JPH07218380A - Heavy-piston driving type shock wind-tunnel and control method thereof - Google Patents

Abstract

PURPOSE:To provide the heavy-piston driving type shock wind-tunnel, which can form supersonic gas stream, whose Mach number is about 1-4 at the normal temperature and normal pressure, and to provide the control method of the heavy-piston driving type shock wind tunnel. CONSTITUTION:In a heavy-piston driving type shock wind tunnel, a driving tube 15 is provided, and a piston 16, which is freely slid, is provided in the inside. The piston 16 is moved at a high speed by breaking a a bursting film 17, which partitions an actuating tube 18 connected to the driving tube 15. High-pressure gas is generated in the actuating tube 18. The generated supersonic high pressure gas stream is jetted into a vacuum measuring chamber 21, which is connected to a blowing nozzle 20, by opening a quick closing valve 19 provided in a nozzle 20 at the end part of the actuating tube 18. In this heavy-piston driving type shock wind tunnel, a plenum chamber 23 having an orifice 22 controlling the temperature and the pressure of the high pressure gas generated in the actuating tube 18 is provided between the actuating tube 18 and the blowing nozzle 19 beforehand. Thus, the temperature and the pressure of the supersonic gas stream jetted into the measuring chamber 21 are controlled at the normal temperature and the normal pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy piston drive type impact wind tunnel generally called a gun tunnel and a control method thereof.

[0002]

2. Description of the Related Art As is well known, a wind tunnel generates a uniform air flow whose wind speed is controlled, and blows this air flow on a model of an object moving in the air, such as an aircraft, a car, and even a ship. This is an experimental device for investigating the influence of the air flow on the real thing of the object by using a similarity law.

Various types of wind tunnels have been proposed so far according to the magnitude of the wind velocity generated.

Among them, as a high-speed wind tunnel capable of conducting a high Mach number experiment, initially, as shown in FIG. 2, a blowout using a tapered Laval tube in a high-pressure chamber 1 filled with high-pressure air. By connecting the low pressure chamber or the exhaust device 3 via the nozzle 2 and opening the pressure regulating valve 4 provided between the high pressure chamber 1 and the blowout nozzle 2, 300 m can be provided inside the low pressure chamber or the exhaust device 3. A configuration has been proposed in which an airflow exceeding a sound velocity of / s or more is generated.

However, this wind tunnel has a problem in that it requires large-scale equipment and the equipment cost is high.

Therefore, the wind tunnel shown in FIG. 3 has been proposed. This connects the high-pressure chamber 5 filled with the high-pressure drive gas and the low-pressure chamber 6 filled with the low-pressure working gas via the rupture membrane (rupture disk) 7, and the other end of the low-pressure chamber 6 is connected. A blow-out nozzle 8 is provided on the side of the portion, and the burst film 7
When the pressure is broken, the pressure difference between the high-pressure chamber 5 and the low-pressure chamber 6 causes an air flow exceeding the sonic velocity.

According to this wind tunnel, it is possible to form an air flow in the low Mach number region, but there is a problem that the duration of the air flow is short.

Therefore, the wind tunnel shown in FIG. 4 has been proposed. This is generally called an impact wind tunnel, and a high pressure chamber 9 as a driving cylinder filled with a high pressure driving gas and a low pressure chamber 10 as a working cylinder filled with a low pressure working gas are connected via a rupture membrane 11. A measurement chamber 13 that is vacuum-sucked by a vacuum pump 13a is arranged on the other end side of the low-pressure chamber 10 via a rapid opening / closing valve 12a and a blow-out nozzle 12 using a Laval tube, and is ruptured. By breaking the membrane 11, the driving gas inside the high pressure chamber 9 rapidly expands to generate a shock wave in the low pressure chamber 10, and while the generated shock wave is reflected at the pipe end of the low pressure chamber 10, the vicinity of this pipe end A high-temperature high-pressure gas (3000 K, about 100 atm) is generated in the chamber, and this high-temperature high-pressure gas is blown into the measurement chamber 13 from the nozzle 12 to form a hypersonic flow for a time of about several ms.

However, in this shock wind tunnel, the temperature of the obtained high-temperature high-pressure gas becomes high, but it is difficult to increase the pressure of the high-temperature high-pressure gas. Therefore, the duration of the hypersonic airflow is several ms.
There was a problem that it was difficult to extend beyond.

