Flow calculation method, device and storage medium of cross-path ultrasonic flowmeter

Abstract

The present invention discloses a flow calculation method for a crossed sound path ultrasonic flow meter. Aiming at the defect that the fixed weight function flow integration method of the traditional multi-sound path time difference method ultrasonic flow meter cannot adapt to the chaotic flow state inside the flow channel to be measured under extreme working conditions of large pumping stations, the present invention monitors the average flow velocity of the sound path of the crossed sound path of each flow layer in real time, reconstructs the average flow velocity size and direction of the corresponding flow layer, judges whether there is undesirable flow state such as backflow inside the flow channel to be measured, and configures different flow integration weight functions according to the flow state change inside the flow channel to be measured, thereby improving the measurement accuracy of the flow integration algorithm of the crossed dual-channel multi-sound path time difference method ultrasonic flow meter under extreme working conditions of large pumping stations.

Description

Technical Field

[0001] The invention relates to the technical field of flow measurement of ultrasonic flowmeters, and specifically designs a flow calculation method, a device and a storage medium of a cross-sound path acoustic flowmeter. Technical Background

[0002] The real-time flow rate of each unit in a large pumping station is an important basis for water dispatching decisions in large pumping stations. Among the many flow measurement methods for large pumping stations, multi-channel ultrasonic flowmeters are increasingly used for real-time flow measurement in large pumping stations due to their advantages such as non-contact and large-range measurement. Currently, all major pumping stations use ultrasonic flowmeters based on the cross-dual-channel multi-channel time difference method arranged at the inlet rectangular contraction section for real-time flow measurement.

[0003] The time difference flowmeter actually superimposes the ultrasonic propagation velocity with the fluid flow velocity by vector, and reflects the flow velocity by measuring the time difference of ultrasonic wave propagation downstream and upstream. Since the single-channel ultrasonic flowmeter is easily affected by the flow velocity distribution, it cannot fully reflect the actual condition of the flow field in the pipeline. Therefore, for the actual situation of large pumping stations with multiple working conditions and complex flow patterns, it is necessary to arrange multiple pairs of cross channels inside the flow channel, and evenly divide the flow section into several flow layers. The average axial velocity of each flow layer is determined by the average velocity of the cross-sound path in the flow layer, and then the flow value is calculated using the flow integration method based on Gauss-Legender integration.

[0004] The existing flow integration methods of ultrasonic flowmeters have a common problem: the preset average velocity distribution of the sound channel line is fixed and does not change with the flow state. In fact, under extreme working conditions, the flow state distribution of the flow channel is very chaotic, and the existing integration method cannot accurately identify adverse flow states such as backflow and vortex, resulting in a significant reduction in the measurement accuracy of the ultrasonic flowmeter. In the actual operation of large pumping stations, it is found that under extreme working conditions, the maximum error of the reading of the cross-dual channel multi-sound path time difference method ultrasonic flowmeter can reach 30%, and it is impossible to accurately determine the real-time flow of the pumping station under extreme working conditions, and the flow error directly affects the rationality of scheduling decisions at all levels. On the other hand, since the ultrasonic transducer in the ultrasonic flowmeter is a pre-buried device in the pump station, once the pump station is built, it is impossible to increase the number of sound paths to improve the measurement accuracy of the ultrasonic flowmeter under extreme working conditions.

[0005] Taking the single-channel time-difference flowmeter as an example, its measurement principle is as follows Figure 1 As shown, S is the straight-line distance of the ultrasonic flowmeter transducer, α is the angle between the flow channel axis and the transducer sound path, the propagation speed of ultrasonic waves in static fluid is c, the fluid flow velocity in the measured pipeline is v, the ultrasonic wave propagation time downstream is T1, and the reverse flow propagation time is T2. The calculation formula is as follows:

[0006]

[0007]

[0008] For liquid ultrasonic flowmeters, the propagation speed of ultrasonic waves in still water is about 1500m / s. According to the measurement range of ultrasonic flowmeters, it can be generally considered that the flow velocity of the liquid to be measured is much smaller than the propagation velocity of ultrasonic waves. The calculation formula for the axial average flow velocity of the fluid in the flow section to be measured is as follows:

[0009]

[0010] The flow rate is calculated based on the formula Q=AV, where A is the cross-sectional area of ​​the flow to be measured.

[0011] Single-channel ultrasonic flowmeters are easily affected by the velocity distribution and cannot fully reflect the actual conditions of the flow field in the pipeline. For large pumping stations with multiple working conditions and complex flow patterns, it is necessary to arrange multiple pairs of cross-channels inside the flow channel to evenly divide the flow section into several flow layers. The average axial velocity of each flow layer is determined by the average velocity of the cross-channels in the flow layer.

[0012] The traditional flow integration method for rectangular pipes is Gauss-Legender integration, and the calculation formula is as follows:

[0013]

[0014] In the formula, Q is the integral flow of the cross-sectional area to be measured, w i is the integral weight of the i-th stream layer, t i is the relative sound path height, v(t i ) is the average axial velocity relative to the height of the sound path, H is the height of the flow section to be measured, B is the width of the flow section to be measured, and n is the number of flow layers.

