JP2006064571A - Wind speed adjusting device of closed-circuit wind tunnel equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform realizable controlled wind speed fluctuation at a blowout hole of wind tunnel equipment so as to simulate a natural wind for a test of an aerodynamic noise of an automobile or the like caused by a fluctuating wind. <P>SOLUTION: The air is forcibly circulated by a fan 2 through an approximately circularly-continuous air blowing passage 3 and blown out to a measuring part 5 through the blowout hole 4. This device is equipped with a high-pressure air storage tank 11A for blowing forcibly the air into the flow of the main stream air in the air blowing passage 3 and increasing the flow rate of the air blown out to the measuring part 5 through the blowout hole 4 to thereby heighten the wind speed, and a vacuum tank 11B for sucking forcibly the air from the air in the air blowing passage 3 and decreasing the flow rate of the air blown out to the measuring part 5 through the blowout hole 4 to thereby lower the wind speed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wind speed adjusting device for a circulating wind tunnel facility used for aerodynamic experiments or the like for simulating natural wind for testing aerodynamic noise caused by fluctuating wind.

  Conventionally, as shown in FIG. 9, for example, as shown in FIG. 9, the recirculating wind tunnel equipment adjusts the air speed of the air collected at the suction port 1 (collector) with a fan 2 (blower), and passes through an air passage 3 that is substantially annularly continuous. The circulation circuit is forcibly circulated, and the air is blown out to the measurement unit 5 through the outlet 4 (nozzle). Then, air is collected from the measuring unit 5 through the suction port 1, and the air is circulated again through the air blowing path 3. In such a recirculation type wind tunnel facility, the flow rate of the main air flow as a steady flow rate flowing through the air passage 3 is determined by the rotational speed of the fan 2 as the wind speed at the outlet 4.

  Corner vanes 6 that change the direction of air flow are provided at each corner portion in the middle of the air passage 3. Among them, an air cooling device (heat exchanger) is provided on the upstream side of the corner vane 6 on the downstream side of the fan 2. Then, three rectifying wire nets 7 a, 7 b, 7 c and a rectifying grid 8 are provided on the downstream side of the corner vane 6 closest to the outlet 4, and the air to the measuring unit 5 is rectified. In addition, a measurement chamber 31 having an internal measurement unit 5 is disposed so as to surround the suction port 1 and the air outlet 4. In addition, a plurality of pulsation prevention ports 32 are provided on the downstream side of the suction port 1 in order to relieve fluctuations in the air volume and adjust the air volume on the suction side of the fan 2.

  When changing the wind speed in such a recirculating wind tunnel facility, conventionally, (i) changing the rotational speed of the fan, (ii) limiting the fan suction flow rate by the inlet guide vane, or (iii) the damper The fan discharge flow rate is limited by (4) or (iv) the flow rate is controlled by the variable pitch of the fan.

  However, in such a conventional method, (1) the response speed is slow and fast wind speed fluctuation cannot be performed, (2) the target minute wind speed fluctuation cannot be accurately performed, and (3) A single device is used to control the wind speed of the mainstream air in the wind tunnel facility and control the wind speed in a minute fluctuation region, so there is a problem that an expensive device with high functionality, high accuracy, high resolution and no hysteresis is required. is there.

  In other words, in a wind tunnel facility that performs a test of the actual vehicle size, the entire facility is large, and even if you try to fluctuate the wind in the wind tunnel facility, the air flow has a large inertia, so you can fluctuate the wind at the desired frequency. It is difficult to reproduce. In addition, since the blower is provided at a position away from the measurement unit, even if fluctuating wind is generated by the blower, the fluctuation is dull in the measurement unit, and it is not suitable for creating high-cycle fluctuating wind. There's a problem.

Accordingly, a plurality of sonic nozzles having opening / closing means and different diameters are arranged in front of the blowing nozzle, and compressed air pressure-adjusted by the pressure control means is supplied to the sonic nozzle, In addition, there is known a technique in which the blowing speed at the blowing nozzle is changed by using the adjustment of the supply pressure in the pressure control means together (for example, see Patent Document 1).
JP-A-10-19721 (paragraphs 0017 to 0022, 0025 to 0028 and FIGS. 1 to 3)

  However, in the technique described in Patent Document 1 using the sonic nozzle, since the opening / closing means for opening and closing the nozzle is provided for each sonic nozzle, the configuration of the nozzle means becomes complicated. The cost increases as the number of sonic nozzles increases.

  Moreover, since the nozzle means and the pressure control means are provided in the middle of the air flow path through which the mainstream air compressed by the compressor flows, the flow rate of the mainstream air must be adjusted by opening and closing the nozzle and controlling the pressure. A large driving force is required for adjustment. Therefore, it is difficult to apply to a wind tunnel facility with a large flow rate, such as a test for an actual vehicle size. In other words, the technique described in Patent Document 1 is merely an apparatus that generates a partial spot wind that applies a fluctuating wind only to the local area of the object to be measured.

