JP2008175710A - Flow velocity measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately and easily measure the flow velocity distribution in a suction pipe installed in a reservoir tank in a flow velocity measuring device. <P>SOLUTION: The flow velocity measuring device 50 includes the reservoir tank 10 for reserving fluid 2 into which particles P are mixed, the cylindrical suction pipe 1 whose lower end is dipped into the fluid 2, and a measuring section 30 for measuring the flow velocity distribution of the fluid flowing inside the suction pipe 1. The suction pipe 1 has a transparent part and a dark part, and the measuring section 30 has a light source 5, an image photographing means 6, and an image analyzing means 22. The light source 5 emits pulse-like sheet light O into the suction pipe 1. The image photographing means 6 photographs images of the particle P group in the sheet light O synchronously with the light source pulse through the transparent part of the suction pipe 1 at the position opposite to the surface of the sheet light O against a background of the dark part 7 of the suction pipe 1. The image analyzing means 22 calculates the flow velocity distribution by determining the variation of the position of the particle P group based on the plurality of the photographed images. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flow velocity measuring device, and is particularly suitable for a flow velocity measuring device that measures a flow velocity distribution in a suction pipe installed in a water tank in a model test of a pump suction water tank.

  A conventional fluid flow measurement system is disclosed in Japanese Patent Laid-Open No. 2003-84005 (Patent Document 1).

  This flow measurement system includes a laser oscillation device that oscillates laser light, a scanning optical system for forming a laser sheet that oscillates the oscillated laser light into a fluid flow field, and a laser sheet from the scanning optical system. Image capturing means for capturing a two-dimensional particle trajectory image, timing control means for synchronously driving the laser oscillation device and the image capturing means at timing, and a two-time particle trajectory image captured by the image capturing means Image processing means for comparing / analyzing the luminance patterns of the particles and measuring the movement direction and movement amount of each particle.

  The fluid flow field is formed by a storage tank made of permeable glass, supplies the fluid from the lower surface of the storage tank, and supplies the fluid overflowing from the upper surface of the storage tank to the supply port on the lower surface of the storage tank. It is formed by circulating back to. The scanning optical system is installed so that laser light is input from above the upper surface opening of the storage tank, and the image pickup means is installed on the side surface of the storage tank.

JP 2003-84005 A

  However, in the flow measurement system of Patent Document 1 described above, the flow velocity distribution of the flow field of the fluid in the storage tank is measured, and the lower end is immersed in the fluid of the storage tank, and the fluid flows from the lower surface opening surface. It is not disclosed to measure the flow velocity distribution of the fluid flowing through the suction pipe. For example, it is not disclosed about measuring the flow velocity distribution in the suction pipe installed in the water tank in the model test of the pump suction water tank. When measuring the flow velocity distribution of the fluid flowing in such a suction pipe, since the suction pipe extends upward, it is difficult to install a scanning optical system so as to inject laser light from above the suction pipe. Since the fluid in the storage tank is interposed in the background of the sheet-like laser light picked up by the image pickup means, it is conceivable that the image pickup accuracy is lowered.

  An object of the present invention is to provide a flow velocity measuring apparatus capable of accurately and easily measuring a flow velocity distribution in a suction pipe installed in a storage tank.

  In order to achieve the above-described object, the present invention includes a storage tank that stores a fluid mixed with particles, a cylindrical suction pipe that has a lower end immersed in the fluid of the storage tank, and sucks the fluid from its lower surface. A measuring part for measuring a flow velocity distribution of the fluid flowing in the suction pipe, the suction pipe having a transparent part and a dark part, and the measuring part includes a light source attached to the outer peripheral surface of the suction pipe and An image capturing means; and an image analyzing means for calculating a flow velocity, wherein the light source is configured to irradiate a sheet light into the suction tube with a predetermined pulse through the transparent portion of the suction tube. The image of the particle group in the sheet light is taken in synchronism with the pulse of the light source through the transparent portion of the suction tube at a position facing the sheet light surface with the dark portion of the suction tube in the background. Configured for image analysis Stage are those that are configured to calculate the change calculated flow velocity distribution of the position of the particles from the photographed plurality of image by the image capturing means.

