JP6475583B2 - Fluid measuring device - Google Patents

Description

  The present invention relates to a fluid measuring device capable of measuring a fluid state based on an image obtained by imaging with a camera.

Conventionally, a flow field mixed with tracer particles or the like is irradiated with laser light, and a plurality of images of a space including the irradiated particles are captured with a slight time difference with a camera, thereby allowing the flow field flow velocity and An apparatus for measuring a pressure distribution or the like two-dimensionally or three-dimensionally is known.
For example, a sheet-like laser beam is formed in the flow field, and a single camera captures the sheet-like surface direction with a minute time difference, so that a two-dimensional velocity or the like can be obtained from the amount of particle displacement in the surface direction. A two-dimensional two-components method for measuring the image, and the surface direction is orthogonal to the surface direction using a predetermined analysis algorithm by imaging the surface direction with a slight time difference between the two cameras. A two-dimensional three-component system that measures three-speed components in the direction in which the signal is transmitted is known. As a method for measuring the three-dimensional flow velocity, etc., a three-dimensional space made up of laser light is formed in the flow field, and this is imaged with a plurality of cameras, and a three-dimensional three-speed using a predetermined analysis algorithm. There is also a three-dimensional three-component method for measuring components.

Patent Document 1 is a device that measures the flow velocity, pressure distribution, and the like of such a flow field, and has been proposed by the patent applicant so that the flow velocity and the like can be measured even in a narrow flow field.
That is, in Patent Document 1, as shown in FIG. 1, a probe 26 that is miniaturized so that it can be inserted into a narrow flow field and a laser oscillation unit 30 that is a relatively large device are separately arranged, 26 and the laser oscillating unit 30 are connected via an optical fiber cable C2 capable of transmitting the laser beam of the laser oscillating unit 30. The probe 26 is fixed with a laser beam irradiation unit 28 for converting the laser beam received from the small cameras 40 and 41 and the optical fiber cable C2 into a sheet beam and irradiating it. By inserting only the probe 26 thus miniaturized into a narrow flow field, irradiating it with laser light, and imaging the irradiated space with the cameras 40 and 41, the fluid state can be measured.

JP 2014-134494 A

  By the way, in a probe-type device that measures a fluid state by inserting a probe into a narrow flow field as in Patent Document 1, the probe may invade the flow of the flow field depending on the narrowness or spatial shape of the flow field. The inventor realized that there was. Therefore, when the flow velocity / pressure distribution around the probe in the flow field was measured, as shown in FIG. 8, it was confirmed that the fluid was disturbing the flow by hitting the probe. Note that the invasiveness of the flow field by such a probe is not limited to the two-dimensional two-component method, the two-dimensional three-component method, or the three-dimensional three-component method, for example.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a fluid measuring apparatus that can reduce the invasiveness of a probe in a flow field and enable accurate measurement.

  According to the present invention, the above-mentioned problem is obtained by having a camera and a laser beam irradiation unit configured to irradiate a laser beam to an imaging space of a flow field imaged by the camera and imaging the laser beam. The fluid measurement device is configured to measure the flow velocity or pressure distribution of the fluid in the imaged space by an image, and at least the camera is fixed to a probe arranged in the flow field, The probe has an opening on a surface to which the fluid hits and an inner passage for guiding the fluid that has entered the opening in a direction away from the imaging space, and the fluid that has entered the opening This is achieved by a fluid measuring device provided with suction means for sucking the fluid.

In the fluid measuring device of the present invention, since at least the camera is fixed to the probe, even in a narrow flow field, the probe is inserted into the flow field and arranged to image the space in the flow field. It will be ready. Then, by flowing tracer particles or the like in the flow field, irradiating laser light from the laser light irradiation unit to the desired imaged space in the flow field, and imaging the imaged space with the camera, the fluid state of the imaged space is changed. Can be measured.
Here, since the probe is disposed in the flow field, the fluid hits the probe. However, the probe of the present invention has an opening on the surface where the fluid hits, and the fluid that has entered the opening is away from the imaging space. It has an inner passage for guiding. Then, the fluid does not hit the entire surface of the probe, and a part thereof enters the opening, passes through the inner passage in the probe, and moves away from the imaging space. Accordingly, the invasiveness of the probe in the flow field can be reduced by the amount of fluid that has entered the opening and the inner passage.
Furthermore, the suction means for sucking the fluid prevents the situation where the fluid that has entered the opening portion comes out of the opening portion again, or the fluid stagnates in the inner passage and cannot enter the new fluid. The possibility of disturbing the flow of the flow field can be effectively prevented.

