Ultrasonic flow measurement method and device

Abstract

The ultrasonic flow measurement method and device provided by the present disclosure include: installing a plurality of ultrasonic velocity measurement probes on the flow measurement cross-section of the flow measurement tank, each ultrasonic velocity measurement probe being used to measure the water flow velocity of a plurality of velocity measurement points in the ultrasonic wave propagation direction, the ultrasonic wave propagation directions of each ultrasonic velocity measurement probe being parallel to each other, coplanar, and obliquely intersecting with the water flow direction, and the velocity measurement points being evenly distributed on the entire flow measurement cross-section; when the flow measurement tank is full-flow, according to the number of velocity measurement points on the flow measurement cross-section, the measured water flow velocity along the ultrasonic wave propagation direction at each velocity measurement point, and the cross-sectional area of the flow passing through perpendicular to the water flow direction around the corresponding velocity measurement point, the flow rate measured by the flow measurement tank is obtained. The ultrasonic flow measurement method and device provided by the present disclosure can achieve accurate measurement of the flow rate under the conditions of full-flow, stable and smooth flow regime in the flow measurement tank.

Description

Technical Field

[0001] This disclosure belongs to the technical field of water measurement, and particularly relates to an ultrasonic flow measurement method and device. Background Art

[0002] With the advancement of the agricultural modernization process, to achieve the conservation and intensive utilization of water resources, water metering is a basic technical guarantee.

[0003] Canal water conveyance is an infrastructure for agricultural irrigation. There are various existing water conveyance metering methods and detection instruments, with uneven accuracies, but the theoretical basis for water volume measurement is the same: at a detection cross-section, the water volume passing through in a certain period is equal to the period length multiplied by the flow rate of that cross-section. Therefore, the basis of water volume measurement is flow rate detection, and the flow rate is equal to the integral of the flow velocity along the cross-section of flow, or the cross-sectional area of flow multiplied by the average cross-sectional flow velocity. It can be seen that the measurement of the flow velocity at the cross-section of flow is the key to flow rate and water volume measurement.

[0004] For the full-flow flow measurement box-type canal flow measurement equipment that is currently used more, the available flow velocity measurement technologies mainly include propeller flow meters, laser Doppler velocimeters, particle image velocimeters, and ultrasonic flow meters. Among them, ultrasonic flow meters can be used for turbid water bodies and are not affected when the sediment concentration is relatively low, and the cost is controllable, having good development prospects.

[0005] Figure 1 A conventional ultrasonic flow measurement device for flow measurement equipment used in large irrigation areas in the northwestern provinces of China includes a flow measurement box 1-1, a first ultrasonic probe 1-2, and a second ultrasonic probe 1-3. The first ultrasonic probe 1-2 and the second ultrasonic probe 1-3 are on the same horizontal axis 1-4, and the first ultrasonic probe 1-2 and the second ultrasonic probe 1-3 are installed facing each other on both side walls of the flow measurement box 1-1. A triangular prism-shaped groove 1-5 is reserved at the side wall of the flow measurement box where the ultrasonic probe is installed, so that the front end face of the ultrasonic probe is flush with one inclined surface of the groove 1-5. This ultrasonic flow measurement device uses the time difference method to measure the average flow velocity of the water cross-section. When working, first, the first ultrasonic probe 1-2 emits sound waves and the second ultrasonic probe 1-3 receives them, and the propagation time δt1 of the sound waves between the two ultrasonic probes is detected; then, the second ultrasonic probe 1-3 emits sound waves and the first ultrasonic probe 1-2 receives them, and the propagation time δt2 of the sound waves between the two ultrasonic probes is detected. Let the distance between the two ultrasonic probes be L, the speed of sound be C, the water flow velocity be V, and the included angle between the sound wave propagation direction and the water flow velocity be θ. When the sound wave propagates against the current and along the current, the propagation speeds of the sound wave in the water body are C1 = C - Vcosθ and C2 = C + Vcosθ respectively, and the propagation times in the water are δt1 = L / (C + Vcosθ) and δt2 = L / (C - Vcosθ) respectively. Then, the time difference Δt = δt1 - δt2 between the downstream and upstream propagation is:

[0006]

[0007] Since the speed of sound C in water is much greater than the water flow speed V, the above formula can be further approximated as:

[0008]

[0009] Therefore, using each pair of ultrasonic probes, the linear average flow velocity of the fluid at the installation height can be measured according to Equation (2). By arranging multiple pairs of ultrasonic probes along the height of the flow measurement box, the linear average flow velocities at different heights are measured, and the cross-sectional average flow velocity is obtained based on the weighted average of each flow velocity. Then, multiplying by the cross-sectional area of the flow-through section can measure the flow rate.

