KR100807372B1 - Flow measurement method by 2d - particle image velocimetry flowmeter - Google Patents

Abstract

A 2D PIV(Particle Image Velocimetry) flowmeter and a measuring method thereof are provided to enhance accuracy by calculating the flow with an equation after calculating flow velocity through displacement of a fluid particle. A 2D PIV flowmeter includes a laser unit(10), a connecting unit(20), a lens unit(30), an image acquiring unit(40), a synchronizing device(50), and a data calculating unit(60). The laser unit radiates laser light. The connecting unit transfers the laser light radiated from the laser unit. The lens unit radiates the laser light source transferred through the connecting unit to a fluid in a pipe(P). The image acquiring unit photographs a fluid particle passing the laser light. The synchronizing device synchronizes a photograph signal to be suitable to a laser pulse. The data calculating unit receives image data photographed at the image acquiring unit from the synchronizing device.

Description

Flow measurement method by 2D-Particle Image Velocimetry Flowmeter

Figure 1a is a conceptual diagram showing the displacement of the fluid particles using the fiave method according to the present invention,

Figure 1b is a photographic view showing the state of qualitative visualization of the fluid particles using the fiave technique according to the present invention,

1C is an analytical photograph showing a state of quantitative velocity measurement of a fluid particle using a fiave technique according to the present invention;

Figure 2 is a block diagram for the measurement of the two-dimensional piage flowmeter according to the present invention,

3 is a configuration diagram for measuring a two-dimensional piage flowmeter according to another embodiment;

Figure 4 is a perspective view showing a half-moon cylinder lens, one side concave cylinder lens, both sides concave cylinder lens according to the present invention,

Figure 5 is a perspective view showing a spherical lens of the two-dimensional piave flowmeter according to the present invention,

6 is a conceptual diagram for measuring the two-dimensional piave flow meter according to FIG.

7 is a conceptual diagram for measuring a two-dimensional piave flow meter according to FIG. 3;

8 is a conceptual diagram for measuring a two-dimensional piave flowmeter using an optical mirror,

9A and 9B are waveform diagrams for synchronizing a photographing signal of an image acquisition unit by a synchronization unit according to the present invention to a laser light source;

10 is a flow chart of a flow measurement method using a two-dimensional piage flowmeter according to the present invention,

11 is a conceptual diagram showing a particle image function and a correlation region according to the present invention;

12 is a three-dimensional image diagram showing the form of the correlation coefficient according to the present invention,

<Description of Symbols for Main Parts of Drawings>

10: laser unit 11: laser shutter

20: connector 21: optical cable

22 connector 23 optical mirror

30 lens unit 31 cylinder lens

31a: Vandal cylinder lens 31b: One side concave cylinder lens

31c: bilateral concave cylinder lens 32: spherical lens

40: image acquisition unit 50: synchronization unit

60: data calculation unit 100: two-dimensional piaf this flow meter

P: Pipe Pa: Flange Pipe

Pb, Pc: Hole Pd: Straight Tube

R: laser light source Ra: plane light source

W: Fluid Wa: Fluid Particle

R (p, q): Correlation coefficient

The present invention relates to a two-dimensional piave flowmeter and a measuring method thereof, and in particular, after irradiating a planar optical laser to a longitudinal section of a fluid flowing through the inside of a tube using a particle image velocity measurement method, the displacement of the fluid particles is measured as a movement time. It is possible to measure and calculate the total flow rate of the cross section of the laser irradiated fluid by dividing, and to measure the accurate flow rate by integrating the calculated flow rate of the particle, and to follow the pipe by using the non-contact measuring method with high accuracy and easy installation. The present invention relates to a flow meter and a method of measuring a two-dimensional fiave, which can be measured without disturbing the flow of a flowing fluid, so that pressure loss of the fluid is not generated, and the measurement range is not limited by the type, viscosity, and specific gravity of the fluid.

Generally, the flow rate is physically referring to the flow rate of the fluid, and the flow rate can be divided into two types. Firstly, there is a volume flow rate representing a volume passing over a given time interval in a given cross section.

Secondly, it can be distinguished by the mass flow rate representing the mass passing by a given time interval in a given cross section, except that the conditions of the measurement method are recognized under the condition that a fluid having the same density is measured.

In addition, the equation for calculating the flow rate can be easily obtained by substituting A = πd² / 4, V = √2gh = √2g (P / γ) at flow rate (Q) = pipe cross-sectional area (A) x flow rate (V). Can be.