Preferably, the amount of suction is controlled based on the measurement result of the pressure sensor provided in the opening so that the pressure on the inner surface side and the pressure on the outer surface side in the opening are equivalent. It is characterized by that.
In this “equivalent” state, there is no turbulence or the like only in the opening, and the inside and outside of the opening are in the same state (the speed and direction of the fluid are the same). By controlling the suction amount so as to maintain such a state, it is possible to create a state as if the probe did not exist in the flow field.
In addition, the above "equivalent" means that the actual pressure inside and outside the opening is equal. For example, when pressure sensors are provided on both the inside and outside of the opening, the specifications of both sensors Depending on the difference, the measured values of both sensors may be at a constant ratio.

Preferably, a flow rate control valve for controlling the suction amount is provided between the opening and the suction means.
Therefore, for example, even if the distance between the opening and the suction means is long or the suction means cannot change the suction amount quickly, the pressure on the inner surface and the pressure on the outer surface at the opening are controlled by the flow control valve. The flow rate of the fluid can be quickly controlled so as to be equivalent, and the possibility of disturbing the flow of the flow field can be effectively prevented even for a short time.

Preferably, the probe is connected to a tubular member that is spatially connected to the inner passage and can be extended in a direction away from the imaging space, and the suction means is interposed via the tubular member. The fluid that has entered the opening is sucked.
Therefore, the fluid that has entered the opening can be guided to a position further away from the imaged space via the tubular member, and factors that affect the imaged space can be more effectively removed. Further, the suction means can also be placed at a position away from the flow field, and the suction means can be prevented from causing turbulence in the flow field.

In a preferred embodiment, the opening has a narrow frame shape at the periphery, and a guide wall for guiding the fluid to the inner passage is formed inside.
Then, since the peripheral part of the opening has a thin frame shape, the amount of fluid that hits the peripheral part can be reduced, and even turbulent flow that occurs when the fluid hits the peripheral part can be suppressed.
In addition, since there is a guide wall for guiding the fluid to the inner passage inside the opening, the fluid that has entered the opening is smoothly guided to the inner passage, and the fluid stagnates in the opening and the new fluid smoothly flows. The fear that it cannot enter can be prevented more effectively.

  As described above, according to the present invention, it is possible to provide a fluid measuring apparatus that can reduce the invasiveness of a probe in a narrow flow field or the like and enable accurate measurement.

1 is a schematic view of a fluid measuring device according to an embodiment of the present invention. The figure which looked at the front end surface of the probe of FIG. AA sectional drawing of FIG. FIG. 2 is a horizontal cross-sectional view of the tip surface side of the probe of FIG. 1. FIG. 5A is a modified example of the pressure sensor of FIG. 4, and FIG. 5A corresponds to the diagram surrounded by the dashed line in FIG. 4, and is a state diagram in which the pressure on the inner surface side and the pressure on the outer surface side are equivalent. 5 (B) is a cross-sectional view taken along the line BB in FIG. 5 (A). FIG. 6 is a diagram in which the piezoelectric element of the pressure sensor in FIG. The figure which mounted the probe of the fluid measuring apparatus of embodiment of this invention on the flow field, and measured the fluid state (the arrow shows the speed and direction of a fluid, and a square part shows a probe) around a probe. The figure which measured the fluid state (The arrow shows the speed and direction of a fluid, and a square-shaped part shows a probe) around the conventional probe mounted in the flow field.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments. Moreover, the same code | symbol attached | subjected in each figure has the same structure.

First, an outline of a fluid measurement device according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is an overall schematic view of a fluid measuring device 20 according to an embodiment of the present invention.
The fluid measuring device 20 (hereinafter referred to as “this device”) 20 in this figure is used for a flow field S in a narrow or complicated space such as a car engine room, a car floor, a place between building models in an urban model wind tunnel test, etc. It is preferably used for measuring a fluid state (flow velocity and direction, or pressure distribution).
In this embodiment, an apparatus for measuring the flow velocity and pressure distribution of the airflow is illustrated, but the present invention is not limited to this, and an apparatus that measures the flow velocity and pressure distribution of the water flow may be used. Absent.

