Water flow velocity measurement method and device

Abstract

The invention relates to the technical field of hydrology, and provides a water flow velocity measurement method and device, and the method comprises the steps: respectively obtaining the first propagation time of a first ultrasonic transducer for propagating a first ultrasonic signal, and the second propagation time of a second ultrasonic transducer for propagating a second ultrasonic signal, and calculating the propagation time difference at the current moment; calculating the water velocity based on the propagation time difference; the direction angle of the first ultrasonic signal and the second ultrasonic signal is a preset angle; the flow meter comprises a flow guide cover, a reflecting plate, a first ultrasonic transducer and a second ultrasonic transducer; the flow guide cover is of a streamline spindle structure; and the reflecting plate is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected with the flow guide cover. According to the method provided by the invention, the propagation time difference formed by the reflection of the ultrasonic signal through the reflecting plate is obtained through the flow velocity meter of the streamline spindle structure, the accurate and general water flow velocity measurement is realized, and the velocity measurement performance of the water flow velocity measurement is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrology, and particularly to a method and device for measuring water flow velocity. Background Art

[0002] Hydrological work is a basic cause for implementing flood control and drought relief, water resources management, and water environment monitoring and protection. Among them, the most basic work is hydrological measurement. For the flow measurement of open channels (including rivers and channels) (the volume of water passing through a certain cross-section per unit time, in m 3 / s as the unit), it is one of the most important works. The current principle of open channel flow measurement mostly adopts the "velocity-area method". That is, measuring and calculating the cross-sectional area of the open channel multiplied by the average water flow velocity (m / s) of this cross-section (m 2 ) to obtain the instantaneous flow rate (m 3 / s). Since the flow velocities at each point on the cross-section are different, in order to obtain the cross-sectional average flow velocity, generally different velocity measurement points are arranged in space (different horizontal positions and different water depth points), and the cross-sectional average flow velocity is calculated based on the flow velocities of these points. Generally, the flow velocities of these points are measured by traditional rotor-type current meters.

[0003] However, the operation of the rotor-type current meter depends on the impact of water flow. When the water flow velocity is too small, the instrument fails to operate in the linear rotation working area, and the accuracy of flow velocity measurement cannot be guaranteed. Therefore, the instrument performance of the traditional rotor-type current meter is not stable. Summary of the Invention

[0004] The present invention provides a method and device for measuring water flow velocity to solve the defect of low accuracy when a rotor-type current meter is used for flow velocity measurement in the prior art.

[0005] The present invention provides a method for measuring water flow velocity, including: respectively obtaining a first propagation time for a first ultrasonic transducer to propagate a first ultrasonic signal, and a second propagation time for a second ultrasonic transducer to propagate a second ultrasonic signal; calculating a propagation time difference at the current moment based on the first propagation time and the second propagation time; calculating a water flow velocity based on the propagation time difference; the first ultrasonic signal is sent from the first ultrasonic transducer to a reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; the second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; the direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; The current meter includes a fairing, a reflector, the first ultrasonic transducer, and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is disposed at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0006] According to a water flow velocity measurement method provided by the present invention, calculating the propagation time difference at the current moment based on the first propagation time and the second propagation time includes: Predicting the predicted propagation time difference at the current moment based on the propagation time difference at the previous moment, the noise covariance matrix at the previous moment, and the state transition matrix; Calculating the duration residual based on the predicted propagation time difference at the current moment and the measured propagation time difference; Updating the propagation time difference at the current moment based on the predicted propagation time difference, the duration residual, and the residual gain, and dynamically updating the noise covariance matrix at the current moment based on the weighting coefficient and the duration residual.

[0007] According to a water flow velocity measurement method provided by the present invention, the initial value of the noise covariance matrix is calculated based on the propagation time difference at a preset historical moment.

[0008] According to a water flow velocity measurement method provided by the present invention, the fairing is made of aluminum alloy or fiberglass.

[0009] According to a water flow velocity measurement method provided by the present invention, the reflector is made of stainless steel.

[0010] According to a water flow velocity measurement method provided by the present invention, the preset angle of the direction angles of the first ultrasonic signal and the second ultrasonic signal is 45° or 60°.

[0011] The present invention also provides a water flow velocity measurement device, including: An acquisition unit that respectively acquires the first propagation time for the first ultrasonic transducer to transmit the first ultrasonic signal and the second propagation time for the second ultrasonic transducer to transmit the second ultrasonic signal; A time difference determination unit that calculates the propagation time difference at the current moment based on the first propagation time and the second propagation time; A flow velocity calculation unit that calculates the water flow velocity based on the propagation time difference; The first ultrasonic signal is transmitted from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; The second ultrasonic signal is transmitted from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; The direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; The current velocity meter includes a fairing, a reflector, the first ultrasonic transducer, and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is disposed at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0012] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the water flow velocity measurement method described in any one of the above is implemented.

