JP2012112757A - Seeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil droplets generated from tracer particles that are injected with air from a seeder and are captured on the inner surface of a hood from being dispersed into a wind tunnel from an opening of the hood.SOLUTION: When tracer particles are injected into a hood 12 together with air from a nozzle 16 of a seeder 13, many of the tracer particles having large diameters are captured on the inner surface of the hood 12, and many of the tracer particles having small diameters flow into a wind tunnel from an opening 12d of the hood 12, minimizing supply of tracer particles having large diameters into the wind tunnel and preventing tracer particles having large diameters from attaching to the walls and the floor of the wind tunnel and being a cause of contamination. Although oil droplets generated from trace particles attached to the inner surface of the hood 12 are pushed by the air flowing in the hood 12 towards the opening 12d, a flange 12f which is bent inward with an obtuse angle formed at the opening 12d captures the oil droplets inside the flange 12f and prevents them from dispersing into the wind tunnel via the opening 12d.

Description

  The present invention relates to a seeding device that includes a hood that guides air and tracer particles ejected from a nozzle of a seeder to deflect a flow path, and supplies the deflected air and tracer particles into an air tunnel from an opening of the hood.

  In an atomizer used in a humidifier that atomizes water or a combustor that atomizes fuel, pressurized liquid is ejected radially outward from the nozzle, and the liquid is arranged to surround the nozzle. Japanese Patent Application Laid-Open No. 2004-151867 discloses that a minute droplet is generated by vertically colliding with an inner peripheral surface of a cylindrical collision body.

Japanese Utility Model Publication No. 63-31715

  By the way, in a wind tunnel experiment, by supplying tracer particles made of minute oil droplets with a diameter of about several μm from the seeding device into the air, and imaging the reflected light by irradiating the tracer particles with a laser beam, A particle image velocity measurement method (PIV: Particle Image Velocimetry) that visualizes an air flow around an object is known.

  When a wind tunnel experiment using the particle image velocimetry is performed, the tracer particles generated by the seeding device flow with the air and adhere to the wall and floor of the wind tunnel, so the adhered tracer particles are removed using a degreasing agent. There was a problem that required a lot of time and cost for the cleaning work.

  It is known that when the diameter of the tracer particle is 4 μm or more, it is easy to adhere to the wall or floor surface of the wind tunnel. If the diameter of the tracer particle can be suppressed to less than 4 μm, the amount of the attached tracer particle is greatly reduced. Cleaning work can be simplified. Therefore, by providing a hood that guides the air and tracer particles ejected from the nozzle of the cedar and deflects the flow path, the tracer particles having a large diameter are captured on the inner surface of the hood, and only the tracer particles having a small diameter are opened in the hood. It is conceivable to supply the wind tunnel from the section.

  However, with this configuration, the oil droplets generated by the tracer particles adhering to the inner surface of the hood are pushed by the air flowing inside the hood and flow toward the opening, so that the oil droplet flows from the opening to the wind tunnel. There is a risk of scattering inside and causing fouling.

  The present invention has been made in view of the above-described circumstances, and prevents oil droplets generated by the tracer particles ejected together with air from the seeder from being captured by the inner surface of the hood from being scattered from the opening of the hood into the wind tunnel. For the purpose.

  In order to achieve the above object, according to the first aspect of the present invention, a hood for guiding the air and tracer particles ejected from the nozzle of the seeder to guide the flow path is provided, and the deflected air and tracer particles are A seeding device for supplying into a wind tunnel from the opening of the hood, wherein a flange bent inwardly at an obtuse angle is formed in the opening of the hood is proposed. .

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the hood includes a collision surface that is inclined with respect to the direction in which the tracer particles are ejected from the nozzle, and the tracer ejected from the nozzle. A seeding device is proposed in which large-diameter tracer particles out of particles collide with the collision surface and are captured, and small-diameter tracer particles are supplied into the wind tunnel from the opening of the hood. .

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, a seeding device is proposed in which an inclination angle of the collision surface is approximately 45 °.

  According to the invention described in claim 4, in addition to the structure of any one of claims 1 to 3, a drain hole for discharging oil droplets of the trapped tracer particles to the lower portion of the hood. A seeding device characterized in that is formed is proposed.

