JPS6146435Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wind tunnel device for gas circulation in simple wind tunnel tests, laser generation, etc.

[Prior art] and [Problems to be solved by the invention] Conventionally, as a circulation type wind tunnel device for circulating air, for example, the following example is shown in Figure 2, Ehara Jiho No. 106, page 17, published on November 15, 1978. As shown in FIG. 1, a work section 1 that accommodates samples for testing and performs measurement work, and a blower section 2 that accommodates a blower are connected to the first body 3 on the suction side. It is connected to the second body 4 on the discharge side to form an air circulation system path. A heat exchanger 5 is provided to prevent the temperature of the circulating air from rising. A heat exchanger 5 is particularly required in the case of heat generating operations, such as laser generation.

In a wind tunnel apparatus having such a structure, the dimensions of the first body 3 and the second body 4 are considerably large in order to improve the air characteristics regarding the flow velocity distribution, turbulence rate, etc. in the working section 1. In cases where it is acceptable even if the characteristics are slightly inferior, the overall size becomes large, and the problem of installation space also arises.

In addition, in the process from the conventional example to the present invention, the inventor devised a wind tunnel device shown in Fig. 2,
investigated. This device consists of a point A of the inlet 12 of the discharge section 14, an inner circumferential wall 23 between the outlet 13 and point B, and an inlet 15 of the suction section 17.
The inner peripheral wall 39 between the point C of the outlet port 16 and the point D of the outlet 16
There is no flat plate, and they are connected by a flat plate. In such a structure, separation starts immediately from points A and C, and develops over a wide area of E and F, which significantly impedes the uniformity of the flow velocity distribution at the inlet of the working section 9.

Furthermore, even if the inner circumferential walls 23 and 39 are provided and the guide vanes 25 and 40 are formed by circular arcs substantially along the ideal streamline, the turning angle per guide vane 25 and 40 is large and the outer surface is Separation occurs at a certain point, and as shown by hatching, the separation gradually grows along the guide vanes 25 and 40, resulting in an intermittent flow velocity distribution at the outlet 13, and mixing up to the working section 9, which approaches uniformity. However, even at the inlet of the working section 9, a considerably non-uniform flow velocity distribution is exhibited, and the air characteristics are quite poor.

The purpose of the present invention is to provide a wind tunnel device that eliminates the above-mentioned problems, makes the entire device small and lightweight, ensures uniform velocity distribution, and can obtain good air characteristics. It is something to do.

[Means for solving problems]

The present invention consists of a blower section that incorporates a blower and has an inlet and an outlet at both ends, a working section that includes a working section and has an inlet and an outlet at both ends, and a substantially semicircular side surface on the diametric side. A discharge section and a suction section each have an inlet and an outlet, and the discharge section and the suction section are connected to both ends of the blower section and the working section, which are arranged in parallel, through a connecting plate, so that the gas can be A circulation system path is formed, and the inside of the discharge and suction section is provided with an inner circumferential wall that protrudes toward the inside of the gas flow chamber between the inlet and the pre-air outlet, and each of the semicircular A plurality of guide vanes substantially along the ideal streamline are provided in the gas flow path chamber at intervals in a direction substantially perpendicular to the flow direction and at intervals in a direction substantially parallel to the flow direction. It is a wind tunnel device.

[Effect]

Among the configurations of the present invention, the particularly important ones are: (A) A discharge section and a suction section that are approximately semicircular and have an inlet and an outlet on the diametric side, forming a gas circulation path. is being done.

(B) The inside of the discharge and suction section 17 is provided with an inner circumferential wall that can protrude toward the inside of the gas flow chamber between the inlet and the outlet.

(C) Inside each of the semicircular gas flow passage chambers, guide vanes extending substantially along the ideal streamline are spaced apart in a direction substantially perpendicular to the flow direction and spaced apart in a direction substantially parallel to the flow direction. Must be equipped with multiple items.

It is a constituent element.