[0015] According to Gaussian integral theory, when n is determined, there exists a set of optimal w i ,t i This maximizes the integration accuracy.

[0016] The relative height of each sound path of the multi-path ultrasonic flowmeter obtained by the Gauss-Legendre integral algorithm and the corresponding weight coefficient are fixed values, and the fully developed flow in the long straight rectangular pipe is used as the calibration state, which does not change with the flow state. For the elbow-shaped water inlet flow channel of a large pump station, the water flow velocity and direction change along the way, the fluid flow is not fully developed, and there are adverse flow states such as backflow and bias flow under low water level and small flow conditions. The fixed weight coefficient cannot adapt to all situations, which will reduce the measurement accuracy of the ultrasonic flowmeter under special conditions. Summary of the invention

[0017] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0018] To this end, the purpose of the present invention is to provide a flow calculation method, device and storage medium for a cross-path ultrasonic flowmeter, so as to improve its measurement accuracy under actual operating conditions of a pump station without changing the installation position of the existing ultrasonic flowmeter.

[0019] In order to achieve the above object, the present invention adopts the following technical solutions:

[0020] A first aspect of the present invention provides a flow calculation method for a cross-sound path ultrasonic flowmeter, comprising:

[0021] S1. Build a pump station model test bench according to the installation of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, where a calibration flowmeter with higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; carry out the ultrasonic flowmeter flow measurement test of the pump station model test bench according to the actual operating conditions of the pump station, and after the readings of the ultrasonic flowmeter and the calibration flowmeter under various operating conditions are stable, calculate the average flow velocity of each acoustic path according to the flow reading of the ultrasonic flowmeter, and record the reading of the calibration flowmeter at the same time;

[0022] S2, according to the arrangement position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average flow velocity of each sound path, the average flow velocity vector of each flow layer is reconstructed, and the angle β between the reconstructed average flow velocity vector of each flow layer and the mainstream direction of the flow layer is calculated, and the average angle of each flow layer is calculated. As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped;

[0023] S3. For each group of pump station operating conditions, the average flow velocity vector of each flow layer reconstructed in the group is obtained by weighted summation to fit the average flow velocity of the pump station model flow section with the actual average flow velocity of the pump station model flow section measured by the calibrated flow meter, and the optimal flow layer integral weight of each group of pump station operating conditions is determined. According to the optimal weights of all pump station operating conditions, a flow velocity vector-integral weight database is established, in which each data includes the angle β and its corresponding pump station operating condition category and group and the optimal flow layer integral weight;

[0024] S4, the average flow velocity of each sound path measured by the ultrasonic flow meter in the pump station to be tested under actual working conditions is reconstructed according to the method of step S2 to obtain the measured value of the average flow velocity vector of each flow layer, and the measured angle β* and the mean value of the measured angle corresponding to each flow layer are obtained. According to the measured angle mean Determine the group of the operating conditions of the pump station, and select the optimal flow layer integral weight corresponding to the group of the operating conditions of the pump station from the established velocity vector-integral weight database to calculate the measured flow.

[0025] In some embodiments, an electromagnetic flowmeter is installed on the water outlet branch pipe corresponding to each pump of the pump station model test bench as the calibration flowmeter.

[0026] In some embodiments, in step S2, the average flow velocity vector of each flow layer in the pump station model test bench is reconstructed according to the following steps:

[0027] Assume that the crossover acoustic path in the flow layer is composed of acoustic path P1 and acoustic path P5, take the intersection of acoustic path P1 and acoustic path P5 as the coordinate origin O, and establish a rectangular coordinate system xOy along the mainstream direction as the positive direction of the x-axis. Assume that the angles between acoustic path P1 and acoustic path P5 and the x-axis are α E and α F , assuming that the average flow velocity of the acoustic path P1 and the average flow velocity of the acoustic path P5 calculated in step S1 are V E and V F , select point E and point F on the acoustic path P1 and acoustic path P5 respectively, and satisfy the distance between the origin O and point E is V E The distance between the origin O and point F is V F The size of the sound path P1 through point E is perpendicular to the line l E , the perpendicular line l passing through point F to the sound path P5 F , according to the vertical line l E With perpendicular line l F The equation determines the coordinates of the intersection point G (x G ,y G )for:

[0028]

[0029]

[0030] The distance between the origin O and point G is taken as the average flow velocity v of the flow layer:

[0031]

[0032] According to the x-axis coordinate x of point G G The size of the flow layer determines the angle β between the average velocity and the x-axis. G > 0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula:

[0033]

[0034] If x G<0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula:

[0035]

[0036] Thus, the average velocity vector of the flow layer is obtained according to the average velocity v of the flow layer and the angle β between the average velocity of the flow layer and the x-axis:

[0037] In some embodiments, the mainstream direction is determined according to the following steps:

[0038] According to the calibration flow meter reading Q t And the flow cross-sectional area A of the pump station model determines the actual average flow velocity v of the flow cross-sectional area of ​​the pump station model under each working condition t =Q t / A,v t The direction is parallel to the center line of the pump station's water inlet channel and is determined as the mainstream direction of the flow section of the pump station model.