Such, a flow meter and a measuring method for measuring the flow rate is a situation that has been developed in various ways.

Representative flowmeters include orifice flowmeters, flow nozzle nozzles, and Venturi tube flowmeters. These flowmeters are Bernoulli theory. It is to use the method of calculating the flow rate by applying the value corresponding to each flow meter to the flow rate formula obtained by obstruction theory.

In other words, Bernoulli's obstacle theory is a method of calculating the average speed through the cross section and converting the flow rate by measuring the secondary pressure loss generated by passing the obstacle by installing a specific shape obstacle inside the straight pipe.

In addition, the type, principle, and problems of the conventional flow meter for measuring the flow rate are as follows.

1.Turbine Meter is designed so that several winged rotating shafts or propellers can rotate freely by bearings and rotating shafts. Fluid flows in and the rotational axis rotates in proportion to the speed of the fluid, the rotational speed is measured as the blade tip of each propeller passes the measuring point, and the output signal from the turbine flowmeter is a frequency signal proportional to the volumetric flow rate. Each pulse signal generated can calculate the flow rate by calculating the condition corresponding to the volume of the measured liquid, and it is used in water meter or industrial turbine meter as an application field.

The flow rate in the turbine flowmeter is converted to the total integration flow rate by the integration meter. In order for the integration to be correct, the value of each pulse must be essentially constant. Thus, turbine flowmeters must be linear and are used within the linear range. Also, integration is only used within a linear range that is part of the operating range.

However, the turbine flowmeter has a complicated installation structure for measuring the flow rate, and there is a problem in that the propeller and the fluid come into contact with the flow of the fluid, as well as causing a loss of pressure. It is difficult, and cannot be used for slurry fluid, and because it operates in the fluid, there is a problem that cavitation occurs when the flow rate increases.

2. Vortex-Shedding Meter is a simple structure that calculates the flow rate after measuring the flow rate by using the frequency of Carman Vortex generated in the wake of the lump body installed in the duct or channel. Although it is applicable to pulsating fluids, cohesive fluids and two-phase (different state) fluids, there is a big problem that the influence of pipe vibration affects the measured values. There was a problem that it is impossible to measure the precise flow rate by generating a pressure loss of.

3. The electromagnetic flowmeter has Faraday's law of electromagnetic induction, that is, when a conductor moves in a magnetic field, an electromotive force is generated in a direction perpendicular to both the magnetic field direction and the direction of motion in the conductor, and its magnitude is proportional to the magnetic flux density and velocity. This is a method of measuring the flow rate.

In addition, the measurement method of an electronic flowmeter is generally configured to form a magnetic field in a direction perpendicular to the electrode direction after installing one electrode in a circular measuring tube having an inner surface insulated in an industrial electromagnetic flowmeter. Only cm) can be measured and there is a problem that can not measure the flow rate in a variety of fluids can not measure pure water.

In addition, a common problem of the conventional turbine flowmeter, vortex flowmeter, and electronic flowmeter is that the pressure loss and flow rate of the fluid flowing along the pipe are concentrated in one section, which is installed inside the pipe, causing a secondary loss in which the flow rate is changed. In addition, there is a problem that the measurement efficiency and accuracy is reduced because the calibration process for the measurement is complicated.

In addition, there is a problem that the wear part is generated and the flowmeter characteristic inspection cycle is shortened, which leads to an increase in maintenance operation costs.

4. Acoustic Flow Meter is a method in which ultrasonic waves propagate through a fluid and have different apparent propagation speeds when the fluid is at rest and when it is flowing.

That is, if the sound velocity in the stationary fluid is c and the flow rate is v, the apparent propagation velocity becomes (c + v) when the flow of sound waves coincides with the flow direction of the fluid, and (cv) in the direction against the flow of the fluid. Becomes This is because the medium that transmits sound waves itself moves, and usually the apparent propagation velocity is expressed as the sum of the velocity components of the sound relative to the propagation direction of the sound waves in the stationary fluid. In addition, there is a difference in arrival time between the sound wave transmitted in the same direction as the flow rate and the sound wave transmitted in the opposite direction. The flow rate is calculated after measuring the flow rate using the Doppler effect.

In addition, the ultrasonic flowmeter is a recently developed method, and the problem is not particularly raised, but other flowmeters have a straight line upstream and downstream of the flowmeter installation position, and there should not be any obstacles. In order to maintain the steady state of the flow of the straight portion has a problem that the length should be long enough.