A more preferable specific configuration example of the present invention is as follows.
(1) The transparent portion and the dark portion of the suction tube are configured by providing a dark portion on the transparent tube.
(2) A transparent portion and a dark portion of the suction pipe are configured by providing a transparent window in a part of the dark pipe.
(3) The suction portion of the suction pipe to which the light source and the image photographing means are attached is formed as a separate member with respect to the piping portion, and the suction portion is detachable from the piping portion and rotates in the circumferential direction. Connected with a structure that can be attached.
(4) In the above (3), the suction pipe is composed of a plurality of suction pipes composed of a suction pipe to which the light source and the image photographing means are attached and other suction pipes. The suction part is formed as a separate member with respect to the pipe part, and the suction part is structured to be replaceable with a suction part of a suction pipe to which the light source and the image photographing means are attached.
(5) A flat portion is formed on the outer peripheral surface of the suction pipe at a position where the image photographing means is attached, and the image photographing means is attached to the flat portion.
(6) In (5), the flat portion of the suction pipe is formed on the bottom surface of a groove formed on the outer peripheral surface of the suction pipe, and at least a part of the image photographing means is accommodated in the groove.

  According to the flow velocity measuring apparatus of the present invention, it is possible to accurately and easily measure the flow velocity distribution in the suction pipe installed in the storage tank.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent. In addition, this invention includes making it more effective by combining each embodiment suitably as needed.
(First embodiment)
A flow velocity measuring apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory perspective view of a flow velocity measuring device 50 according to the first embodiment of the present invention. In FIG. 1, a part of the storage tank 10 is broken and illustrated so as to represent the periphery of the lower end portion of the suction pipe 1.

  The flow velocity measuring device 50 of the present embodiment is a device for measuring the flow velocity distribution of the fluid (water) flowing through the suction pipe installed in the water tank in the model test of the pump suction water tank, for example. The flow velocity measuring device 50 has a storage tank 10 for storing the fluid 2 mixed with the particles P as a tracer, and a cylindrical shape in which the lower end is immersed in the fluid 2 of the storage tank 10 and the fluid 2 is sucked from the lower surface opening. A suction pipe 1 and a measurement unit 30 that measures the flow velocity distribution of the fluid 2 flowing through the suction pipe 1 are provided.

  The storage tank 10 is for temporarily storing the fluid 2 and is formed in a box shape or a cylindrical shape that is long in the front-rear direction. The storage tank 10 is configured such that the fluid 2 is supplied from a fluid supply port on one side (back side), and the fluid 2 is discharged through a suction pipe 1 installed near the other side (front side). The suction pipe 1 and the fluid supply port are connected via a booster pump, and the fluid 2 is circulated through the storage tank 10 and the suction pipe 1. In this embodiment, since the suction pipe 1 is provided with a dark color portion and the measuring device is installed, it is not necessary to make the storage tank 10 a transparent member. Therefore, the storage tank 10 can be manufactured with an inexpensive member. it can.

  The suction pipe 1 is configured to have a transparent portion and a dark portion. This transparent portion may be transparent so long as it can irradiate or shoot the sheet light O of a strobe 5 that is a light source described later or a camera 6 that is an image photographing means. In the present embodiment, a transparent portion is formed using a transparent tube, and a dark color portion is formed by attaching a dark color (for example, black color) sheet 7 to the transparent tube. A dark paint may be applied instead of the sheet 7. The suction pipe 1 has an open bottom surface and extends vertically upward in the storage tank 10.

  The measuring unit 30 is a measuring unit based on the PIV (Particle Image Velocimetry) method, and includes an electronic flash 5 and a camera 6 attached to the outer peripheral surface of the suction pipe 1, a control device 21, and an image analysis unit that is a computer that calculates a flow velocity. 22. In the PIV method, particles P that follow the fluid 2 are put in the fluid, a sheet light having an appropriate thickness is emitted in a pulsed manner to produce a visualized cross section in the fluid 2, and the particles in the visualized cross section are produced. P is emitted, the camera 6 is exposed within the emission time, the tracer in the visualization cross section is visualized and captured, the image data is input to the computer 22, and the two image data repeatedly taken continuously are mutually correlated. By applying the correlation calculation, a fluid velocity vector is obtained, and based on the velocity vector, data such as vorticity, strain velocity, and Reynolds stress are obtained and visualized.

