JPH0472538A - Wind tunnel for making air current visible - Google Patents

Abstract

PURPOSE:To prevent an offensive smell and environmental pollution or the like and to make the visibility of an air current more excellently by using powder or particulate substance continuously or intermittently supplied as a tracer to, and recovering it in a wind tunnel circuit. CONSTITUTION:A tracer recovering device 13 is directly connected at the downstream side of an observation part 3 provided inside an air duct 1. A conductor 22 is connected from the downstream side of an air tunnel fan 2 in the air duct 1 to a tracer tank 21 and further to a tracer nozzle 11. The tracer is continuously or intermittently emitted in a direction denoted with an arrow 12 from the tip of the nozzle 11 into an air current, and powder or particulate substance 15 is recovered in a recovering tank. On the other hand, an exhaust air discharged from the tracer recovering device 13 is partially supplied through a return duct 16 to the tunnel fan 2, and enters the tracer tank 21 to be agitated there for mixing with the particulate substance, and further emitted into the air current in the air duct 1 through a control valve 25 again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wind tunnel for visualizing airflow.

[Prior art] Conventional visualization wind tunnels use "smoke" etc. as a means (tracer) to make it possible to visually see the trajectory of airflow, and exhaust the smoke outside after a certain period of operation. Or, in Elafel-type wind tunnels, smoke was exhausted directly to the outside.

Figure 7 shows a conventional Göttingen type (circulation type) wind tunnel.
Figure 8 shows a conventional Elafel type wind tunnel, in which an airflow 6 is generated in the wind pipe l by a blower 2, and the flow around a model (test specimen) 4 placed in an observation tunnel 3 is controlled. For visualization purposes, a method was adopted in which smoke generated by a smoke generator (not shown) installed separately was discharged from a bright line nozzle 5 into the airflow in the direction of the arrow 7. Therefore, the smoke released into the airflow is diffused and circulated within the wind pipe 1 in the case of FIG. 7, and is discharged into the atmosphere in FIG. 8.

The conventional visualization wind tunnel has the following problems.

(1) If the recirculation type shown in Fig. 7 is operated for a long time, the wind tunnel will be filled with smoke, making it difficult to see the flow of smoke clearly.

Another drawback is that smoke particles adhere to the inner walls of the wind tunnel, causing them to become dirty.

(2) In the case of the Elafel type shown in FIG. 8, smoke is emitted into the laboratory room or into the outside air, resulting in a significant odor and causing health and pollution problems.

(3) In order to solve the problem in item (2) above, research is being conducted to generate odorless and harmless smoke, but when using water vapor mist or dry ice, for example, the concentration of smoke is insufficient. However, there was a drawback that the black-and-white contrast deteriorated, resulting in poor visibility and insufficient visualization.

(4) If smoke, dry ice, etc. are used, they are temperature dependent and may cause temperature changes to the test specimen, so they cannot be used when thermal effects must be considered at the same time.

[Problem to be solved by the invention]

An object of the present invention is to provide a visualization wind tunnel that eliminates the drawbacks of the prior art, allows good visualization of airflow, and does not cause problems such as odor and pollution.

[Means to solve the problem]

The structure of the present invention uses powder or fine particles as a tracer instead of smoke, and includes means for continuously or intermittently supplying these, and means for collecting the tracer in a wind tunnel circuit. It is characterized by:

[Function] The powder or fine particles released into the airflow from the powder or fine particle discharge nozzle installed on the upstream side of the observation side flows in the wind pipe together with the gas and influences the flow around the model (test specimen). It can be visualized. Further downstream, a device for recovering these tracers is installed, so that the tracers are separated from the air stream and stored in a collection tank.

Therefore, in both the Genotingen type and the Enofel type 1, smoke etc. do not scatter into the outside air as in the conventional case, and there is no problem as in the case of smoke tracers.

〔Example〕

FIG. 1 shows an embodiment of the Göttingen type, and parts given the same reference numerals as those in the conventional example in FIG. 7 represent the same parts or the same parts. The wind pipe 1 is a closed circuit as a whole, and a test specimen 4 is placed in an observation section 3 provided inside, and a tracer collection device 13 is directly connected to the downstream side of the observation section 3. Exhaust from the tracer recovery device 13 is sent to the wind tunnel via the return duct 16.
It is connected to IT machine 2. Reference numeral 14 denotes a recovery tank for collecting recovered powder or fine particles 15 in the form of hollow microcapsules made of a polymeric material with a diameter of 5 to 10 microns. The recovery tank 14 in the illustrated embodiment is a cyclone type dust collector, which is the cheapest and performs highly efficient tracer collection, but other collection devices may be installed.