  In view of this, the inventor changed the flow rate of the entire system by forcibly blowing air to the mainstream air (steady flow rate) by the fan or forcibly sucking air from the mainstream air in the wind tunnel facility. It was conceived that the wind speed at the outlet can be adjusted relatively easily by changing the wind speed at the outlet, and the present invention has been made.

  It is an object of the present invention to perform a controlled wind speed variation that is feasible at the outlet of a wind tunnel facility so as to simulate natural wind for testing aerodynamic noise of automobiles or the like due to the fluctuating wind.

  According to the first aspect of the present invention, there is provided a wind speed adjusting device for a recirculation type wind tunnel facility that forcibly circulates air in a blower through a substantially circular continuous air passage and blows out the air through a blowout port to a measurement unit. The flow rate variation means for forcibly varying the flow rate of the air flowing through the air passage is provided, and the flow rate variation means is external to the main flow air having a steady flow rate that is flowed through the air passage by the blower. It is characterized by forcibly changing the flow rate of air flowing through the air blowing path by blowing air (auxiliary air) or sucking (partial) air from the mainstream air to the outside. In other words, the invention of claim 1 is a steady flow rate that is flowed by a blower that operates in a steady state, and changes in an increasing direction or a decreasing direction around the flow rate of a large volume of mainstream air.

  In this way, the flow rate of the air flowing through the air passage is forcibly changed by the flow rate changing means, and the wind speed at the outlet of the wind tunnel facility changes according to the change. Centering on the steady flow rate of the mainstream air flowing through the air flow path by the blower, the amount of air is considerably smaller than the steady flow rate, and the wind speed is fluctuated, so the wind speed at the outlet is fluctuated instantaneously, Further, it is relatively easy to change the frequency with a controlled period.

  According to a second aspect of the present invention, the flow rate varying means includes a high-pressure air reservoir that stores compressed air that is blown into the air passage, and a flow rate adjusting means that adjusts the amount of air that is blown from the high-pressure air reservoir into the air passage. The flow rate of the air blown out through the air outlet to the measuring unit can be increased with respect to the steady flow rate of the mainstream air.

  In this way, in the wind tunnel facility, a predetermined amount of air is forcibly blown into the main flow air at a steady flow rate determined by the blower, so that the air flow rate of the entire system is changed in the increasing direction. The wind speed at the air outlet can be increased relatively easily.

  According to a third aspect of the present invention, the flow rate varying means includes a vacuum tank in a negative pressure state for sucking air from the air passage, and a flow rate adjusting means for adjusting the amount of air sucked into the vacuum tank from the air passage. And it is also possible to make it the structure which reduces the flow volume of the air which blows off through the said blower outlet with respect to the said measurement part with respect to the steady flow volume of the said mainstream air.

  In this way, in the wind tunnel facility, the air flow rate of the entire system is changed in the decreasing direction by forcibly sucking a predetermined amount of air from the main flow air of the steady flow rate determined by the blower, and the measurement unit The wind speed at the air outlet can be reduced relatively easily.

  According to a fourth aspect of the present invention, the air volume variation means includes a high-pressure air reservoir that stores compressed air that is blown into the air passage, and a flow rate adjusting means that adjusts the amount of air that is blown from the high-pressure air reservoir into the air passage. First flow rate variation means, and the flow rate variation means includes: a vacuum tank in a negative pressure state for sucking air from the air blowing path; and a flow rate adjusting means for adjusting the amount of air sucked into the vacuum tank from the air flow path. The second flow rate variation means may be provided, and the flow rate of the air blown out through the outlet to the measurement unit may be increased or decreased with respect to the steady flow rate of the mainstream air.

  In this way, in the wind tunnel equipment, a predetermined amount of air is forcibly blown into the mainstream air at a steady flow rate by the blower, the air flow rate of the entire system is changed in the increasing direction, and the wind speed at the outlet is increased. Or by forcibly sucking a predetermined amount of air from the main flow air at a steady flow rate by the blower, the flow rate of the entire system can be changed in a decreasing direction, and the wind speed at the outlet can be reduced. Can be increased or decreased relatively easily.

  As described above, according to the present invention, the flow rate variation means increases or decreases the amount of air that is considerably smaller than the steady flow rate around the steady flow rate of the mainstream air that flows through the blower passage, and the air flowing through the blower passage. Since the flow rate is forcibly changed, the wind speed at the outlet of the wind tunnel facility can be changed instantaneously and in a controlled cycle. Therefore, it is possible to perform a controlled wind speed variation that is feasible at the outlet of the wind tunnel facility so as to simulate natural wind for testing aerodynamic noise of automobiles and the like.