  This apparatus 20 is an apparatus for measuring a fluid state of two-dimensional three components, and irradiates a laser beam LB1 to a flow field S in which tracer particles are mixed, so that a sheet-like laser sheet is applied to an imaging space. The light SP is formed, and the scattered light irradiated on the particles in the laser sheet light SP is photographed by the two cameras 40 and 41, and the surface direction XY and the out-of-plane direction Z of the laser sheet light SP are measured. (The directions X, Y, and Z in the figure are orthogonal to each other.) Therefore, since the laser sheet light SP is a sheet and does not require a thickness, it is suitable for measuring the fluid state of the flow field S that is narrow in width or close to the object surface.

  Further, the apparatus 20 includes a main body 22 and a probe 26 connected to the main body 22 via a tube 24. In the present embodiment, only the cameras 40 and 41 and the laser beam irradiation unit 28 are arranged as a relatively large device and the size is reduced. Thereby, the miniaturized probe 26 is inserted into the narrow flow field S so that the flow velocity and the like can be measured.

[Outline of configuration other than probe]
Next, the configuration of the apparatus 20 other than the probe 26 will be described.
1 includes a laser oscillation unit 30, a laser power source 31, a camera power source 32, a controller 33, a computer 34, and a cooling device 35.
The laser oscillating unit 30 is a device that oscillates laser light. The oscillated laser light passes through the tube 24 and the laser light irradiating unit 28 of the probe 26, and the planar laser light LB 1 toward the imaging space of the flow field S. It is irradiated so that it becomes. The laser beam LB1 of the present embodiment is a double pulse laser, and for example, a YAG laser having a wavelength of 532 nm can be used.
The laser power source 31 supplies power to the laser oscillation unit 30 and energizes in accordance with the pulse width of the pulse laser.

The camera power supply 32 is electrically connected to the plurality of cameras 40 and 41 in the probe 26, supplies power, and transmits and receives signals to and from the cameras 40 and 41. The camera power source 32 and the laser power source 31 are connected to the controller 33.
The controller 33 synchronizes the camera power supply 32 and the laser power supply 31 to synchronize the timing of oscillating the laser beam from the laser oscillation unit 30 and the timing of photographing with the cameras 40 and 41. The controller 33 is connected to a computer 34 and transmits image data captured by the cameras 40 and 41 to the computer 34.
The computer 34 calculates the flow velocity and the like of the flow field S using a known analysis algorithm (for example, see Japanese Patent Application Laid-Open No. 2004-20385) based on a plurality of received image data. That is, the data of two images (scattered light images in the laser sheet light SP, etc.) sent from the two cameras 40 and 41 that are set to have a difference in photographing angle with each other with a minute time difference, and From the difference in the photographing angle, the moving amount of the particle in the plane direction vector XY of the laser sheet light SP and the vector Z orthogonal thereto is calculated using a mapping function.

The tube 24 is a flexible tube, and even if the flow field S has a complicated shape, the probe 26 attached to the tip of the flow field S can be inserted into the flow field S while being twisted. That is, the tube 24 is a hollow cable, and is a so-called composite cable in which a plurality of flexible cables or tubes C1 to C4 are inserted. In FIG. 1, C1 is a cooling tube, C2 is an optical fiber cable capable of transmitting laser light from the laser oscillation unit 30, and C3 and C4 are power sources and signal cables for the cameras 40 and 41, respectively. These cables or tubes C1 to C4 are inserted into the probe 26 and fixed in the probe 26.
In this way, the flexible tube 24 can be used because a plurality of cameras 40 and 41 and a laser beam irradiation unit 28 described later are accommodated and fixed toward the probe 26, and the main body unit 22 and the probe 26. This is because the positional relationship is not questioned.

[About the probe]
Next, the probe 26 will be described with reference to FIGS. 1 and 2 to 3 described above.
2 is a front end view of the probe 26 as viewed from the F direction (front end side) in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG. In FIG. 3, in order not to complicate the drawing, a part of the cables C <b> 3 and C <b> 4 is omitted, and hatching indicating a cross section is appropriately omitted.
As shown in FIG. 3, the probe 26 disposed at the tip of the apparatus 20 fixes a plurality of cameras 40 and 41, a laser beam irradiation unit 28, and an optical fiber cable C2 to a housing 29. Since the relative positional relationship with each other is determined in advance, it is not necessary to adjust the position using calibration during use.