  According to the invention described in claim 5, in addition to the configuration of any one of claims 1 to 4, the opening of the hood is formed only at a position facing the downstream side of the collision surface. A seeding device is proposed which is characterized in that:

  According to the configuration of the first aspect, when the tracer particles are ejected into the hood together with the air from the nozzle of the seeder, most of the tracer particles having a large diameter are trapped on the inner surface of the hood, and many of the tracer particles having a small diameter are formed in the hood opening. The tracer particles with a large diameter are prevented from being supplied into the wind tunnel by flowing out from the section into the wind tunnel, and the tracer particles with a large diameter adhere to the wall surface or floor surface of the wind tunnel and cause fouling. Can be prevented. The oil droplets generated by the tracer particles adhering to the inner surface of the hood flow toward the opening by being pushed by the air flowing inside the hood, and the hood opening has a flange bent inward at an obtuse angle. Since it is formed, it is possible to prevent the oil droplets from being scattered inside the wind tunnel by capturing the oil droplets inside the flange.

  According to the second aspect of the present invention, since the hood has a collision surface that is inclined with respect to the ejection direction of the tracer particles from the nozzle, the large-diameter tracer particles out of the tracer particles ejected from the nozzle collide with the collision surface. Thus, the small-diameter tracer particles are supplied into the wind tunnel from the opening of the hood, so that the large-diameter tracer particles can be more effectively prevented from being supplied into the wind tunnel.

  According to the third aspect of the present invention, since the inclination angle of the collision surface is approximately 45 °, it is possible to efficiently capture large-diameter tracer particles.

  According to the fourth aspect of the present invention, since the drain hole for discharging the oil droplets of the trapped tracer particles is formed in the lower portion of the hood, not only the oil droplets can be prevented from accumulating in the hood. The oil droplets can be collected and reused.

  Further, according to the configuration of claim 5, since the opening of the hood is formed only at a position facing the downstream side of the collision surface, the tracer particles ejected from the nozzle are not captured without colliding with the collision surface. Larger tracer particles can be prevented from being fed directly into the wind tunnel through the hood opening.

The perspective view of a seeding apparatus. (First embodiment) FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. (First embodiment) FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. (First embodiment) Action | operation explanatory drawing of a collision surface. (First embodiment) 5 (A) enlarged view of FIG. 2 and FIG. (First embodiment) The perspective view of a seeding apparatus. (Second Embodiment)

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 to 3, a seeding device 11 for supplying tracer particles obtained by atomizing DOS (lubricating oil-based oil) or a mixture of water and glycerin (hereinafter referred to as oil) into a wind tunnel is a synthetic resin. And a seeder 13 provided on the bottom wall 12a of the hood 12 and ejecting tracer particles together with air.

  The hood 12 includes a hood main body 12b that stands vertically upward from a flat bottom wall 12a. The upper portion of the hood main body 12b is covered with a ceiling wall 12c. The cross section of the hood main body 12b is U-shaped so as to minimize the turbulence of the airflow in the wind tunnel. That is, the hood main body 12b is closed on the upstream side in the air flow direction in the wind tunnel, and the opening 12d is formed on the downstream side in the air flow direction. In the embodiment, the first half portion of the symmetrical airfoil (NACA0025) is adopted as the cross-sectional shape of the hood main body 12b.

  The ceiling wall 12c of the hood 12 is gently curved obliquely upward from the front edge of the hood main body 12b toward the downstream side, and a flat collision surface 12e is formed on the inner surface thereof. The collision surface 12e is inclined at an inclination angle α = 45 ° so that the upstream side is lower and the downstream side is higher than the ejection direction V (vertical direction) of the tracer particles from the seeder 13.

  A flange 12f is formed along the periphery of the opening 12d of the hood 12 by bending the hood main body 12b and the ceiling wall 12c inward. As shown in FIG. 5A, the flange 12f of the hood 12 forms an obtuse angle β with respect to the downstream ends of the hood main body 12b and the ceiling wall 12c, and is curved convexly toward the inside. . Note that the flange is bent at a right angle to the hood main body 12b only at the lower end of the opening 12d, that is, at the portion facing the bottom wall 12a.

  A drain hole 12 g is formed in the upstream portion of the bottom wall 12 a of the hood 12, and the drain hole 12 g is connected to the tank 15 via the oil discharge hose 14.