[0013] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the water flow velocity measurement method described in any one of the above is implemented.

[0014] The present invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, the water flow velocity measurement method described in any one of the above is implemented.

[0015] The water flow velocity measurement method and device provided by the present invention respectively obtain the first propagation time of the first ultrasonic signal propagated by the first ultrasonic transducer and the second propagation time of the second ultrasonic signal propagated by the second ultrasonic transducer through a current velocity meter with a streamlined spindle structure; based on the first propagation time and the second propagation time, the propagation time difference is calculated; based on the propagation time difference, the water flow velocity is calculated, realizing accurate and general water flow velocity measurement and greatly improving the velocity measurement performance of water flow velocity measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is a flowchart of the water flow velocity measurement method provided by the present invention; Figure 2 is a schematic diagram of the working principle of the current velocity meter provided by the present invention; Figure 3 is a sectional view of the current velocity meter provided by the present invention; Figure 4 is a schematic structural diagram of the water flow velocity measurement device provided by the present invention; Figure 5It is a schematic structural diagram of the electronic device provided by the present invention. Detailed implementation manners

[0018] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0019] It should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the embodiments of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0020] It should be noted that a traditional rotor-type current meter consists of an instrument body, a speed-measuring rotor and a signal transmission mechanism. According to different shapes of the rotor, the traditional rotor-type current meter is further divided into a cup-type current meter and a propeller-type current meter. Its working principle is that when the water flow impacts the speed-measuring rotor, the rotor will rotate around the rotating shaft. Since the rotor is strictly designed and calibrated in advance, its rotational speed is linearly positively correlated with the measured water flow velocity. In other words, the faster the water flow velocity, the faster the rotor rotates. The signal transmission mechanism driven by the rotor shaft emits a switching signal every few rotations, and the secondary instrument can obtain the water flow velocity at the point where the instrument is located according to the rate of the detected signal.

[0021] The performance indicators of the rotor-type current meter depend on the shape of the rotor, the friction coefficient of the rotating shaft, and the mechanical damping of the signal transmission mechanism itself. Due to mechanical wear, rotor deformation, and damage or replacement of the signal transmission mechanism, its service performance and the accuracy of the flow velocity measurement will be affected. Therefore, this type of current meter must be returned to the factory for calibration every year or after being repaired due to accidental impact or replacement of accessories, etc., in order to re-obtain an accurate flow measurement relationship line. The time and economic costs of using the instrument are very high. In addition, due to the need for mechanical structure and signal detection, the rotational speed of the rotating mechanism of a single instrument is limited. For this reason, the traditional rotor-type current meter is divided into two categories: propeller-type and cup-type. The former is mainly used in high-flow velocity environments, and the latter is used in low-flow velocity environments. This brings inconvenience to the equipment and use selection of the instrument.

[0022] Moreover, the operation of the rotor current meter depends on the impact of the water flow. When the water flow velocity is too small, the instrument fails to operate in the linear rotational speed working area, and thus the accuracy of the current measurement cannot be guaranteed. Additionally, when the flow velocity is lower than the starting flow velocity of the instrument (generally about 0.04 m / s), it cannot even operate.

[0023] To address the above problems, the present invention provides a method for measuring water flow velocity to achieve accurate, highly practical, and stable water flow velocity measurement. Figure 1 is a schematic flow chart of the water flow velocity measurement method provided by the present invention, as Figure 1 shown, the method includes: Step 110, respectively obtain the first propagation time for the first ultrasonic transducer to propagate the first ultrasonic signal, and the second propagation time for the second ultrasonic transducer to propagate the second ultrasonic signal; Step 120, based on the first propagation time and the second propagation time, calculate the propagation time difference at the current moment; Step 130, based on the propagation time difference, calculate the water flow velocity; The first ultrasonic signal is sent from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; The second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; The direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; The current meter includes a fairing, a reflector, the first ultrasonic transducer, and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is disposed at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0024] Here, the current meter includes a fairing, a reflector, a first ultrasonic transducer, and a second ultrasonic transducer. Among them, the first ultrasonic transducer and the second ultrasonic transducer each include an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic transmitter is used to transmit ultrasonic signals, and the ultrasonic receiver is used to receive the ultrasonic signals transmitted by the other ultrasonic transducer.