[0010] According to the above measurement principle, the accuracy of existing ultrasonic measurement devices is easily affected by various factors. For example, errors caused by changes in the speed of sound due to changes in water temperature and sediment concentration, errors caused by the asynchronization of the timing systems of the two ultrasonic probes resulting in inaccurate time differences between downstream and upstream flows; at the same time, the flow velocity measured by each pair of ultrasonic probes is the combined velocity of all water bodies on the acoustic wave propagation path. There is a complex difference between this combined velocity and the true linear average flow velocity, which is related to the flow velocity distribution form. This difference causes the flow measurement error to vary with the flow regime and flow field; similarly, when calculating the cross-sectional average flow velocity by weighted averaging the linear average flow velocities, the weight coefficient (hydrodynamic correction factor) also varies with the flow regime and flow field, resulting in measurement errors. Summary of the Invention

[0011] The disclosure aims to solve one of the above problems.

[0012] To this end, the embodiments of the present disclosure provide an ultrasonic flow measurement method that can meet the high-precision flow measurement requirements when the flow measurement box is full-flow and the streamline of the flow measurement section is parallel to the axis of the flow measurement box, including:

[0013] The ultrasonic flow measurement method provided by the first aspect embodiment of the present disclosure is suitable for ultrasonic flow measurement of a flow measurement box, and the ultrasonic flow measurement method includes:

[0014] Install multiple ultrasonic velocity measurement probes on the flow measurement section of the flow measurement box. Each ultrasonic velocity measurement probe is used to measure the water flow velocity of multiple velocity measurement points in the ultrasonic wave propagation direction. The ultrasonic wave propagation directions of each ultrasonic velocity measurement probe are parallel to each other, coplanar, and obliquely intersect with the water flow direction. The velocity measurement points are evenly distributed on the entire flow measurement section;

[0015] When the flow measurement box is full-flow, according to the number of velocity measurement points on the flow measurement section, the measured water flow velocity along the ultrasonic wave propagation direction at each velocity measurement point, and the cross-sectional area of the flow-through section perpendicular to the water flow direction around the corresponding velocity measurement point, the flow rate measured by the flow measurement box is obtained.

[0016] The ultrasonic flow measurement method provided by the first aspect embodiment of the present disclosure has the following characteristics and beneficial effects:

[0017] The ultrasonic flow measurement method provided by the first aspect embodiment of the present disclosure can be conveniently installed at the measurement section of the irrigation ditch. When the flow box is full and the streamline of the measurement section is parallel to the axis of the flow box, accurate measurement of the flow rate can be achieved.

[0018] In some embodiments, the flow rate measured by the flow box is calculated according to the following formula:

[0019]

[0020] where Q is the flow rate measured by the flow box; N is the number of flow velocity measurement points on the measurement section; V i is the actual water flow velocity along the ultrasonic propagation direction at the i-th flow velocity measurement point, i = 1, 2,..., N, and the flow velocity measurement point closest to the ultrasonic velocity measurement probe is numbered 1, and the rest increase in sequence; A i is the cross-sectional area perpendicular to the water flow direction surrounding the i-th flow velocity measurement point; θ is the angle between the ultrasonic propagation direction of the ultrasonic velocity measurement probe and the water flow direction.