[0039] In some embodiments, in step S2, the flow state in the flow channel is divided into G levels according to the distribution of the mean angle calculated from the flow measurement test data, and the pump station operating conditions are divided into G groups accordingly.

[0040] In some embodiments, in step S2, the angles of each flow layer are averaged. All corresponding pump station operating conditions are divided into the first group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the second group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the third group of pump station operating conditions.

[0041] In some embodiments, in step S3, determining the optimal flow layer integral weight for each group of pump station operating conditions specifically includes:

[0042] For each group of pump station operating conditions, the nonlinear least squares method is used to fit the average flow velocity of the pump station model flow section obtained by weighted summing the average flow velocity vectors of each flow layer reconstructed in the same group to the actual average flow velocity of the pump station model flow section. The error is the square sum of the measurement error S, which is expressed as follows:

[0043]

[0044] Where m represents the number of operating conditions contained in a set of pump station operating conditions for nonlinear least squares fitting; n represents the number of flow layers contained in the flow section; v ij represents the magnitude of the average velocity vector of the flow layer reconstructed for the i-th flow layer under the i-th type of pumping station operating conditions in a group of pumping station operating conditions; v tjRepresents the actual average flow velocity of the flow section of the pumping station model under the first type of pumping station operating conditions in a group of pumping station operating conditions;

[0045] A series of integral weights w that minimize the sum of squared errors S i , i = 1, 2, ..., n, and this series of integral weights is used as the optimal integral weights of the flow layer corresponding to the operating conditions of a set of pumping stations under analysis.

[0046] In some embodiments, in step S4, the measured flow rate of the pump station to be measured can be obtained by weighted summing the integrated weights of the selected optimal flow layers and the sizes of the reconstructed average flow velocity vectors of each flow layer.

[0047] A second aspect of the present invention provides a flow calculation device for a cross-sound path ultrasonic flowmeter, comprising:

[0048] The test data storage module is used to store test data, and the test data is obtained according to the following steps: a pump station model test bench is built according to the installation status of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, wherein a calibration flowmeter with a higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; a pump station model test bench ultrasonic flowmeter flow measurement test is carried out according to the actual operating conditions of the pump station, and after the readings of the ultrasonic flowmeter and the calibration flowmeter under various operating conditions are stable, the average flow velocity of each acoustic path is calculated according to the flow reading of the ultrasonic flowmeter, and the calibration flowmeter reading is recorded as the test data;

[0049] The flow layer velocity reconstruction and pump station operation condition grouping module is used to reconstruct the average flow velocity vector of each flow layer according to the layout position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average flow velocity of each sound path, calculate the angle β between the reconstructed average flow velocity vector of each flow layer and the mainstream direction of the flow layer, and average the angle of each flow layer. As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped;

[0050] The velocity vector-integral weight database construction module is used to fit the average velocity vector of each flow layer reconstructed in the group to the average flow velocity of the pumping station model flow section obtained by weighted summation with the actual average flow velocity of the pumping station model flow section measured by the calibrated flow meter for each group of pumping station operating conditions, determine the optimal flow layer integral weight of each group of pumping station operating conditions, and establish a velocity vector-integral weight database based on the optimal weights of all pumping station operating conditions. In the database, each data includes the angle β and its corresponding pumping station operating condition category and group and the optimal flow layer integral weight;

[0051] The calculation module is used to input the average flow velocity of each sound path measured by the ultrasonic flow meter in the pump station to be tested under actual working conditions into the flow layer velocity reconstruction and pump station operation condition grouping module to obtain the measured angle β* and the average value of the measured angle corresponding to each flow layer. According to the measured angle mean The group of the operating condition of the pump station is determined, and the optimal flow layer integral weight corresponding to the group of the operating condition of the pump station is screened out from the velocity vector-integral weight database, so as to calculate the measured flow rate.

[0052] A third aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the flow calculation method described in any embodiment of the first aspect of the present invention.

[0053] The present invention has the following characteristics and beneficial effects:

[0054] Compared with the existing multi-path ultrasonic flowmeter integration method, the present invention builds a typical pump station simulation test bench, reproduces the pump station's variable rectangular contraction elbow-shaped flow channel and the existing ultrasonic flowmeter installation position, and conducts ultrasonic flowmeter flow measurement experiments on the flow channel section installed with ultrasonic transducers to obtain the flow velocity information of each channel of the elbow-shaped flow channel under actual operating conditions of the pump station. Under each operating condition of the pump station model test bench, the actual average flow velocity vector of each flow layer is reconstructed based on the cross-sound path flow velocity data of the same flow layer obtained by the actual flow measurement of the ultrasonic flowmeter. The operating conditions of the pump station are grouped according to the deviation range between the flow layer velocity direction and the mainstream direction. Each group of operating conditions corresponds to a deviation range between the flow layer velocity direction and the mainstream direction. Each type of operating condition is fitted with the flow by the nonlinear least squares method to determine the optimal integration weight. The results show that the multi-path ultrasonic flowmeter data fusion method based on the classification of flow layer velocity vectors can improve the measurement accuracy of the existing ultrasonic flowmeter of the pump station. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of the measurement principle of the existing flow meter based on the single-channel time difference method.