Therefore, as an improved type of impact wind tunnel, as shown in FIG. 5, a piston 1 slidable inside the low pressure chamber 10 is provided.
4 is internally provided, the high-temperature high-pressure gas is not formed by the shock wave when the rupturable membrane 11 is broken, and the enthalpy compression such as the thermal loss is reduced by the piston 14 so that the duration of the air flow is increased. A wind tunnel was proposed that expands to around 200 ms. In this specification, this type of wind tunnel is referred to as a heavy piston drive type impact wind tunnel (gantannel).

The operating conditions of the heavy piston drive type impact wind tunnel are as follows:
It is determined by the piston weight and the piston drive pressure ratio.
In this type of heavy piston drive type impact wind tunnel, since equal enthalpy compression with low thermal loss is performed, the pressure can be increased without raising the temperature of the obtained high temperature high pressure gas as compared with the impact wind tunnel. Therefore, the duration of the airflow can be expanded.

[0012]

By the way, there is a case where it is desired to conduct an experiment by forming a supersonic airflow at room temperature and atmospheric pressure having a Mach number of about 1 to 4 in the measurement chamber depending on the experiment subject.

However, in the wind tunnel shown in FIG. 2 or 3, although a supersonic air flow having a Mach number of about 1 to 4 can be formed, the temperature of the air flow ejected from the blowing nozzle is extremely lowered to room temperature or lower. Resulting in. To bring the temperature of the airflow to about room temperature, the temperature of the high-pressure gas in the high-pressure chamber may be raised by using, for example, a heater, etc. Not easy to do.

Further, in the impact wind tunnel shown in FIG. 4 and the heavy piston drive type impact wind tunnel shown in FIG. 5, since the total enthalpy becomes too high, the temperature and pressure of the air flow become too high, and the actual gas effect in the wind tunnel experiment. It becomes difficult to eliminate the effect of.

The present invention has been made in order to solve the problems of the above-mentioned conventional techniques, and can form a supersonic airflow at room temperature and atmospheric pressure, for example, having a Mach number of about 1 to 4. An object of the present invention is to provide a heavy piston drive type impact wind tunnel that can be performed and a method for controlling a heavy piston drive type impact wind tunnel that can form a supersonic airflow at room temperature and atmospheric pressure.

[0016]

A heavy piston drive type impact wind tunnel according to the present invention has a high pressure chamber filled with a high pressure drive gas and a slidable piston inside and is filled with a low pressure working gas. A tubular low-pressure chamber connected to the high-pressure chamber, and a rupture membrane separating the high-pressure chamber and the low-pressure chamber,
A blowout nozzle with a quick opening / closing valve provided at an end of the both ends of the low pressure chamber that is not connected to the high pressure chamber, and a vacuum suction measurement chamber connected to the blowout nozzle. A heavy piston drive type impact wind tunnel, further comprising a plenum chamber provided between the low pressure chamber and the blowout nozzle, the plenum chamber having an orifice for controlling the temperature and pressure of the high pressure gas generated in the low pressure chamber before the blowout. It is characterized by being provided.

A method for controlling a heavy piston drive type impact wind tunnel according to the present invention comprises: a high pressure chamber filled with a high pressure drive gas;
A shock wave is generated inside the low-pressure chamber by breaking a rupture film that has a slidable piston inside and is filled with a low-pressure working gas and separates from a cylindrical low-pressure chamber connected to the high-pressure chamber. By driving the piston, high-pressure gas is generated inside the blow-out nozzle side with the quick opening / closing valve connected to the end of the both ends of the low-pressure chamber that is not the side connected to the high-pressure chamber, and is generated. A method for controlling a heavy piston drive type impact wind tunnel in which the high pressure gas is ejected as a supersonic air flow into a vacuum suctioned measurement chamber connected to the blowout nozzle by opening the rapid on-off valve, and the low pressure is previously set. The measurement chamber by providing a plenum chamber having an orifice for controlling the temperature and pressure of the high-pressure gas generated in the low-pressure chamber before the gas is blown, between the chamber and the blow-out nozzle. And it is characterized in controlling the temperature and pressure of the air flow ejected.

[0018]

In the heavy piston drive type impact wind tunnel and the control method therefor according to the present invention, the temperature and pressure of the high temperature and high pressure gas generated in the low pressure chamber between the low pressure chamber and the blowing nozzle are set in advance to, for example, normal temperature and normal pressure. Since a plenum chamber having an orifice to be controlled is provided, the temperature of the supersonic airflow ejected from the quick opening / closing valve provided in the blowing nozzle because pressure loss is given to the high pressure gas by the orifice in the plenum chamber. And the pressure is controlled.