In addition, the ultrasonic flowmeter is a point measurement method for measuring one section of a fluid flowing along a pipe, and a change in flow rate due to a change in flow rate is not detected outside the measurement section. There was a problem.

In order to solve the problems of the conventional flowmeters, it is possible to measure the flow rate with sufficient accuracy even in the vicinity of an elbow, a valve, or the like having a short length of straight pipe portion, and there are no parts to be worn and the characteristic life of the flowmeter is long. Extends, does not cause fluid flow pressure loss, the development and production process is simple, the flowmeter characteristics calibration test is very simple in operation, especially in the operation process for measurement, As the diameter increases, there is an urgent need to develop an improved flow meter that does not raise the price of the measuring equipment.

Therefore, the present invention has been made in view of the problems of the prior art as described above, but the non-contact measuring method that penetrates the tube to calculate the flow rate of the fluid flowing inside the tube, does not interfere with the flow of the fluid flowing inside the tube. The purpose of the present invention is to provide a flowmeter and a measuring method for a two-dimensional piave whose structure is improved so as not to cause a pressure drop of the fluid.

In addition, another object of the present invention is to measure the flow rate without being constrained by conditions such as the type, temperature, viscosity of the fluid, measuring device for measuring by forming a hole in the tube through which the fluid flows to install the lens unit and the image acquisition unit The structure is simple, and the fluid particles contained in the fluid passing through the laser light source determine the displacement of the fluid particles moving for a certain time, calculate the flow rate, and then improve the structure by increasing the accuracy by calculating the flow rate by the equation It is an object of the present invention to provide a flow meter and a measuring method thereof.

In order to achieve the above object, the present invention provides a laser unit to which the laser light source is irradiated, a connection unit for transferring the laser light source irradiated from the laser unit, and a laser light source transferred through the connection unit to the fluid flowing inside the tube. An image acquisition unit for photographing the state of the fluid particles passing through the lens unit, the laser light source irradiated through the lens unit, a synchronization unit unit connected to the image acquisition unit to synchronize the photographing signal to the laser pulse, and from the synchronization unit unit In the two-dimensional piaeyi flow meter, characterized in that consisting of a data operation unit for receiving the image data captured by the image acquisition unit is synchronized,
The lens unit is characterized by consisting of a cylindrical lens for converting the laser light source supplied through the connecting portion to a planar light source, and a spherical lens for adjusting the thickness of the planar light source converted through the cylinder lens.
In addition, the lens portion is located at the upper apex of the flange tube, a portion of the front is inserted into the inside of the flange tube so as to irradiate a laser light source to the fluid flowing inside the tube, the image acquisition portion is located on one side of the left and right measurement points of the flange tube A fixed, but two-dimensional piage flow meter, characterized in that the portion of the front is configured to be inserted into the interior of the flange flows fluid is formed.

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In addition, the method for measuring the flow rate of the fluid using the two-dimensional piave flowmeter is a laser irradiation step of irradiating the fluid flowing through the inside of the tube with the laser light source irradiated through the laser unit, and the laser light source irradiated to the fluid in the laser irradiation step To capture the flow state of the fluid particles contained in the passing fluid at the first t ₀ time, and to synchronize the laser pulse and the imaging signal by using the synchronization unit to take a second time after t ₀ + △ t time, image acquisition Display the two images by using the two parts, and the two images taken in the shooting step on the screen of the data operation unit, and compare the time t ₀ and time In order to measure the movement displacements Δx and Δy of fluid particles at t ₀ + Δt, we use a cross-correlation fluid particle tracking technique, where a function representing the brightness of light is f (m, n), g, respectively. Calculation of the correlation coefficient assuming (m, n) and the displacement of the fluid particles most moved from the peak position of the correlation coefficient obtained through the correlation correlation calculation step Δx and Δy In the two-dimensional piave flow rate measuring method comprising a flow rate calculation step of calculating a velocity vector U (u, v) of a fluid by dividing Δt time, the velocity vector U (u, v) of the fluid obtained in the flow rate calculation step is calculated. It is characterized by consisting of a flow rate calculation step of calculating the flow rate of the fluid by integrating the cross-sectional area of the tube.

The preferred embodiment of the present invention as described above will be described in detail based on the accompanying drawings.

