WO2019054006A1

WO2019054006A1 - Smoke generation device and wind tunnel test device provided with same

Info

Publication number: WO2019054006A1
Application number: PCT/JP2018/024431
Authority: WO
Inventors: 宏典竹澤
Original assignee: ＴｏｙｏＴｉｒｅ株式会社
Priority date: 2017-09-15
Filing date: 2018-06-27
Publication date: 2019-03-21
Also published as: JP2019052979A; JP6865140B2

Abstract

This smoke generation device 5 provided in a wind tunnel test device 1 is provided with a fine metal wire 21 and an electrical energization device 22 for electrically energizing the fine metal wire 21. The fine metal wire 21 is provided with: loop sections 21a; and twisted sections 21b which are provided on the base ends of the loop sections 21a and with which the fine metal wire is in contact. A smoke-emission material 23 which generates heat by being heated is held inside each of the loop sections 21a.

Description

Smoke generating device and wind tunnel test device comprising the same

The present invention relates to a smoke generating device and a wind tunnel test device including the same.

The smoke wire method is known as one of the methods of visualizing air flow with a wind tunnel test device (see, for example, Patent Document 1). In the conventional smoke wire method, a liquid fuming material such as liquid paraffin is applied to the surface of a metal wire stretched in an air stream, and the smoke generating material is heated to generate smoke by heat generation of the metal wire by energization. . The smoke visualizes the air flow.

Unexamined-Japanese-Patent No. 5-264397 gazette

In the conventional smoke wire method, the smoke producing material is applied to the metal wire, so the amount of the smoke producing material is small and the smoke generation time is short. In addition, since the smoke is continuously generated from the fuming material applied to the metal wire, the streamlines of the air flow can be visualized, but it is difficult to obtain information on the flow velocity of the air flow.

An object of the present invention is to provide a smoke generating apparatus capable of extending smoke generation time and obtaining information on the flow velocity of an air flow, and a wind tunnel test apparatus including the same.

A first aspect of the present invention comprises a metal wire and an energization device for energizing the metal wire, wherein the metal wire is provided at a loop portion and at a proximal end of the loop portion, and the metal wire is A smoke generating apparatus is provided, comprising: contact parts that contact each other, wherein a fuming material that generates heat due to temperature rise is held in the loop part.

The metal wire energized by the energizing device generates heat, which generates smoke from the fuming material. The fuming material is not applied to the surface of the metal wire, but is held in the loop. By holding the metal wire in the loop portion rather than applying it to the surface of the metal wire, it is possible to increase the amount of the fuming material to be smoked. As a result, the smoke generation time can be extended.

The smoke is not continuously and continuously generated from the fuming material held in the loop portion, but the intermittent or discontinuous dot-like smoke is emitted from the fuming material held in the loop portion at short time intervals. Occur. Therefore, not only can the streamlines of the air flow be visualized, it is possible to obtain information on the velocity of the air flow.

In the conventional smoke wire method of applying a fuming liquid material to the surface of a metal wire, it is difficult to control the shape of the generated smoke and to control at which position of the metal wire the smoke is generated. On the other hand, in the smoke generating device according to the present invention, smoke is generated only from the fuming material held in the loop portion, so control of the shape of the generated smoke and generation of smoke at any position of the metal wire Control is easy.

In the conventional smoke wire method of applying the fuming liquid material to the surface of the metal wire, when the flow velocity of the air flow is high, the fuming liquid material is easily blown away from the metal wire by the air flow. On the other hand, in the smoke generating device according to the present invention, the fuming material is not simply applied to the surface of the metal wire, but held in the loop portion. Therefore, even if the flow rate is relatively high, the fuming material is not blown off from the metal wire by the air flow, and the flow rate of the air flow can be used even if it is about 5 m / min.

The smoke generating material is obtained by adding a viscosity imparting material to a smoke generating liquid material which smokes when the temperature rises.

The fuming liquid material is, for example, liquid paraffin.

The tackifying material is, for example, a powder material.

The powder material is, for example, talc or boron nitride.

The viscosity of the fuming material is preferably 2 Pa · s or more and 12 Pa · s or less.