When operating a wind tunnel device, air discharged from a blower passes through a discharge section, a working section, and a suction section, and is sucked into the blower again for circulation.The discharge section and suction section are approximately semicircular. By forming the air blower section and the working section, the connection between the blower section and the work section can be made as short as possible and can be connected through a smooth flow path. The blower section and working section have the necessary dimensions according to the specifications of the wind tunnel, but the discharge section and suction section can be of the smallest dimensions that can maintain a smooth air flow, reducing the overall dimensions of the wind tunnel equipment. It can be made significantly smaller.

However, if the discharge section and the suction section are simply semicircular, the air flow within the section will be considerably disturbed and it will be difficult to obtain a stable and uniform flow. and (C) guide vanes.

That is, in the case of (B) which lacks the inner circumferential wall and connects the inlet and outlet of the discharge section or suction section with a flat wall, air flows from each inlet of the discharge or suction section. When flowing, there is a sudden change in the cross section, causing severe separation over a wide area, which significantly impedes the uniformity of the flow velocity distribution in the working area.

To deal with this, in the present invention, as shown in (B), an inner circumferential wall that protrudes toward the inside of the gas passage chamber is provided between the inlet and the outlet. This inner circumferential wall makes it possible to minimize the separation area, prevent disturbance of air flow due to separation, and make the flow velocity distribution uniform.

The shape of the circumferential wall is semicircular or other protruding shape that prevents peeling.

Therefore, even if the inner circumferential wall is provided to prevent separation from the inlet as described above, the degree of change in direction of the gas flow in the discharge or suction section is
It can be said that this is much smaller than the conventional one that changes almost at right angles at one point as shown in FIG. 1, but it is still quite large, and it accompanies some degree of turbulence, which impedes the uniformity of the flow velocity distribution.

In order to deal with this, in the present invention, as shown in (C), a plurality of guide vanes approximately along the ideal streamline are provided at intervals in a direction approximately perpendicular to the flow direction within the semicircular gas flow path chamber. There is. Due to the action of this guide vane,
The inflowing gas is divided into multiple rows of narrow flow paths between the multiple guide vanes and flows. Although the degree of change in direction is large in each narrow channel, there is little turbulence because it follows the ideal streamline and is narrow, and there is no mixing of flows between the narrow channels. A flow with almost no turbulence is obtained as a whole, and the flow velocity distribution is uniform.

Further, in the present invention, since a plurality of guide vanes substantially along the ideal streamline are provided at intervals substantially parallel to the flow direction, the turning angle per guide vane is small and separation is unlikely to occur. Further, even if separation occurs, the separation layer disappears at the end of the guide vane, so it does not grow, and the entire separation area is extremely small, suppressing disturbances to the flow.

As described above, in the wind tunnel apparatus of the present invention, the entire apparatus is extremely compact, and there is little air turbulence in the flow path, and the flow velocity can be made uniform, so that considerably good air characteristics can be obtained.

〔Example〕

To explain the present invention with reference to the drawings, FIG. 3 shows a blower section 2 incorporating a blower 6 and having a suction port 7 and a discharge port 8 (see FIG. 10) at both ends, and a laser generating section. The working section 1 includes a working section 9 such as a device or a gas force measuring device, and has an inlet 10 and an outlet 11 (see FIG. 8) at both ends, and is approximately semicircular;
An inlet 12 and an outlet 13 (fourth
A blower section 2 and a working section are arranged in parallel, comprising a discharge section 14 with a diaphragm (see figure) and a suction section 17, which is also approximately semicircular and has an inlet 15 and an outlet 16 on its diametric side. 1, a discharge section 14 and a suction section 17 are connected to each other via connecting plates 18 and 19.
are connected to form a gas circulation path.

4 and 5 show the discharge section 14, which has a substantially semi-cylindrical outer peripheral wall 20 and side plates 2 on both sides.
1 and 22, and an inner circumferential wall 23 that protrudes inward, and a gas flow path chamber 24 that opens to the inlet 12 and the outlet 13 is formed. Inside the gas flow path chamber 24, a plurality of arc-shaped guide vanes 25 are arranged substantially along the ideal streamline, spaced apart in a direction substantially perpendicular to the flow direction, and spaced apart in a direction substantially parallel to the flow direction. There are multiple locations. 26 and 27 are flanges and bolt holes for tightening.