Further, in the heavy piston drive type impact wind tunnel according to the present invention, since the orifice is installed in a replaceable manner, the orifice diameter can be changed.

Therefore, the stagnation state of the measurement chamber is adjusted by exchanging the orifice and changing the orifice diameter, so that the operating condition of the wind tunnel is controlled with extremely high degree of freedom, and the air flow in the measurement chamber is controlled. For example, the temperature is controlled at room temperature and pressure.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view showing an example of the configuration of a heavy piston drive type impact wind tunnel according to the present invention.
1A is an overall view, and FIG. 1B is an enlarged view of a portion surrounded by a broken line in FIG.

As shown in FIG. 1A, a drive cylinder 15 which is a high-pressure chamber filled with a high-pressure drive gas is arranged, and is separated from the drive cylinder 15 through a rupturable membrane 17 so that the inside of the drive cylinder 15 is separated. An operating cylinder 18, which has a slidable piston 16 and is a low-pressure chamber filled with a low-pressure working gas, is connected. Both the drive cylinder 15 and the operation cylinder 18 are hollow cylindrical members, and a shock wave is generated in the operation cylinder 18 due to the pressure difference inside the drive cylinder 15 and the operation cylinder 18 when the rupture film 17 is broken.

Inside the operating cylinder 18, a piston 16 is installed which slides on the inner surface and moves in the longitudinal direction of the operating cylinder 18 by using the above-mentioned shock wave as a drive source.

As shown in FIGS. 1 (a) and 1 (b), one of both ends of the actuating cylinder 18 which is not connected to the drive cylinder 15 is compressed by the piston 16 and is generated. A plenum chamber 23 having an orifice 22 for controlling the temperature and pressure of high-temperature high-pressure gas of, for example, about 80 to 100 atm is provided.

In this embodiment, the orifice 22 is fastened to the flange surface of the plenum chamber 23 and can be replaced with another orifice having a different diameter. The diameter of the orifice 22 is appropriately set according to the control conditions for the high temperature and high pressure gas.

The orifice 22 has a function of restricting the flow rate of the high-pressure gas generated in the operating cylinder 18 and controlling the conditions of the air flow blown out from the blow-out nozzle 20 described later and formed in the measurement chamber 21.

As shown in FIG. 1A, the plenum chamber 23 is provided with a blowing nozzle 20 having a quick opening / closing valve 19. As the rapid opening / closing valve, a diaphragmless valve using a solenoid valve is used, but a rupturable membrane may be used. As the blowing nozzle 20, a known Laval tube is used.

A vacuum measuring chamber 21 is connected to the blowing nozzle 20. The measurement chamber 21 has a vacuum pump 24 for measurement.
Vacuum suction is performed, and the duration of the airflow is maintained at about 200 ms.

A model to be measured such as an aircraft is arranged in the measuring room 21. In this embodiment, the model (not shown) is configured to be held by a jig, but it may be naturally dropped or flown in accordance with the timing of airflow generation. Higher precision experimental results can be obtained by not using a jig or the like.

The procedure for conducting a wind tunnel experiment using the heavy piston drive type impact wind tunnel according to the present invention having the above-mentioned configuration, that is, the method for controlling the heavy piston drive type impact wind tunnel according to the present invention, is described with reference to FIG. A description will be given with reference to a) and FIG.

The inside of the drive cylinder 15 is pressurized to a high pressure, and the inside of the actuation cylinder 18 is pressurized to a low pressure. Further, the piston 16 is arranged in a predetermined position on the side of the drive cylinder 15 in the operation cylinder 18. Further, the quick opening / closing valve 19 is closed and the inside of the measurement chamber 21 is vacuumed by the vacuum pump 24.

In this state, the rupturable film 17 is broken. Then, due to the pressure difference generated between the drive cylinder 15 and the operating cylinder 18, the drive gas in the drive cylinder 15 expands rapidly toward the operating cylinder 18, and a shock wave is generated inside the operating cylinder 18. The shock wave causes the piston 16 to slide at high speed inside the operating cylinder 18, so that the operating cylinder 18 in the plenum chamber 23 provided on the measurement chamber 21 side of the operating cylinder 18 is divided into two spaces by the orifice 22. A high pressure gas of about 80 to 100 atm is retained on the side.