1A is a conceptual diagram illustrating displacement of a fluid particle using a fiave technique according to the present invention, and FIG. 1B is a photographic view showing a state of qualitative visualization of fluid position using a fiave technique according to the present invention. 1c is an analytical photograph showing the state of quantitative velocity measurement of fluid particles using the fiave technique according to the present invention, FIG. 2 is a configuration diagram for measuring a two-dimensional piave flow meter according to the present invention, and FIG. The two-dimensional piave according to the example is a configuration diagram for the measurement of the flow meter, Figure 4 is a perspective view showing a half-moon cylinder lens, one side concave cylinder lens, both sides concave cylinder lens according to the present invention, Figure 5 is a two-dimensional piave 2 according to the present invention Fig. 6 is a perspective view showing a spherical lens of the flow meter, and Fig. 6 is a conceptual diagram for measuring the flow meter of the two-dimensional piave according to Fig. 7 is a conceptual diagram for measuring a two-dimensional piave flow meter according to Figure 3, Figure 8 is a conceptual diagram for measuring a two-dimensional piave flow meter using an optical mirror, Figure 9a, 9b is an image by the synchronization unit according to the present invention 10 is a waveform diagram of synchronizing an image pickup signal with a laser light source, and FIG. 10 is a flow chart of a flow measurement method using a two-dimensional piabe flowmeter according to the present invention, and FIG. 11 is a conceptual diagram showing a particle image function and a correlation region according to the present invention. 12 is a stereoscopic image showing the shape of the correlation coefficient according to the present invention.

As shown in the drawing, the flow meter using the fiave method according to the present invention includes a laser unit 10 to which the laser light source R is irradiated, and a connection unit for transferring the laser light source R irradiated from the laser unit 10 ( 20 and the lens unit 30 for irradiating the fluid W flowing through the inside of the tube P with the laser light source R supplied through the connecting unit 20, and the laser irradiated through the lens unit 30. An image acquisition unit 40 for capturing the state of the fluid particle Wa passing through the light source R, and a synchronization device unit 50 connected to the image acquisition unit 40 to synchronize the photographing signal to be suitable for the laser pulse; The flowmeter 100 is configured as a two-dimensional piave a data operation unit 60 is synchronized from the synchronization device unit 50 receives the data captured by the image acquisition unit 40.

First, the piave used in the present invention is a method of calculating the flow rate after calculating the flow rate of a fluid, and is referred to as PIV (Particle Imaging Velocimetry) or particle image velocity measurement. The particles to be injected are particles that are almost equal to the specific gravity of the flow field, such as nylon particles, aluminum powder, spherical glass particles, and silicon particles of 1 to 100 μm in size, and then their motion is visualized and digital image processing technology (Imaging It is a measurement technique that obtains velocity two-dimensional velocity vector throughout the flow field by analyzing using Processing Technique.

In other words, the measurement method of the Piave is a non-contact measurement technique that can measure the flow field in the space multi-simultaneous method. The Piave technique using particle image containing displacement information of the flow particles has been developed, Rather, it can measure quantitative velocity fields.

In addition, the principle of velocity field measurement by Piave's measurement method is to find the velocity by measuring the displacement of particles inserted into the flow field for a given time interval. Therefore, it is a characteristic that the speed compensation equation for the electric signal is not necessary as the direct measurement using the time-displacement rather than the indirect measurement using the electric signal.

As shown in FIG. 1A, when the piave is a conceptual diagram for calculating the flow rate (velocity field) of the fluid particles Wa contained in the fluid W by the measuring method, the fluid is contained in the flowing state. After selecting one fluid particle Wa, it is assumed that the initial position time of the fluid particle Wa is t ₀ .

Thereafter, the first fluid particle Wa moves in the movement displacement by Δx and Δy for t ₀ + Δt time so that the fluid particle Wa flows along the fluid W.

Then, by substituting the displacement obtained in FIG. 1A, the velocity vectors U (u and v) may be obtained using Equation 1 below.

Here, U is the velocity vector of the whole, u: the flow velocity in the x-axis direction obtained by dividing the movement displacement of Δx by Δt, and the flow velocity in the y-axis direction obtained by dividing the movement displacement of v: Δy by Δt.

In other words, the two-dimensional flow velocity U (u, v) is calculated by obtaining the flow velocity u in the x-axis direction and the flow velocity v in the y-axis direction.

As shown in FIGS. 1B and 1C, first, FIG. 1B shows a fluid W at t ₀ (a portion shown in black) and a fluid particle Wa contained in a fluid W (a portion shown in white). Figure 1c is a picture showing the flow, Figure 1c is shown by analyzing for the quantitative velocity measurement using the Piave two measurement method, the portion shown in white represents the fluid (W), the fluid particle (Wa) is a black arrow Simultaneously showing the direction of movement to the portion shown by the can be accurately grasp the flow state of the fluid particles (Wa) and is a technique that can easily measure the speed of the flow rate for each cross section.