[0025] In addition, the fairing of the current meter is a streamlined spindle structure. The reflector is disposed at the intersection of the emission directions of the first ultrasonic signal and the second ultrasonic signal and is used to reflect the first ultrasonic signal and the second ultrasonic signal so that the ultrasonic signals are received by the corresponding ultrasonic transducers. Moreover, the reflector can be welded to the fairing by metal. Figure 2 is a schematic diagram of the working principle of the current meter provided by the present invention, as Figure 2As shown, the fairing of the current meter is a streamlined spindle structure, and the reflector can be welded to the fairing through a metal support frame, so that the reflector is at the intersection of the first ultrasonic signal and the second ultrasonic signal.

[0026] Specifically, first, during the actual water flow velocity measurement process, the current meter device is placed in an open channel, and the water flow passes through the gap between the fairing and the reflector in the Figure 2 direction shown, thus forming the velocity measurement condition of the current meter. At this time, the first ultrasonic signal can be emitted by the ultrasonic transmitter in the first ultrasonic transducer. After the first ultrasonic signal propagates through the water body, it is reflected by the reflector, changing the propagation direction of the first ultrasonic signal. After propagating through the water body, the first ultrasonic signal is received by the ultrasonic receiver in the second ultrasonic transducer. Thus, the time from the emission to the reception of the first ultrasonic signal can be recorded as the first propagation time.

[0027] Similarly, the second ultrasonic signal is emitted by the ultrasonic transmitter in the second ultrasonic transducer. After the second ultrasonic signal propagates through the water body, it is reflected by the reflector, changing the propagation direction of the second ultrasonic signal. After propagating through the water body, the second ultrasonic signal is received by the ultrasonic receiver in the first ultrasonic transducer. Thus, the time from the emission to the reception of the second ultrasonic signal can be recorded as the second propagation time.

[0028] In one embodiment, the first propagation time can be expressed by the following formula, as shown below:

[0029] In the formula, represents the first propagation time; represents the acoustic ray length, which refers to the straight-line distance between the first ultrasonic signal emitted by the first ultrasonic wave and the reflector; represents the propagation speed of the first ultrasonic signal in the downstream water, represents the propagation speed of the ultrasonic signal in water, which can be treated as a constant; represents the average velocity of the water flow through the gap between the fairing and the reflector of the current meter; represents the direction angle of the first ultrasonic signal.

[0030] Similarly, the second propagation time can be expressed by the following formula, as shown below:

[0031] In the formula, represents the second propagation time; represents the acoustic ray length, which refers to the straight-line distance between the second ultrasonic signal emitted by the second ultrasonic wave and the reflector, and is equal to the straight-line distance between the first ultrasonic signal emitted by the first ultrasonic wave and the reflector; represents the propagation speed of the second ultrasonic signal against the water flow, represents the propagation speed of the ultrasonic signal in water, which can be treated as a constant; V represents the average speed of the water flow between the fairing and the reflector of the current meter; represents the direction angle of the second ultrasonic signal, which is equal to the direction angle of the first ultrasonic signal.

[0032] Next, the propagation time difference at the current moment can be calculated through the time difference between the first propagation time and the second propagation time, that is, the time difference caused by the reflection through the reflector is obtained. Propagation time difference can be obtained through calculation.

[0033] Furthermore, the water flow speed can be calculated through the propagation time difference. It should be noted that the streamlined spindle structure of the current meter can better cooperate with the working principle of ultrasonic time difference measurement. In this principle, after the ultrasonic wave propagates through the water body and is reflected, the propagation time difference measured by the two transducers is directly related to the water flow speed. And the streamlined spindle structure helps to form a uniform water flow channel to ensure that the propagation time difference of the ultrasonic signal can accurately reflect the water flow speed.

[0034] From the above calculation formulas for the first propagation time and the second propagation time, the calculation formula for the water flow speed V can be derived as shown in the following formula:

[0035] In the formula, represents the average speed of the water flow between the fairing and the reflector of the current meter; represents the propagation time difference.