The contact portion is a twist portion provided on the metal wire at the proximal end of the loop portion.

According to a second aspect of the present invention, there is provided a wind tunnel in which an observation target is disposed, a blower for sending air into the wind tunnel to generate an air flow in the wind tunnel, and a metal wire disposed in the wind tunnel. An energization device for energizing the metal wire, wherein the metal wire comprises a loop portion and a contact portion provided at a base end of the loop portion and in which the metal wires are in contact with each other; Further, the present invention provides a wind tunnel test apparatus in which a fugitive material that generates heat by heating is held.

The contact portion is located downstream of the air flow with respect to the loop portion.

ADVANTAGE OF THE INVENTION According to the smoke generating apparatus which concerns on this invention, and a wind tunnel test apparatus provided with the same, smoke generation time can be extended and the information regarding the flow velocity of an airflow can be obtained.

1 is a schematic cross-sectional view showing a tire evaluation device according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view along the line II-II in FIG. The enlarged view of the III section of FIG. The expanded sectional view along the IV-IV line of FIG. The schematic diagram for demonstrating formation of a loop part. The conceptual diagram for demonstrating movement of a dot-like smoke. The typical sectional view similar to Drawing 2 showing the modification of the tire evaluation system concerning a 1st embodiment. Typical sectional drawing which shows the tire evaluation apparatus which concerns on 2nd Embodiment of this invention. FIG. 9 is a schematic cross-sectional view taken along line IX-IX in FIG. The typical sectional view similar to Drawing 9 showing the modification of the tire evaluation system concerning a 1st embodiment.

First Embodiment
1 and 2, a tire evaluation device (wind tunnel test device) 1 according to a first embodiment of the present invention includes a wind tunnel 2, a blower 3, a rotating device (holding device) 4, a smoke generating device 5, and a video. A camera (shooting device) 6 and a laser light generator (illumination device) 7 are provided.

The wind tunnel 2 in the present embodiment includes a bottom wall 2a, a top wall 2b, and a pair of side walls 2c, and the internal space 8 of the wind tunnel 2 extends in the horizontal direction (X direction in the figure).

In the present embodiment, the blower 3 is disposed on one end side (right end side in FIG. 1) of the wind tunnel 2 and feeds air into the internal space 8, and the other end side of the wind tunnel 2 (left end side in FIG. (Direction of air flow is shown by arrow F in FIG. 1). An air blower may be disposed on the other end side of the wind tunnel 2, and air in the internal space 7 may be sucked to generate an air flow in the direction indicated by the arrow F.

The rotating device 4 has a base portion 4a located outside the wind tunnel 2 and a casing 4b extending from the base 4a in the vertical direction (Z direction in the figure) and entering the internal space 8 of the wind tunnel 2 via the bottom wall 2a. And At the upper end side of the casing 4b located in the internal space 8, a drive shaft 4c is provided which rotates around an axis AX extending horizontally in the width direction (Y direction) of the wind tunnel 2. The tire 11 to be observed is mounted on the wheel 12. The wheel 12 is attached to the drive shaft 4c. That is, the tire 11 is held in the internal space of the wind tunnel 2 by being fixed to the drive shaft 4 c of the rotation device 4. The base 4a is provided with a motor 4d. The rotation of the output shaft of the motor 4d is transmitted to the drive shaft 4c via a transmission mechanism (not shown) incorporated in the casing 4b. Accordingly, the tire 11 rotates around the axis AX together with the drive shaft 4c in the internal space 8 of the wind tunnel 2 (see arrows R1 and R2 in FIG. 1).

In the present embodiment, the smoke generating device 5 is provided with a single thin metal wire 21 stretched in the internal space 8 of the wind tunnel 2 and an energization device 22 for energizing the thin metal wire 21.