  The seeder 13 provided in the central portion of the bottom wall 12a of the hood 12 includes two nozzles 16 and 16 whose axis lines L and L intersect each other. Each nozzle 16 is provided with an oil passage 16a formed at the center and an air passage 16b formed so as to surround the oil passage 16a. Oil in the tank 15 is supplied to the oil pump 17 and the oil passage 16a. While being supplied via the oil supply hose 18, air from the air compressor 19 is supplied to the air passage via the air supply hose 20.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  The oil pumped up from the tank 15 by the oil pump 17 is supplied to the oil passages 16a of the nozzles 16 of the seeder 13 via the oil supply hose 18, and at the same time, the air compressed by the air compressor 19 is It is supplied to the air passage 16 b of the nozzle 16. The oil ejected from the tip of the oil passage 16a is atomized by the air ejected from the tip of the air passage 16b and sprayed as tracer particles. At this time, since the two nozzles 16 and 16 are arranged so as to intersect the axes L and L, the tracer particles sprayed from both the nozzles 16 and 16 collide with each other, and the tracer particles having a smaller diameter and And ejected upward along the ejection direction V. In this way, the tracer particles ejected from the seeder 13 include a mixture of particles having a large diameter and particles having a small diameter.

  As shown in FIG. 4, the air jetted upward from the seeder 13 is guided by the collision surface 12e of the hood 12 blocking the upper side thereof, and is deflected by 90 ° toward the downstream side in the air flow direction of the wind tunnel. It flows out into the wind tunnel through the opening 12d. At this time, the tracer particles mixed with the air ejected upward from the seeder 13 also try to deflect toward the downstream side together with the air. However, since the large-diameter tracer particles are difficult to deflect, they collide with the collision surface 12e and have a small diameter. Since the tracer particles are easily deflected, the tracer particles are supplied from the opening 12d into the wind tunnel without colliding with the collision surface 12e.

  The reason is that the inertial force of the tracer particle is proportional to its mass, and its mass is proportional to the cube of the diameter, whereas the aerodynamic force that the tracer particle receives from the air is proportional to its surface area, and its surface area is This is because it is proportional to the square. That is, when the diameter of the tracer particle is doubled, for example, the inertial force is eight times, whereas the aerodynamic force received from the air is only four times, and the straightness is increased and it is difficult to deflect.

  In this way, most of the tracer particles having a diameter of 4 μm or more collide with the collision surface 12e, and only a very small part of the tracer particles having a diameter of less than 4 μm and the tracer particles having a diameter of 4 μm or more are hooded together with the deflected air. The 12 openings 12d are supplied into the air flow in the wind tunnel. Therefore, since most of the tracer particles contained in the air flow in the wind tunnel have a diameter of less than 4 μm, it is difficult to adhere to the wall surface or floor surface of the wind tunnel, and even if it adheres, the amount is small. The time and labor required for the cleaning work can be greatly reduced and the cost can be reduced.

  Tracer particles having a diameter of 4 μm or more colliding with the collision surface 12e of the hood 12 adhere to the collision surface 12e and grow into large oil droplets, and flow down to the bottom wall 12a along the inner surface of the hood main body 12b. From the drain hole 12g provided in the tank 15 through the oil discharge hose 14, it is collected in the tank 15 and reused.

  As shown in FIG. 5A, a part of the oil droplets adhering to the inner surface of the hood main body 12b is caused to flow downstream by the air flow deflected inside the hood main body 12b, and the hood main body 12b. And is captured by a corner 12h sandwiched between the flange 12f. The oil droplets captured by the corner 12h are about to be pushed out toward the edge of the flange 12f by the air flow (see arrow a) flowing along the inner surface of the hood main body 12b. Since the obtuse angle β is formed with respect to the portion 12b and the outer surface of the flange 12f (the surface facing the air flow in the wind tunnel) is curved in a concave shape, the vortex generated on the downstream side of the hood 12 (arrow b) Part of the gas flow (see arrow c) flows along the inner surface of the flange 12f, and the oil droplets captured by the corner 12h are prevented from being pushed out toward the edge of the flange 12f. As a result, the oil droplets trapped in the corner 12h flow down to the bottom wall 12a along the flange 12f and are discharged from the drain hole 12g without scattering into the wind tunnel.

  FIG. 5B shows a case where the hood 12 is not provided with the flange 12 f, and oil drops pushed by the air flow (see arrow a) flowing along the inner surface of the hood main body 12 b are downstream of the hood 12. The vortex (see arrow b) generated on the side is sucked out downstream and scattered in the wind tunnel.

  FIG. 5C shows a case where the flange 12f 'of the hood 12 is bent inward from the hood main body 12b at a right angle. In this case, not only a large amount of oil droplets are trapped in the corner portion 12h ′ sandwiched between the hood main body portion 12b and the flange 12f ′, but also vortices generated on the downstream side of the hood 12 (see arrow b). Since the influence does not reach the captured oil droplets, the oil droplets pushed by the air flow (see arrow a) flowing along the inner surface of the hood main body 12b are scattered in the wind tunnel.