[0056] Figure 2 It is an overall flow chart of a flow calculation method for a cross-path ultrasonic flowmeter provided in an embodiment of the first aspect of the present invention.

[0057] Figure 3 It is a schematic diagram of the layout of ultrasonic transducers in a pump station model test bench constructed in the calculation method provided in an embodiment of the present invention.

[0058] Figure 4 It is a schematic diagram of the process of reconstructing the tropospheric flow velocity vector in the calculation method provided in an embodiment of the present invention.

[0059] Figure 5It is a schematic diagram of the structure of an electronic device provided by an embodiment of the third aspect of the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0061] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application without the description of these details.

[0062] See also Figure 2 The first aspect of the present invention provides a flow calculation method for a cross-path ultrasonic flowmeter, comprising the following steps:

[0063] Step S1, building a pump station model test bench according to the installation situation of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, wherein a calibration flowmeter with a higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; carrying out a flow measurement test of the ultrasonic flowmeter on the pump station model test bench according to the actual operating conditions of the pump station, after the readings of the ultrasonic flowmeter and the calibration flowmeter under various operating conditions are stable, calculating the average flow velocity of each acoustic path according to the flow reading of the ultrasonic flowmeter (the average flow velocity of the acoustic path refers to the average flow velocity of the fluid on the acoustic path formed by the two transducers), and recording the reading of the calibration flowmeter at the same time;

[0064] Step S2, reconstruct the average velocity vector of each flow layer according to the arrangement position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average velocity of each sound path, calculate the angle β between the reconstructed average velocity vector of each flow layer and the mainstream direction of the flow layer, and average the angle of each flow layer As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped;

[0065] Step S3, for each group of pump station operating conditions, the size of the average flow velocity vector of each flow layer reconstructed in the group is obtained by weighted summation and the average flow velocity of the pump station model flow section is fitted with the actual average flow velocity of the pump station model flow section measured by the calibrated flow meter, and the optimal flow layer integral weight of each group of pump station operating conditions is determined, and a flow velocity vector-integral weight database is established according to the optimal weights of all pump station operating conditions, in which each data includes the angle β and its corresponding pump station operating condition category and group and the optimal flow layer integral weight;

[0066] Step S4: The average flow velocity of each acoustic path measured by the ultrasonic flowmeter in the pump station to be tested under actual working conditions is reconstructed according to the method of step S2 to obtain the measured value of the average flow velocity vector of each flow layer, and the measured angle β corresponding to each flow layer is obtained. * And the measured angle mean According to the measured angle mean Determine the group of the operating conditions of the pump station, and select the optimal flow layer integral weight corresponding to the group of the operating conditions of the pump station from the established velocity vector-integral weight database to calculate the measured flow.

[0067] The specific implementation process of the flow calculation method provided by the present invention is described in detail below in conjunction with Example 1.

[0068] This embodiment 1 is aimed at the reconstruction of the laminar velocity and the laminar integral weight fitting process of an ultrasonic flow meter with 8 cross sound paths in a set application scenario, wherein the set application scenario refers to the type of flow channel where the flow meter is installed and the type of pump station measured. The flow calculation method of this embodiment specifically includes the following steps:

[0069] Step S1: Acquisition of experimental data

[0070] Step S11: Preliminary investigation of the actual operation of a typical pump station, reproducing the forebay and elbow-shaped water inlet channel of the typical pump station at a ratio of 1:20, and constructing Figure 3 The pump station model test bench shown in the figure assumes that the height of the flow section of the pump station model is H and the width is B; according to the actual installation position of the ultrasonic flowmeter in the typical pump station, ultrasonic transducer measuring points are cross-arranged at the corresponding positions of the test bench to carry out ultrasonic flowmeter flow measurement experiments and obtain the average flow velocity data of each flow layer acoustic path under various working conditions. At the same time, an electromagnetic flowmeter is installed on the outlet branch pipe corresponding to each pump as a calibration flowmeter. In this embodiment, a total of 16 ultrasonic transducers are provided, such as Figure 3 As shown in R1 to R16, every 4 ultrasonic transducers form a group, and the relative arrangement heights of the 4 ultrasonic transducers in a group are the same, forming 4 ultrasonic transducer groups arranged in sequence along the height direction of the flow section of the pump station model, corresponding to 4 flow layers; in each ultrasonic transducer group, an acoustic path is formed between the two diagonally arranged transducers, such as Figure 3 As shown in P1 to P8 in FIG. 1 , a cross acoustic path is formed in each ultrasonic transducer group.

[0071] Step S12: Determine the corresponding working conditions of the pump station model test bench according to the working conditions existing in the actual operation process of the pump station obtained from the investigation, such as changing the water level of the forebay, starting the operation of a single unit, etc.