[0036] It should be noted that the water flow velocity calculated directly from mathematical formulas is more accurate, which can improve the velocity measurement accuracy of the current meter. Of course, due to the disturbances caused by the fairing, reflector, etc., errors in the flow measurement results will occur. However, this kind of error has the characteristics of stability and predictability, and can be simply obtained through the verification of hydrological instruments, providing conditions for the application of the current meter. The hydrological instrument verification method here can be to calibrate the measurement accuracy of the instrument through known standard flow velocities. By placing the instrument in a fluid with a known flow velocity, measuring the output of the instrument and comparing it with the actual flow velocity, its error can be determined. Since the disturbances (such as the effects caused by the fairing, reflector, etc.) are stable and predictable, after verification, an error model of the instrument under specific conditions can be established, thereby further improving the accuracy of the calculated water flow velocity. It can be understood that once the law of the instrument error is understood, these error characteristics can be applied to the actual measurement of the instrument. Through this calibration, the output of the instrument can be corrected. That is to say, in daily use, the actual flow velocity measurement results can be corrected according to the error information obtained during the verification process, thereby improving the accuracy of the instrument. In addition, hydrological instruments may exhibit different error characteristics under different flow velocities or different environmental conditions. Therefore, by performing multiple verifications under different conditions, a more accurate error model can be established, further reducing the measurement error in actual use.

[0037] It should also be noted that the fairing of the current meter provided by the present invention is a streamlined spindle structure. Among them, the streamlined spindle shape can allow the water flow to flow smoothly along the surface of the instrument, avoiding the introduction of measurement errors due to irregular disturbances of the water flow, and thus can effectively reduce the resistance and disturbance when the water flow passes through the current meter. And considering that turbulent and unstable water flows will interfere with the propagation of ultrasonic waves, thereby affecting the measurement results. The streamlined design can minimize the generation of turbulence, making the flow velocity measurement more stable and accurate.

[0038] In addition, the spindle shape has higher mechanical strength than other shapes (such as square or cylindrical) in terms of structure. The streamlined spindle structure can withstand the pressure and impact in the water flow. Especially in a complex water flow environment, it can maintain the stability of the instrument and avoid damage to the instrument. Moreover, due to the more compact and firm shape of the spindle structure, it can effectively resist the impact of sediment and other floating objects in the water, avoid the influence of these factors on the instrument performance, ensure long-term stable operation, and thus improve the service life of the instrument and reduce the maintenance cost of the instrument.

[0039] It should also be noted that the streamlined spindle structure can exhibit good performance under different flow velocities. From low flow velocities to high flow velocities, it can work efficiently and stably. This structural design is particularly important for measuring instruments that require a wide flow velocity range (such as 0.01 m / s to 10 m / s), enabling it to adapt to different hydrological measurement requirements and enhancing the practical applicability of the current meter.

[0040] Moreover, the streamlined design helps the water flow through the measuring component in a consistent direction and speed, reducing errors in flow velocity measurement. With such a design, when the water flows through the instrument, the changes in the propagation speed and direction of ultrasonic waves can be captured more precisely, thereby improving the measurement accuracy of the instrument.

[0041] In addition, the surface of the streamlined spindle structure is usually smooth, without protruding components and complex shapes, reducing the chance of debris and sediment in the water staying on the instrument surface. Therefore, the fairing of the streamlined spindle structure also reduces the maintenance difficulty caused by debris accumulation and decreases the need for instrument cleaning and maintenance.

[0042] In summary, as the main body of the current meter, the streamlined spindle structure not only improves the measurement accuracy and stability of the instrument, but also enhances the mechanical strength, durability and adaptability of the instrument, greatly improving the performance of the instrument in actual hydrological measurement and the reliability of long-term use.

[0043] The method provided by the embodiment of the present invention uses a current meter with a streamlined spindle structure to respectively obtain the first propagation time for the first ultrasonic transducer to propagate the first ultrasonic signal and the second propagation time for the second ultrasonic transducer to propagate the second ultrasonic signal; based on the first propagation time and the second propagation time, calculate the propagation time difference; based on the propagation time difference, calculate the water flow velocity, realizing accurate and general water flow velocity measurement and greatly improving the velocity measurement performance of water flow velocity measurement.

[0044] It should be noted that the water flow velocity is calculated through the propagation time difference of ultrasonic waves. However, in actual water flow velocity measurement, ultrasonic signals are often interfered by various factors, resulting in signal noise and errors, which in turn affect the measurement accuracy. The main sources of interference include unstable water flow, bubbles, impurities, temperature changes, etc. To further improve the accuracy of the velocity measurement result, based on any of the above embodiments, step 120 includes: Predict the predicted propagation time difference at the current moment based on the propagation time difference at the previous moment, the noise covariance matrix at the previous moment and the state transition matrix; Calculate the duration residual based on the predicted propagation time difference at the current moment and the measured propagation time difference; Update the propagation time difference at the current moment based on the predicted propagation time difference, the duration residual, and the residual gain, and dynamically update the noise covariance matrix at the current moment based on the weighting coefficient and the duration residual.

