JP2005249705A - Wind tunnel testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wind tunnel testing device capable of reducing total cost of a construction cost, a facility cost and the like, capable of shortening a term of work, and capable of uniformizing a wind velocity distribution in a diffusing port or a measuring part, by bringing a bottom face of a contraction nozzle into the level same to a floor face of the measuring part, saying in another expression, by adopting an asymmetric nozzle. <P>SOLUTION: The contraction nozzle 2 is symmetric laterally, and a ceiling face 2c is asymmetric to the bottom face 2b. A bottom face 2b side of the contraction nozzle 2 is a low wind flow velocity area of a low flow velocity lower than those in the ceiling face 2c and both side faces 2d, a plurality of lines of slits 5 are provided width-directionally with spacing along a longitudinal direction in the bottom face 2b, and an acceleration flow is blown out diagonally from each of the slits 5 toward the diffusing port 2a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wind tunnel test apparatus for measuring the air resistance of a vehicle body of, for example, an automobile, and more particularly to an asymmetric contraction nozzle.

  In the above-described wind tunnel test apparatus, in order to make the wind speed distribution uniform at the outlet, a so-called symmetrical nozzle which is a symmetric omnidirectional or left-right and up-down symmetric contraction nozzle is used. FIG. 10 shows a conventional general wind tunnel test apparatus 21 having a symmetric nozzle 22, and FIG. 11 shows a wind speed distribution of the symmetric nozzle 22.

  As this type of prior art, a symmetrical nozzle comprising a tapered wall portion and a laval-shaped portion having a throat portion on the downstream side and extending downstream is provided on the wall surface near the throttle outlet of the reduced flow nozzle body. A wind tunnel test apparatus has been proposed (see, for example, Patent Document 1).

In addition, a wind tunnel testing device has been proposed in which the upper and lower surfaces and both left and right surfaces are formed from symmetrical flow-reducing plates, only the upper surface is movable up and down, and the flow-reducing pads are detachably attached to the inner sides of both flow-reducing plates. (For example, see Patent Document 2).
JP-A-8-201216 (paragraph numbers 0005 to 0007 and FIG. 2) JP-A-5-10847 (paragraph number 0006 and FIGS. 1 to 3)

Each of the conventional wind tunnel test apparatuses described above has a symmetric nozzle as a reduced flow nozzle (blow-off nozzle), and thus has the following disadvantages. That is,
The portion of the rectifying cylinder 23 located on the upstream side of the reduced flow nozzle 22 is expanded vertically and horizontally as compared to the outlet 22a, so that it is dug down below the floor surface of the measuring unit 24 on which an automobile or the like is placed. On the contrary, it is necessary to lift the floor surface of the measurement unit 24 upward. Specifically, normally, in order to make the contraction ratio 5 times or more, assuming that the outlet 22a has an opening cross section of 3 m × 3 m in length and width, the bottom surface of the rectifying cylinder 23 is about 3 m from the floor surface of the measuring unit 24. It must be dug down a considerable distance in the longitudinal direction. Therefore, the total cost such as the basic cost for digging and the construction cost is greatly increased, and the construction period is lengthened. On the other hand, when lifting the floor of the measuring unit above the bottom of the rectifying motion, the foundation is raised, the import path for the object to be tested such as an automobile is built to a considerably high position from the ground, or the crane is Or other facilities.

  The present invention has been made in view of the above points. Basically, the bottom surface of the reduced flow nozzle is set to the same level as the floor surface of the measurement unit, in other words, by adopting an asymmetric nozzle, construction costs and equipment costs. The purpose of the present invention is to provide a wind tunnel test apparatus that can reduce the overall cost, shorten the construction period, and make the wind speed distribution at the outlet or the measurement part uniform.

  In order to achieve the above object, a wind tunnel testing apparatus according to the present invention includes an asymmetric contracted flow nozzle (blowing nozzle), and a low speed flow wind speed at which a wind speed generated by the contracted flow nozzle is slower than other surfaces. It is characterized by providing wind speed acceleration means on the area.