  As shown in FIG. 1, the housing 29 has a substantially rectangular outer shape as a whole, and is formed so that the four wall surfaces 29 </ b> A to 29 </ b> D are along the fluid flow direction FL. Thereby, the influence which wall surface 29A-29D of the housing | casing 29 has on the flow FL can be suppressed to the minimum. Note that the outer shape of the housing 29 of the present invention is not limited to a rectangular shape, but at this time, other shapes in which as many wall surfaces as possible follow the fluid flow FL (for example, a cylindrical shape, a triangular prism shape, or the like). ) Is preferred.

  The housing 29 accommodates and fixes the cameras 40 and 41, and between the reflecting mirrors 12 and 13 described later and the space to be imaged (that is, the space in which the laser sheet light SP is formed) and the laser light irradiation. A transparent or translucent window portion 15 is disposed between the portion 28 and the imaged space so as to constitute a part of the wall surface 29A. Thereby, the laser beam LB1 can be irradiated from the laser beam irradiation unit 28, and the laser sheet beam SP can be formed outside. Then, the cameras 40 and 41 accommodated in the sealed space AC (see FIG. 3) of the probe 26 can capture the scattered light of the outer laser sheet light SP via the reflecting mirrors 12 and 13. In addition, the window part 15 of this embodiment is one piece, and is arrange | positioned in all the center area | regions except the substantially peripheral part of wall surface 29A.

As the cameras 40 and 41, a digital type COMS camera, a CCD camera, or the like can be used, and images scattered light hitting the particles of the laser sheet light SP. In the figure, two cameras 40 and 41 are arranged in the same direction Z as the fluid flow FL, and are fixed to the probe 26 through the reflecting mirrors 12 and 13 so that imaging with an angular difference is possible. ing.
In the cameras 40 and 41 shown in FIG. 3, the imaging lenses 42 and 43 and the body portions 45 and 46 are separated, and the light collected by the imaging lenses 42 and 43 is imaged on the body portions 45 and 46. It has an image sensor 52 such as a CCD sensor that converts it into an electrical signal, and a substrate 53 on which the image sensor 52 and a capacitor are mounted. The cameras 40 and 41 have a so-called Scheimpflug function, and the imaging lenses 42 and 43 are fixed to the probe 26, whereas the body portions 45 and 46 are in the R direction in FIG. In this way, the optical axis of the imaging lenses 42 and 43 and the optical axis of the imaging element 52 can be tilted. Therefore, even with the laser sheet light SP having a predetermined length in the irradiation direction X, the cameras 40 and 41 can be focused.

The laser beam irradiation unit 28 irradiates the emitted light LB2 from the optical fiber cable C2 as a sheet-like laser sheet light SP, and a sheet light forming unit 28a which is an optical system for generating the laser sheet light SP; The bending optical unit 28b for bending the laser light from the sheet light forming unit 28a and irradiating the laser beam LB1 toward the imaging space. The sheet light forming part 28a and the bending optical part 28b are arranged along the direction Z in which the two cameras 40 and 41 are arranged.
Specifically, the sheet light forming unit 28a has an optical system lens 60 made of, for example, a convex cylindrical lens that converges the emitted light LB2 from the optical fiber cable C2 inserted into the housing 29 only in the XZ plane direction in the figure. ing.
The bending optical unit 28b has an irradiation direction changing unit 66 for changing the irradiation direction. The irradiation direction changing unit 66 can use a prism, a cube mirror, or the like for changing the direction Z of the laser light from the optical system lens 60. In this embodiment, a right-angle prism that bends the laser light by 90 degrees is used. Yes.

  In this regard, the two cameras 40 and 41 are arranged along the out-of-plane direction Z of the laser sheet light SP orthogonal to the direction X in which the laser light LB1 is irradiated from the laser light irradiation unit 28. For this reason, by arranging the cameras 40 and 41 having the largest outer shape among the probes 26, the probe 26 is in a direction orthogonal to the arrangement direction Z of the cameras 40 and 41 (that is, the direction in which the laser beam LB1 is irradiated). ) The dimension D of X can be reduced.