A tracer supply nozzle 11 for powder or fine particles is installed on the upstream side of the observation unit 3, and the tracer is continuously or intermittently fed into the air stream from the tip of the 7° x 2°:11 in the direction shown by the arrow 12. It is now possible to release it to An example of a device for sending a tracer to the nozzle 11 is shown in FIG. That is, the conduit 22 is connected to the tracer tank 2 from the downstream side of the wind tunnel blower 2.
1 and further connected by conduit 23 to tracer nozzle 11
A valve 25 (which may also be a damper) and an electromagnetic valve 24 are interposed in the middle of the conduit 23, and the electromagnetic valve 24 is configured to be opened and closed intermittently by a control device 26. Further, there is a stirring device 27 at the bottom of the tracer tank 21 to stir the tracer.

In this way, a part of the airflow extracted from the downstream side of the wind tunnel blower 2 enters the tracer tank 21 and mixes with the stirred fine particles, and can be released into the airflow in the wind pipe 1 via the control valve 25 again. It is something. At that time, control valve 2
Thus, the amount of the tracer mixture gas can be adjusted, and the electromagnetic valve 24 can cause the tracer to flow out intermittently at arbitrary time intervals.

FIG. 4 shows a modification of the tracer tank 21.
The conduit 22 is not connected to the wind pipe I, but is connected to the air supply fan 31, and the tracer is placed in advance in a cloth storage bag 32.

Then, a protrusion 34 is provided on the inner wall surface of the tracer tank 21,
The storage bag 32 is rotatably supported by being connected to a motor 33 via a shaft 33a, and when the motor 33 is rotated, the storage bag 32 hits the protrusion 34 and rotates, and the tracer inside the bag is scattered from the bag, and the tracer 28 It floats in the tank 21 as shown in .

The air supply fan 31 is operated to send the floating tracer to the conduit 23 and eject it from the nozzle 11 into the air stream.

FIG. 5 shows another embodiment of the tracer supply device, in which a tracer receiver 44 is provided in the recovery tank A, and a conduit 43 led out from this is connected to the tracer tank 21 via a pump 42 capable of transporting powder. 41, the fine particles 15 collected in the recovery tank are further sent from the tracer receiver 44 through the conduit 43 to the conduit 41 by the pump 42, and then enter the tracer supply tank 21.

On the other hand, as explained in FIG.
sent to. The following is the same as in FIG.

FIG. 6 shows a diagram in which the tip 11a of the nozzle 11 is divided into multiple parts in order to view various locations widely in the wind pipe 1, in other words, to widen the visualization range.
Multiple stripes of tracer can be simultaneously flowed out from a. The nozzle is streamlined as shown in FIG. 6(b) to reduce turbulence in the airflow.

Next, FIG. 2 shows an example in which the blower 2 is connected to the recovery device 13 through the return duct 16.
The downstream side of the gas is discharged into the atmosphere via a filter 17. Therefore, the powder or particulate tracer discharged from the tracer discharge nozzle 11 is completely collected by the cyclone 3 and the final filter 17 and is not discharged into the atmosphere.

In the present invention, tracers in the form of powder or fine particles released into the wind tunnel airflow are collected by a collection device downstream of the observation unit and circulated in the wind tunnel, and are not discharged into the outside air. This is the gist of the invention.

〔Effect of the invention〕

According to the visualized wind tunnel of the present invention, various excellent effects shown below are exhibited.

(1) Since powder or fine particles are used as a tracer,
Since the disadvantages of conventional smoke and dry ice are removed and these are recovered downstream, the tracer is not discharged to the outside and problems such as odor and pollution do not occur.

(2) Powder and fine particles have excellent performance as tracers and reflect light well, so the contrast of the tracer trace is good and the visualization of airflow is improved. , will not adhere to the surface of the test specimen or form condensation. And since it is used at room temperature, there is no temperature effect like with dry ice.

(3) The recovered fine particles can be used again from the release device as a tracer, which is economical.

[Brief explanation of drawings]

1 and 2 show examples of the visualization wind tunnel according to the present invention, with FIG. 1 showing the Göttingen type and FIG. 2 showing the Enfel type. FIG. 3 is a joint cross-sectional side view of the tracer supply device, FIG. 4 is a vertical cross-sectional side view showing a tracer tank and another embodiment of the tracer supply device, and FIG. 5 is a longitudinal cross-sectional view showing still another embodiment of the tracer supply device. Side view, Figure 6 (a
) is a vertical side view showing another embodiment of the tracer discharge nozzle, FIG. 6(b) is a cross-sectional plan view taken along line xx' in FIG. 6(a), and FIG. 7 is a conventionally known Genotingen type wind tunnel. FIG. 8 is a longitudinal side view of the Esofer type wind tunnel. 1-Wind pipe, 2-Blower, 3-Observation section, 4-Test specimen, 11
~Tracer sending nozzle, 13~Tracer recovery device, 14
~ Recovering acid, 15 ~ Powder, fine granule tracer

Claims (1)

[Claims] A visualization wind tunnel comprising means for continuously or intermittently supplying a tracer made of powder or microcapsule-like fine particles, and means for collecting the tracer into a wind pipe circuit.