[0021] In some embodiments, the ultrasonic velocity measurement probe measures the water flow velocity of multiple flow velocity measurement points in the ultrasonic propagation direction through the following steps:

[0022] In each working cycle, the ultrasonic velocity measurement probe emits a pulsed ultrasonic wave sequence according to the emission frequency, and each pulsed ultrasonic wave sequence contains at least 1 ultrasonic pulse;

[0023] The ultrasonic velocity measurement probe receives the echo signal sequence, equally divides the echo signal sequence into N segments of echo signals, calculates the Doppler frequency shift amount of each segment of echo signal relative to the emitted pulsed ultrasonic wave, and calculates the velocity of the solid particles in the water body along the ultrasonic propagation direction corresponding to each segment of echo signal, that is, the water flow velocity along the ultrasonic propagation direction at each flow velocity measurement point.

[0024] In some embodiments, the emission frequency is between 1 and 10 MHz.

[0025] In some embodiments, when measuring the water flow velocity of multiple flow velocity measurement points in the ultrasonic propagation direction through the ultrasonic velocity measurement probe, the echo signals of the same flow velocity measurement point in consecutive M working cycles are used as an overall sample for Doppler frequency shift calculation, or the statistical values of the water flow velocities measured in M working cycles are used as the measured water flow velocity.

[0026] The ultrasonic flow measurement device provided by the second aspect embodiment of the present disclosure is suitable for ultrasonic flow measurement of the flow box. The ultrasonic flow measurement device includes:

[0027] The ultrasonic velocity measurement component includes a plurality of ultrasonic velocity measurement probes installed on the flow measurement cross-section of the flow measurement box. Each ultrasonic velocity measurement probe is used to measure the water flow velocity at a plurality of flow velocity measurement points in the ultrasonic wave propagation direction. The ultrasonic wave propagation directions of each ultrasonic velocity measurement probe are parallel to each other, coplanar, and obliquely intersect with the water flow direction at a certain angle. The flow velocity measurement points are evenly distributed throughout the flow measurement cross-section; and

[0028] An ultrasonic signal processing module, which is used to control the ultrasonic velocity measurement probe to emit a pulsed ultrasonic wave sequence and receive an echo signal sequence in each working cycle. Each pulsed ultrasonic wave sequence contains at least 1 ultrasonic pulse; the echo signal sequence is equally spaced into several segments of echo signals with the same number as the flow velocity measurement points, calculate the Doppler frequency shift amount of each segment of echo signal relative to the emitted pulsed ultrasonic wave, and calculate the velocity of the solid particles in the water body corresponding to each segment of echo signal along the ultrasonic wave propagation direction, that is, the water flow velocity at each flow velocity measurement point along the ultrasonic wave propagation direction.

[0029] In some embodiments, the ultrasonic velocity measurement component further includes a mounting frame, a cover plate sealed at the top of the mounting frame, and a water isolation film sealed at the bottom of the mounting frame. An upper water cavity is formed between the upper part of the mounting frame and the cover plate, and a lower water cavity is formed between the lower part of the mounting frame and the water isolation film. The mounting frame is provided with a water passing hole for communicating the lower water cavity and the upper water cavity; a plurality of ultrasonic velocity measurement probes are obliquely arranged on the mounting frame, the emitting end of the ultrasonic velocity measurement probe is located in the lower water cavity, and the signal line of the ultrasonic velocity measurement probe passes through the upper water cavity and then passes out of the cover plate and is connected to the ultrasonic signal processing module.

[0030] In some embodiments, the water isolation film has an outward turned edge, and the outward turned edge is embedded in a groove reserved in the lower part of the mounting frame and is pressed tightly by a water isolation film pressing strip.

[0031] In some embodiments, a mounting position is reserved at the top of the flow measurement box, the ultrasonic velocity measurement component is embedded in the mounting position, and the lower plane of the ultrasonic velocity measurement component is flush with the lower plane of the top of the flow measurement box. Description of the Drawings

[0032] Figure 1 It is a schematic structural diagram of an existing ultrasonic flow measurement device.

[0033] Figure 2 It is a schematic layout diagram of the flow velocity measurement points in ultrasonic flow measurement provided by the first aspect embodiment of the present disclosure.

[0034] Figure 3 It is a schematic structural diagram of an ultrasonic flow measurement device provided by the second aspect embodiment of the present disclosure.

[0035] Figure 4 ForFigure 3 The top view of the ultrasonic velocity measurement component in the ultrasonic flow measurement device shown.