The cameras 40 and 41 are arranged so that the imaging lenses 42 and 43 face the opposite side to the laser sheet light SP side with the irradiation direction X of the laser light LB1 as the center. The laser sheet light SP is imaged through the plate-like reflecting mirrors 12 and 13 which are the front and fixed to the probe 26. Accordingly, the probe 26 is arranged in the arrangement direction Z of the cameras 40 and 41 by the amount that the body portions 45 and 46 can be moved to the laser beam LB1 side without substantially changing the fixing positions of the imaging lenses 42 and 43 of the cameras 40 and 41. The dimension W can be reduced.
That is, since it is preferable to take an image with a large angle with respect to the laser sheet light SP in order to accurately grasp the amount of movement of the particles, the center CN of the laser sheet light SP (the convergence point of the laser light in the Z direction). And the imaging directions of the cameras 40 and 41 cannot be reduced, and the body portions 45 and 46 are swung to the laser beam LB1 side while maintaining the different intersection angles θ1 and θ2. .
In this way, the probe 26 can be reduced in both the dimension D and the dimension W.

  In the present embodiment, the reflecting mirrors 12 and 13 have predetermined inclinations θ3 and θ4 with respect to the irradiation direction X so that the main surfaces thereof face the laser sheet light SP. In the figure, the inclination θ3 of the reflecting mirror 13 closer to the laser beam LB1 is formed larger than the inclination θ4 of the reflecting mirror 12. Thereby, even if the cameras 40 and 41 are shaken more greatly along the Z direction in the figure and an inner passage 72 and a flow rate control valve 80 which will be described later are provided, a situation in which the size D in the irradiation direction X becomes excessive is avoided. ing.

  Further, in the present embodiment, the laser beam irradiation unit 28 and the plurality of cameras 40 and 41 are arranged in this order toward the imaging space in the irradiation direction X of the laser beam LB1 from the probe 26. As a result, the laser sheet light SP that is difficult to form a space that expands in the Y direction in the vicinity of the probe 26 is brought as close to the probe 26 as possible. If the laser sheet light SP can be brought close to the probe 26, even a small flow field S can be dealt with, and further, the imaging direction via the reflecting mirrors 12 and 13 of the cameras 40 and 41 and the laser sheet light SP can be handled. By making the crossing angles θ1 and θ2 large, it is possible to perform accurate measurement.

As described above, the probe 26 that is miniaturized and can be imaged close to the imaging space (ie, the laser sheet light) SP of the flow field S causes the fluid to impinge on the probe 26 and disturb the flow, thereby adversely affecting the measurement. There is a risk of giving.
Therefore, the present apparatus 20 is devised in various ways to prevent this adverse effect. This is illustrated in FIGS. 1 to 3 described above, and further, a horizontal sectional view (cross sectional view in the XZ plane direction) of the distal end surface side of the probe 26. This will be described below with reference to FIG. In FIG. 4, hatching representing a cross section is appropriately omitted so as not to complicate the drawing.

[Regarding configuration for preventing turbulence]
First, as shown in FIGS. 1 and 3, the probe 26 has an opening 70 on the surface that the fluid contacts, and an inner passage for guiding the fluid that has entered the opening 70 away from the imaging space SP. 72. Then, the fluid does not hit the entire distal end surface of the probe 26, and a part thereof enters the opening 70, passes through the inner passage 72, and moves away from the imaging space SP. Therefore, the invasiveness to the flow field of the probe 26 can be reduced by the amount of the fluid that has entered the inner passage 72.

As shown in FIGS. 1 to 3, the opening 70 of the present embodiment is formed on the distal end surface of the probe 26 (the surface on which the fluid first hits in this embodiment), and its peripheral portion (in other words, the distal end surface). A peripheral edge portion 65 has a thin frame shape. As a result, the flow FL of the fluid collides with the thin frame-shaped portion having a small area on the front end surface of the probe 26, and therefore, the turbulent flow generated when the fluid hits the peripheral portion 65 can be reduced.
As shown in the diagram surrounded by the two-dot chain line in FIG. 4, the peripheral portion 65 on the imaging space side has a small thickness on the front end side, and gradually becomes thicker from this front end toward the rear end side (left side in FIG. 4). Has an inclined surface 65a. The peripheral edge 65 is preferably substantially pointed, and more preferably has a single-edged shape in which only the inside of the opening 70 is scraped off. When the peripheral edge portion 65 has such a shape, the flow FL1 hitting the substantially pointed portion of the tip smoothly branches, and one branched flow FL2 smoothly flows inside the opening 70 along the inclined surface 65a. Led. And about the other flow FL3 branched, it goes to the outer side of the opening part 70, However, It becomes easy to flow along the wall surface 29A along the whole flow FL of fluid by the viscosity. In this way, the flow FL1 hitting the peripheral edge portion 65 is slightly disturbed at the time of branching, but the disturbance does not affect the measurement result.