In addition, in this specification, "ideal streamline" means
In a certain gas flow path, when the flow velocity distribution and flow direction at a predetermined inlet cross section and outlet cross section are given, it refers to a theoretical streamline obtained by flow analysis based on potential theory.
For the discharge section 14, the inlet cross-section is the cross-section at the inlet 12, the outlet cross-section is the inlet cross-section of the working part 9, and for the suction section 17, the inlet cross-section is the cross-section at the inlet 15, and the outlet cross-section is the cross-section at the outlet 16. shall be.

The suction section 17 has an inner peripheral wall 39 and a guide blade 4.
0, and has almost the same structure as the suction section 14, but has a built-in heat exchanger 28, and the guide vanes 40 extend only to the upper side of the heat exchanger 28. The portion of the outlet 13 in FIG. 4 becomes the inlet 15, and the portion of the inlet 12 becomes the outlet 16.

6 and 7 show a connecting plate 18 (the connecting plate 19 has the same structure), the outer circumference of which is the same as the flange 26 of the discharge section 14 or the suction section 17, and bolt holes 29 are provided at the same positions. ing. 30 is a hole for the outlet 13 or the inlet 15, and 31 is a hole for the outlet 8 of the blower section 2. 32 and 33 are screw holes.

8 and 9 show working section 1. FIG.
34 is a flange, and 35 is a bolt hole.

10 and 11 show the body 36 of the blower section 2. FIG. 37 is a flange, and 38 is a bolt hole.

The assembled state is as shown in FIG. 3. Since the suction section 17 can be attached to and detached from the connecting plate 19 with bolts, the working section 1 and the blower can be connected via the connecting plate 19 after the heat exchanger 28 is installed. Can be connected to section 2 with bolts. If the connecting plate 19 is not made removable and is welded to the suction section 17, it becomes difficult to insert and attach the heat exchanger 28. In addition, especially in laser generators using gases such as He and CO ₂ ,
First, the internal pressure is brought to a vacuum of about 0.1 Torr, and then these gases are introduced and maintained at a vacuum of about 35 Torr.
Therefore, the walls themselves and the welded parts of each part are required to have considerable strength. The flange 26 as shown in FIG. 4 allows for stronger and more reliable welding from the inside and outside. However, if a plate such as the connecting plate 18 is welded as a flange instead of the flange 26, welding on the back side becomes extremely difficult and reliable. It lacks strength and strength cannot be reliably expected.

When used in a high vacuum such as the one described above, grooves for O-rings are provided on the mating surfaces of the flange 34 of the work section 1 and the mating surface of the flange 37 of the blower section 2, and sealed with O-rings.

Note that the inner peripheral walls 23 and 39 may be provided on the connecting plates 18 and 19. The inner circumferential walls 23 and 39 are not limited to semicircular shapes, but may have other protruding shapes that are less prone to peeling.

FIG. 12 shows another embodiment. In the above-described embodiment, the guide vanes 25 and 40 are shaped as if they were separated from one continuous piece, so the number is the same at the wide inlet 12 and the narrow outlet 13, and the mutual spacing is smaller at the wide inlet 12. There is room for improvement in that the outlet 13 is too narrow, resulting in large turbulence, and the outlet 13 is too narrow, resulting in large fluid resistance and increased loss.
FIG. 12 shows an embodiment that improves this point, and has the following structure.

Guide vanes A1, A2, A3, A4, A5, B1,
B2, B3, B4, C1, C2, and C3 are divided into relatively short pieces in the longitudinal direction. This results in
The turning angle per guide vane is small, making it difficult for peeling to occur, and even if peeling occurs, the peeling layer disappears at the end of the guide vane and does not grow.

