A three-dimensional flow velocity measurement device and method based on mechanics

Abstract

The present invention relates to the technical field of water body flow pressure detection, and discloses a three-dimensional flow velocity measurement device and method based on mechanics, wherein the device comprises a measuring ball on which a pressure sensor and a fixing rod are symmetrically arranged and fixedly mounted; a three-dimensional force sensor is fixedly mounted on the fixing rod at a predetermined distance from the measuring ball; a collection end is fixedly mounted at the end of the fixing rod; wherein the three-dimensional force sensor and the pressure sensor are both completely submerged in the measured fluid. The three-dimensional flow velocity measurement device and method based on mechanics provided by the invention can be applied to the flow velocity measurement of water bodies with high sand content, and can measure small-scale three-dimensional flow velocity in narrow areas, thereby solving the problem that traditional detection devices cannot perform three-dimensional flow velocity measurement in scenes with high sand content, narrow areas, and between structures.

Description

Technical Field

[0001] The present invention relates to the technical field of water flow pressure detection, and in particular to a three-dimensional flow velocity measurement device and method based on mechanics. Background Art

[0002] In hydraulic model tests of water conservancy and river engineering, it is necessary to measure the flow velocity data of the fluid. The commonly used flow velocity measurement methods in model tests are propeller flowmeters and ultrasonic Doppler flowmeters. Specifically:

[0003] The propeller velocity meter uses a reflective layer on the propeller to identify the number of turns of the propeller under the water flow to calculate the flow rate. This method cannot measure three-dimensional flow rate information, but can only measure the flow rate component in one direction. In addition, if the water body has a high sand content, the reflective sheet cannot receive the reflected light, and the propeller velocity meter cannot work. Refer to the Chinese patent, publication number: CN118837578A, which discloses an intelligent propeller velocity meter and a flow rate measurement method;

[0004] The ultrasonic Doppler flowmeter uses the ultrasonic Doppler effect to measure the flow rate. The typical structure is a four-claw type. It can measure the three-dimensional flow rate value 2 cm in front of the probe. The measurement is accurate and the sampling rate is high. However, if the water body contains a lot of sand, the ultrasound dissipates quickly in the water body, and the measurement result of this method is inaccurate. In addition, due to the measurement principle, the ultrasonic Doppler measurement probe has a measurement blind spot, and it needs to be at a certain distance from the side wall or other structures during measurement. It is difficult to apply in model tests in narrow areas or diving areas. Refer to Chinese patent, publication number: CN118759217A, which discloses an ultrasonic Doppler flowmeter.

[0005] In the existing technologies including the above two patents, in river engineering model tests, how to conduct three-dimensional flow velocity measurement in waters with high sand content, narrow areas, between structures and other scenarios is expected to be well solved. Summary of the invention

[0006] The purpose of the present invention is to provide a three-dimensional flow velocity measurement device and method based on mechanics to solve the above problems.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A three-dimensional flow velocity measuring device based on mechanics comprises a measuring ball on which a pressure sensor and a fixing rod are symmetrically and fixedly mounted;

[0009] A three-dimensional force sensor is fixedly mounted on the fixed rod at a predetermined distance from the measuring ball;

[0010] A collecting end is fixedly mounted on the end of the fixing rod;

[0011] Wherein, the three-dimensional force sensor and the pressure sensor are both completely immersed in the measured fluid.

[0012] Preferably, it also includes an external fixing pile, on which a connecting hoop for fixing the fixing rod is fixedly installed.

[0013] Preferably, the acquisition end includes:

[0014] An analog-to-digital conversion module converts the three-dimensional force analog signal and the pressure signal collected by the three-dimensional force sensor and the pressure sensor into digital signals;

[0015] The data processing module analyzes the acquired digital signal, analyzes the force data into a flow rate data sequence, analyzes the pressure signal into a depth signal sequence, binds the flow rate data sequence and the depth signal sequence in time, and obtains the three-dimensional flow rate information of the monitoring point.