[0045] Specifically, first, the predicted propagation time difference at the current moment can be predicted through the propagation time difference at the previous moment of the current moment, the noise covariance matrix at the previous moment, and the state transition matrix. The predicted propagation time difference here can be calculated by the following formula:

[0046] In the formula, represents the predicted propagation time difference at the current moment ; represents the state transition matrix. Assuming that the state quantity changes little within the time step, the identity matrix or an approximate identity matrix is used to model the state transition; represents the propagation time difference at the previous moment ; represents the noise covariance matrix at the previous moment , and the noise covariance matrix here can be used to represent the process noise and the measurement noise.

[0047] Furthermore, the duration residual at the current moment can be calculated through the actually measured propagation time difference and the predicted propagation time difference at the current moment. The duration residual here can be calculated by the following formula, as shown below:

[0048] In the formula, represents the duration residual at the current moment t; represents the actually measured propagation time difference at the current moment; represents the measurement matrix, taking [1, 0]; represents the current moment ;

[0049] Next, the residual gain at the current moment can be calculated through the Kalman gain. Then, the propagation time difference at the current moment can be updated through the predicted propagation time difference, the duration residual, and the residual gain. The propagation time difference here can be calculated by the following formula, as shown below:

[0050] In the formula, represents the propagation time difference at the current moment; represents the predicted propagation time difference at the current moment; represents the residual gain at the current moment; Represents the duration residual at the current moment.

[0051] In addition, the noise covariance matrix at the current moment can be dynamically updated through the weighting coefficient and the duration residual, that is, the covariance matrices of the process noise and the measurement noise are updated to facilitate the calculation of the propagation time difference at the next moment. Here, the noise covariance matrix at the current moment obtained by dynamic update can be calculated by the following formula, as shown below:

[0052] In the formula, Represents the noise covariance matrix at the current moment; Represents the adjustment coefficient at the previous moment, used for cycle adjustment; Represents the residual gain at the current moment; Represents the duration residual at the current moment, Represents the transpose of the duration residual; Represents the transpose of the residual gain at the current moment; Represents the error covariance at the current moment; Represents the state transition matrix, Represents the transpose of the state transition matrix; Represents the error covariance at the previous moment.

[0053] Among them, , Represents the forgetting factor, Represents the forgetting factor at the next moment. By adjusting the forgetting factor, it can adapt to different working environments and measurement accuracy requirements. In addition, the residual gain at the current moment can be calculated by the following formula, as shown below:

[0054] In the formula, Represents the estimated error covariance at the previous moment; Represents the measurement matrix, which is [1, 0]; Represents the transpose of the measurement matrix; Represents the sensor noise.

[0055] The method provided by the embodiments of the present invention updates the actually measured propagation time difference at the current moment through the adaptive Kalman filtering algorithm, and continuously adjusts the filter parameters according to the real-time measurement data, thereby greatly reducing the error caused by environmental interference, improving the accuracy of the propagation time difference, and further improving the accuracy of the water flow velocity calculated based on the propagation time difference.

[0056] Based on any of the above embodiments, the initial value of the noise covariance matrix is calculated based on the propagation time difference at a preset historical moment.

[0057] Specifically, before filtering the propagation time difference of the actual measurement at the current moment, the initial value of the noise covariance matrix and the measurement error can be estimated through the propagation time difference at a preset historical moment, providing sufficient historical data for the filter to judge the noise characteristics and providing initial conditions for subsequent filtering algorithms. For example, the initial value of the noise covariance matrix can be obtained by preliminarily estimating the process noise and measurement noise through 50 pre-recorded propagation time differences.

[0058] Based on any of the above embodiments, the fairing is made of aluminum alloy or fiberglass.

[0059] Specifically, for the fresh water environment where the current meter is applied, considering portability, corrosion resistance, and material strength, the fairing can be made of aluminum alloy or fiberglass to extend the service life of the current meter.

[0060] It should be noted that the main function of the reflector is to reflect ultrasonic signals. Therefore, it needs to have good ultrasonic reflection ability. Generally, metal materials have high density and good reflection characteristics, and can effectively reflect ultrasonic signals. The reflector of the velocity measuring instrument will be in the water flow environment for a long time, and the chemical components, salts, and sediment in the water may accelerate the corrosion of the metal, affecting the performance and service life of the reflector. In addition, the reflector needs to withstand the impact in the water flow and the friction of floating objects in the water. Therefore, the reflector should have high mechanical strength and be able to withstand long-term physical wear without deformation or damage. And maintain an appropriate weight. To solve this problem, based on any of the above embodiments, the reflector is made of stainless steel.