  According to the wind tunnel test apparatus having the above-described configuration, when the contracted nozzle is, for example, left-right symmetric and vertically asymmetric and the lower surface is in the low-speed flow velocity region, that is, in the case of claim 2, the lower surface of the contracted nozzle is flat. By adopting a horizontal plane, the vertical position from the bottom surface of the rectifying cylinder to the floor surface of the measuring unit can be made the same level, thereby reducing costs such as construction costs and equipment costs and shortening the construction period. On the other hand, the wind speed on the lower surface of the contracted flow nozzle is slower than in other areas, but since the wind speed flow acceleration means is provided on the lower surface, the wind speed distribution blown out from the outlet by accelerating the wind speed flow with the same means. Can be made uniform throughout.

  In the invention of this claim, the low-speed flow wind velocity area surface is not limited to the lower surface because the upper surface or one of the left and right sides is asymmetrical rather than the lower surface, depending on the terrain where the device is installed and other conditions. This is because the present invention can be applied in some cases.

  According to a second aspect of the present invention, the low-speed flow wind speed area surface is a floor surface, and a symmetric / vertical asymmetric contraction nozzle can be provided.

  The wind tunnel testing apparatus according to claim 2 can be said to be a general configuration in the present invention.

  As described in claim 3, the wind velocity flow acceleration means provides either a blowing flow, a bleed flow (suction flow), or a wall flow in the same direction as the air flow. Or a combination thereof.

  According to the wind tunnel test apparatus of the third aspect, the wind speed flow is accelerated in the low-speed flow wind speed region so that it is equal to the wind speed flow in the other region, faster than the wind flow in the other region, or slightly slower. Can be.

  As described in claim 4, a detector for measuring the mainstream wind speed installed in the mainstream wind speed area and a detector for measuring the low speed wind speed installed in the low speed wind speed area are provided, and the low speed wind speed is the mainstream wind speed. It is desirable to provide control means for controlling the wind speed acceleration means so as to be equal to.

  With this configuration, the main wind speed and the low speed wind speed are measured by the detector, and the wind speed flow is accelerated so that the wind speed difference becomes zero. That is, if the accelerated wind speed becomes too high and exceeds the mainstream wind speed, it is fed back to the control means and the acceleration is suppressed. On the other hand, when the wind speed is less than the mainstream wind speed, it is fed back to the control means and the acceleration by the acceleration means is increased.

  The wind tunnel testing apparatus according to the present invention having the above configuration has the following excellent effects.

  In particular, the bottom of the blowout nozzle as a reduced flow nozzle is flattened to be asymmetric with the ceiling surface, and no throttle is provided. Can be much cheaper. On the other hand, if this is done, the bottom surface where the throttling effect cannot be obtained will not be accelerated, and the wind speed flow at the outlet will be slower than the mainstream region and the wind speed distribution will not be uniform. Since it is provided, it is possible to accelerate the wind speed flow in the bottom region and make the wind speed distribution uniform. In the present invention, wind speed acceleration means is required, but the total cost including the construction cost is greatly reduced since the construction cost is much less than the cost for reducing the construction cost.

  Hereinafter, embodiments of the wind tunnel testing apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 is a central sectional view schematically showing an embodiment of the wind tunnel testing apparatus of the present invention. As shown in FIG. 1, the wind tunnel test apparatus 1 of this example includes a contracted nozzle 2 having a rectangular or square outlet 2a at the front end, and the bottom surface 2b of the contracted nozzle 2 is formed from a flat surface without restriction. Become. In this example, a box-shaped plenum chamber 3 is installed on the downstream side of the outlet 2 a and covers the vehicle under test X placed on the measuring unit 4. The measuring unit 4 is flush with the bottom surface 2b of the contracted nozzle 2 and is not provided with a step.

  The reduced flow nozzle 2 of this example is symmetrical, and the ceiling surface 2c and the bottom surface 2b are asymmetric. The bottom surface 2b side of the reduced flow nozzle 2 is a wind speed flow slow region where the wind speed flow is slower than the ceiling surface 2c and both side surfaces 2d, and there are slits 5 in the bottom surface 2b spaced in the width direction in the width direction. The acceleration flow from each slit 5 is blown obliquely toward the blowout port 2a. Although illustration is omitted, an air intake is provided on the upstream side of the duct provided below the slit 5, and the air taken in from this is accelerated by a blower and blown out from the slit 5.