In this way, the high temperature and high pressure gas is stored in the working cylinder 18 side of the two spaces in the plenum chamber 23 which are divided by the orifice 22. Is opened to blow out from the blow-out nozzle 20 into the measurement chamber 21 to form a supersonic airflow. Prior to ejection from the blow-out nozzle 20, the high-temperature high-pressure gas passes through an orifice 22 provided in the plenum chamber 23, so that a pressure loss is given by this orifice 22 and the pressure and temperature of the air flow are kept at room temperature and atmospheric pressure. Controlled by.

In this way, the pressure and temperature of the air flow formed in the heavy piston drive type impact wind tunnel according to the present invention are controlled, and it becomes possible to generate, for example, an air flow at normal temperature and normal pressure.

When the conditions of the driving gas filled in the high-pressure chamber are different, the orifice is exchanged and the orifice diameter is appropriately changed to control the obtained airflow at room temperature and atmospheric pressure.

[0036]

As described above in detail, in the heavy piston drive type impact wind tunnel according to the present invention, since the plenum chamber having the orifice is provided between the low pressure chamber and the blowing nozzle, the high temperature ejected from the blowing nozzle is high. It is possible to control the temperature and pressure of the enthalpy of the high-pressure gas. Also, the orifice is replaceable. Therefore, by replacing the orifice and changing the orifice diameter, the stagnation state of the wind tunnel inside the measurement chamber can be adjusted, and it becomes possible to control the operating conditions of the wind tunnel with extremely high degrees of freedom. It is possible to control the air flow at room temperature and pressure.

[Brief description of drawings]

1 is an explanatory view showing the structure of a heavy piston drive type impact wind tunnel according to the present invention, FIG. 1 (a) is an overall view, FIG.
FIG. 1B is an enlarged view of a broken line portion of FIG.

FIG. 2 is an explanatory diagram showing an example of a structure of a conventional high speed wind tunnel.

FIG. 3 is an explanatory diagram showing another example of the structure of a conventional high-speed wind tunnel.

FIG. 4 is an explanatory view showing a structure of a conventional impact wind tunnel.

FIG. 5 is an explanatory view showing a structure of a conventional heavy piston drive type impact wind tunnel called a gun tannel.

[Explanation of symbols]

 15 Drive Cylinder (High Pressure Chamber) 16 Piston 17 Bursting Membrane 18 Working Cylinder (Low Pressure Chamber) 19 Quick Open / Close Valve 20 Blow-out Nozzle 21 Measuring Chamber 22 Orifice 23 Plenum Chamber 24 Vacuum Pump

Claims (3)

[Claims] 1. A high-pressure chamber filled with high-pressure drive gas,
A cylindrical low-pressure chamber having a slidable piston therein and filled with a low-pressure working gas, and connected to the high-pressure chamber, a rupture film separating the high-pressure chamber and the low-pressure chamber, and both ends of the low-pressure chamber. A heavy-piston-driven impact wind tunnel including a blow-out nozzle with a quick opening / closing valve provided at an end portion on the side not connected to the high-pressure chamber, and a vacuum suctioned measurement chamber connected to the blow-out nozzle. A plenum chamber provided between the low pressure chamber and the blowout nozzle, the plenum chamber having an orifice for controlling the temperature and the pressure of the high pressure gas generated in the low pressure chamber before the blowout is provided. Heavy piston drive type impact wind tunnel. 2. The heavy piston drive type impact wind tunnel according to claim 1, wherein the orifice is replaceable. 3. A high-pressure chamber filled with a high-pressure drive gas,
A shock wave is generated inside the low-pressure chamber by breaking a rupture film that has a slidable piston inside and is filled with a low-pressure working gas and separates from a cylindrical low-pressure chamber connected to the high-pressure chamber. By driving the piston, high-pressure gas is generated inside the blow-out nozzle side with the quick opening / closing valve connected to the end of the both ends of the low-pressure chamber that is not the side connected to the high-pressure chamber, and is generated. A method for controlling a heavy piston drive type impact wind tunnel in which the high pressure gas is ejected as a supersonic air flow into a vacuum suctioned measurement chamber connected to the blowout nozzle by opening the rapid on-off valve, and the low pressure is previously set. The measurement chamber by providing a plenum chamber having an orifice for controlling the temperature and pressure of the high-pressure gas generated in the low-pressure chamber before the gas is blown, between the chamber and the blow-out nozzle. The method of the heavy piston driven shock tunnel, characterized by controlling the temperature and pressure of the air flow ejected.