In the figure, the arc-shaped dotted line indicates an ideal streamline, and each guide vane is arranged approximately along the ideal streamline. However, when properly aligned with the ideal streamline, the airflow off the end of the guide vane will be deflected outward by slip, resulting in a bias toward the larger radius.

In order to prevent this slippage, each guide vane is biased inward from the ideal streamline near its terminal end. That is, if we look at the guide vane A1, for example, if we assume that the ideal streamline L1 passes through its front end 41, the vicinity of the front end 41 is mostly along L1, but it gradually deviates inward, and at the terminal end 42, only a ₁ biased inward. Similarly, the rear ends of the other guide vanes are biased inward with respect to the ideal streamline passing through the front ends. The shape of the guide vane A1 etc. has a front end 41 and a terminal end 4.
2 by an arc with a radius slightly smaller than the radius of the ideal streamline L1, the guide vane A1 will have a smooth curved surface that does not go beyond the ideal streamline L1, but a part will be slightly outside the ideal streamline L1. There is no problem if you go to

By dividing the guide vanes in the longitudinal direction in this manner, the turning angle per guide vane is reduced, the occurrence of peeling is suppressed, and even if it occurs, its growth is prevented, and the gas flow path chamber 24 The most appropriate number of guide vanes can be selected according to the cross-sectional area in the airflow direction of each part of the guide vane, and slips can be prevented by biasing the end of each guide vane inward from the ideal streamline. The air properties at the inlet of the working section 9 are therefore good. For example, although the air characteristics are not comparable to those of a large wind tunnel, the flow velocity distribution reaches approximately 3% and the turbulence rate reaches approximately 3%. Therefore, the wind tunnel apparatus is small and lightweight and can be used for applications where these values or higher are acceptable.

The distance l ₁ from the rear end of the final guide vanes C1, C2, C3 to the inlet of the working section 9 is approximately l ₁ = (2 to 5) H, where the height of the working section 9 is H, and this interval It is preferable to mix the air currents to promote uniformity.

The distance l ₂ between the first guide vane A3 and the rear end of the differential user of the blower 6 is approximately l ₂ = (0.2 to 1) d, where d is the diameter of the rear end of the differential user of the blower 6, to prevent blockage by the differential user. Preferably avoided.

If l ₂ is relatively large, the first guide vane A1,
It is preferable that the vicinity of the front end 41 of A2, A3, A4, A5, etc. be partially bent inward from the ideal streamline so as to be brought closer to the direction of the airflow from the blower 6.

Guide vanes D1, D in suction section 17
2, D3, E1, E2, E3, E4, F1, F
The same applies to 2, F3, F4, and F5.

If there is no heat exchanger 28, the distance l ₃ between the final guide vane F1 etc. and the outlet 16 is approximately l ₃ = (0.2 to 0.5)D, where D is the inner diameter of the body 36 of the blower section 2. preferable.

FIG. 13 shows another embodiment, in which the distance l ₄ from the rear end of the blower 6 to the front end of the guide blade 25 is l ₄ = (0.3 to 1), where d is the diameter of the rear end of the differential user of the blower 6. d, and the distance l ₅ from the rear end to the entrance of the working section 9 is set as l ₅ = (3 to 8) H, when the height of the working section 9 is H, and a relatively long distance is set. The aim is to achieve uniformity through the mixing effect.

The vicinity of the front end of the guide vane 25 is bent slightly inward from the ideal streamline so as to approach the direction of the airflow from the blower 6, and the vicinity of the end is also bent slightly inward from the ideal streamline to prevent slipping.

In the suction section 17, the direction of the streamline near the front end of the guide vane 40 is close to the ideal streamline, so there is no particular deviation, but the direction near the rear end is slightly biased inward from the ideal streamline to prevent slipping. .

Distance l ₆ between the rear end of the guide vane 40 and the heat exchanger 28
Assuming that the length of the heat exchanger 25 is G, it is preferable to provide a mixing section such that l ₆ =(0.15 to 0.5)G to ensure uniformity.