The metal thin wire 21 in the present embodiment is stretched in the internal space 8 so as to extend linearly in the vertical direction (in the Z direction), the upper end thereof is located on the top wall 2 b side of the wind tunnel 2, and the lower end is the wind tunnel 2. It is located on the bottom wall 2a side. In addition, the thin metal wire 21 is stretched upstream of the air flow than the tire 11 held by the rotating device 4. The metal thin wires 21 are provided with a plurality of loop portions 21a at intervals. In each of the loop portions 21a, a fuming material 23 that generates heat due to temperature rise is held. The

terminal parts

24A and 24B provided in the both ends of the metal fine wire 21 are electrically connected to the electricity supply apparatus 22 through

conducting wire

25A, 25B. The energization device 22 in the present embodiment applies a DC voltage to the thin metal wire 21. The fine metal wires 21 energized by the energizing device 22 generate resistance heat, and the resistance heat generates smoke from the fuming material 23 held in the individual loop portions 21 a. The fine metal wires 21 and the fuming material 23 will be described in detail later.

The video camera 6 captures at least an area around the tire 11 in the internal space 8 of the wind tunnel 2. That is, the video camera 6 captures an air flow around the tire 11 visualized by the smoke generated by the fuming material 23. The streamlines of the air flow visualized by the smoke can be photographed by the video camera 6 and the air flow around the tire 11 can be evaluated by the photographed moving image. The irradiation direction of the laser light generated by the laser light generator 7 is directed to the periphery of the tire 11. By irradiating the smoke around the tire 11 with laser light, the video camera 6 can capture the air flow around the tire 11 visualized by the smoke more clearly.

Hereinafter, the fine metal wires 21 and the fuming material 23 will be described in detail.

In the present embodiment, the thin metal wire 21 is a nichrome wire. The thin metal wire 21 may be a single wire or a stranded wire. 1 mm or more and 20 mm or less are preferable, and, as for the diameter of the metal

fine wire

21, 5 mm or more and 10 mm or less are more preferable.

Referring to FIGS. 3 to 5, the loop portion 21a in the present embodiment is formed by winding the thin metal wire 21 and then twisting the thin metal wire 21 only once at the base end of the wound portion. . That is, at the base end of the loop portion 21a, a twisted portion (contact portion) 21b in which the thin metal wires 21 contact with each other is formed.

The loop portion 21a in the present embodiment is elliptical. The loop portion 21a may be circular or polygonal such as triangular. In addition, the loop portion 21a may be in a coil shape in which the metal thin wire 21 is wound a plurality of times. The circumferential length of the loop portion 21a is preferably set such that the diameter of the loop portion 21a when circularly deformed is 1 mm or more and 20 mm or less, preferably 5 mm or more and 10 mm or less.

The smoke generating material 23 in this embodiment is obtained by mixing liquid paraffin as the smoke generating liquid material with talc, which is an example of a powder material, as a viscosity-applying material, and adding viscosity so as not to fall off from the loop portion 21a. It is. The fuming liquid material is not limited to liquid paraffin, and may be a material having similar characteristics. The powder material as the tackifying material is not limited to talc, and for example, powder of boron nitride (BN) can be adopted.

The viscosity of the fuming material is preferably 0.1 Pa · s or more and 100 Pa · s or less, and more preferably 2 Pa · s or more and 12 Pa · s or less. When the viscosity of the fuming liquid material is 0.1 Pa · s or more and 100 Pa · s or less, in order to obtain the fuming material having a viscosity of 2 Pa · s or more and 12 Pa · s or less, the powder material as a viscosity imparting material The particle diameter is preferably 2 μm or more and 75 μm or less.

When the metal fine wire 21 is energized by the energization device 22, the smoke generating material 23 held in the loop portion 21a is heated by the heat generation of the metal fine wire 21, and the smoke forming liquid material contained in the smoke forming material 23 is vaporized and smoke is generated. Occur. At this time, smoke is not continuously and continuously generated from the fuming material 23 held in the loop portion 21a, but intermittently or not at short time intervals from the fuming material 23 held in the loop portion 21a. Discontinuous dot-like smoke is generated. Reference numeral 26 in FIG. 3 indicates a dot-like smoke lump (hereinafter simply referred to as "dot 26"). The time interval at which the dots 26 occur is about 40 msec.

The fuming material 23 is not applied to the surface of the thin metal wire 21 but is held in a lump in the loop portion 21a. Therefore, the amount of the fuming material 23 used for smoking can be increased. As a result, it is possible to extend the smoke generation time, and hence the time when the stream of air stream visualized by the smoke can be photographed by the video camera 6.