[0036] Figure 5 For Figure 3 The cross-sectional view of the ultrasonic velocity measurement component in the ultrasonic flow measurement device shown.

[0037] Figure 6 (a), (b), and (c) of Figure 3 The schematic structural view of the water isolation film in the ultrasonic flow measurement device shown.

[0038] Reference numerals:

[0039] 1: Inlet connection member; 2: Top of the flow measurement box; 3: Bottom of the flow measurement box; 4: Ultrasonic velocity measurement component, 4-1: Mounting frame, 4-2: Cover plate, 4-3: Upper water chamber, 4-4: Water passing hole, 4-5: Signal line, 4-6: Filler, 4-7: Ultrasonic velocity measurement probe, 4-8: Lower water chamber, 4-9: Water isolation film pressing strip, 4-10: Water isolation film, 4-10a: Turned-out edge; 5: Ultrasonic signal processing module. Specific embodiments

[0040] In order to make the purpose, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to 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.

[0041] On the contrary, the present application covers any alternatives, modifications, equivalent methods, and solutions made within the spirit and scope of the present application as defined by the claims. Further, in order to enable the public to have a better understanding of the present application, some specific details are described in detail in the following detailed description of the present application. Those skilled in the art can fully understand the present application without the description of these detail parts.

[0042] The embodiments of the first aspect of the present disclosure provide an ultrasonic flow measurement method, including:

[0043] Referring to Figure 2 , install a plurality of ultrasonic velocity measurement probes on the flow measurement section of the flow measurement box. Each ultrasonic velocity measurement probe is used to measure the water flow velocity of a plurality of flow velocity measurement points in the ultrasonic wave propagation direction. The ultrasonic wave propagation directions of the ultrasonic velocity measurement probes are parallel to each other, coplanar, and intersect obliquely with the water flow direction at a certain angle. The flow velocity measurement points are evenly distributed on the entire flow measurement section;

[0044] When the flow measurement box is full of water, obtain the flow rate measured by the flow measurement box according to the number of flow velocity measurement points on the flow measurement section, the actually measured water flow velocity along the ultrasonic wave propagation direction at each flow velocity measurement point, and the cross-sectional area of the flow passing perpendicular to the water flow direction around the corresponding flow velocity measurement point.

[0045] In some embodiments, the ultrasonic probe is mounted on both side walls or the top plate of the flow box.

[0046] In some embodiments, the flow rate measured by the flow measuring box is calculated according to the following formula:

[0047]

[0048] Where Q is the flow rate measured by the flow measuring box; N is the number of flow velocity measuring points on the flow measuring section; V i A is the water velocity measured at the i-th velocity measuring point along the ultrasonic propagation direction, i = 1, 2, ..., N, and the velocity measuring point closest to the ultrasonic velocity measuring probe is numbered 1, and the others increase in sequence; A i is the flow cross-sectional area perpendicular to the water flow direction around the i-th flow velocity measurement point; θ is the angle between the ultrasonic propagation direction of the ultrasonic velocity measuring probe and the water flow direction.

[0049] In some embodiments, measuring the water flow velocity along the ultrasonic wave propagation direction at each flow velocity measurement point by using an ultrasonic velocity measurement probe includes the following steps:

[0050] In each working cycle, the ultrasonic velocity measuring probe transmits a pulse ultrasonic sequence according to the transmitting frequency, and each pulse ultrasonic sequence contains at least one ultrasonic pulse;

[0051] The ultrasonic velocity measuring probe receives an echo signal sequence (since ultrasonic waves are constantly reflected by solid particles suspended in the water when propagating in the water body, the ultrasonic velocity measuring probe can continuously receive echo signals to form an echo signal sequence), divides the echo signal sequence into N segments of echo signals at equal intervals, calculates the Doppler frequency shift of each segment of the echo signal relative to the transmitted pulse ultrasonic wave, and calculates the speed of the solid particles in the water body along the ultrasonic wave propagation direction corresponding to each segment of the echo signal based on the Doppler frequency shift, that is, the water flow velocity along the ultrasonic wave propagation direction at each flow velocity measuring point.

[0052] In some embodiments, the transmission frequency is between 1 and 10 MHz.

