JPH0114902Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a circulation wind tunnel device used for wind tunnel testing of various specimens.

Figure 1 shows a conventional circulation wind tunnel device (1983-
13947), the wind sent by the blower 1 driven by the drive motor is recovered from the dynamic pressure of the flow to static pressure in the diffusion shell 2, and is then transferred to the variable flow blade group 4 in the connecting shell 3. , 5 change the direction of the flow with little pressure loss, the honeycomb 6 and straightening wire mesh 7 reduce the turbulence and unify the airflow direction, and the contracting cylinder 8 reduces the turbulence and improves the flow velocity distribution. The flow direction is uniformized and the flow direction is unified, and the flow is sent to the measurement shell 9 where the specimen is placed, and then it is circulated to the blower 1 via the diffusion shell 10 and the current transformation blade groups 12 and 13 in the connection shell 11. In addition, the temperature of the air circulating in the recirculation wind tunnel is raised by the heat generated by the blower 1, and in the summer, the temperature is about 10 to 20 degrees Celsius higher than the atmospheric temperature, and the material of the specimen is heated. Because some materials (such as clay) are deformed by the influence of heat, it is necessary to prevent the temperature of the circulating air from rising.
A hollow cylinder 14 with openings at both ends is provided in the middle, _{perpendicular} to the flow in the cylinder and penetrating through the cylinder wall. ₂ and the downstream cylindrical part 14 ₃ are provided, and the upstream cylindrical part 1
A discharge window hole 14 ₁ for the in-shell flow is provided in the center of the cylinder 4 ₂ , and an introduction window 14 ₄ for outside air is provided in the center of the downstream cylindrical portion 14 ₃ to utilize the dynamic pressure within the diffusion shell 10 . After introducing a part of the internal flow into the discharge window hole ₁₄₁ ,
The gas is emitted from the openings at both ends through the upstream cylindrical portion 14 ₂ , while the introduction window hole 1 is oriented toward the downstream side in the diffusion barrel 10 .
By the ejector effect of 4 ₄ , external low temperature air is introduced into the cylinder by opening at both ends, passing through the downstream cylinder part 14 ₃ and flowing in through the introduction window hole 14 ₄ into the cylinder. This is designed to prevent the temperature of the circulating air inside the tank from rising.

However, in the recirculation wind tunnel apparatus described above, approximately 5 of the recirculation amount Q is
% can be replaced and the temperature rise of the recirculating air can be reduced by 5%.
Although it is a natural ventilation method, the amount introduced + ΔQ tends to be smaller than the amount released - ΔQ, and the pressure inside the recirculation wind tunnel tends to be lower than that on the outside air side during operation. Outside air locally flows in from the entrance and exit window for the specimen in the measurement cylinder 9,
Local turbulence is generated in the airflow within the measurement body 9, and
There is a drawback that the drop in atmospheric pressure adversely affects the measurement of the specimen.

This proposal relates to an idea to solve the above-mentioned difficulties in conventional circulation wind tunnel equipment, and includes a circulation wind tunnel consisting of a diffusion cylinder, a contraction cylinder, a measurement cylinder, and a connection cylinder,
In the circulating wind tunnel apparatus, the circulating wind tunnel apparatus includes a blower disposed in the circulating wind tunnel, and a slit provided around the downstream side of the measurement barrel; a hollow cylinder with openings at both ends, an upstream cylinder part and a downstream cylinder part with external openings at both ends formed by vertical partitions in the hollow cylinder, and a hollow cylinder provided in the center of the upstream cylinder part. a discharge window hole for introducing the flow inside the downstream side cylinder and discharging it to the outside; an introduction window hole provided in the center of the downstream side cylinder part for introducing outside air into the downstream side cylinder; and the downstream side cylinder. It is characterized by the fact that it is equipped with outside air feeding fans connected to the outer openings at both ends of the wind tunnel, and its purpose is to increase the temperature of the air circulating inside the circulation wind tunnel. An object of the present invention is to provide a recirculation wind tunnel device which can prevent this problem by replacing parts and can maintain circulating air at atmospheric pressure.

The present invention has the above-mentioned configuration, and is provided in a hollow cylinder that is open at both ends and is disposed perpendicular to the flow inside the shell and penetrates the shell wall. The amount of low-temperature outside air introduced by the natural ventilation function of the downstream cylinder part and the introduction window provided in the hollow cylinder and the forced ventilation by the fan is compared to the amount released by the discharge window hole and the upstream cylinder part. are almost the same, and an appropriate amount of inlet air is secured to correspond to the temperature rise of the air circulating in the circulation wind tunnel, so the temperature reduction effect of the circulation air is significantly improved, and a drop in pressure of the circulation air is prevented. Ru.
In addition, if air is forced in with a fan, there will inevitably be an excess or deficiency of the exhaust amount, but in this case, a slit is provided around the barrel wall near the downstream of the measuring barrel, so the slit allows the intake and exhaust Through this action, the above-mentioned excess and deficiency can be naturally resolved, and in particular, the pressure inside the measurement body can be brought to atmospheric pressure, which can bring about remarkable results in measuring the specimen.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Figures 2 and 3 show an example of the present invention.
1 is a blower driven by a motor not shown; 2 is a diffusion cylinder; 3 is a connecting cylinder; 4 and 5 are a group of flow-changing blades; 6 is a honeycomb; 7 is a straightening wire mesh; 8 is a contraction cylinder; 9 is a measurement cylinder; 1
0 is a diffusion cylinder, 11 is a connection cylinder, and 12 and 13 are a group of flow-changing blades, and each of the above-mentioned cylinders constitutes a circulation wind tunnel.