  Embodiments of the present invention will be described below with reference to the drawings. Since the basic configuration is the same as that shown in FIG. 9, the same reference numerals are used for the same components, and the description thereof is omitted.

  FIG. 1 is a diagram showing a schematic configuration of a wind speed adjusting device for a circulating wind tunnel facility according to a first embodiment of the present invention.

  As shown in FIG. 1, a high-pressure air reservoir 11 </ b> A is connected in the middle of the air passage 3 and downstream of the fan 2 through a connection passage 13 </ b> A having a flow rate adjusting valve 12 </ b> A. This connection position is on the upstream side of the rectifying wire net 7. High pressure compressed air is stored in the high pressure air storage tank 11A by the compressor 14A. That is, the flow rate fluctuation means for forcibly changing the flow rate of the air flowing through the blower passage 3 in the middle of the blower passage 3 and downstream of the fan 2 (increasing the flow rate of air blown out through the outlet to the measurement unit) Flow rate variation means) is provided.

  Accordingly, the flow rate G2 adjusted by the flow rate adjustment valve 12A is blown as an air flow through the connection passage 13A with respect to the steady flow rate G1 by the fan 2, and flows through the blower passage 3 on the downstream side of the high-pressure air storage tank 11A. The flow rate fluctuates (increases) to G1 + G2, and air is blown out from the outlet 4 (opening sectional area A1) with the increased wind speed v. That is, apart from the main flow by the fan 2 that is the main air source, a predetermined air flow rate is increased with respect to the steady flow rate of the main flow air by the air blown from the high-pressure air storage tank 11A that is the auxiliary air source, and the wind speed at the outlet 4 is increased. Increase.

  In this case, the opening cross-sectional area of the flow rate adjusting valve 12A is adjusted, and the flow rate of the air blown from the high-pressure air storage tank 11A in which the compressed air is stored at the pressure P2 (> pressure P1: pressure in the mainstream air portion) is adjusted. The

  At this time, the wind speed v at the outlet 4 is obtained as follows.

ここで、Ｇ２は、高圧貯気槽１１Ａでの速度０、圧力Ｐ２の静止状態から圧力Ｐ１状態の送風路へ速度ｖ１で吹き込む流量であり、ベルヌーイの定理から、

Here, G2 is a flow rate at which the velocity 0 in the high-pressure reservoir 11A is blown at a velocity v1 from a stationary state of the pressure P2 to the air passage of the pressure P1 state, and from Bernoulli's theorem,

ｖ１は単位時間あたり、断面積Ａ２を流れる流量に相当するので、

Since v1 corresponds to the flow rate flowing through the cross-sectional area A2 per unit time,

と表すことができる。

It can be expressed as.

  That is, when it is desired to change the wind speed by 10%, it can be realized by changing the flow rate by 10%.

  Here, when the pressure P2 is fixed and the cross-sectional area A2 is periodically changed, the flow rate can also be periodically changed. In addition, the fluctuation amplitude can be changed by changing the pressure P2.

  Moreover, as shown in FIG. 2, it is also possible to provide a vacuum tank 11B in a negative pressure state to which a vacuum pump 14B is connected, instead of the high-pressure gas storage tank 11A. That is, the flow rate fluctuation means for forcibly changing the flow rate of the air flowing through the blower passage 3 in the middle of the blower passage 3 and downstream of the fan 2 (the flow rate of the air blown out through the outlet 4 to the measuring unit 5). A flow rate variation means for reducing the flow rate can be provided.

  In this case, the adjusted flow rate G3 is sucked from the flow rate G1 by the fan 2, and the flow rate fluctuates (decreases) to G1-G3, so that air flows from the blowout port 4 (open sectional area A1) with the wind speed v. Blown out. That is, by sucking a part of the flow rate of the mainstream air from the fan 2 into the vacuum chamber 11B, which is outside, the flow rate of the air flowing through the blower passage 3 is reduced and the wind speed at the outlet 4 is reduced. Also in this case, the air is sucked through the connection passage 13B provided with the flow rate adjusting valve 12B.

  At this time, the opening cross-sectional area of the flow rate adjusting valve 12B is adjusted, and the adjusted predetermined amount of flow rate is sucked into the vacuum chamber 11B having the pressure P3 (<pressure P1 in the main flow portion). The pressure in the vacuum chamber 11B is adjusted by the vacuum pump 14B, and the suction amount is adjusted by adjusting the opening cross-sectional area A3 of the flow rate adjusting valve 12B.

  At this time, the wind speed v at the outlet 4 is obtained as follows.

Ｇ３は、前記図１の場合と同様にして、

G3 is the same as in the case of FIG.

と表すことができる。

It can be expressed as.

  In this case as well, similarly to FIG. 1, the flow rate, that is, the wind speed can be periodically changed by periodically changing the opening cross-sectional area A3 of the flow rate adjusting valve 12B.