[0053] In some embodiments, assuming that the distance from the front end of the ultrasonic velocity measuring probe to the opposite flow box wall along the ultrasonic wave propagation direction is L, and the ultrasonic wave propagation speed in water is C, the duration of the echo signal sequence received by the ultrasonic velocity measuring probe is: T=L / C.

[0054] In some embodiments, the velocity of solid particles in the water body corresponding to each echo signal along the ultrasonic propagation direction (assuming that the solid particle velocity is consistent with the water flow velocity) is calculated according to the following formula, that is, the water flow velocity V measured along the ultrasonic propagation direction at the i-th flow velocity measurement point i for:

[0055]

[0056] Among them, f d is the Doppler frequency shift of each echo signal relative to the transmitted pulse ultrasonic wave; f s is the emission frequency of the pulsed ultrasonic wave, and the distance L between the ith velocity measurement point and the front end of the ultrasonic velocity measurement probe is i for:

[0057]

[0058] In some embodiments, in order to improve the flow velocity measurement accuracy, the echo signal of the same flow velocity measurement point in M ​​consecutive working cycles can be used as the overall sample for Doppler frequency shift calculation, or the statistical value of the water flow velocity measured in M ​​working cycles (such as averaging) can be used as the measured water flow velocity. Assuming that the repetition frequency of the ultrasonic velocity probe emitting the sound wave pulse is f, the measured water flow velocity and flow sampling frequency is f / M.

[0059] As a preferred embodiment of the present disclosure, 8 ultrasonic velocity measuring probes are installed on the top plate of the flow measuring section of the flow measuring box. Each ultrasonic velocity measuring probe can measure the water flow velocity at 10 flow velocity measuring points in the ultrasonic propagation direction. The angle between the ultrasonic propagation direction of the ultrasonic velocity measuring probe and the water flow direction is 45°. According to the above arrangement method, the number of flow velocity measuring points N on the flow measuring section is equal to 80, and the flow rate through the flow measuring box is:

[0060]

[0061] The ultrasonic probe transmitting frequency f used in this embodiment s The frequency is 5MHz, each pulse ultrasonic sequence contains 9 ultrasonic pulses, and the repetition frequency f of the ultrasonic velocity measuring probe emitting sound wave pulses is 100Hz. The vertical distance between the top and bottom plate of the flow measuring box is 40cm, and the angle θ between the ultrasonic propagation direction and the water flow direction is 45°. The distance L from the front end of the ultrasonic velocity measuring probe to the opposite wall of the flow measuring box along the ultrasonic propagation direction is 56.6cm. The propagation speed of ultrasonic waves in water is C=1450m / s, so the echo signal sequence received by each ultrasonic velocity measuring probe in each working cycle lasts T=390.3μs. The echo signal sequence of each ultrasonic velocity measuring probe is divided into 10 echo signal segments, and the Doppler frequency shift f of each echo signal segment is obtained using the fast Fourier transform algorithm. d , then the average velocity of solid particles in the water along the ultrasonic propagation direction corresponding to each echo signal is:

[0062]

[0063] The distance between the velocity measurement point and the ultrasonic velocity measurement probe corresponding to this velocity is:

[0064]

[0065] In order to improve the accuracy of flow velocity measurement, the echo signals of the same flow velocity measurement point in 100 consecutive working cycles are used as the overall sample for Doppler frequency shift calculation, and the corresponding flow velocity and flow sampling frequency is 1Hz.

[0066] The second aspect of the present disclosure provides an ultrasonic flow measurement device suitable for ultrasonic flow measurement of a flow measurement box, see Figure 3 , the ultrasonic flow measurement device of the embodiment of the present disclosure comprises:

[0067] The ultrasonic velocity measuring assembly 4 comprises a plurality of ultrasonic velocity measuring probes installed on the flow measuring section of the flow measuring box, each ultrasonic velocity measuring probe can measure the water flow velocity at a plurality of flow velocity measuring points in the ultrasonic wave propagation direction, the ultrasonic wave propagation directions of the ultrasonic velocity measuring probes are parallel to each other, coplanar and intersect with the water flow direction at a certain angle, and the flow velocity measuring points are evenly distributed in the entire flow measuring section; and