[0072] Step S13, carry out ultrasonic flow meter flow measurement experiments under various working conditions determined in step S12, and read the ultrasonic flow meter reading and the electromagnetic flow meter reading at the same time after the ultrasonic flow meter reading and the electromagnetic flow meter reading are stable under each working condition; derive the real-time flow velocity of each acoustic path of the ultrasonic flow meter within a period of time (generally one minute), and the average value thereof is regarded as the average flow velocity of each acoustic path of the ultrasonic flow meter under this working condition.

[0073] Step S2: Reconstruction of flow velocity in the flow layer and grouping of pump station operation conditions

[0074] Step S21: Reconstruction of flow velocity of flow layer

[0075] Step S211: Determine the actual average flow velocity v of the flow section of the pump station model under the working condition according to the electromagnetic flow meter reading and the flow section area of ​​the pump station model. t =Q t / A,v t is the actual average flow velocity of the flow section, Q t is the measured value of the electromagnetic flowmeter, A is the flow cross-sectional area of ​​the pump station model, A=B×H; v t The direction is parallel to the center line of the pump station inlet channel (an elbow-shaped channel) and is determined as the mainstream direction of the flow section of the pump station model.

[0076] Step S212, reconstruct the average flow velocity vector of each flow layer according to the arrangement position of the ultrasonic transducer in each flow layer in the pump station model test bench and the average flow velocity of each sound path calculated in step S13, and the arrangement position parameters of the ultrasonic transducer in each flow layer include the straight-line distance between the ultrasonic transducers and the angle between the sound channel line and the center line of the elbow flow channel. The reconstruction process of the average flow velocity vector of each flow layer is the same, and the reconstruction process is specifically described by taking the average flow velocity vector of one flow layer as an example, and the steps are as follows:

[0077] See also Figure 4 , take the intersection of the flow layer cross sound path as the coordinate origin O, the mainstream direction as the x-axis, establish the rectangular coordinate system xOy, and set the angle between the sound path P1 and the x-axis as α E , the angle between the acoustic path P5 and the x-axis is α F , according to the average flow velocity V of the acoustic path P1 calculated in step S13 E Determine point E in the rectangular coordinate system xOy. Point E is on the sound path P1, and the distance between the origin O and point E is V. E Similarly, according to the average flow velocity V of the acoustic path P5 calculated in step S13 F Determine point F in the rectangular coordinate system xOy. Point F is located on the sound path P5, and the distance between the origin O and point F is V. F The size of the sound path P1 through point E is perpendicular to the line l E , the perpendicular line l passing through point F to the sound path P5 F .

[0078] Vertical line E The expression is as follows:

[0079] y E =k E x+b E

[0080]

[0081]

[0082] Vertical line F The expression is as follows:

[0083] y F =k F x+b F

[0084]

[0085]

[0086] Simultaneous perpendicular lines E With perpendicular line l F The expression for the coordinates of the intersection point G (x G ,y G )for:

[0087]

[0088]

[0089] The distance between the origin O and point G is taken as the average flow velocity v of the flow layer:

[0090]

[0091] According to the x-axis coordinate x of point G G The size of the flow layer determines the angle β between the average velocity and the x-axis. G > 0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula:

[0092]

[0093] If x G <0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula:

[0094]

[0095] Thus, the average velocity vector of the flow layer is obtained according to the average velocity v of the flow layer and the angle β between the average velocity of the flow layer and the x-axis:

[0096] Step S22: Pump station operation condition grouping

[0097] The mean value of the angle β between the average velocity of each flow layer in the flow section obtained in step S21 and the x-axis is recorded as the mean angle The mean angle As the flow pattern identification index of the flow section, according to the mean value of the angle The size of the angle is used to determine whether there is a bad flow state such as backflow or vortex inside the flow channel. It is used to group the operating conditions of the pump station. The larger the angle, the greater the deviation between the mainstream direction in the flow channel and the centerline direction of the flow channel, and the more turbulent the flow pattern in the flow channel. According to the distribution of the mean angle calculated from the flow measurement test data, the flow pattern in the flow channel is divided into G levels, and the operating conditions of the pump station are divided into G groups. The size of the flow is divided into three flow levels, and the operating conditions of the pump station are divided into three groups: The mean angle All corresponding pump station operating conditions are divided into the first group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the second group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the third group of pump station operating conditions.

[0098] Step S3: velocity vector-integral weight database construction

[0099] Step S31: Flow layer integrated weight fitting

[0100] For each group of pump station operating conditions, a group of flow layer integral weights are fitted using the nonlinear least squares method. The fitting process is as follows:

[0101] The nonlinear least squares method is used to fit the average flow velocity of the pumping station model flow section obtained by weighted summation of the magnitude of the average flow velocity vector of each flow layer reconstructed to the actual average flow velocity of the pumping station model flow section. The error is the square sum of the measurement error S, which is expressed as follows:

[0102]

[0103] Where m represents the number of operating conditions contained in a set of pump station operating conditions for nonlinear least squares fitting; n represents the number of flow layers contained in the flow section; v ij represents the magnitude of the average velocity vector of the flow layer reconstructed for the i-th flow layer under the i-th type of pumping station operating conditions in a group of pumping station operating conditions; v tjRepresents the actual average flow velocity of the flow section of the pump station model under the operating conditions of the jth type of pump station.