[0061] Specifically, stainless steel is the most ideal reflective metal material, especially low-carbon austenitic Cr-Ni stainless steel, abbreviated as 316L stainless steel. It not only has excellent ultrasonic reflection characteristics, but also is corrosion-resistant, high-strength, and wear-resistant, suitable for long-term use in the water environment. In addition, if there are specific requirements for the overall weight of the current meter, aluminum alloy treated by anodic oxidation can be considered as the material of the reflector, but its corrosion resistance is poor. Therefore, the embodiments of the present invention preferably use stainless steel as the reflector material.

[0062] Based on any of the above embodiments, the preset angle of the direction angles of the first ultrasonic signal and the second ultrasonic signal is 45° or 60°.

[0063] It should be noted that the smaller the direction angle of the ultrasonic signal, the larger the value of, then the time difference is larger, and the measurement sensitivity is higher; the larger the direction angle of the ultrasonic signal (close to 90°), the smaller the value of, then the propagation time difference The smaller it is, the lower the measurement sensitivity, and when it approaches 0, the flow velocity result cannot be measured. However, when ultrasonic waves propagate along the water flow direction, the interference of bubbles and sediment will be amplified, that is, impurities moving in the same direction as the water flow may cause signal attenuation or misjudgment. Therefore, in order to ensure that the propagation time difference is large enough and reduce the co-directional interference of impurities in the water flow on the signal, the direction angles of the first ultrasonic signal and the second ultrasonic signal can be 45° or 60°. More specifically, when the water flow velocity is low, such as when the water flow velocity is less than 0.5 m / s, the direction angles of the first ultrasonic signal and the second ultrasonic signal can be 45°, so that the larger the propagation time difference, the higher the velocity measurement sensitivity in a low-flow environment; when the water flow velocity is high, such as when the water flow velocity is greater than 5 m / s, the direction angles of the first ultrasonic signal and the second ultrasonic signal can be 60°, improving the anti-water-flow disturbance ability, which is suitable for fixed installation.

[0064] It should be noted that compared with the ultrasonic velocity measurement instrument for large-diameter water pipes, since the water flow pattern is laminar flow and there are fewer bubbles and sediment in the pipeline, the included angle is set to 0°, but the influence of bubbles and sediment cannot be completely avoided. However, the method provided by the embodiments of the present invention limits the preset angles of the direction angles of the first ultrasonic signal and the second ultrasonic signal to 45° or 60°, which is beneficial to achieving high-sensitivity velocity measurement at low flow rates and improving the anti-water-flow disturbance ability in high-flow situations, thereby improving the accuracy of the overall velocity measurement result.

[0065] In one embodiment, Figure 3 is a schematic cross-sectional view of the flow velocity meter provided by the present invention. As Figure 3 shown, the flow velocity meter includes an output line, a sensing circuit, a transducer 1 (the first ultrasonic transducer), a transducer 2 (the second ultrasonic transducer), and a reflector. Among them, the direction angle represents the direction angle of the ultrasonic signal, and the acoustic ray represents the straight-line distance between the ultrasonic signal and the reflector, that is, the transmission distance of the ultrasonic signal. The digital signal collected by the ultrasonic transducer is output through the output circuit, and a computer or a secondary instrument can be used to receive the digital signal based on the collection and calculate the water flow velocity.

[0066] It should be noted that the flow velocity meter proposed by the present invention can be installed on the lead fish to measure the water flow velocity in the target area. Or, the flow velocity meter proposed by the present invention can be installed on the flow velocity measuring rod for manual wading to measure the water flow velocity.

[0067] Based on any of the above embodiments, Figure 4 is a schematic structural diagram of the water flow velocity measuring device provided by the present invention. As Figure 4 shown, the device includes: An acquisition unit 410 acquires the first propagation time of the first ultrasonic signal propagated by the first ultrasonic transducer and the second propagation time of the second ultrasonic signal propagated by the second ultrasonic transducer respectively. A time difference determination unit 420 calculates the propagation time difference at the current moment based on the first propagation time and the second propagation time. A flow velocity calculation unit 430 calculates the water flow velocity based on the propagation time difference. The first ultrasonic signal is sent from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer. The second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer. The direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles. The flow velocity meter includes a fairing, a reflector, the first ultrasonic transducer and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0068] The device provided by the embodiment of the present invention, through a flow velocity meter with a streamlined spindle structure, respectively acquires the first propagation time of the first ultrasonic signal propagated by the first ultrasonic transducer and the second propagation time of the second ultrasonic signal propagated by the second ultrasonic transducer; calculates the propagation time difference based on the first propagation time and the second propagation time; calculates the water flow velocity based on the propagation time difference, realizing accurate and general water flow velocity measurement and greatly improving the velocity measurement performance of water flow velocity measurement.