In addition, the fluid particle Wa is an arbitrary particle added to the fluid W for measuring the flow rate Q. The diameter of the fluid particle Wa is very important to the measurement uncertainty of the system. Smaller ones have better fluid followability, but the strength of the planar light source Ra may be weak, which may result in a high signal-to-noise ratio.

 Therefore, in the present invention, it is possible to use the fluid particles Wa such as nylon particles, aluminum powder, spherical glass particles, silicon particles, etc. It does not generate a recovery process for recovering the fluid particles Wa after completion, and is configured to replace the suspended solids contained in the fluid W with the fluid particles Wa to prevent contamination of the measurement fluid.

2 to 9B, the laser unit 10 is a device for irradiating the laser light source (R) by receiving power from the outside.

The laser light source R is subject to irradiation with visible light.

In addition, the laser light source (R) may be divided into two types of irradiation.

First, the pulsed laser is a laser forming a constant pulse, the intensity of the laser light source (R) is configured so that the energy per pulse is irradiated with 1mJ or more.

Secondly, the continuous laser generates a laser light source R continuously without generating pulses, and the intensity of the laser light source R is configured to irradiate a maximum power of 500 mW or more.

However, the laser unit 10 using the continuous laser is preferably used with the laser shutter 11 capable of forming a constant pulse on the laser light source R irradiated continuously.

In addition, the laser shutter 11 should be capable of oscillating at 10 Hz or more in order to change the continuous laser light source into a pulse method, and each pulse should be configured to be controlled with an accuracy of 1 μs or less.

However, in the present invention, it is preferable to use the pulsed laser unit 10 which generates the pulsed laser light source R for simple and accurate measurement and convenience, and the structure and cost of the measuring device for measuring the flow velocity. It would be desirable.

The connecting portion 20 is a device for transferring the laser light source R irradiated from the laser portion 10.

On the other hand, the connector 20 is a connector 22 is formed on both ends of the optical cable 21, one connector 22 is connected to the laser unit 10, the other connector 22 is the lens unit 30 It is connected to and configured.

In addition, the connection unit 20 is configured to transfer the laser light source R generated by the laser unit 10 to the lens unit 30 to be measured.

In addition, the present invention is configured to transfer the laser light source (R) using the optical cable 21 and the connector 22 of the connecting portion 20.

In addition, the connection part 20 as another embodiment may be configured by using the optical mirror 23 which can reflect the laser light source R of the laser part 10 and then reflect it to the lens part 30.

However, in the case of using the optical mirror 23 or the optical cable 21, it should be configured that does not affect the pulse and intensity of the laser light source (R).

In addition, the lens unit 30 is a device for irradiating the fluid (W) flowing inside the tube (P) to the laser light source (R) supplied through the connecting portion (20).

In addition, the lens unit 30 is provided with a cylinder lens 31 for directly receiving the laser light source (R) transferred from the connecting portion 20 to convert the pulsed laser light source into a planar light source (Ra), the cylinder lens It consists of a spherical lens 32 which passes through the 31 and controls and disperses the thickness of the laser light source R converted into the planar light source Ra.

The cylinder lens 31 uses a half moon cylinder lens 31a having a half moon shape, one side of which is planar, and one side concave cylinder lens 31b having a concave shape, and both side concave cylinder lenses 31c having both concave shapes. Can be configured.

In addition, the shape of the vandal cylinder lens 31a, the one side concave cylinder lens 31b, and the two side concave cylinder lens 31c is shown in a planar view, and in the case of the vandal cylinder lens 31a, the laser is flat on the flat surface. The light source R is incident and transmitted through the rounded surface to irradiate the laser light source R. The one side concave cylinder lens 31b and the two side concave cylinder lens 31c are incident to the concave surface with the laser light source R incident. It is configured to be irradiated with light.

On the other hand, the spherical lens 32 is configured to be irradiated by extending the thickness of the laser light source (R) converted to the planar light source (Ra) by passing through the cylinder lens 31 in a convex raised circular shape.

In the present invention, although the fiave constitutes the flowmeter 100 using the spherical lens 32, the lens unit 30 may be configured without using the spherical lens 32 in some cases.

In addition, the planar light source Ra is This means that It is a light source used in particle image flow rate measurement. It is a diffusive distribution of a line-shaped laser light source R in a two-dimensional plane form. In order to convert the line-shaped laser light source R into a planar light source Ra, a cylinder lens is used. In addition to the method of using (31), it can be configured using a variety of techniques such as a rotating mirror or a tilting mirror, a prism.