  FIG. 2 is a central sectional view schematically showing a second embodiment of the wind tunnel testing apparatus of the present invention. As shown in FIG. 2, the wind tunnel testing apparatus 1-2 of this example has a plurality of suction slits 6 provided on the bottom surface 2 b, and a suction duct 7 is installed on the downstream side below the slit 6. Inside, a suction fan and a bleed air outlet (both not shown) are arranged downstream in this order. Since other configurations are the same as those in the above embodiment, the description thereof is omitted, and common members are denoted by the same reference numerals.

  In the wind tunnel test apparatus 1-2 of this example, the bottom surface 2b of the contracted nozzle 2 has a slower wind speed than the other regions 2c and 2d, but the bottom surface 2b side from the upstream side of the contracted duct 2 to the outlet 2a. The air flow can be accelerated by sucking it into the suction slit 6.

  FIG. 3 is a central sectional view schematically showing a third embodiment of the wind tunnel testing apparatus of the present invention. As shown in FIG. 3, the wind tunnel test apparatus 1-3 of this example includes a part of the bottom surface 2 b constituted by a moving belt device 8. That is, the endless belt 8a having a width close to the bottom surface 2b is passed over the front and rear rollers 8b and 8c and the guide rollers 8d and 8e, and the endless belt 8a is rotated so that the surface side travels in the direction of the blowout port 2a. By doing in this way, in the wind tunnel test apparatus 1-3 of this example similarly to the said Example 1 * 2, compared with other area | regions 2c * 2d by making the bottom face 2b of the contraction nozzle 2 flat. Although the wind speed is slow, the air flow on the bottom surface 2b side can be accelerated by the rotation of the moving belt device 8 from the upstream side to the outlet 2a. Since other configurations are the same as those in the above embodiment, the description thereof is omitted, and common members are denoted by the same reference numerals.

  FIG. 4 is a central sectional view schematically showing a fourth embodiment of the wind tunnel testing apparatus of the present invention. Although the wind tunnel test apparatus 1-4 of this example uses an asymmetrical nozzle as the contraction nozzle 2 and has a flat bottom surface 2b without a restriction, the wind speed acceleration means is shown in FIG. Thus, the acceleration device 9a that separates and sucks the wind velocity flow that is slower than the other regions and the acceleration device 9b that blows out while rectifying the acceleration flow in parallel are deployed. That is, the upper plate 10 is provided slightly above the floor surface 2b in parallel with the main stream, and below the upper plate 10, the accelerator 9a is disposed upstream and the accelerator 9b is disposed adjacent to the downstream. Further, the acceleration device 9a has a suction port 11 on the upstream side, and sucks a wind speed flow by suction with a suction fan (not shown) provided at the lower downstream side of the duct 12 below the upper plate 10. Further, the acceleration device 9b has a structure in which an acceleration flow is blown out from the blow-out port 14 by a blower (not shown) provided in the lower portion on the upstream side of the duct 13 below the upper plate 10.

  Since other configurations are the same as those in the above embodiment, the description thereof is omitted, and common members are denoted by the same reference numerals.

  FIG. 5 is a central sectional view schematically showing a fifth embodiment of the wind tunnel testing apparatus of the present invention. In the wind tunnel test apparatus 1-5 of this example, any of the apparatuses used in the above-described Examples 1 to 4 is used as the wind speed acceleration apparatus 17, but in the vicinity of the outlet 2a of the asymmetrical contraction nozzle 2 (slightly A mainstream wind speed detector 15 and a lower wind speed detector 16 are arranged on the upstream side, respectively, so that the wind speed blown out from the blowout port 2a toward the measurement unit 4 can be measured. In this example, a pitot tube is used for each of the detectors 15 and 16. However, for example, a hot-wire anemometer or a manometer may be used. With this configuration, it is possible to measure the wind speed in the main flow area and the wind speed in the low speed flow area, and accelerate the wind speed in the low speed flow area by the acceleration device 17 so as to be the same as the wind speed in the main flow area, thereby making the wind speed distribution uniform.

  FIG. 6 is a block circuit diagram showing an example of an apparatus for automatically calculating and controlling the acceleration flow target value generated by the acceleration device 17 in the wind tunnel test apparatus 1-5. As shown in FIG. 6, the present control device 18 has a configuration in which the main flow wind speed detection value is compared with the low speed flow wind speed detection value, and the acceleration flow target value is calculated by the calculation means 19 so that both detection values are the same. . A typical calculation means 19 includes a PID calculation.