The inner passage 72 shown in FIGS. 1 and 3 is formed along the fluid flow FL, and extends in the direction Z perpendicular to the irradiation direction X of the laser beam LB1 and away from the bending optical portion 28b. . If the inner passage 72 is excessively large, the probe 26 itself becomes large, so that the cross-sectional area is at least smaller than the cross-sectional area of the opening 70 in the XY direction in the figure, and preferably the flow field S is large. In addition, the distance may be determined in consideration of the distance between the probe 26 and the imaging space SP, the fluid velocity, and the like.
In the case of the figure, a housing portion 67 is formed inside the probe 26 to seal the cameras 40 and 41, the laser light irradiation portion 28, and the like, and the wall surface 29B farthest from the housing portion 67 and the imaging space SP of the housing 29 is formed. An inner passage 72 is formed using a space defined by
The opening 70 is formed with a guide wall 67A for guiding the fluid to the inner passage 72 in order to effectively prevent the possibility that a new fluid may not smoothly enter due to the fluid stagnating inside the opening 70. ing. In the case of the figure, the guide wall 67 </ b> A is an inclined wall surface facing the opening 70 of the housing portion 67. That is, since the wall 67A is first contacted by the fluid that has substantially entered the opening 70, the wall 67A is inclined toward the inner passage 72 toward the rear end side (left side in FIG. 3) of the probe 26. I am letting.
In this way, the inner passage 72 is located farthest from the imaging space SP in the irradiation direction X, and has a guide wall (wall surface 67A) that smoothly guides the fluid to the inner passage 72. The fluid can be smoothly flowed into the inner passage 72 while effectively preventing the flow FL from being disturbed on the imaging space SP side in the irradiation direction X.

Next, as a configuration for preventing turbulence, the fluid passing through the inner passage 72 is guided to a place that does not substantially affect the measurement.
That is, as shown in FIG. 3, the apparatus 20 is connected to the probe 26 with a tubular member C6 that is spatially connected to the inner passage 72 and extends in a direction away from the imaging space SP.
The tubular member C6 has one end C6a inserted into the probe 26, and the inserted end C6a also serves as the inner passage 72. The tubular member C6 has flexibility, and is bundled together with the optical fiber cable C2 and the like into the tube 24. The other end C6b is disposed outside the flow field S as shown in FIG. Connected to the main body 22. As a result, as shown in FIGS. 1 and 3, the fluid that has passed through the inner passage 72 can be discharged to the outside of the flow field S via the tubular member C6, thus affecting the imaging space SP. Can be prevented.

  Next, the other end C6b of the tubular member C6 is connected to a suction means 39 such as a fan or a pump provided on the main body 22 side, and the fluid that has entered the opening 70 by the suction means 39 is tubular. Suction is performed through the member C6. Specifically, the suction means 39 has a suction amount that does not affect the required velocity and pressure distribution of the fluid outside the probe 26 in the flow field S, that is, the opening area (when facing the opening 70). Suction is performed so that the flow rate is the same as the flow rate passing through the area of the portion indicated by the parallel diagonal lines in FIG. Thereby, even when the cross-sectional area of the inner passage 72 and the tubular member C6 in the XY direction is smaller than the opening area of the opening 70 (cross-sectional area in the XY direction), the fluid is passed through the inner passage 72 and the tubular member. By actively leading to C6, the invasiveness of the probe 26 to the flow field S can be effectively prevented.

In this regard, the suction amount of the suction means 39 may be determined in advance by calculation or test, but the fluid flow in the flow field S such as the engine room may be complicated. For this reason, it is difficult to accurately determine the same flow rate as the flow rate that passes through the opening area (the area indicated by the parallel diagonal lines in FIG. 2) when the opening 70 is viewed directly. Therefore, as shown in FIG. 4, based on the measurement results of the pressure sensors 75 and 76 provided in the opening 70, the pressure on the inner surface 70A side and the pressure on the outer surface 70B side in the opening 70 are equivalent. The suction volume is controlled.
As shown in FIG. 1, it is preferable that the suction amount can be controlled in real time even if there is a predetermined distance between the suction means 39 and the opening 70. The flow rate is controlled by a flow rate control valve 80 disposed between the opening 70 and the suction means 39, preferably in the inner passage 72, as shown in FIGS. As the flow rate control valve 80, for example, a known valve that adjusts the flow path using a gate valve, a globe valve, a ball valve, or a butterfly valve can be used. The flow control valve 80 is connected to the valve drive circuit unit 37 shown in FIG. 1 and is driven by a signal from the valve drive circuit unit 37.