The image acquisition unit 40 determines the state of the fluid particles Wa passing through the laser light source R irradiated through the lens unit 30 at a predetermined time t ₀ and time t _0. Two images are taken by shooting at + Δt.

As an image input device that can configure the image acquisition unit 40, the image acquisition unit 40 can be configured using a CCD camera or a CMOS camera.

On the other hand, since the resolution of the camera constituting the image acquisition unit 40 is closely related to the spatial resolution of the fluid (W) flow velocity (velocity field), it may be preferable to use a higher resolution.

In addition, the image signal used in the image acquisition unit 40 can be divided into analog and digital methods.

That is, in the present invention, both analog and digital methods can be used, but the analog video signal has a measurement error than the digital method due to the error caused by A / D conversion and the effect of jittering. Since it becomes larger, it would be desirable to use a digital camera.

In this case, the frame rate of the camera used in the image acquisition unit 40 is an important factor that determines the performance of the particle image flowmeter system and is configured to be 20 frames or more per second.

In addition, the cross-correlation particle image flowmeter system of the image acquisition unit 40 extracts the flow velocity (velocity field) from two consecutive images, so that the dead zone between the frame and the frame of the image is 100 μs or less. do.

Here, dead zone means time t ₀ and time t _0. When shooting at + Δt, shoot t ₀ first, then t ₀ It means the area where the camera shutter until the second shooting is closed at + DELTA t.

In addition, the image acquisition unit 40 preferably selects and uses the full frame method rather than the interlace method in selecting an image grabber, and uses a digital camera having a dedicated image grabber to It should be configured to prevent deterioration.

On the other hand, the lens portion 30 is located at the upper peak of the flange tube (Pa), the front portion of the flange tube (Pa) to irradiate the laser light source (R) to the fluid (W) flowing inside the tube (P). Is inserted into the inside, and the image acquisition unit 40 is fixed to one side of the left and right apex of the flange tube (Pa), a part of the front is formed to be inserted into the inside of the flange tube (Pa) flowing fluid to be photographed The contact between the lens unit 30 and the image acquisition unit 40 is configured to form 90 °.

In the present invention, in order to measure the flow rate with respect to the pipe (P) installed in the field and the preferred measurement, first cut a portion of the straight pipe (P), and then form a flange (not shown) around the cut portion, Construct a flange tube (Pa) that is the same size as the part.

Thereafter, a hole Pb is formed at the uppermost point of the flange tube Pa to insert the front of the lens unit 30, and then the leak of the fluid W flowing inside the tube P is prevented by sealing. It is fixed to the outside using a bolting method or a fixed clamp (not shown).

In addition, after the front of the image acquisition unit 40 is formed by forming a hole Pc at one of both apex of the flange pipe Pa, the leak of the fluid W flowing inside the pipe P is sealed. It is prevented and fixed to the outside using a bolting method or a fixed clamp (not shown).

The flange pipe Pa is fastened by inserting a rubber ring (not shown in the drawing) between the cut straight pipe Pd and the flange of the straight pipe Pd and the flange of the flange pipe Pa so that watertightness can be maintained. It is configured to make a measurement.

That is, the laser light source R irradiated from the laser unit 10 flows the inside of the tube P to the plane light source Ra through which the laser light source R transferred to the lens unit 30 through the connection unit 20 flows. Irradiation from the top to the bottom of the fluid (W).

In this way, the laser light source R of the planar light source Ra irradiated from the lens unit 30 passes through the fluid W to be irradiated to the bottom of the tube P. At this time, the image acquisition unit 40 is a plane It is configured to photograph the fluid particles (Wa) contained in the fluid (W) flowing through the planar light source (Ra) at the side of the light source (Ra).

In addition, the synchronization device unit 50 is connected to the image acquisition unit 40 and passes the image pickup signal of the camera constituting the image acquisition unit 40 while passing through the cylinder lens 31 of the lens unit 30. ) And is configured to properly synchronize to the pulses of the laser light source R dispersed using the spherical lens 32.

That is, the synchronization device unit 50 is a device for generating a TTL-type signal for synchronizing the image acquisition unit 40 and the laser light source (R) is configured to use the accuracy of the signal within 1μs.

In addition, the synchronization signal generated from the synchronization device unit 50 may be used in one of the following two methods, the camera signal and the pulsed laser signal control.

