JPS60213843A - Supersonic-speed wind tunnel - Google Patents

Abstract

PURPOSE:To reduce the using pressure of each piece of equipment, by varying the restriction of the second throat in supersonic-speed wind tunnel, which discharges the compressed air that is stored in an air storage tank into an atmosphere through a valve, a collecting tube, a nozzle, a measuring tube, the second throat and a diffusing tube. CONSTITUTION:An air exhausting device 10 in supersonic-speed wind tunnel is operated, and the pressure in a measuring tube S is made to be an atmospheric pressure of 0.6kg/cm<2> ABS. By opening a regulating valve 4 quickly, a gas, which is stored in an air storage tank 3 at the pressure of about 10kg/cm<2> G, is sent to the measuring tube S through a collecting tube 5. Under this state, the pressure in the measuring tube S is reduced by the air exhausting device 10. A shock wave is pushed toward the downstream of a second throat 7 readily by the low pressure of about 5kg/cm<2> G in the collecting tube 5. The wind speed of Mach 4 is obtained in the measuring tube S. Then a jack 9 is operated, the second throat 7 is restricted and the air exhausting device 10 is stopped. Even though the second throat 7 is restricted and the air exhausting device 10 is stopped, the shock wave does not enter the measuring tube S.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in blowdown type supersonic wind tunnels.

When performing performance tests on flying objects, etc., various tests are often conducted using the blowdown type supersonic wind tunnel shown in FIG.

In the figure, 1 is a compressor, 2 is a dryer that dries the compressed air sent from the compressor [1], and 3 is an air storage tank that stores the compressed air.

4 is a pressure regulating valve, 5 is a collection tube, 6 is a nozzle, S is a measurement tube, 7
8 is a second throat, 8 is a diffusion cylinder, and compressed air stored in the air storage tank 3 by rapidly opening the SI pressure valve 4 is transferred to the collecting cylinder 5.
After passing through the nozzle 6 and applying wind pressure to the two-person measuring tube S6, it is released into the atmosphere via the diffusion tube 8.

Immediately after the pressure regulating valve 4 is suddenly opened, a shock wave is generated within the measuring tube S. In order to obtain the required pressure of the Matsuh number in the measuring tube S, this shock wave must be transmitted downstream from the second throat 7. It is necessary to push it out, and the pressure inside the collecting cylinder 5 required for this can be calculated in advance.

Now, when generating the wind speed of, for example, Matsuha 4 in the measuring tube S, the pressure in the collecting tube 5 is set to 9 kg/cd 0.
or more, and considering the pressure loss of the pressure regulating valve 4, etc., the air storage tank 3. Dryer 2. The operating pressure of the pressure Wi machine is required to be 10 kg/cdG or more.

Therefore, the main part of the equipment needs to be a pressure vessel that can withstand pressures of 15 kg/d0 or more! ! ! This leads to an increase in production costs, etc. Furthermore, if these devices are damaged, the high voltage will not affect the surrounding areas and the impact will be significant.

This invention consists of a nozzle, a measuring tube, a second
It consists of a throat, a diffusion cylinder, an air storage tank, and a collecting cylinder that communicates with the air storage tank through a valve and communicates with the nozzle. , in a supersonic wind tunnel in which air is discharged into the atmosphere through a nozzle, a measuring tube, a second throat, and a diffusion tube, the aperture of the second throat is made variable, and an exhaust device is provided that communicates with the diffusion tube. It is something.

That is, in the supersonic wind tunnel of the present invention, since the exhaust device is connected to the diffusion tube, the pressure inside the measurement tube can be lowered, and there is no need to increase the pressure in the air storage tank.

Therefore, it becomes possible to generate supersonic velocity within the measuring tube with equipment that does not require a design capable of withstanding high pressure.

The present invention will now be described with reference to an embodiment of a supersonic wind tunnel shown in FIG.

The supersonic wind tunnel in FIG. 2 is also basically the same as that in FIG. 2, and is given the same reference numeral. Therefore.

To explain only the different parts, reference numeral 9 is a jack, which adjusts the opening degree (aperture) of the second throat 7. Also, 1
Reference numeral 0 denotes an exhaust device, which communicates with the downstream side of the second throat 7 via a duct IOA, and lowers the pressure inside the measuring tube S to below atmospheric pressure.

A known device such as a vacuum pump or ejector may be used. 2 Now, in the supersonic wind tunnel constructed as described above, 1 For example, in order to obtain the speed of the Matsuha 4 in the measurement tube S, it is preferable to do the following.

First, the exhaust device IO is activated to bring the pressure inside the measuring tube S to atmospheric pressure 0.6 kg/cmABs.

The gas accumulated in the air storage tank 3 at a pressure of about 10 kg/aaG is sent to the measuring cylinder S via the collecting cylinder 5 by rapidly opening the regulating valve 4.

In this state, since the pressure inside the measuring cylinder 6 is lowered by the exhaust device 10, the shock wave force ζ is easily pushed downstream of the second throat 7 by a low pressure of about 5 kg/cdG inside the collecting cylinder 5. A wind speed of 4 is obtained in the measuring tube S.

Next, operate the jack 9 to narrow down the nozzle 6.

The exhaust device 10 is stopped.

In addition, the second throw! -7, even if the exhaust system 10 is stopped, shock waves will not enter the measuring tube S, and a stable Mannha number wind speed can be obtained in the measuring tube S.

As explained above, according to the Φ supersonic wind tunnel of the present invention, the compressor 1. Dryer, 2. Air storage tank 3. The operating pressure of each device such as the collecting tube 5 can be lowered.

For example, in the conventional supersonic wind tunnel, the working pressure of each of the above-mentioned devices was 15 kg/aaG, but according to the method of the present invention, it is possible to reduce the working pressure to 10 kg/aaG:%, thereby reducing the cost.

[Brief explanation of drawings]

Fig. 1A is a diagram of a blowdown type supersonic wind tunnel, and Fig. 21 is a diagram of a supersonic wind tunnel showing an embodiment of the present invention. 1. Compressor, 2. Dryer, 3. Air storage tank. 4. Pressure regulating valve, 5. Collecting tube, 6. Nozzle. 7. Second throat, 8. Diffusion tube. 9:... Jacket, 10... Exhaust system S... Measuring tube

Claims (1)

[Scope of Claims] A nozzle, a measuring tube, a second throat, and a diffusion tube arranged in series, an air storage tank, and communicating with the air storage tank via a valve,
and a collecting tube communicating with the nozzle, and transmitting the compressed air stored in the air storage tank to the valve, the collecting tube, the nozzle, the measuring tube, and the second throat. A supersonic wind tunnel that discharges air into the atmosphere through a diffusion tube, characterized in that the second throat has a variable aperture and is equipped with an exhaust device that communicates with one of the diffusion tubes.