  The strobe 5 is configured to irradiate the suction flow F in the suction pipe 1 with a predetermined pulse through the transparent portion of the suction pipe 1. The sheet light O forms a sheet-like surface in the radial direction through the center of the suction pipe 1. Since the strobe 5 is immersed in the fluid 2, it has a waterproof structure.

  The camera 6 synchronizes the image of the particles P in the sheet light O with the pulse of the strobe 5 through the transparent portion of the suction pipe 1 at a position facing the surface of the sheet light O with the sheet 7 of the suction tube 1 in the background. It is configured to shoot. The strobe 5 and the camera 6 are installed at positions shifted by 90 degrees in the circumferential direction of the suction pipe 1, and the sheet 7 is installed on at least half the circumference on the opposite side of the circumferential direction of the camera 6. Since this camera 6 is immersed in the fluid 2, it has a waterproof structure.

  The control device 21 controls the irradiation of the sheet light of the strobe 5 and the image capturing of the camera 6 and is connected to the strobe 5 and the camera 6 via a control line.

  The computer 22 is configured to calculate a flow velocity distribution by obtaining a change in the position of the particle P group from a plurality of images taken by the camera 6. A cross-correlation method is used in the calculation of the flow velocity distribution. In this cross-correlation method, first, a cross-correlation function between the inspection area of the first image and the exploration area of the second image is obtained, then an area showing the peak of the correlation function is obtained, and the movement The velocity of the particles in a certain region is calculated from the quantity. Note that the velocity vector is calculated for each inspection region.

According to the present embodiment, it is possible to provide a flow velocity measuring device that can accurately and easily measure the flow velocity distribution in the suction pipe 1 installed in the storage tank 10. That is, since the strobe 5 and the camera 6 are attached to the outer peripheral surface of the suction pipe 1 whose lower end is immersed in the fluid 2 of the storage tank 10, the flow velocity distribution in the suction pipe 1 is measured from the outside of the storage tank 10. Compared to the case, the flow velocity distribution in the suction pipe 1 can be measured accurately and easily. Further, the suction pipe 1 is divided into a transparent portion and a dark color portion, the strobe 5 irradiates the sheet light O in a pulse shape through the transparent portion of the suction tube 1, and the camera 6 makes a sheet with the dark color portion of the suction pipe 1 as a background. Since the image of the particle P group in the sheet light O is photographed in synchronization with the pulse of the strobe 5 through the transparent portion of the suction tube 1 at a position facing the surface of the light O, the suction tube 1 is transparent. Compared with the case where the dark color part is provided outside the storage tank 10, the flow velocity distribution in the suction pipe 1 can be measured with high accuracy and in a simple manner.
(Second Embodiment)
Next, a flow velocity measuring device 50 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a peripheral view of the suction part of the suction pipe 1 in the flow velocity measuring device 50 according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the second embodiment, a dark color portion of the suction tube 1 is configured using a dark color tube, and transparent windows 25 and 26 are provided in a part of the dark color tube to configure a transparent portion of the suction tube 1. . The window 25 and the window 26 are provided so as to be shifted by 90 degrees in the circumferential direction. The strobe 5 is attached to the outer surface of the window 25, and the camera 6 is attached to the outer surface of the window 26. The dark portion of the suction tube 1 may be configured by coating the outer surface of the tube with a dark color even if the tube material is dark.