[0016] A three-dimensional flow velocity measurement method based on mechanics is applied to the three-dimensional flow velocity measurement device based on mechanics described in the above scheme, comprising the following steps:

[0017] S01, collecting data based on a preset periodic interval, and uploading the data to the collection end through a timestamp;

[0018] S02: The acquisition end analyzes the acquired data to obtain the F force on the measuring ball collected by the three-dimensional force sensor. x 、F y 、F z The water pressure P1 at the lower end of the measuring ball collected by the pressure sensor;

[0019] S03. Based on the analytical results, the flow velocity values ​​of the measured fluid in the x, y, and z directions of the measuring ball are calculated using the following formula:

[0020] ;

[0021] ;

[0022] ;

[0023] Among them, C a is the flow resistance coefficient of the flow-facing surface, ρ is the liquid density, λ is the empirical compensation coefficient, F x 、F y 、F z The three-dimensional force sensor collects three-dimensional force analog signals in the x, y and z directions of the measuring ball;

[0024] S04. Calculate the water depth h of the measuring ball in the water body using the following formula:

[0025] ;

[0026] Wherein, g is the weight of the measuring ball;

[0027] S05. Bind the water depth h with the flow velocity values ​​in the x, y, and z directions and the corresponding timestamps to obtain a time series value of the three-dimensional flow velocity and water depth.

[0028] Preferably, ρ is the liquid density of the measured fluid obtained by checking in a static water environment.

[0029] Preferably, the C a is the known flow resistance coefficient around the flow surface obtained corresponding to the known ρ.

[0030] Preferably, before executing step S01, the three-dimensional flow velocity measurement device is arranged in a static water environment, and in the static water environment, the value measured by the three-dimensional force sensor obtained by the acquisition end is reset to zero.

[0031] Preferably, the step S02 further includes verifying the acquired water pressure P1, and the steps include:

[0032] S21. Obtain the flow rate of the measured fluid through the water flow rate sensor , and then calculate the dynamic water pressure P2 on the flow surface of the measuring ball due to the flow velocity in the measured fluid. The calculation formula is as follows:

[0033] ;

[0034] Among them, C a is the flow resistance coefficient of the flow-facing surface, which is generally 0.8 for a sphere, ρ is the density of the liquid, and λ is the empirical compensation coefficient, which is 0.25-0.3;

[0035] S22, then based on the dynamic water pressure P2 and the known spherical surface roughness β, calculate the dynamic water pressure F of the measuring ball d , the calculation formula is as follows:

[0036] ;

[0037] Where r is the radius of the measuring ball, and β is the spherical roughness of the measuring ball;

[0038] S23, if the dynamic water pressure F d If it is equal to the water pressure P1, then proceed to step S03. If it is not equal to, then the three-dimensional force sensor and pressure sensor are re-collected until the dynamic water pressure F d When the water pressure is equal to P1, stop, and record the number of times the verification is repeated and the time period, and upload them.

[0039] In the above technical solution, the present invention provides a three-dimensional flow velocity measurement device and method based on mechanics, which has the following beneficial effects:

[0040] The device adopts a split design, that is, the measuring ball, fixed rod, three-dimensional force sensor and acquisition end are independently set up, so that measuring balls of different sizes can be replaced according to different measurement requirements and working conditions, which improves the applicability and flexibility of the device and enables it to cope with more types of fluid environments and measurement tasks.

[0041] By cooperating with pressure sensors and three-dimensional force sensors, the flow velocity in water bodies with high sand content can be effectively measured. It is suitable for flow velocity measurement in water bodies with high sand content, and can also measure small-scale three-dimensional flow velocity in narrow areas.

[0042] The solution also has a verification mechanism that verifies the accuracy of the measurement results by calculating the dynamic water pressure and the dynamic water pressure. If the two are not equal, the data will be automatically re-collected until they are consistent, further improving the accuracy and credibility of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0044] Figure 1 A schematic diagram of the structure of a three-dimensional flow velocity measurement device provided by an embodiment of the present invention;

[0045] Figure 2 A schematic diagram of the implementation status of a three-dimensional flow velocity measurement device provided in an embodiment of the present invention.