[0104] By performing nonlinear least squares fitting calculation on the above formula, a series of integral weights w with the minimum error square sum S can be obtained. i (i=1, 2, ..., n), and use this series of integral weights as the optimal integral weights of the flow layer corresponding to the operating conditions of a group of pump stations under analysis.

[0105] Step S32: Database construction

[0106] After obtaining the optimal integral weight of the flow layer under each group of operating conditions, a velocity vector-integral weight database is established. In this database, each data includes the angle β and its corresponding pump station operating condition category and group and the optimal flow layer integral weight corresponding to the group.

[0107] Step S4: Calculation of flow rate of the flow section of the pump station to be tested

[0108] Obtain the average flow velocity of each acoustic path measured by the ultrasonic flowmeter in the pump station to be tested, and obtain the measured value of the average flow velocity vector of each flow layer and its corresponding measured angle mean according to the reconstruction method in step S21 According to the measured angle mean Determine the group of the operating conditions of the pump station, and select the optimal flow layer integral weight corresponding to the group of the pump station operating conditions from the velocity vector-integral weight database constructed in step S32. The actual flow rate of the pump station to be tested can be obtained based on the optimal flow layer integral weight and the size of the reconstructed average flow velocity vector of each flow layer.

[0109] The embodiment of the present invention takes the actual pump station as the research object, builds the actual pump station model test bench according to the transducer measurement point arrangement and sound path form of its multi-path ultrasonic flowmeter, and carries out the ultrasonic flowmeter real flow measurement experiment. The experimental results show that: under the operating conditions of the asymmetric start-up unit, the flow integration method with a fixed sound path integral coefficient leads to an absolute value of the maximum error of the ultrasonic flowmeter measurement of 23%; under various operating conditions of the pump station, the flow integration method with a variable sound path integral coefficient based on the flow layer reconstruction flow velocity vector direction and the mainstream direction angle classification has a maximum error of 0.978%, which can meet the engineering accuracy requirement of ±1.0%.

[0110] The present invention aims at a cross-arranged multi-path ultrasonic flowmeter in a specific application scenario. By building a typical pump station simulation test bench, the pump station's variable rectangular contraction elbow-shaped flow channel and the existing ultrasonic flowmeter installation position are reproduced, and an ultrasonic flowmeter flow measurement experiment is carried out on the flow channel section installed with an ultrasonic transducer to obtain the linear flow velocity information of each channel under the actual operating conditions of the pump station. Under each operating condition of the pump station model test bench, the actual average flow velocity vector of each flow layer is reconstructed based on the cross-path flow velocity data of the same flow layer obtained by the actual flow measurement of the ultrasonic flowmeter. The operating conditions of the pump station are grouped using the deviation range between the flow layer velocity direction and the mainstream direction. Each group of operating conditions is fitted with the flow by the nonlinear least squares method to determine the optimal integral weight, thereby improving the measurement accuracy of the existing ultrasonic flowmeter of the pump station.

[0111] A flow calculation test data storage module for a cross-sound path ultrasonic flowmeter provided in an embodiment of the second aspect of the present invention is used to store test data, wherein the test data is obtained according to the following steps: a pump station model test bench is built according to the installation status of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, wherein a calibration flowmeter with a higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; a flow measurement test of the ultrasonic flowmeter of the pump station model test bench is carried out according to the actual operating conditions of the pump station, and after the readings of the ultrasonic flowmeter and the calibration flowmeter under each operating condition are stable, the average flow velocity of each sound path is calculated according to the flow reading of the ultrasonic flowmeter, and the reading of the calibration flowmeter is recorded as the test data;

[0112] The flow layer velocity reconstruction and pump station operation condition grouping module is used to reconstruct the average flow velocity vector of each flow layer according to the layout position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average flow velocity of each sound path, calculate the angle β between the reconstructed average flow velocity vector of each flow layer and the mainstream direction of the flow layer, and average the angle of each flow layer. As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped;

[0113] The velocity vector-integral weight database construction module is used to fit the average velocity vector of each flow layer reconstructed in the group to the average flow velocity of the pumping station model flow section obtained by weighted summation with the actual average flow velocity of the pumping station model flow section measured by the calibrated flow meter for each group of pumping station operating conditions, determine the optimal flow layer integral weight of each group of pumping station operating conditions, and establish a velocity vector-integral weight database based on the optimal weights of all pumping station operating conditions. In the database, each data includes the angle β and its corresponding pumping station operating condition category and group and the optimal flow layer integral weight;

[0114] The calculation module is used to input the average flow velocity of each acoustic path measured by the ultrasonic flow meter in the pump station to be tested under actual working conditions into the flow layer velocity reconstruction and pump station operation condition grouping module to obtain the measured angle β corresponding to each flow layer* And the measured angle mean According to the measured angle mean The group of the operating condition of the pump station is determined, and the optimal flow layer integral weight corresponding to the group of the operating condition of the pump station is screened out from the velocity vector-integral weight database, so as to calculate the measured flow rate.