First, in the manner used in the present invention, the first pulse of the laser light source R is emitted after the first frame of the camera photographing signal and the second pulse of the laser light source R is emitted at the beginning of the second frame of the camera photographing signal. It may become.

Secondly, a pair of pulses of the laser light source R may be irradiated at the center of the first frame and the second frame of the camera photographing signal.

On the other hand, the data operation unit 60 is configured to receive the data captured by the image acquisition unit 40 is synchronized from the synchronization device unit 50.

That is, the data operation unit 60 is provided with software for comparing, analyzing, and contrasting two images captured by the operation and image acquisition unit 40, and using a computer or other device capable of windowing. It is composed.

The method for obtaining the flow rate using the two-dimensional piave of the present invention configured as described above is as follows.

10 to 12, first, the laser irradiation step (S1) is a step of irradiating the fluid (W) flowing inside the tube (P) through the laser unit (10). .

That is, when power is applied to the laser unit 10, the pulsed laser light source R adopted and used in the present invention is irradiated to form a constant pulse.

On the other hand, in the case of using the continuous laser light source (R) to form a pulse on the laser light source (R) irradiated in the continuous method to form a pulse by using the laser shutter (11).

In this way, the laser light source R irradiated from the laser unit 10 is transferred to the connector 22 and the optical cable 21 sequentially connected to the laser unit 10, and then the connector 22 connected to the lens unit 30. The laser light source (R) is transferred to the lens unit 30 through).

Subsequently, in the lens unit 30, the laser light source R transferred through the connection unit 20 passes through the cylinder lens 31 and is converted into a two-dimensional planar light source Ra having a thin thickness.

Then, the laser light source R converted by the cylinder lens 31 into the planar light source Ra is irradiated to the fluid W flowing inside the pipe P.

However, when the area of the fluid W flowing inside the tube P is low in transmittance of the planar light source Ra converted by the cylinder lens 31, the cylinder lens ( The planar light source Ra converted by 31 is passed through the spherical lens 32 to irradiate the fluid with the triangular planar light source Ra having a thick thickness.

That is, the laser light source R converted into the planar light source Ra through the lens unit 30 is irradiated perpendicularly to the flow direction of the fluid W flowing in the longitudinal direction of the tube P.

Then, the photographing step (S2) is given a flow state of the fluid particles (Wa) contained in the fluid (W) passing through the laser light source (R) irradiated to the fluid (W) in the laser irradiation step (S1) t ₀ time To take the first shot, to synchronize the laser pulse and the shooting signal using the synchronizing unit 50 in order to take a second shot after t ₀ + △ t time, and to take two images using the image acquisition unit 40 It's a step.

In addition, the image acquisition unit 40 in the photographing step (S2) is installed on the same circumference in which the lens unit 30 is installed, it is installed at one of both side vertices of the tube to form 90 ° with the lens unit 30.

That is, when the side surface of the laser light source (R) irradiated through the lens unit 30 through the image acquisition unit 40 is viewed in a triangle shape.

In addition, the synchronizing device unit 50 in the photographing step (S2) is photographed under the condition of t ₀ time and any first pulse peak of the planar light source Ra irradiated through the lens unit 30 to capture the first image. After the acquisition, at the next consecutive second pulse peak and t ₀ + Δt time A second image is taken to obtain two images capable of measuring the displacement displacements Δx and Δy of the flow velocity particles Wa contained in the fluid W passing through the plane light source Ra.

In this way, a correlation region of (M × N) size is extracted from the entire image photographed in the photographing step S2.

That is, M is a function of the horizontal pixel value, N is a function of the vertical pixel value, and the setting of the pixel can be set to a size of 64x64 or 32x32.

The correlation coefficient calculating step S3 displays two images taken in the shooting step S2 on one screen of the data calculating unit 60, and then compares t ₀ with t ₀ In order to measure the displacements Δx and Δy of the fluid particles Wa at Δt time, a fluid particle Wa tracking technique is used. It is a step of calculating the correlation coefficient R (p, q) on the assumption that, n) and g (m, n).

In other words, the correlation coefficient R (p, q) is obtained using the following equation.

In addition, the correlation coefficient R (p, q) is _equal to the fluid particle Wa at a time t ₀ . t ₀ It is to grasp the state in which the fluid particle Wa moves at the movement displacement of Δx and Δy after + DELTA t.

In addition, the flow rate calculation step S4 includes movement displacements Δx and Δy of the fluid particles Wa most moved through the correlation coefficients R (p, q) obtained through the correlation coefficient calculation step S3. It is a step of calculating the velocity vector U (u, v) of the fluid W by dividing by [Delta] t time.