In the conventional smoke wire method of applying a fuming liquid material to the surface of a metal fine wire, it is difficult to control the shape of the generated smoke and to control at which position of the metal fine wire the smoke is generated. On the other hand, in the smoke generating device 5 in the present embodiment, smoke is generated only from the fuming material 23 held in the loop portion 21a, so control of the shape of the generated smoke and which position of the metal thin wire 21 Control of smoke generation is easy.

As described above, the reason why the smoke dots 26 are intermittently generated from the fuming material 23 held in the loop portion 21a is presumed as follows. The electrical resistance is the largest at the portion of the twisted portion 21b where the thin metal wires 21 are in contact with each other around the loop portion 21a. Therefore, when the thin metal wire 21 is energized by the energizing device 22, the heat of resistance heat is generated at the twisted portion 21b. It is most noticeable. Therefore, the fuming liquid material (liquid paraffin in the present embodiment, as described above) contained in the fuming material 23 is vaporized in the part closest to the twisting part 21b in the fuming material 23 in the loop part 21a. Smoke is generated. At the time of smoke generation, that is, at the time of vaporization of the fuming liquid material, the temperature of the twisting portion 21b is instantaneously lowered by the heat of vaporization, and as a result, the generation of smoke (vaporization of the fuming liquid material) is instantaneously stopped. However, due to the resistance heat, the temperature of the twisting portion 21b is instantaneously raised again, and the fuming liquid material is vaporized to generate smoke again. As described above, it is surmised that the dot 26 of the smoke is intermittently generated from the fuming material 23 by repeating the instantaneous decrease and increase of the temperature of the twist portion 21 b.

The intermittent generation of the smoke dots 26 from the fuming material 23 continues until the fuming liquid material contained in the fuming material 23 held in the loop portion 21a is consumed. The smoke generation time from the fuming material 23 depends on the amount of the fuming material 23 held in the loop portion 21a, and hence the size of the loop portion 21a, and is about 10 seconds to 600 seconds or less.

The smoke generation material 23 held in the loop portion 21a does not continuously generate smoke continuously, but intermittently or discontinuously at short time intervals from the smoke material 23 held in the loop portion 21a Smoke dots 26 occur. Therefore, not only can the streamlines of the air flow be visualized, it is possible to obtain information on the velocity of the air flow. For example, FIG. 6 shows a plurality of dots 26 in an image of a certain time "T seconds" taken by the video camera 6 and 1 / f seconds after the time "T seconds" (f is the frame rate of the video camera (fps) And a plurality of dots 26 in the "T + 1 / f sec" image of. By comparing the positions in the X direction of the individual dots 26 in these two images, it is possible to obtain information on the velocity in the X direction of the air flow. That is, by taking pictures with the video camera 6, not only information on the streamline of the air flow can be obtained, but also information on the speed of the air flow (for example, the velocity distribution of the air flow around the tire 11) can be obtained. The tire 11 can be evaluated with high accuracy.

As described above, it is surmised that the fuming liquid material contained in the fuming material 23 in the loop portion 21a is vaporized by the resistance heat generated in the twist portion 21b, and the smoke dot 26 is generated. Therefore, in order to stably generate the smoke dots 26, it is preferable that the air flow is not directly blown to the twisting portion 21b. In the present embodiment, as shown most clearly in FIGS. 3 and 4, the twisting portion 21b is positioned downstream of the air flow with respect to the loop portion 21a, whereby from the fuming material 23 in the loop portion 21a. The generation of smoke dots 26 is stabilized.

In the conventional smoke wire method of applying the fuming liquid material to the surface of the metal thin wire, when the flow velocity of the air flow is high, the fuming liquid material is easily blown away from the metal thin wire by the air flow. On the other hand, in the smoke generating device 5 in the present embodiment, the fuming material 23 is not simply applied to the surface of the metal wire, but held in the loop portion 21a. Therefore, even if the air flow is at a relatively high flow rate, the fuming material 23 is not blown away from the metal wire by the air flow. Therefore, the smoke generating device 5 in the present embodiment can be used even if the flow velocity of the air flow is about 5 m / min. In order to avoid the dropout of the fuming material 23 from the loop portion 21 a, it is preferable that the air flow is not directly blown to the fuming material 23. Therefore, in the present embodiment, as shown in FIG. 4, the surface S formed by the loop portion 21a is parallel to the direction of the air flow.