[0069] Based on any of the above embodiments, the time difference determination unit is specifically configured to: Predict the predicted propagation time difference at the current moment based on the propagation time difference at the previous moment, the noise covariance matrix at the previous moment and the state transition matrix. Calculate the duration residual based on the predicted propagation time difference at the current moment and the measured propagation time difference. Update the propagation time difference at the current moment based on the predicted propagation time difference, the duration residual and the residual gain, and dynamically update the noise covariance matrix at the current moment based on the weighting coefficient and the duration residual.

[0070] Based on any of the above embodiments, the initial value of the noise covariance matrix is calculated based on the propagation time difference at a preset historical moment.

[0071] Based on any of the above embodiments, the fairing is made of aluminum alloy or fiberglass.

[0072] Based on any of the above embodiments, the reflector is made of stainless steel.

[0073] Based on any of the above embodiments, the preset angle of the direction angles of the first ultrasonic signal and the second ultrasonic signal is 45° or 60°.

[0074] Figure 5 An example of a schematic physical structure diagram of an electronic device is shown as Figure 5 shown. The electronic device may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540. Among them, the processor 510, the communication interface 520, and the memory 530 complete communication with each other through the communication bus 540. The processor 510 can call the logical instructions in the memory 530 to execute the water flow velocity measurement method. The method includes: respectively obtaining the first propagation time for the first ultrasonic transducer to propagate the first ultrasonic signal and the second propagation time for the second ultrasonic transducer to propagate the second ultrasonic signal; calculating the propagation time difference at the current moment based on the first propagation time and the second propagation time; calculating the water flow velocity based on the propagation time difference; the first ultrasonic signal is sent from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; the second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; the direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; the flow velocity meter includes a fairing, a reflector, the first ultrasonic transducer, and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is disposed at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0075] In addition, when the logical instructions in the above-mentioned memory 530 can be implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0076] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the water flow velocity measurement method provided by the above-mentioned various methods. The method includes: respectively obtaining the first propagation time for the first ultrasonic transducer to propagate the first ultrasonic signal, and the second propagation time for the second ultrasonic transducer to propagate the second ultrasonic signal; calculating the propagation time difference at the current moment based on the first propagation time and the second propagation time; calculating the water flow velocity based on the propagation time difference; the first ultrasonic signal is sent from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; the second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; the direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; the flow velocity meter includes a fairing, a reflector, the first ultrasonic transducer, and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0077] In another aspect, the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the water flow velocity measurement method provided by the above-mentioned various methods. The method includes: respectively obtaining the first propagation time for the first ultrasonic transducer to propagate the first ultrasonic signal, and the second propagation time for the second ultrasonic transducer to propagate the second ultrasonic signal; calculating the propagation time difference at the current moment based on the first propagation time and the second propagation time; calculating the water flow velocity based on the propagation time difference; the first ultrasonic signal is sent from the first ultrasonic transducer to the reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; the second ultrasonic signal is sent from the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; the direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; the flow velocity meter includes a fairing, a reflector, the first ultrasonic transducer and the second ultrasonic transducer; the fairing is a streamlined spindle structure; the reflector is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal and is connected to the fairing.