According to this 2nd Embodiment, compared with 1st Embodiment which attaches the sheet | seat 7 by making the suction pipe 1 whole transparent, the suction pipe 1 can be manufactured cheaply.
(Third embodiment)
Next, a flow velocity measuring device 50 according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is an explanatory perspective view of the flow velocity measuring device 50 according to the third embodiment of the present invention, and FIG. 4 is a diagram for explaining calibration work for correcting image distortion of the flow velocity measuring device 50 of FIG. The third embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In this 3rd Embodiment, the suction pipe 1 is isolate | separated into the suction part 1a which consists of another member, and the piping part 1b. The suction part 1a is configured by attaching the strobe 5, the camera 6 and the seat 7 in the same manner as in the first embodiment. Moreover, the suction part 1a and the piping part 1b are comprised by the loose flange structure 12 which the suction part 1a can attach or detach with respect to the piping part 1b, and can be rotated and attached to the circumferential direction. With this configuration, by rotating the suction part 1a in the circumferential direction with respect to the pipe part 1b, it becomes possible to measure the flow velocity distribution in all directions in the suction pipe 1, and more detailed flow measurement in the suction pipe 1 Is possible.

Further, in this type of flow velocity measuring device 50, before the measurement of the flow velocity distribution is started, the camera 6 and the dot-type lattice plate 23 and the like are attached to the suction pipe 1 so that an image can be captured in water under the same conditions as the measurement state. It is necessary to carry out calibration work for distortion correction. According to the third embodiment, as shown in FIG. 4, the suction part 1 a to which the camera 6 is attached can be easily calibrated in another container in a single state. In addition, calibration work in a state where workability of the suction pipe 1 is poor can be avoided.
(Fourth embodiment)
Next, a flow velocity measuring device 50 according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective explanatory view of a flow velocity measuring device 50 according to the fourth embodiment of the present invention. The fourth embodiment is different from the third embodiment in the points described below, and the other points are basically the same as those in the third embodiment, and thus redundant description is omitted.

  In the fourth embodiment, the suction pipe 1 includes a plurality of suction pipes 1A each having a strobe 5, a camera 6 and a seat 7 and other suction pipes 1B having no strobe 5, the camera 6 and the seat 7 attached. It consists of a suction pipe. The other suction pipe 1B has a structure in which the suction part 1a 'is formed as a separate member from the pipe part 1b, and the suction part 1a' can be replaced with the suction part 1a of the suction pipe 1A. The suction portion 1a 'has the same shape as the suction portion 1a except for the portion to which the strobe 5, the camera 6 and the seat 7 are attached.

According to the fourth embodiment, the flow velocity distributions of a plurality of suction pipes can be easily measured by the suction pipe 1A provided with a set of the strobe 5 and the camera 6.
(Fifth embodiment)
Next, a flow velocity measuring device 50 according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a peripheral view of the suction portion of the suction pipe 1 of the flow velocity measuring device 50 according to the fifth embodiment of the present invention. The fifth embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

In the fifth embodiment, a flat portion 27 is provided on the outer peripheral curved surface of the suction pipe 1, and the strobe 5 and the camera 6 are attached to this position. When the outer peripheral surface of the suction pipe 1 has a complicated curved surface, the calibration work itself for correcting image distortion may be impossible. In that case, the calibration work can be carried out very simply by providing the flat portion 27 on the outer peripheral surface of the suction pipe 1 in this way. In the fifth embodiment, the arrangement relationship of the strobe 5 and the camera 6 in the circumferential direction is reversed from that of the first embodiment, but even in this case, the flow velocity distribution can be measured as in the first embodiment.
(Sixth embodiment)
Next, a flow velocity measuring device 50 according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a peripheral view of the suction portion of the suction pipe 1 of the flow velocity measuring device 50 according to the sixth embodiment of the present invention. 7A shows a cylindrical shape in which the outer peripheral surface of the suction portion of the suction pipe 1 is simply cylindrical, and FIG. 7B shows a cylindrical shape in which the outer peripheral surface of the suction portion of the suction pipe 1 swells.

  The sixth embodiment is different from the fifth embodiment in the points described below, and the other points are basically the same as those in the fifth embodiment, and thus redundant description is omitted.