Specifically, as shown in FIGS. 3 and 4, a hole formed in the inner surface 70 </ b> A is formed in the peripheral edge 65 of the opening 70 (in the case, a position about 10 mm rearward from the end surface of the opening 70). The inner pressure sensor 76 exposed toward the inner surface 70A and the outer pressure sensor 75 exposed toward the outer surface 70B are embedded in a hole formed in the outer surface 70B. The inner pressure sensor 76 simultaneously measures the negative pressure generated according to the flow FL4 on the inner surface 70A side, and the outer pressure sensor 75 simultaneously measures the negative pressure generated according to the flow FL5 on the outer surface 70B side.
As these inner and outer pressure sensors 75 and 76, for example, small known pressure sensors using a crystal vibrating piece or a diaphragm can be used, and preferably have the same specifications and are arranged to face each other. Is preferred.
Since the inner and outer pressure sensors 75 and 76 are provided, the wall thickness D2 of the peripheral edge 65 increases. Therefore, the inner and outer pressure sensors 75 and 76 are the most from the imaged space SP so that even if the flow that hits the thickness D2 portion is disturbed, it does not affect the fluid state of the imaged space. It has a double-edged shape that is spaced apart and scraped off so that the tip of the peripheral edge portion 65 is tapered.

Then, the measurement result of the inner pressure sensor 76 is amplified through the signal line C5a and the measurement result of the outer pressure sensor 75 is amplified through the signal line C5b, and then transmitted to the determination unit 38 in FIG. 1 as signals G1 and G2.
1 compares the measured value of the inner pressure sensor with the measured value of the outer pressure sensor to determine the difference between the two values, and transmits the difference as a signal G3 to the connected computer 34. To do. The computer 34 transmits a flow rate setting signal G4 to the valve drive circuit unit 37 so that the difference becomes zero, and the valve drive circuit unit 37 drives the flow rate control valve 80 of FIG. 4 based on the signal G4. It has become.

  In addition, the sensor of the same specification is used for the inner side pressure sensor 76 and the outer side pressure sensor 75 shown in FIG. 4, and the flow control valve 80 is controlled so that both measured values become equal. However, the present invention is not limited to such an embodiment. For example, the specifications of the inner pressure sensor 76 and the outer pressure sensor 75 are different from each other, and the measured value of the inner pressure sensor 76 and the outer pressure sensor are considered in consideration of the specification difference. The flow control valve 80 may be controlled so that the measured value of 75 has a certain ratio.

Further, in this embodiment, two of the inner pressure sensor 76 and the outer pressure sensor 75 are used, but two pressure sensors of the present invention are not necessarily required. For example, the inner pressure sensor 76 is surrounded by a one-dot chain line in FIG. As shown in FIG. 5 which is a modification of the pressure sensor corresponding to the figure, one pressure sensor 82 may be used.
In FIG. 5, a through hole 85 connecting the inner surface 70 </ b> A side and the outer surface 70 </ b> B side is formed in the peripheral edge portion 65 of the opening, and one pressure sensor 82 is disposed in the through hole 85. . This pressure sensor 82 has a diaphragm 86 facing the inner surface 70A side and a diaphragm 87 facing the outer surface 70B side, and electrodes 88 are provided on the front and back surfaces in a space S1 sealed by these two diaphragms 86, 87. A piezoelectric element 90 is accommodated. With such a configuration, as shown in FIG. 6, for example, when the outer flow FL5 is stronger than the inner flow FL4, the negative pressure on the outer surface 70B side of the through-hole 85 increases, resulting in piezoelectricity. The element 90 will bend outward. Therefore, since the voltage changes according to the amount of deflection, the flow rate of the flow rate control valve 80 in FIG. 4 may be controlled with reference to a predetermined data table based on the change amount.