[0078] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0079] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course also by hardware. Based on such an understanding, the above technical solution, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disc, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring water flow velocity, characterized in that: include: respectively acquiring a first propagation time of a first ultrasonic signal propagated by the first ultrasonic transducer and a second propagation time of a second ultrasonic signal propagated by the second ultrasonic transducer; Calculate the propagation time difference at a current moment based on the first propagation time and the second propagation time; Based on the propagation time difference, the water flow velocity is calculated; The first ultrasonic signal is sent by the first ultrasonic transducer to a reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; The second ultrasonic signal is sent by the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; The direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; The flow meter includes a flow guide cover, a reflector, the first ultrasonic transducer and the second ultrasonic transducer; the flow guide cover is a streamlined spindle structure; the reflector is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal, and is connected to the flow guide cover; When the water flow velocity is less than 0.5 m / s, the preset angle of the direction angle is 45°; when the water flow velocity is greater than 5 m / s, the preset angle of the direction angle is 60°; The first propagation time is expressed by the following formula, as shown below: ； In the formula, represents the first propagation time; represents the sound line length, which refers to the straight-line distance between the first ultrasonic signal and the reflector; represents the propagation speed of the first ultrasonic signal in downstream water, Indicates the propagation speed of ultrasonic signals in water; represents the water flow velocity; represents the direction angle of the first ultrasonic signal; The second propagation time is expressed by the following formula, as shown below: ； In the formula, represents the second propagation time; The sound line length refers to the straight-line distance between the second ultrasonic signal and the reflector, which is equal to the straight-line distance between the first ultrasonic signal and the reflector; represents the propagation speed of the second ultrasonic signal in upstream water, represents the propagation speed of ultrasonic signal in water; V represents the water flow speed; represents the direction angle of the second ultrasonic signal, which is equal to the direction angle of the first ultrasonic signal; The propagation time difference Expressed as ; The water flow rate The calculation formula is as follows: 。 2. The water flow velocity measurement method according to claim 1, characterized in that: The calculating the propagation time difference at the current moment based on the first propagation time and the second propagation time includes: Based on the propagation time difference at the previous moment, the noise covariance matrix at the previous moment, and the state transfer matrix, predicting the predicted propagation time difference at the current moment; Based on the predicted propagation time difference and the measured propagation time difference at the current moment, the duration residual is calculated; Based on the predicted propagation time difference, the duration residual, and the residual gain, the propagation time difference at the current moment is updated, and based on the weighting coefficient and the duration residual, the noise covariance matrix at the current moment is dynamically updated.

3. The water flow velocity measurement method according to claim 2, characterized in that: The initial value of the noise covariance matrix is ​​calculated based on the propagation time difference at the preset historical moment.

4. The water flow velocity measurement method according to any one of claims 1 to 3, characterized in that: The deflector cover is made of aluminum alloy or glass fiber reinforced plastic.

5. The water flow velocity measurement method according to any one of claims 1 to 3, characterized in that: The reflecting plate is made of stainless steel.

6. A water flow velocity measuring device, characterized in that: include: an acquisition unit, for respectively acquiring a first propagation time of the first ultrasonic transducer propagating the first ultrasonic signal and a second propagation time of the second ultrasonic transducer propagating the second ultrasonic signal; A time difference determining unit, which calculates a propagation time difference at a current moment based on the first propagation time and the second propagation time; A flow velocity calculation unit, which calculates the water flow velocity based on the propagation time difference; The first ultrasonic signal is sent by the first ultrasonic transducer to a reflector, and the reflector reflects the first ultrasonic signal to the second ultrasonic transducer; The second ultrasonic signal is sent by the second ultrasonic transducer to the reflector, and the reflector reflects the second ultrasonic signal to the first ultrasonic transducer; The direction angles of the first ultrasonic signal and the second ultrasonic signal are preset angles; The flow meter includes a flow guide cover, a reflector, the first ultrasonic transducer and the second ultrasonic transducer; the flow guide cover is a streamlined spindle structure; the reflector is arranged at the intersection of the first ultrasonic signal and the second ultrasonic signal, and is connected to the flow guide cover; When the water flow velocity is less than 0.5 m / s, the preset angle of the direction angle is 45°; when the water flow velocity is greater than 5 m / s, the preset angle of the direction angle is 60°; The first propagation time is expressed by the following formula, as shown below: ； In the formula, represents the first propagation time; represents the sound line length, which refers to the straight-line distance between the first ultrasonic signal and the reflector; represents the propagation speed of the first ultrasonic signal in downstream water, Indicates the propagation speed of ultrasonic signals in water; represents the water flow velocity; represents the direction angle of the first ultrasonic signal; The second propagation time is expressed by the following formula, as shown below: ； In the formula, represents the second propagation time; The sound line length refers to the straight-line distance between the second ultrasonic signal and the reflector, which is equal to the straight-line distance between the first ultrasonic signal and the reflector; represents the propagation speed of the second ultrasonic signal in upstream water, represents the propagation speed of ultrasonic signal in water; V represents the water flow speed; represents the direction angle of the second ultrasonic signal, which is equal to the direction angle of the first ultrasonic signal; The propagation time difference Expressed as ; The water flow rate The calculation formula is as follows: 。 7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the water flow velocity measurement method according to any one of claims 1 to 5 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the water flow velocity measurement method according to any one of claims 1 to 5 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the water flow velocity measurement method according to any one of claims 1 to 5 is implemented.

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