  As a method for setting the above acceleration flow target value, for example, as shown in FIG. 7, a method of setting by multiplying the main flow wind speed target value by an acceleration gain, and as shown in FIG. 8, main flow wind speed detection of a Pitot tube or the like. There is a setting method by measuring the mainstream wind speed with the instrument 15 (FIG. 5) and multiplying this measured value by the acceleration gain. The acceleration gain may be a constant value, but a more accurate wind speed distribution can be obtained by using a variable gain with the wind speed as a parameter. By adjusting the variable gain, the wind speed distribution at the outlet 2a can be made uniform, or the wind speed distribution can be forcibly given.

  Although the several Example was shown about the wind tunnel test apparatus of this invention above, it can also implement as follows, for example.

  As shown in FIG. 9, the blowout port 2a of the contraction nozzle 2 ′ has a substantially semicircular shape, the bottom surface 2b is flattened, and the acceleration device 17 (FIG. 5) is provided below the floor surface 2b. (See the wind tunnel test device 1-6 of the sixth embodiment).

  Although not shown in the drawings, it is also possible to arrange the acceleration device as described above on one side surface of the low-speed flow region by making the contracted flow nozzle 2 vertically symmetric and asymmetric left and right.

1 is a central sectional view schematically showing a first embodiment of a wind tunnel testing apparatus of the present invention. It is a center sectional view showing roughly the 2nd example of the wind tunnel testing device of the present invention. It is a center sectional view showing roughly a 3rd example of a wind tunnel testing device of the present invention. It is a center sectional view showing roughly a 4th example of a wind tunnel testing device of the present invention. It is a center sectional view showing roughly a 5th example of a wind tunnel testing device of the present invention. It is a block circuit diagram which shows an example of the apparatus which calculates and controls automatically the acceleration flow target value generated with the acceleration apparatus 17 in the wind tunnel test apparatus 1-5. It is a circuit diagram which shows an example of the method of setting the target value of acceleration flow control. It is a circuit diagram which shows the other example of the method of setting the target value of acceleration flow control. It is a front view which shows the blower outlet of the asymmetrical reduced flow nozzle concerning 6th Example of the wind tunnel test apparatus of this invention. It is a center longitudinal cross-sectional view which shows the conventional common wind tunnel testing apparatus 21 provided with the symmetrical nozzle 22. FIG. It is a wind speed distribution by the symmetrical nozzle 22 shown in FIG.

Explanation of symbols

1-1-2-6 Wind tunnel testing device 2.2 'contraction nozzle (blowing nozzle)
2a outlet 2b bottom surface of the contracted nozzle 2 2c ceiling surface of the contracted nozzle 2 2d both sides of the contracted nozzle 2 3 plenum chamber 4 measuring section 5 slit 6 suction slit 7 suction duct 8 moving belt device 8a endless belt 8b 8c roller 9a / 9b acceleration device 10 Upper plate 11 Suction port 12/13 Duct 14 Outlet 17 Wind velocity accelerator 15 Main wind velocity detector 16 Lower wind velocity detector 17 Accelerator 18 Controller 19 Arithmetic means X Test vehicle

Claims (4)

  A wind tunnel test apparatus comprising an asymmetrical reduced flow nozzle and provided with a wind speed acceleration means on a low speed flow velocity region where a wind velocity flow created by the reduced flow nozzle is slower than other surfaces.   The wind tunnel testing apparatus according to claim 1, wherein the low-speed flow velocity area surface is a floor surface and includes a symmetric and vertical asymmetric contraction flow nozzle.   The said wind velocity flow acceleration means consists of either giving a blow flow, giving a bleed air flow, or giving a wall surface flow in the same direction as an air flow, or those combinations. Wind tunnel testing equipment. Installed in the mainstream wind speed area to measure the mainstream wind speed and installed in the low speed wind speed area to measure the low speed wind speed, the wind speed acceleration so that the low speed wind speed is equal to the mainstream wind speed The wind tunnel testing apparatus according to any one of claims 1 to 3, further comprising control means for controlling the means.

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