JPH0131947Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flow rate adjustment mechanism that adjusts the flow rate and position of shock waves of fluid flowing in a shell placed in a flow path of a wind tunnel or the like.

A model test of an aircraft air intake system using a wind tunnel is conducted as shown in Figure 1.

In the figure, A indicates a flow of wind in a wind tunnel (not shown), and a model 1 of an air intake port is disposed within the flow A by means of a fixture 2. This model 1 has a two-stage lamp 1a, a throat lamp 1b, and a rear lamp 1c, and experiments are conducted by measuring pressure at an assumed engine surface 4 in a shell 3 formed inside the model 1.

The air flow rate or shock wave position within the shell 3 is controlled by a flow rate adjustment mechanism 5 disposed near the outlet on the downstream side of the shell 3, and the details of this mechanism are shown in Fig. 2. .

A conical plug 6 having a diameter approximately equal to the diameter of the barrel 3 is slidably fitted to the tip of the cover 7. The plug 6 has its axis aligned with the axis of the shell 3, and is slid back and forth in the direction of the axis by a linear head motor 8 housed in the cover 7, thereby connecting the plug 6 and the outlet 3a of the shell 3. By adjusting the interval between the two, the flow rate or the position of the shock wave can be adjusted.

In particular, in model experiments conducted to improve the pressure recovery efficiency in the air intake of an aircraft, it is necessary to control shock waves caused by gusts of wind flowing inside the shell 3 of the model 1 and to adjust the flow rate. In order to counter air resistance, the linear head motor 8 was required to have relatively high horsepower, and the cover 7 also had to be made larger. on the other hand,
In wind tunnel model experiments, in order to ensure the reliability of experimental data, the maximum permissible value of the model cross-sectional area ratio (Blockage Ratio) to the flow path area is regulated, so a flow adjustment mechanism using a large linear head motor is required. This seriously hampered the purpose of the experiment.

The flow rate adjustment mechanism according to the present invention includes a conical plug disposed near the downstream outlet of a barrel disposed in a flow path with its axis aligned with the axis of the barrel; a cover slidably fitted at the portion;
It comprises a linear head motor that is housed in the cover and slides the plug back and forth in the axial direction, and the flow rate in the barrel is adjusted by adjusting the distance between the outlet of the barrel and the plug. However, since the plug is made hollow and a hole is bored in the conical surface of the plug, it can be used even if the linear head motor is small, as will be described later, and the overall size can be made relatively small. This provides an adjustable adjustment mechanism.

That is, in the conventional technology, the horsepower of the linear head motor had to be increased in order to advance the plug facing the outlet of the cylinder against the pressure of the fluid discharged from the cylinder, but the present invention By making the shaped plug hollow and drilling a hole in its conical surface, the fluid flowing into the plug from the hole acts as a back pressure on the plug, and as a result, the force that the plug receives in the axial direction due to the fluid is reduced. This reduces the horsepower of the linear head motor that moves the plug against the fluid.

An embodiment of the present invention will be described below with reference to FIG.

In the figure, the conical plug 6 is located at the same position as in FIG.
It is disposed near the outlet on the downstream side of the barrel with its axis aligned with the axis of the shell 3, and is formed hollow with holes 6a and 6b drilled in the horizontal direction of the conical surface (up and down in Fig. 3). It is set up. Further, reference numeral 7 indicates a cover into which the plug 6 is slidably fitted at its tip, and reference numeral 8 indicates a linear head motor that moves the plug 6 back and forth in its axial direction.

Since the flow rate adjustment mechanism according to the present invention has the above configuration, it is disposed at the downstream outlet of the barrel 3 as in FIG. 1, and the plug 6 is moved back and forth to adjust the barrel 3.
A plug 6 that can adjust the flow rate of air flowing out from the plug 6 and is moved back and forth by a linear head motor 8.
Air resistance acts on the surface of the plug, but in this case, air flows into the hollow part from the holes 6a and 6b drilled in the conical surface and acts as a back pressure from the inside of the plug. Due to the back pressure from the inside of the plug, which is based on the perforations that take pressure distribution into consideration, a force is applied in a direction opposite to the resistance acting on the conical surface of the plug.

As a result, even if a large aerodynamic force is acting on the plug 6, the force required to move the plug itself is small, and the horsepower of the linear head motor is also small, making it possible to avoid increasing the volume of the entire mechanism. Extremely useful.

Note that holes 6a and 6b formed in the conical surface of the plug 6
It is preferable to provide the plugs on the left and right sides so that there is little aerodynamic difference at the position where the surface pressure is generated by balancing the drag force and the back pressure, but it is also effective to divide the plug surface area into two equal parts. Further, although there is no direct relationship between the area of the hole and the level of back pressure, it does affect the time at which the back pressure starts acting, so it is better to decide appropriately in consideration of the test time.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a model experiment, FIG. 2 is an explanatory diagram of a conventional flow rate adjustment mechanism, and FIG. 3 is an explanatory diagram of an embodiment of the flow rate adjustment mechanism according to the present invention. 1...Model, 2...Mounting tool, 3...Body, 5...
Flow rate adjustment mechanism, 6... plug, 6a, 6b...
Hole, 7...Cover, 8...Linear head motor.

Claims (1)

[Scope of utility model registration request] A conical plug is disposed near the outlet on the downstream side of the barrel disposed in the flow path so that its axis coincides with the axis of the barrel, and the plug is slidably fitted at its tip. A linear head motor is housed in the cover and slides the plug back and forth in the axial direction.The flow rate inside the barrel is adjusted by adjusting the distance between the outlet of the barrel and the plug. A flow rate adjusting mechanism characterized in that the plug is hollow and a hole is bored in a conical surface of the plug.