That is, the velocity vector U (u, v) is obtained using the same calculation formula used in Equation (1).

In addition, the flow rate calculation step S5 integrates the velocity vectors U (u, v) of the fluid W obtained in the flow rate calculation step S4 by the cross section of the pipe P to determine the flow rate Q of the fluid W. Calculation step.

That is, the flow rate Q is obtained through the following formula.

Here, U: velocity vector dy: cross section of the tube, Uj: j-th velocity on the cross section of the tube, Δy: j and the distance between the neighboring j.

In the above, the present invention has been illustrated and described with reference to certain preferred embodiments, but the present invention is not limited to the above-described embodiments, and the present invention is not limited to the spirit of the present invention. Various changes and modifications can be made by those who have

As described above, the present invention penetrates the pipe to calculate the flow rate of the fluid flowing inside the pipe, so as not to cause a pressure drop of the fluid by using a non-contact measurement method that does not interfere with the flow of the fluid flowing inside the pipe. There is an effect that the structure is improved.

And, it is possible to measure the flow rate without being restricted by the conditions such as the type, temperature, viscosity of the fluid, and the structure of the measuring device for the measurement is simple by forming a hole in the tube through which the fluid flows and installing the lens unit and the image acquisition unit, After the fluid particle passing through the laser light source determines the displacement of the fluid particle moved for a predetermined time, the flow rate is calculated, the flow rate is calculated by the equation, and the structure is improved to increase the accuracy.

Claims (9)

delete delete delete delete delete delete delete The laser unit 10 irradiated with the laser light source R, the connecting unit 20 for transferring the laser light source R irradiated from the laser unit 10, and the laser light source R moved through the connecting unit 20. ) To photograph the state of the fluid portion (W) passing through the lens unit 30 and the laser light source (R) irradiated through the lens unit 30 to the fluid (W) flowing inside the tube (P). An image acquisition unit 40, a synchronization device unit 50 connected to the image acquisition unit 40 to synchronize the photographing signal to be suitable for the laser pulse, and an image acquisition unit 40 synchronized with the synchronization device unit 50. It consists of a data operation unit 60 for receiving the image data captured by the lens unit 30 is a cylindrical lens 31 for converting the laser light source (R) supplied through the connecting portion 20 to a planar light source (Ra) ) And a two-dimensional piave composed of a spherical lens 32 for controlling the thickness of the planar light source Ra converted through the cylinder lens 31. In the system, the lens unit 30 is located at the upper apex of the flange tube (Pa), the front portion of the plan so that the laser light source (R) can be irradiated to the fluid (W) flowing inside the tube (P) Inserted into the inside of the branch pipe (Pa), the image acquisition unit 40 is fixed to one side of the left and right measurement points of the flange pipe (Pa), a portion of the front is inserted into the inside of the flange pipe (Pa) through which fluid flows so as to be photographed Two-dimensional piave flow meter, characterized in that is configured to be formed. A laser irradiation step S1 of irradiating the fluid W flowing through the inside of the tube P with the laser light source R irradiated through the laser unit 10, In the t ₀ time given the current state of the medium particles (Wa) containing the fluid (W) passing through the laser light source (R) irradiating the fluid (W) in the laser irradiation step (S1) and up to the primary, t ₀ In step (S2) of synchronizing the laser pulse and the photographing signal using the synchronizing device unit 50 to take a secondary shot after + Δt time, and using the image acquisition unit 40 to take two images, Display two images taken in the photographing step (S2) on one screen of the data operation unit 60, and then compare the time t ₀ and time In order to measure the displacement displacements Δx and Δy of the fluid particles Wa at t ₀ + Δt, a fluid particle Wa tracking technique is used. a correlation coefficient calculation step S3 for calculating the correlation coefficient R (p, q) assuming m, n) and g (m, n); The fluid displacement Δx and Δy of the fluid particles Wa most moved at the apex position of the correlation coefficient R (p, q) obtained through the correlation correlation calculation step S3 are divided by Δt time In the measuring method of the flowmeter, the two-dimensional piave which consists of the flow velocity calculation step S4 which calculates the velocity vector U (u, v) of (W), Flow rate calculation step (S5) of calculating the flow rate (Q) of the fluid (W) by integrating the velocity vectors (U, v) of the fluid (W) obtained in the flow rate calculation step (S4) to the cross section of the pipe (P). Two-dimensional piave is a flow meter measuring method, characterized in that consisting of.

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