[0046] Description of reference numerals:

[0047] 1. Measuring ball; 2. Pressure sensor; 3. Connecting rod; 4. Three-dimensional force sensor; 5. Fixing rod; 6. Collection end; 8. External fixing pile; 9. Connecting clamp; 10. Water flow rate sensor. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Embodiment 1:

[0050] like Figure 1-2As shown, a three-dimensional flow velocity measurement device based on mechanics includes a measuring ball 1, on which a pressure sensor 2 and a fixing rod 5 are symmetrically fixedly mounted, and a three-dimensional force sensor 4 is fixedly mounted on the fixing rod 5 at a predetermined distance from the measuring ball 1. A collection terminal 6 is fixedly mounted at the end of the fixing rod 5, and a circuit board and a battery are fixedly mounted in the collection terminal 6, which can be directly powered by an external 220V mains electricity, or supplemented by a photovoltaic panel, which belongs to the prior art and will not be disclosed in detail.

[0051] In the embodiment process, combined with Figure 2 It can be seen that before installing the three-dimensional flow velocity measurement device, it is necessary to construct an external fixing pile 8 at a predetermined position, and then install the fixing rod 5 through the connecting clamp 9, so that the three-dimensional force sensor 4 and the pressure sensor 2 are completely immersed in the measured fluid.

[0052] It should be noted that in the embodiment, the diameter of the fixing rod 5 is generally less than one-fourth of the radius r of the measuring ball 1, and the length is generally about six times the radius r of the measuring ball 1 to avoid the vortex area of ​​the backflow. One end of the fixing rod 5 is screwed into the upper fixing hole of the sensing end of the three-dimensional force sensor 4, and the other end is connected to the collection end 6.

[0053] Secondly, the three-dimensional force sensor 4 is a miniature waterproof three-dimensional force sensor, which outputs a three-dimensional force analog signal after being subjected to force. It adopts a low-range, high-response, and high-decoupling design mode, has a small measurement range, a fast response speed, and a high three-dimensional force decoupling degree. The sensing end of the three-dimensional force sensor 4 has a three-dimensional direction mark.

[0054] Furthermore, the circuit board built into the acquisition terminal 6 in the above embodiment is integrated with:

[0055] The analog-to-digital conversion module converts the three-dimensional force analog signal and the pressure signal collected by the three-dimensional force sensor 4 and the pressure sensor 2 into digital signals;

[0056] The data processing module analyzes the acquired digital signals, analyzes the force data into a flow rate data sequence, analyzes the pressure signal into a depth signal sequence, binds the flow rate data sequence and the depth signal sequence by time, and obtains the three-dimensional flow rate information of the monitoring point.

[0057] The above technology adopts a split design, that is, the measuring ball 1, the fixing rod 5, the three-dimensional force sensor 4 and the acquisition end 6 are independently set up, so that the measuring ball 1 of different sizes can be replaced according to different measurement requirements and working conditions, thereby improving the applicability and flexibility of the device, enabling it to cope with more types of fluid environments and measurement tasks.

[0058] Furthermore, by cooperating with the pressure sensor 2 and the three-dimensional force sensor 4, the flow velocity in a water body with high sand content can be effectively measured, which is applicable to the flow velocity measurement of a water body with high sand content, and can also measure small-scale three-dimensional flow velocity in a narrow area.