[0068] The ultrasonic signal processing module 5 is used to control the ultrasonic velocity measuring probe to transmit a pulse ultrasonic sequence and receive an echo signal sequence in each working cycle, each pulse ultrasonic sequence contains at least one ultrasonic pulse; the echo signal sequence is evenly spaced into a number of echo signal segments that are the same as the number of velocity measuring points, and the Doppler frequency shift of each echo signal segment relative to the transmitted pulse ultrasonic wave is calculated. According to the Doppler frequency shift, the velocity of solid particles in the water body corresponding to each echo signal segment along the ultrasonic wave propagation direction is calculated, that is, the water flow velocity along the ultrasonic wave propagation direction at each velocity measuring point.

[0069] The ultrasonic flow measuring device provided in the second aspect of the present disclosure is suitable for installation on a measuring box, which includes a flow measuring box top 2, a flow measuring box bottom 3 and two side walls. The inlet end of the flow measuring box is a rectangular flange connected to the hydraulic structure, and the outlet end is welded to the flow measuring box top 2 and the flow measuring box bottom 3 as a whole. The flow measuring box top 2, the flow measuring box bottom 3 and the two side walls are closed to form a rectangular prism-shaped flow cavity. The flow measuring box top 2, the flow measuring box bottom 3 and the two side walls are all stainless steel plates. The inner wall of the cavity is smooth and smooth. The downstream section of the flow measuring box top 2 is reserved with an installation hole for the ultrasonic velocity measuring component 4.

[0070] In some embodiments, see Figure 4 and Figure 5The ultrasonic velocity measuring component 4 also includes a mounting frame 4-1, a cover plate 4-2 sealed on the top of the mounting frame 4-1 and a waterproof membrane 4-10 sealed on the bottom of the mounting frame 4-1, an upper water chamber 4-3 is formed between the upper part of the mounting frame 4-1 and the cover plate 4-2, a lower water chamber 4-8 is formed between the lower part of the mounting frame 4-1 and the waterproof membrane 4-10, and a water hole 4-4 for connecting the lower water chamber 4-8 with the upper water chamber 4-3 is provided on the mounting frame 4-1; a plurality of ultrasonic velocity measuring probes 4-7 are obliquely arranged on the mounting frame 4-1, and the transmitting end of the ultrasonic velocity measuring probe 4-7 is located in the lower water chamber 4-8, and the signal line 4-5 of the ultrasonic velocity measuring probe 4-7 passes through the upper water chamber 4-3 and then passes through the cover plate 4-2 and is connected to the ultrasonic signal processing module 5.

[0071] In one embodiment, a mounting position is reserved on the top 2 of the flow measuring box, and the ultrasonic velocity measuring component 4 is embedded in the mounting position. The lower plane of the ultrasonic velocity measuring component 4 is flush with the lower plane of the top 2 of the flow measuring box, so that the ultrasonic velocity measuring component 4 is fixed.

[0072] In one embodiment, the mounting frame 4-1 located between the upper water cavity 4-3 and the lower water cavity 4-8 is provided with 8 mounting holes for ultrasonic velocity measuring probes 4-7, each with a diameter of 1 cm. Each ultrasonic velocity measuring probe 4-7 is placed obliquely in the corresponding mounting hole, and a filler 4-6 is provided between each ultrasonic velocity measuring probe 4-7 and the hole wall of the corresponding mounting hole to fix the ultrasonic velocity measuring probe 4-7. The transmitting end of each ultrasonic velocity measuring probe 4-7 is located in the lower water cavity 4-8, and the ultrasonic wave propagation direction points to the inlet of the flow measuring box and is oblique to the axis of the flow measuring box. The signal line 4-5 of each ultrasonic velocity measuring probe passes through the upper water cavity 4-3 and is led out from the corresponding through hole reserved on the cover plate 4-2, and connected to the ultrasonic signal processing module 5.

[0073] In one embodiment, the diameter of the water hole 4-4 connected between the upper water chamber 4-3 and the lower water chamber 4-8 is 5 mm. By setting the water hole 4-4, it can be ensured that during the operation of the device, the lower water chamber 4-8 is always in a water-filled state, so that the ultrasonic wave is always propagated in the same medium.