The structure shown in FIG. 12 and the structure shown in FIG. 13 can also be combined. For example, the first
The discharge section 14 of FIG. 2 and the suction section 17 of FIG. 13 may be combined, or the discharge section 14 of FIG. 13 and the suction section 17 of FIG. 12 may be combined.

The heat exchanger 25 has a mixing effect on the airflow and is useful for uniformity, but even if the heat exchanger 28 is not provided, a resistor such as a punched metal or rectifying wire mesh can be provided to achieve uniformity.

Note that if the inside of the device is not under high pressure or vacuum, and there are few problems with strength and leakage, connect the connecting plate 18,
There is no longer a need for a three-piece connection via the connection plate 19, and plates such as the connection plates 18 and 19 may be welded instead of the flange 26 (if there are fewer problems with the insertion of the heat exchanger 28). The flanges of the working section 1 and the blower section 2 may be formed by dividing the plates 18 and 19 horizontally between the holes 30 and 31.

[Effect of idea]

The present invention makes it possible to provide a wind tunnel device that is small and lightweight, has a uniform velocity distribution, and has good air performance, and has extremely great practical effects.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional wind tunnel device, Fig. 2 is an explanatory diagram of a wind tunnel device devised in the process leading up to the present invention, and Figs. 3 to 13 are related to embodiments of the present invention. The figure is a front view, FIG. 4 is a sectional view of the discharge section taken along the - line (center line) in FIG. 5, FIG. 5 is a view taken along the arrow in FIG.
The figures are cross-sectional views of the connection plate, taken along the - line (center line) in Figure 7, Figure 7 is a view taken in the direction of the arrow in Figure 6, Figure 8 is a cross-sectional view of the working section, and Figure 9 is a cross-sectional view taken along the - line (center line) in Figure 9. 9 is a cross-sectional view of the body of the blower section, FIG. 9 is a cross-sectional view of the body of the blower section, and FIG. 11 is a cross-sectional view of FIG. , FIG. 12, and FIG. 13 are longitudinal sectional explanatory views of different embodiments. 1... Working section, 2... Blower section, 3... First body, 4... Second body, 5... Heat exchanger, 6... Blower, 7... Suction port, 8... Discharge port, 9...Working section, 10...Inflow port, 11...
Outlet, 12... Inlet, 13... Outlet, 14
...Discharge section, 15...Inflow port, 16...
Outlet, 17... Suction section, 18, 19...
... Connection plate, 20 ... Outer peripheral wall, 21, 22 ... Side plate, 23 ... Inner peripheral wall, 24 ... Gas flow path chamber, 25
... Guide vane, 26 ... Flange, 27 ... Bolt hole, 28 ... Heat exchanger, 29 ... Bolt hole, 3
0,31...hole, 32,33...screw hole, 34...
...Flange, 35... Bolt hole, 36... Body,
37...flange, 38...bolt hole, 39...
Inner peripheral wall, 40... Guide vane, 41... Front end, 42...
...terminal.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A blower section containing a built-in blower and having an inlet and an outlet at both ends, and a working section including a working section and having an inlet and an outlet at both ends, forming a substantially semicircular shape. , comprising a discharge section and a suction section having an inlet and an outlet on the diametric side, and at both ends of the blower section and the working section arranged in parallel,
The discharge section and the suction section are connected through a connecting plate to form a gas circulation path, and inside the discharge and suction section, there is a gas flow path inside the chamber between the inlet and the outlet. In each of the semicircular gas flow passage chambers, guide vanes extending substantially along the ideal streamline are spaced apart in a direction substantially perpendicular to the flow direction and are provided with an inner circumferential wall projecting toward the flow direction. A wind tunnel device characterized in that a plurality of wind tunnel devices are provided at intervals in a parallel direction. 2. The wind tunnel apparatus according to claim 1, wherein the vicinity of the terminal end of the guide vane is biased inward from the ideal streamline. 3. The front end of the guide vane of the discharge section is
The wind tunnel apparatus according to claim 1, wherein the wind tunnel apparatus starts at a position further back than the inlet and is biased inward from the ideal flow line toward the blower.