In addition, 14 in the figure is a hollow cylinder with both ends open, which is disposed in the middle of the diffusion cylinder 10 (downstream side of the slit S), perpendicular to the flow inside the cylinder and penetrating the cylinder wall. Inside 14, there is a vertical partition plate 15 ₅
The upstream cylinder part 14 has external openings at both ends with a vertical partition.
₂ and a downstream cylinder part 14 ₃ are provided, and a discharge window hole 14 is provided in the center of the upstream cylinder part 14 ₂ for introducing the flow toward the upstream side of the flow inside the cylinder and discharging it to the outside.
₁ , and an introduction window hole ₁₄₄ is provided in the center of the downstream cylinder part ₁₄₃ to allow outside air to flow into the cylinder toward the downstream side of the flow of the cylinder. As shown in the figure, there are two vertical lines in the body with appropriate intervals,
There are 4 in total, 2 in the horizontal direction.

Furthermore, an annular duct 15 disposed around the diffusion barrel 10 is connected to the openings at both ends of the downstream cylinder portion 14 ₃ of each hollow cylinder 14 .
A fan 17 is disposed in an outside air intake tube 16 connected to the hollow tube 1.
It has a structure in which it is fed into the openings at both ends of each downstream cylinder portion 14 ₃ in the direction shown by the arrow. In addition, 1 in the figure
8 is a damper that adjusts the air volume of the fan 17.

Furthermore, in this embodiment, as shown in FIG. 2, a slit S with a small gap α is provided around the wall of the measurement barrel 9 near the downstream side.

The embodiment of the present invention shown in FIG. 2 and FIG.
At this time, a part of the recirculated air is introduced into each upstream cylinder part 14 2 from each discharge window hole 14 ₁ of each hollow cylinder ₁₄ due to its dynamic pressure, and is discharged from the openings at both ends thereof.
On the other hand, due to the ejector effect and the fan 17 in each introduction window hole 14 ₄ of each hollow cylinder 14, low-temperature outside air is transferred to the outside air intake cylinder 16, the annular duct 15, and each hollow cylinder 14.
It is introduced toward the downstream side in the cylinder from each introduction window hole 14 ₄ through the downstream side cylindrical portion 14 ₃ . The introduction amount +ΔQ of the low-temperature outside air is adjusted by the damper 18 to an amount commensurate with the discharge amount −ΔQ of the recirculated air.

Therefore, according to the above embodiment, the amount of low-temperature outside air introduced is an amount commensurate with the amount of recirculated air released by adding the forced air intake force by the fan 17 to the natural ventilation force due to the ejector effect, and the amount of low-temperature outside air introduced is equal to the amount of recirculated air released. The flow rate Q can be kept approximately constant, and the pressure in the measuring barrel 9 can be maintained at approximately atmospheric pressure.In addition, by introducing an appropriate amount of outside air, the temperature reduction function of the recirculated air is significantly improved, and the temperature of the recirculated air is reduced. can be kept constant. Further, if the temperature of the recirculating air is to be further lowered, this can be easily done by increasing the air volume of the fan.

Furthermore, when introducing low-temperature outside air by forced air intake using the fan 17 as described above, it is very difficult to adjust the air volume of the fan so that the amount of introduced air completely matches the amount of recirculated air released. This requires a troublesome operation and inevitably results in excess or deficiency in the amount of recirculated air in the cylinder, but in this embodiment, a slit S is provided around the body wall near the downstream of the measurement cylinder 9, so that this small amount of excess or deficiency can be avoided. This amount is automatically eliminated by the communication with outside air in the slit S. Especially measuring cylinder 9
Since the inside of the measuring cylinder 9 is brought to match the atmospheric pressure, the inside of the measuring cylinder 9 can be made into an ideal environment. In addition,
Since the slit S is provided around the peripheral wall, it does not disturb the flow inside the cylinder.

In addition, as shown in FIG. 3, the hollow shell 14 is
Since a plurality of them are arranged in the horizontal direction, the exchange performance of the circulating air is significantly improved.

[Brief explanation of drawings]

Fig. 1 is a mechanical diagram of a conventional circulating wind tunnel device, and Fig. 2 is a mechanical diagram of a circulating wind tunnel device showing an embodiment of the present invention.
FIG. 3 is a perspective view showing the structure of the air exchange device according to the embodiment of the present invention. 1: Blower, 2, 10: Diffusion cylinder, 3, 11: Connection cylinder, 8: Contraction cylinder, 9: Measurement cylinder, 14: Hollow cylinder,
14 ₁ : Release window hole, 14 ₂ : Upstream cylinder part, 14 ₃ :
Downstream cylinder part, 14 ₄ : introduction window hole, 14 ₅ : vertical partition plate, 17 : fan, S : slit.

Claims (1)

[Scope of utility model registration request] In a circulation wind tunnel apparatus comprising a circulation wind tunnel consisting of a diffusion shell, a contraction shell, a measurement shell, and a connecting shell, and a blower disposed in the circulation wind tunnel, a slit provided around a wall on the downstream side of the measurement shell. a hollow cylinder with openings at both ends perpendicular to the flow in the cylinder on the downstream side of the slit and penetrating the cylinder wall; and an upstream cylinder with external openings at both ends formed by vertical partitions in the hollow cylinder. and a downstream cylinder part, a discharge window hole provided in the center of the upstream cylinder part to introduce the flow in the downstream cylinder and discharge it to the outside, and a discharge window hole provided in the center of the downstream cylinder part. A recirculation wind tunnel device comprising: an introduction window for introducing outside air into the downstream body; and outside air feeding fans connected to outer openings at both ends of the downstream cylindrical portion.