FIG. 7 shows a modification of the first embodiment. In this modification, three metal thin wires 21 are stretched in the internal space 8 at intervals in the width direction (Y direction) of the wind tunnel 2 so as to extend linearly in the vertical direction (Z direction). The number of metal wires 21 stretched in the internal space 8 so as to extend linearly in the vertical direction may be two or four or more. Further, one or more metal wires 21 may be stretched in the internal space 8 so as to extend linearly in the width direction (Y direction) of the wind tunnel 2. Furthermore, one or more metal wires 21 are inclined with respect to at least one of the vertical direction (Z direction), the width direction of the wind tunnel 2 (Y direction), and the longitudinal direction of the wind tunnel 2 (Z direction) It may be stretched in the inner space 8 so as to extend linearly.

Second Embodiment
Referring to FIGS. 8 and 9, in the tire evaluation device (wind tunnel test device) 1 according to the second embodiment of the present invention, the single thin metal wire 21 provided in the smoke generating device 5 is the drive shaft 4c of the rotating device 4. Are arranged to surround the tread portion of the tire 11 held by the tire at an interval. By arranging the thin metal wires 21 in this manner, the shape and speed of the air flow around the tire 11 can be evaluated in more detail.

Other configurations and operations of the second embodiment are the same as those of the first embodiment.

FIG. 10 shows a modification of the second embodiment. In this modification, three thin metal wires 21 are disposed so as to surround the periphery of the tire 11. The number of thin metal wires 21 arranged to surround the periphery of the tire 11 may be two or four or more.

Although the present invention has been described by taking a tire test apparatus as an example, the present invention can be applied to a wind tunnel test apparatus for observing objects other than tires.

1 Tire evaluation system (wind tunnel test system)
2 wind tunnel 2a bottom wall 2b top wall 2c side wall 3 blower 4 rotating device 4a base 4b casing 4c drive shaft 4d motor 5 smoke generator 6 video camera (shooting device)
7 Laser beam generator (illuminator)
8 Internal space 11 Tire 12 Wheel 21 Fine metal wire (metal wire)
21a loop portion 21b twist portion (contact portion)
22 energization device 23 fuming

material

24A,

24B terminal

25A, 25B conductor 26 dots

Claims

With metal wire,
An energizing device for energizing the metal wire;
The metal wire is
The loop section,
And a contact portion provided at the proximal end of the loop portion, the metal wires being in contact with each other,
The smoke generating device, wherein a fuming material that generates heat due to a temperature rise is held in the loop portion.
The smoke generating device according to claim 1, wherein the smoke generating material is a smoke generating liquid material which smokes when the temperature is raised, and a viscosity giving material is added.
The smoke generating apparatus according to claim 2, wherein the fuming liquid material is liquid paraffin.
A smoke generating device according to any of the preceding claims, wherein the tackifying material is a powder material.
5. A smoke generating device according to claim 4, wherein the powder material is talc or boron nitride.
The smoke generating device according to any one of claims 1 to 4, wherein the viscosity of the fuming material is 2 Pa · s or more and 12 Pa · s or less.
The smoke generating device according to any one of claims 1 to 6, wherein the contact portion is a twist portion provided to the metal wire at the proximal end of the loop portion.
A wind tunnel where the observation target is placed,
A blower for feeding air into the wind tunnel to generate an air flow in the wind tunnel;
A metal wire disposed in the wind tunnel,
An energizing device for energizing the metal wire;
The metal wire is
The loop section,
And a contact portion provided at the proximal end of the loop portion, the metal wires being in contact with each other,
A wind tunnel test device, wherein a fuming material that generates heat due to temperature rise is held in the loop portion.
The wind tunnel test device according to claim 8, wherein the contact portion is located downstream of the air flow with respect to the loop portion.