[0074] In some embodiments, in order to avoid the generation of a horizontal axis vortex in the lower water cavity 4-8 that affects the measurement accuracy, a water-proof membrane 4-10 of metal, polymer material or composite material that is not easy to deform, wear-resistant and not easy to rust is embedded in the lower plane of the ultrasonic velocity measurement component 4 to form a closed lower water cavity 4-8. Preferably, the thickness of the metal water-proof membrane is 1 / 2 of the wavelength of the ultrasonic wave emitted by the ultrasonic velocity measurement probe 4-7, and the ultrasonic wave will penetrate completely without reflection. In one embodiment, the ultrasonic frequency is 5MHz, the ultrasonic wavelength is 0.29mm, and the thickness of the metal water-proof membrane is 0.145mm.

[0075] In some embodiments, the metal water barrier film is shaped as Figure 6As shown, a rectangular dish made of stainless steel is processed to have an outward-turned edge 4-10a, and the outward-turned edge 4-10a is embedded in a groove reserved at the lower part of the mounting bracket 4-1, and then Figure 5 the water-proof membrane pressing strip 4-9 shown in the figure is pasted and pressed tightly, and the formed lower plane is flush with the lower plane of the top 2 of the flow measurement box.

[0076] After the ultrasonic velocity measurement component 4 is encapsulated, it is placed obliquely, and water is filled into the water cavity 4-8 from the water passing hole 4-4 at the low end. After completely exhausting the gas in the water cavity 4-8, the ultrasonic velocity measurement component 4 is placed flat, and then the upper water cavity 4-3 is filled with water, and the cover plate 4-2 is sealed. The through hole of the signal line 4-5 reserved on the cover plate 4-2 is not waterproofed, and the pressure in the water cavity can be naturally adjusted while minimizing water evaporation.

[0077] In some embodiments, the ultrasonic signal processing module 5 includes a power supply sub-module, a pulse emission sub-module, an echo reception sub-module, and a signal processing sub-module, which are connected to each ultrasonic velocity measurement probe 4-7 mounted on the mounting bracket 4-1 through a signal line 4-5, so as to drive the ultrasonic velocity measurement probe 4-7 to transmit and receive ultrasonic signals, and calculate the flow velocity of each flow velocity measurement point according to the ultrasonic signals.

[0078] Furthermore, the signal processing sub-module also calculates the flow value passing through the flow measurement box according to the flow velocity of each flow velocity measurement point measured, in combination with the preset size of the flow measurement box, and stores and uploads the flow value to the dispatching platform in real time.

[0079] In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. 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 can be combined in a suitable manner in any one or more embodiments or examples.

[0080] Although the embodiments of the present disclosure have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present disclosure, and the scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. An ultrasonic flow measurement device, suitable for ultrasonic flow measurement in a flow measurement tank, characterized in that, The ultrasonic flow measurement device includes: An ultrasonic velocity measurement component, including a plurality of ultrasonic velocity measurement probes installed on the flow measurement section of the flow measurement box. Each ultrasonic velocity measurement probe is used to measure the water flow velocity at a plurality of flow velocity measurement points in the ultrasonic wave propagation direction. The ultrasonic wave propagation directions of each ultrasonic velocity measurement probe are parallel, coplanar, and intersect obliquely with the water flow direction at a certain angle. The flow velocity measurement points are evenly distributed throughout the flow measurement section; and An ultrasonic signal processing module, which is used to control the ultrasonic velocity measurement probe to emit a pulsed ultrasonic wave sequence and receive an echo signal sequence in each working cycle. Each pulsed ultrasonic wave sequence contains at least 1 ultrasonic pulse; the echo signal sequence is equally spaced into several segments of echo signals equal to the number of flow velocity measurement points, calculate the Doppler frequency shift amount of each segment of echo signal relative to the emitted pulsed ultrasonic wave, and calculate the velocity of the solid particles in the water body corresponding to each segment of echo signal along the ultrasonic wave propagation direction, that is, the water flow velocity at each flow velocity measurement point along the ultrasonic wave propagation direction; The ultrasonic velocity measurement component further includes a mounting frame, a cover plate sealed at the top of the mounting frame, and a water isolation film sealed at the bottom of the mounting frame. An upper water cavity is formed between the upper part of the mounting frame and the cover plate, and a lower water cavity is formed between the lower part of the mounting frame and the water isolation film. The mounting frame is provided with a water passing hole for communicating the lower water cavity and the upper water cavity; a plurality of ultrasonic velocity measurement probes are obliquely arranged on the mounting frame. The emitting end of the ultrasonic velocity measurement probe is located in the lower water cavity, and the signal line of the ultrasonic velocity measurement probe passes through the upper water cavity and then passes out from the cover plate and is connected to the ultrasonic signal processing module.