  In the sixth embodiment, the flat portion 27 of the suction pipe 1 is formed by the bottom surface of the groove 28 formed on the outer peripheral surface of the suction pipe 1, and at least a part of the strobe 5 and the camera 6 is accommodated in each groove 28. . Thereby, the influence of the strobe 5 and the camera 6 on the flow in the vicinity of the suction pipe 1 can be suppressed, and the flow velocity distribution in the suction pipe can be accurately measured. Although not shown, a cover is provided so as to cover the strobe 5, the camera 6, and the groove 28.

It is an isometric view explanatory drawing of the flow velocity measuring device of a 1st embodiment of the present invention. It is a peripheral view of the suction part of the suction pipe in the flow velocity measuring apparatus of 2nd Embodiment of this invention. It is a perspective explanatory view of the flow velocity measuring device of a 3rd embodiment of the present invention. It is a figure explaining the calibration operation | work of the distortion correction of the image of the flow velocity measuring apparatus of FIG. It is a perspective explanatory view of a flow velocity measuring device according to a fourth embodiment of the present invention. It is a peripheral view of the suction part of the suction pipe of the flow velocity measuring apparatus of 5th Embodiment of this invention. It is a peripheral view of the suction part of the suction pipe of the flow velocity measuring apparatus of 6th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A, 1B ... Suction pipe, 1a, 1a '... Suction part, 1b ... Piping part, 2 ... Working fluid (water), 5 ... Strobe (light source), 6 ... Camera (image photographing means), 7 ... Black system 10 ... Reservoir, 12 ... Loose flange structure, 21 ... Control device, 22 ... Computer (image analysis means), 23 ... Lattice plate, 25, 26 ... Window, 27 ... Planar part, 28 ... Groove, 30 ... Measuring unit, 50 ... flow velocity measuring device, F ... suction flow in suction pipe, P ... particle (tracer).

Claims (7)

A storage tank for storing fluid mixed with particles;
A cylindrical suction pipe whose lower end is immersed in the fluid of the storage tank and sucks fluid from its lower surface,
A measurement unit for measuring the flow velocity distribution of the fluid flowing in the suction pipe,
The suction pipe has a transparent part and a dark part;
The measurement unit includes a light source and an image photographing unit attached to the outer peripheral surface of the suction pipe, and an image analysis unit that calculates a flow velocity.
The light source is configured to irradiate sheet light with a predetermined pulse into the suction pipe through the transparent portion of the suction pipe,
The image photographing means synchronizes the image of the particle group in the sheet light with the pulse of the light source through the transparent portion of the suction tube at a position facing the surface of the sheet light with the dark portion of the suction tube as a background. Configured to shoot,
The image analysis means is configured to calculate a flow velocity distribution by obtaining a change in the position of the particle group from a plurality of images photographed by the image photographing means.   2. The flow velocity measuring apparatus according to claim 1, wherein the transparent portion and the dark portion of the suction pipe are formed by providing a dark portion on the transparent tube.   2. The flow velocity measuring apparatus according to claim 1, wherein a transparent portion and a dark portion of the suction pipe are formed by providing a transparent window in a part of the dark pipe.   In Claim 1, the suction part of the said suction pipe which attached the said light source and the said image pick-up means is formed in another member with respect to a piping part, and this suction part can be attached or detached with respect to the said piping part, and is the circumferential direction. A flow velocity measuring device characterized by being coupled with a structure that can be rotated and attached.   5. The suction pipe according to claim 4, wherein the suction pipe is composed of a plurality of suction pipes including a suction pipe to which the light source and the image photographing means are attached and other suction pipes. A flow velocity measuring device, wherein the suction portion is formed as a separate member with respect to the portion, and the suction portion can be replaced with a suction portion of a suction pipe to which the light source and the image photographing means are attached.   2. The flow velocity measuring apparatus according to claim 1, wherein a flat portion is formed on an outer peripheral surface of the suction pipe where the image photographing means is attached, and the image photographing means is attached to the flat portion.   7. The flow velocity measurement according to claim 6, wherein a flat portion of the suction pipe is formed by a bottom surface of a groove formed on an outer peripheral surface of the suction pipe, and at least a part of the image photographing means is accommodated in the groove. apparatus.

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