  As indicated by a chain line in FIG. 2, the height of the hood 12 (distance from the seeder 13 to the collision surface 12e) is an appropriate height depending on the ejection speed of the air and the tracer particles from the nozzles 16 and 16 of the seeder 13. Set to

  That is, when the ejection speed of the air and the tracer particles is high, if the height of the hood 12 is too low, not only the tracer particles having a small diameter collide with the collision surface 12e but are captured, but also the collision surface 12e. There is a possibility that the oil droplets of the tracer particles having a large diameter captured by the collision are blown off again by the strong air flow and supplied into the wind tunnel.

  On the other hand, when the jet speed of air and tracer particles is low, if the height of the hood 12 is too high, the inertial force of the tracer particles is weakened by gravity, so even tracer particles having a large diameter can reach the collision surface 12e. There is a possibility that the air will be deflected and supplied into the wind tunnel.

  As described above, according to the present embodiment, among tracer particles having various diameters ejected from the seeder 13, tracer particles having a large diameter are captured and collected by the hood 12, and only tracer particles having a small diameter are selected. Therefore, it is possible to minimize the tracer particles having a large diameter from adhering to the wall surface or floor surface of the wind tunnel.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  The hood 12 of the first embodiment has an opening 12d formed on the entire downstream surface thereof, but the opening 12d of the hood 12 of the second embodiment has an upper portion (on the ceiling wall 12c side). The other portions are covered with a shielding plate 21.

  The reason is that when the opening 12d is formed on the entire downstream surface of the hood 12, the tracer particles ejected from the nozzles 16 and 16 of the seeder 13 are ejected toward the downstream side of the hood main body portion 12b. This is because there is an increased probability that tracer particles having a large diameter do not collide with the inner surface or the collision surface 12e and are directly supplied into the wind tunnel through the opening 12d. In the present embodiment, by providing the shielding plate 21, the tracer particles ejected from the nozzles 16, 16 of the seeder 13 toward the downstream side collide with the shielding plate 21, and the tracer particles having a large diameter are caused by the shielding plate 21. It can be captured and prevented from being supplied into the wind tunnel.

  In the second embodiment, an opening 12i is formed between the lower edge of the shielding plate 21 and the bottom wall 12a. The opening 12i cleans oil droplets adhering to the bottom wall 12a. It is for facilitating maintenance of the seeder 13 and can be omitted. Further, if a flange bent toward the inside of the hood 12 is formed on the upper edge of the shielding plate 21 facing the opening 12d of the hood 12, oil droplets generated by the collision of the tracer particles with the inner surface of the shielding plate 21 are generated. It can be prevented from being pushed by air and flowing upward along the inner surface of the shielding plate 21 and being scattered from the opening 12d into the wind tunnel.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the inclination angle α of the collision surface 12e is set to 45 °, but the angle is not limited to 45 °.

  In the embodiment, the seeder 13 in which the axes L, L of the two nozzles 16 and 16 are crossed is illustrated, but a seeder 13 having any other structure can be adopted.

12 Hood 12d Opening 12e Colliding surface 12f Flange 12g Drain hole 13 Seeder 16 Nozzle V Tracer particle ejection direction α Colliding surface inclination angle β Obtuse angle

Claims (5)

A hood (12) for deflecting the flow path by guiding air and tracer particles ejected from the nozzle (16) of the seeder (13) is provided, and the deflected air and tracer particles are opened in the opening (12d) of the hood (12). A seeding device for supplying air into the wind tunnel,
A seeding device, wherein an opening (12d) of the hood (12) is formed with a flange (12f) bent inwardly at an obtuse angle (β).   The hood (12) has a collision surface (12e) inclined with respect to the ejection direction (V) of the tracer particles from the nozzle (16), and has a large diameter among the tracer particles ejected from the nozzle (16). The tracer particles collide with the collision surface (12e) and are captured, and small-diameter tracer particles are supplied into the wind tunnel from the opening (12d) of the hood (12). The seeding device described.   The seeding device according to claim 2, wherein the inclination angle (α) of the collision surface (12e) is approximately 45 °.   The drain hole (12g) which discharges | emits the oil droplet of the trapped tracer particle | grain is formed in the lower part of the said food | hood (12), The any one of Claims 1-3 characterized by the above-mentioned. Seeding device.   The opening (12d) of the hood (12) is formed only at a position facing the downstream side of the collision surface (12e), according to any one of claims 1 to 4. Seeding device.

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