[0059] Embodiment 2:

[0060] This embodiment aims to provide a method for measuring the three-dimensional flow velocity of a fluid based on the three-dimensional flow velocity measurement device provided in Embodiment 1, and the steps include the following:

[0061] S01, collecting data based on a preset periodic interval, and uploading the data to the collection terminal 6 through a timestamp;

[0062] S02: The acquisition terminal 6 analyzes the acquired data to obtain the F force on the measuring ball 1 acquired by the three-dimensional force sensor 4. x 、F y 、F z The value (i.e., the x, y, z forces on the measuring ball 1 detected by the three-dimensional force sensor 4) and the water pressure P1 at the lower end of the measuring ball 1 collected by the pressure sensor 2;

[0063] S03. Based on the analytical results, the flow velocity values ​​of the measured fluid in the x, y, and z directions about the measuring ball 1 are calculated, and the formula is as follows:

[0064] ;

[0065] ;

[0066] ;

[0067] Among them, C a is the flow resistance coefficient of the flow-facing surface, ρ is the liquid density, λ is the empirical compensation coefficient, F x 、F y 、F z The three-dimensional force sensor 4 collects three-dimensional force analog signals about the above-mentioned measuring ball 1 in the x, y, and z directions;

[0068] S04. Calculate the water depth h of the measuring ball 1 in the water body using the following formula:

[0069] ;

[0070] Where, g is the weight of the measuring ball 1;

[0071] S05. Bind the water depth h with the flow velocity values ​​in the x, y, and z directions and the corresponding timestamps to obtain a time series value of the three-dimensional flow velocity and water depth.

[0072] It should be noted that ρ in the above embodiment is the liquid density of the measured fluid obtained by checking in a static water environment. a is the known flow resistance coefficient around the flow surface obtained corresponding to the known ρ.

[0073] After the device is installed and started, the system will automatically place the three-dimensional flow velocity measurement device in a static water environment before executing step S01, and in the static water environment, the value measured by the three-dimensional force sensor 4 obtained by the acquisition end 6 is reset to zero;

[0074] Embodiment three:

[0075] This embodiment aims to verify the water pressure P1 collected in step S02 of the first embodiment, and the detailed steps include:

[0076] S21, obtaining the flow rate of the measured fluid through the water flow rate sensor 10 (which can be arranged separately in the measured fluid) Then calculate the dynamic water pressure P2 on the flow surface of the measuring ball 1 due to the flow velocity in the measured fluid (i.e. the pressure on the side of the pressure sensor 2 facing the flow of the measured fluid), the calculation formula is as follows:

[0077] ;

[0078] Among them, C a is the flow resistance coefficient of the flow-facing surface, which is generally 0.8 for a sphere, ρ is the density of the liquid, and λ is the empirical compensation coefficient, which is 0.25-0.3;

[0079] S22, then based on the dynamic water pressure P2 and the known spherical surface roughness β, the dynamic water pressure F of the measuring ball 1 is calculated d (i.e. the pressure on the detection end of pressure sensor 2), the calculation formula is as follows:

[0080] ;

[0081] Wherein, r is the radius of the measuring ball 1, and β is the spherical roughness of the measuring ball 1;

[0082] S23, if the obtained dynamic water pressure F d If the water pressure is equal to P1, then continue to step S03. If it is not equal, the three-dimensional force sensor 4 and the pressure sensor 2 are re-collected until the dynamic water pressure F d When the water pressure is equal to P1, the sensor stops and the number of verification repetitions and time periods are recorded and uploaded. The terminal server manually evaluates the uploaded data and checks whether the sensor is damaged or blocked by garbage.

[0083] The above technology verifies the accuracy of the measurement results by calculating the dynamic water pressure and the hydrodynamic pressure. If the two are not equal, the data will be automatically re-collected until they are consistent, further improving the accuracy and reliability of the measurement.

