpolation, the velocity distribution functions for the two sub-sections are established, expressed as: In the formula, , , This is the normalized position parameter, with a value range of [0, 1]. , , , Defined as: In the formula, , , , These are cubic Hermite basis functions.

7. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 5, characterized in that, The step of calculating the velocity variation coefficient based on the velocity distribution function and determining the velocity state of the aquaculture pond based on the velocity variation coefficient includes: For each area within the aquaculture pond, the coefficient of variation of the flow velocity is calculated based on the average flow velocity of that area, and is expressed as: ； In the formula, The standard deviation of the flow rate, The average flow velocity in the region; For each area within the aquaculture pond, if the coefficient of variation of the flow velocity in that area is less than 15%, the flow velocity in that area is considered uniform; otherwise, the adjustment mode is entered. In the adjustment mode, the velocity state of each sub-segment is determined to be abrupt change, dead zone, or excessively high velocity based on the velocity distribution function.

8. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 5, characterized in that, The calculation of the power adjustment of the water-pushing and aeration equipment based on the deviation between the average flow velocity and the target flow velocity in the core aquaculture area includes: The deviation between the average flow velocity and the target flow velocity in the core aquaculture area is calculated and expressed as: Based on the aforementioned deviation, the power adjustment of the water-pushing and oxygenating equipment, expressed through a PID control algorithm, is as follows: ； In the formula, , , These are the proportional, integral, and differential coefficients, respectively. This is the error from the previous cycle. For the sampling period, when At that time, increase the power of the water-push aeration equipment to increase the flow rate; when At this time, reduce the power of the water-pushing and aeration equipment to maintain a stable flow.

9. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 1, characterized in that, The display terminal provides a parameter setting interface, a historical data query interface, and a real-time display interface; Set the target flow rate in the parameter setting interface. Anomaly detection threshold, PID control parameters, and data acquisition cycle; The real-time display interface displays the flow velocity distribution curve, the average flow velocity at each measuring point, the flow velocity variation coefficient, and alarm information in real time. The historical data query interface allows users to query and export flow rate data curves by time period.

10. The Doppler flow measurement system for racetrack-type aquaculture ponds according to claim 1, characterized in that, The water-pushing and oxygenating equipment adopts vector control frequency conversion speed regulation technology, which is used to adjust its own operating power according to the control signal within the power adjustment range; wherein, the power adjustment range is 30% to 120% of the rated power.

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