The present apparatus 20 is configured as described above, and the probe 26 has an opening 70 so as to leave only the peripheral edge portion 65 in the form of a thin frame on the front end surface where the fluid hits, and enters the opening 70. An inner passage 72 that guides the fluid away from the imaging space SP is provided. Further, the inner passage 72 is spatially connected to the tubular member C6, and the other end of the tubular member C6 is located away from the flow field S. As a result, most of the fluid directed toward the distal end surface enters the opening 70 and leaves the imaging space SP via the inner passage 72 and the tubular member C6. At this time, since suction is performed by the suction means 39 in accordance with the flow rate of the fluid that has entered the opening 70, it has entered the opening 70 even if the inner diameter of the inner passage 72 and the tubular member C6 is small. The fluid can be discharged out of the flow field S as it is.
FIG. 7 is a diagram in which the probe 26 according to such an embodiment is placed on the flow field S and the fluid state (flow velocity and direction) around the probe 26 is measured. As can be seen by comparing FIG. 7 with FIG. 8 in which the fluid state around the conventional probe placed in the flow field is measured, this apparatus 20 has at least a turbulent flow that affects the imaged space. I couldn't see it.

By the way, this invention is not limited to the said embodiment, A various modified example is employable.
For example, the fluid measuring device is a two-dimensional two component that measures a two-dimensional velocity or the like from the amount of displacement of particles in the surface direction of laser sheet light formed in the imaging space, or a columnar shape in the imaging space. Multi-section 2D3C (2 dimensional 3 components) may be obtained by forming a laser beam and using two or more light field cameras to shoot a plurality of focal plane images having different focal lengths to form a volume PIV by multi-section stereo PIV. .
Moreover, in the said embodiment, although both the some cameras 40 and 41 and the laser beam irradiation part 28 are accommodated in the probe 26, the laser beam irradiation part 28 is with the probe 26 which fixed the cameras 40 and 41. You may make it the structure fixed to another probe.
Further, the number of cameras accommodated in the probe 26 is not limited to two, and may be one or three or more.
Moreover, the tubular member C6 shown in FIG. 3 is not necessarily required, and fluid may be sucked through the tube 24 of FIG. 1 in which the tubular member C6 is not accommodated. In this case, for example, the tube 24 shown in FIG. 1 and the casing of the main body portion 22 are connected, and a fan attached to the casing is driven to make the inside of the casing have a negative pressure. The fluid in 72 may be aspirated.
Moreover, although the suction means 39 of the said embodiment is arrange | positioned at the main-body part 22, this invention is not restricted to this, For example, you may arrange | position in the probe 26 and the middle of the tube 24. FIG.

  DESCRIPTION OF SYMBOLS 12,13 ... Reflection mirror, 20 ... Fluid measuring apparatus, 26 ... Probe, 28 ... Laser beam irradiation part, 30 ... Laser oscillation part, 39 ... Suction means, 40, 41 ... Camera, 70 ... Opening, 72 ... Inner passage, 75 ... Outer pressure sensor, 76 ... Inner pressure sensor, 80 ... Flow control valve, S ... Flow field, LB1 ... Laser beam, SP ... Laser sheet beam (imaged space), C2 ... Optical fiber cable, C6 ... Tube-shaped member

Claims (5)

A laser and a laser beam irradiation unit configured to irradiate a laser beam to an imaging space of a flow field imaged by the camera, and an image obtained by imaging the fluid in the imaging space A fluid measurement device that measures flow velocity, pressure distribution, etc.
At least the camera is fixed to a probe arranged in the flow field,
The probe has an opening on a surface where the fluid hits, and an inner passage for guiding the fluid that has entered the opening in a direction away from the imaging space,
A fluid measuring device, comprising: suction means for sucking the fluid that has entered the opening.   Based on the measurement result of the pressure sensor provided in the opening, the amount of suction is controlled so that the pressure on the inner surface side and the pressure on the outer surface side in the opening are equivalent. The fluid measuring device according to claim 1.   The fluid measuring device according to claim 2, wherein a flow rate control valve for controlling the amount of suction is provided between the opening and the suction means. The probe is connected to a tube-like member that is spatially connected to the inner passage and can be extended in a direction away from the imaging space.
The fluid measuring device according to any one of claims 1 to 3, wherein the suction means sucks the fluid that has entered the opening through the tubular member.   5. The opening according to claim 1, wherein a peripheral edge of the opening has a thin frame shape, and a guide wall for guiding the fluid to the inner passage is formed inside. Fluid measuring device.