[0084] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A three-dimensional flow velocity measurement method based on mechanics, characterized in that: The following steps are involved: S01, collecting data based on a preset periodic interval, and uploading the data to the collection end (6) through a timestamp; S02, the acquisition end (6) analyzes the acquired data to obtain the F force exerted on the measuring ball (1) acquired by the three-dimensional force sensor (4). x 、F y 、F z numerical value and the water pressure P1 at the lower end of the measuring ball (1) collected by the pressure sensor (2); S03. Based on the analytical results, the flow velocity values ​​of the measured fluid in the x, y, and z directions of the measuring ball (1) are calculated using the following formula: Among them, C a is the flow resistance coefficient of the flow-facing surface, ρ is the liquid density, λ is the empirical compensation coefficient, F x 、F y 、F z A three-dimensional force sensor (4) is used to collect three-dimensional force analog signals in the x, y and z directions of the measuring ball (1); S04. Calculate the water depth h of the measuring ball (1) in the water body using the following formula: Wherein, g is the weight of the measuring ball (1); S05, binding the water depth h with the flow velocity values ​​in the x, y, z directions and the corresponding timestamps to obtain a time series value of the three-dimensional flow velocity and water depth; The step S02 also includes verifying the acquired water pressure P1, and the steps include: S21. Calculate the dynamic water pressure P2 on the flow-facing surface of the measuring ball (1) due to the flow velocity in the measured fluid. S22, calculate and obtain the dynamic water pressure F of the measuring ball (1) d ; S23, if the dynamic water pressure F d If it is equal to the water pressure P1, then proceed to step S03. If it is not equal to, then the three-dimensional force sensor (4) and the pressure sensor (2) are re-collected until the dynamic water pressure F d When the water pressure is equal to P1, stop, and record the number of repetitions and time period of the verification and upload them.

2. A three-dimensional flow velocity measurement method based on mechanics according to claim 1, characterized in that: The ρ is the liquid density of the measured fluid obtained by checking in a static water environment.

3. A three-dimensional flow velocity measurement method based on mechanics according to claim 1, characterized in that: The C a is the known flow resistance coefficient around the flow surface obtained corresponding to the known ρ.

4. A three-dimensional flow velocity measurement method based on mechanics according to claim 1, characterized in that: Before executing step S01, the three-dimensional flow velocity measurement device is arranged in a static water environment, and in the static water environment, the value measured by the three-dimensional force sensor (4) obtained by the acquisition end (6) is reset to zero.

5. The three-dimensional flow velocity measurement method based on mechanics according to claim 1 is characterized in that: The verification of the obtained water pressure P1 comprises the following steps: S21, obtain the flow velocity υ of the measured fluid through the water flow velocity sensor (10), and then calculate the dynamic water pressure P2 on the flow-facing surface, the calculation formula is as follows: Among them, C a is the flow resistance coefficient of the flow-facing surface, which is generally 0.8 for a sphere, ρ is the density of the liquid, and λ is the empirical compensation coefficient, which is 0.25-0.3; S22, then calculate the dynamic water pressure F based on the dynamic water pressure P2 and the known spherical surface roughness β d , the calculation formula is as follows: Fd=πr2 βP 2; Wherein, r is the radius of the measuring sphere (1), and β is the spherical roughness of the measuring sphere (1).

6. A three-dimensional flow velocity measurement device based on mechanics, applied to the three-dimensional flow velocity measurement method based on mechanics as described in any one of claims 1 to 5, characterized in that: It comprises a measuring ball (1) on which a pressure sensor (2) and a fixing rod (5) are symmetrically arranged and fixedly mounted; A three-dimensional force sensor (4) is fixedly mounted on the fixed rod (5) and is at a predetermined distance from the measuring ball (1); A collecting end (6) is fixedly mounted on the end of the fixing rod (5); Wherein, the three-dimensional force sensor (4) and the pressure sensor (2) are both completely immersed in the fluid to be measured.

7. A three-dimensional flow velocity measurement device based on mechanics according to claim 6, characterized in that: It also comprises an external fixing pile (8) on which a connecting hoop (9) for fixing the fixing rod (5) is fixedly mounted.

8. The three-dimensional flow velocity measurement device based on mechanics according to claim 6, characterized in that: The acquisition end (6) comprises: An analog-to-digital conversion module converts the three-dimensional force analog signal and the pressure signal collected by the three-dimensional force sensor (4) and the pressure sensor (2) into digital signals; The data processing module analyzes the acquired digital signal, analyzes the force data into a flow rate data sequence, analyzes the pressure signal into a depth signal sequence, binds the flow rate data sequence and the depth signal sequence in time, and obtains the three-dimensional flow rate information of the monitoring point.

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