2. The ultrasonic flow measurement device according to claim 1, wherein The water isolation film has an outward-turned edge, and the outward-turned edge is embedded in a groove reserved at the lower part of the mounting frame and is pressed tightly by a water isolation film pressing strip.

3. The ultrasonic flow measurement device according to claim 1 or 2, characterized in that, A mounting position is reserved at the top of the flow measurement box, and the ultrasonic velocity measurement component is embedded in the mounting position, and the lower plane of the ultrasonic velocity measurement component is flush with the lower plane of the top of the flow measurement box.

4. An ultrasonic flow measurement method based on the ultrasonic flow measurement device according to any one of claims 1 to 3, wherein the ultrasonic flow measurement method is suitable for ultrasonic flow measurement of a flow measurement tank, characterized in that, The ultrasonic flow measurement method includes: When the flow measurement box is full of water, according to the number of flow velocity measurement points on the flow measurement section, the measured water flow velocity at each flow velocity measurement point along the ultrasonic wave propagation direction, and the cross-sectional area of the flow passing through perpendicular to the water flow direction around the corresponding flow velocity measurement point, the flow rate measured by the flow measurement box is obtained.

5. The ultrasonic flow measurement method according to claim 4, wherein The ultrasonic velocity measurement probes are installed on the two side walls or the top plate of the flow measurement box.

6. The ultrasonic flow measurement method according to claim 4, characterized in that, The flow rate measured by the flow measurement box is calculated according to the following formula: Among them, Q is the flow rate measured by the flow measurement box; N is the number of velocity measurement points on the flow measurement cross-section; V i is the measured water flow velocity in the ultrasonic propagation direction at the i-th velocity measurement point, where i = 1, 2, …, N, and the velocity measurement point closest to the ultrasonic velocity measurement probe is numbered 1, and the rest increase in sequence; A i is the cross-sectional area perpendicular to the water flow direction surrounding the i-th velocity measurement point; θ is the angle between the ultrasonic propagation direction of the ultrasonic velocity measurement probe and the water flow direction.

7. The ultrasonic flow measurement method according to claim 6, characterized in that, The ultrasonic velocity measurement probe measures the water flow velocity at a plurality of flow velocity measurement points in the ultrasonic wave propagation direction through the following steps: In each working cycle, the ultrasonic velocity measurement probe emits a pulsed ultrasonic wave sequence according to the emission frequency. Each pulsed ultrasonic wave sequence contains at least 1 ultrasonic pulse; The ultrasonic velocity measurement probe receives an echo signal sequence, equally spaces the echo signal sequence into N segments of echo signals, calculates the Doppler frequency shift amount of each segment of echo signal relative to the emitted pulsed ultrasonic wave, and calculates the velocity of the solid particles in the water body corresponding to each segment of echo signal along the ultrasonic wave propagation direction, that is, the water flow velocity at each flow velocity measurement point along the ultrasonic wave propagation direction.

8. The ultrasonic flow measurement method according to claim 7, characterized in that, The emission frequency is between 1 and 10 MHz.

9. The ultrasonic flow measurement method according to claim 7, wherein When measuring the water flow velocity at multiple flow velocity measurement points in the ultrasonic wave propagation direction through the ultrasonic velocity measurement probe, the echo signals of the same flow velocity measurement point in consecutive M working cycles are used as an overall sample for Doppler frequency shift calculation, or the statistical values of the water flow velocities measured in M working cycles are used as the measured water flow velocity.

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