[0115] It should be noted that the above-mentioned explanation of the embodiment of the flow calculation method of a cross-path ultrasonic flowmeter is also applicable to the flow calculation device of a cross-path ultrasonic flowmeter of this embodiment, and will not be repeated here.

[0116] In order to implement the above embodiment, the embodiment of the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. The program is executed by a processor to execute the flow calculation method of the cross-path ultrasonic flowmeter of the above embodiment.

[0117] Reference below Figure 5 , which shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiments of the present disclosure. It should be noted that the electronic device in the embodiments of the present disclosure may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, servers, etc. Figure 5 The electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0118] like Figure 5 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processor, etc.) 101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 102 or a program loaded from a storage device 108 to a random access memory (RAM) 103. In the RAM 103, various programs and data required for the operation of the electronic device are also stored. The processing device 101, the ROM 102, and the RAM 103 are connected to each other via a bus 104. An input / output (I / O) interface 105 is also connected to the bus 104.

[0119] Typically, the following devices may be connected to the I / O interface 105: an input device 106 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, etc.; an output device 107 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 108 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 109. The communication device 109 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Figure 5 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0120] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the present embodiment includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication device 109, or installed from the storage device 108, or installed from the ROM 102. When the computer program is executed by the processing device 101, the above-mentioned functions defined in the method of the embodiment of the present disclosure are executed.

[0121] It should be noted that the computer-readable medium disclosed above may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0122] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0123] The computer-readable medium carries one or more programs. When the one or more programs are executed by the electronic device, the electronic device executes the flow calculation method of the cross-path ultrasonic flowmeter.

[0124] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, python, and conventional procedural programming languages, such as "C-" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0125] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0126] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0127] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0128] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0129] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0130] A person of ordinary skill in the art may understand that all or part of the steps carried out in the above-mentioned embodiment method may be completed by instructing the relevant hardware through a program, and the developed program may be stored in a computer-readable storage medium, which, when executed, includes one of the steps of the method embodiment or a combination thereof.

[0131] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0132] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A flow calculation method for a cross-path ultrasonic flowmeter, characterized in that: include: S1. Build a pump station model test bench according to the installation of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, where a calibration flowmeter with higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; carry out the ultrasonic flowmeter flow measurement test of the pump station model test bench according to the actual operating conditions of the pump station, and after the readings of the ultrasonic flowmeter and the calibration flowmeter under various operating conditions are stable, calculate the average flow velocity of each acoustic path according to the flow reading of the ultrasonic flowmeter, and record the reading of the calibration flowmeter at the same time; S2, according to the arrangement position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average flow velocity of each sound path, the average flow velocity vector of each flow layer is reconstructed, and the angle β between the reconstructed average flow velocity vector of each flow layer and the mainstream direction of the flow layer is calculated, and the average angle of each flow layer is calculated. As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped; S3. For each group of pump station operating conditions, the average flow velocity vector of each flow layer reconstructed in the group is obtained by weighted summation to fit the average flow velocity of the pump station model flow section with the actual average flow velocity of the pump station model flow section measured by the calibrated flow meter, and the optimal flow layer integral weight of each group of pump station operating conditions is determined. According to the optimal weights of all pump station operating conditions, a flow velocity vector-integral weight database is established, in which each data includes the angle β and its corresponding pump station operating condition category and group and the optimal flow layer integral weight; S4, the average flow velocity of each sound path measured by the ultrasonic flow meter in the pump station to be tested under actual working conditions is reconstructed according to the method of step S2 to obtain the measured value of the average flow velocity vector of each flow layer, and the measured angle β corresponding to each flow layer is obtained * And the measured angle mean According to the measured angle mean Determine the group of the operating conditions of the pump station, and select the optimal flow layer integral weight corresponding to the group of the operating conditions of the pump station from the established velocity vector-integral weight database to calculate the measured flow.

2. The flow calculation method according to claim 1, characterized in that: An electromagnetic flowmeter is installed on the water outlet branch pipe corresponding to each pump of the pump station model test bench as the calibration flowmeter.

3. The flow calculation method according to claim 1, characterized in that: In step S2, the average flow velocity vector of each flow layer in the pump station model test bench is reconstructed according to the following steps: Assume that the crossover acoustic path in the flow layer is composed of acoustic path P1 and acoustic path P5, take the intersection of acoustic path P1 and acoustic path P5 as the coordinate origin O, and establish a rectangular coordinate system xOy along the mainstream direction as the positive direction of the x-axis. Assume that the angles between acoustic path P1 and acoustic path P5 and the x-axis are α E and α F , assuming that the average flow velocity of the acoustic path P1 and the average flow velocity of the acoustic path P5 calculated in step S1 are V E and V F , select point E and point F on the acoustic path P1 and acoustic path P5 respectively, and satisfy the distance between the origin O and point E is V E The distance between the origin O and point F is V F The size of the sound path P1 through point E is perpendicular to the line l E , the perpendicular line l passing through point F to the sound path P5 F , according to the vertical line l E With perpendicular line l F The equation determines the coordinates of the intersection point G (x G ,y G )for: The distance between the origin O and point G is taken as the average velocity v of the flow layer: According to the x-axis coordinate x of point G G The size of the flow layer determines the angle β between the average velocity and the x-axis. G >0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula: If x G <0, the angle β between the average velocity of the flow layer and the x-axis is calculated according to the following formula: Thus, the average velocity vector of the flow layer is obtained according to the average velocity v of the flow layer and the angle β between the average velocity of the flow layer and the x-axis:

4. The flow calculation method according to claim 3, characterized in that: The main flow direction is determined according to the following steps: According to the calibration flow meter reading Q t And the flow cross-sectional area A of the pump station model determines the actual average flow velocity v of the flow cross-sectional area of ​​the pump station model under each working condition t =Q t / A,v t The direction is parallel to the center line of the pump station's water inlet channel and is determined as the mainstream direction of the flow section of the pump station model.

5. The flow calculation method according to claim 1, characterized in that: In step S2, the flow state in the flow channel is divided into G levels according to the distribution of the mean value of the angle calculated from the flow measurement test data, and G groups of pump station operating conditions are divided accordingly.

6. The flow calculation method according to claim 5, characterized in that: In step S2, the angles of each flow layer are averaged All corresponding pump station operating conditions are divided into the first group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the second group of pump station operating conditions, and the angle mean All corresponding pump station operating conditions are divided into the third group of pump station operating conditions.

7. The flow calculation method according to claim 1, characterized in that: In step S3, the optimal flow layer integral weight of each group of pump station operating conditions is determined, specifically including: For each group of pump station operating conditions, the nonlinear least squares method is used to fit the average flow velocity of the pump station model flow section obtained by weighted summing the average flow velocity vectors of each flow layer reconstructed in the same group to the actual average flow velocity of the pump station model flow section. The error is the square sum of the measurement error S, which is expressed as follows: Where m represents the number of operating conditions contained in a set of pump station operating conditions for nonlinear least squares fitting; n represents the number of flow layers contained in the flow section; v ij represents the magnitude of the average velocity vector of the flow layer reconstructed for the i-th flow layer under the j-th type of pumping station operation conditions in a group of pumping station operation conditions; v tj represents the actual average flow velocity of the flow section of the pumping station model under the jth type of pumping station operating condition in a group of pumping station operating conditions; A series of integral weights w that minimize the sum of squared errors S i , i = 1, 2, ..., n, and this series of integral weights is used as the optimal integral weights of the flow layer corresponding to the operating conditions of a set of pumping stations under analysis.

8. The flow calculation method according to claim 1, characterized in that: In step S4, the measured flow rate of the pump station to be measured is obtained by weighted summing the integrated weights of the selected optimal flow layers and the sizes of the reconstructed average flow velocity vectors of each flow layer.

9. A flow calculation device for a cross-path ultrasonic flowmeter, characterized in that: include: The test data storage module is used to store test data, and the test data is obtained according to the following steps: a pump station model test bench is built according to the installation status of the ultrasonic transducer of the ultrasonic flowmeter in the pump station to be tested, wherein a calibration flowmeter with a higher measurement accuracy than the ultrasonic flowmeter is installed on the outlet branch pipe corresponding to each pump; a pump station model test bench ultrasonic flowmeter flow measurement test is carried out according to the actual operating conditions of the pump station, and after the readings of the ultrasonic flowmeter and the calibration flowmeter under various operating conditions are stable, the average flow velocity of each acoustic path is calculated according to the flow reading of the ultrasonic flowmeter, and the calibration flowmeter reading is recorded as the test data; The flow layer velocity reconstruction and pump station operation condition grouping module is used to reconstruct the average flow velocity vector of each flow layer according to the layout position of the ultrasonic transducer in each flow layer in the pump station model test bench and the calculated average flow velocity of each sound path, calculate the angle β between the reconstructed average flow velocity vector of each flow layer and the mainstream direction of the flow layer, and average the angle of each flow layer. As the flow pattern identification index of the flow section, the operating conditions of the pump station are grouped; The velocity vector-integral weight database construction module is used to fit the average velocity vector of each flow layer reconstructed in the group to the average flow velocity of the pumping station model flow section obtained by weighted summation with the actual average flow velocity of the pumping station model flow section measured by the calibrated flow meter for each group of pumping station operating conditions, determine the optimal flow layer integral weight of each group of pumping station operating conditions, and establish a velocity vector-integral weight database based on the optimal weights of all pumping station operating conditions. In the database, each data includes the angle β and its corresponding pumping station operating condition category and group and the optimal flow layer integral weight; The calculation module is used to input the average flow velocity of each acoustic path measured by the ultrasonic flow meter in the pump station to be tested under actual working conditions into the flow layer velocity reconstruction and pump station operation condition grouping module to obtain the measured angle β corresponding to each flow layer * And the measured angle mean According to the measured angle mean The group of the operating condition of the pump station is determined, and the optimal flow layer integral weight corresponding to the group of the operating condition of the pump station is screened out from the velocity vector-integral weight database, so as to calculate the measured flow rate.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the flow calculation method according to any one of claims 1 to 8.

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