  FIG. 3 is also an embodiment of the present invention, but it is assumed that the flow rate, that is, the fluctuation range (adjustment range) of the wind speed can be increased by using the high-pressure reservoir 11A and the vacuum chamber 11B together. . 14C is an actuator that functions as a compressor for the high-pressure gas storage tank 11A located on the downstream side and functions as a vacuum pump for the vacuum tank 11B located on the upstream side.

  About the fluctuation range of the wind speed in the blower outlet 4 in FIG. 3, it becomes the combination of the apparatus shown in FIG.2 and FIG.3, and the fluctuation | variation range of the flow volume of the air which flows through a ventilation path in the apparatus of FIG. %, If the fluctuation range in the apparatus of FIG. 2 is −10% to 0, the wind speed can be adjusted in the fluctuation range of −10% to + 10% in the apparatus of FIG.

  As the flow rate adjusting valves 12A and 12B, well-known ones capable of changing the opening cross-sectional area can be used. However, for example, (1) a valve that is rotationally driven such as a butterfly valve is continuously operated by an electric motor ( It is also possible to use one that rotates (opens and closes) at a constant speed, and (2) one that arbitrarily controls the opening and closing speed and opening of the valve. Here, if the valve is operated continuously (at a constant speed) with an electric motor as in (1), the valve opening can be varied with a sine wave, and the opening and closing speed of the valve as in (2), and If the opening degree is controlled arbitrarily, flow rate fluctuations can be performed not only in sine waves but also in arbitrary waveforms / cycles.

  As described above, the parameters to be changed when the wind speed is changed are the pressure, the opening cross-sectional area and the fluctuation cycle (speed), and the parameters of the flow rate fluctuation means are those of the high-pressure reservoir 11A or the vacuum tank 11B. The pressure, the opening cross-sectional area of the flow rate adjusting valves 12A and 12B, and the fluctuation period (speed) thereof.

  In the above-described embodiment, only the flow rate adjusting valves 12A and 12B are provided in the connection passages 13A and 13B, but in addition to the flow rate adjusting valves 12A and 12B as in the device shown in FIG. Thus, it is also possible to provide pressure regulating valves 12A ′ and 12B ′.

  The target value to be adjusted by the wind speed fluctuation control may be a constant pressure target value of the auxiliary air source. For example, as shown in FIG. 4, the auxiliary air is obtained by multiplying the maximum fluctuation value of the wind speed fluctuation target value by a gain. You may make it change the target value of the pressure of a source (the high pressure air tank 11A, the vacuum tank 11B).

  In addition, as shown in FIG. 5, the flow rate adjustment valve 12A is obtained by dividing the wind speed fluctuation target value by the square root of the absolute value of the auxiliary air source pressure (high pressure reservoir pressure, vacuum chamber pressure) and multiplying that value by the gain. , 12B, the target value of the opening cross-sectional area can be set. Further, if the pressure of the auxiliary air source is controlled to be constant, as shown in FIG. 6, the target value of the opening cross-sectional area of the flow rate adjusting valve can be set by multiplying the target wind speed fluctuation value by a gain. Although the gain may be a constant value, more accurate fluctuation control can be performed by using a variable gain with the wind speed fluctuation target value as a parameter.

  FIG. 7 is an example of a configuration in the case of automatically controlling and calculating a changing target value in one embodiment of the present invention.

  In this case, pressure detectors 21A and 21B are provided in the high-pressure gas storage tank 11A and the vacuum tank 11B. Flow rate adjusting valves 12A and 12B provided in the connection passages 13A and 13B (connecting the high pressure reservoir 11A and the vacuum chamber 11B to the air passage 3) and (connecting the high pressure reservoir 11A and the vacuum chamber 11B to the actuator 14C) ) Opening detectors 22A, 22B, 22A 'and 22B' are provided in the pressure regulating valves 12A 'and 12B' provided in the connection passages 13C and 13D, respectively. A fan wind speed detector 23 is provided on the downstream side of the fan 2, and an outlet air speed detector 24 is provided on the outlet 4.

  Based on the signals from these detectors 21A, 21B, 22A, 22B, 22A ′, 22B ′, 23, 24, the pressure target values P2, P3 of the auxiliary air source (the high pressure storage tank 11A and the vacuum tank 11B) or The (opening) cross-sectional area target value of the flow rate adjusting valves 12A, 12B is set. FIG. 8 is a control block diagram at that time. Here, the control calculation is performed so that the target value and the detected value (measured value) are the same with respect to the wind speed v at the outlet 4, and a typical example is a PID calculation.

  That is, it is determined from the polarity of the wind speed fluctuation target value whether air is blown from the high-pressure reservoir 11A to increase the air flow rate, or air is sucked into the vacuum chamber 11B to decrease the air flow rate. The cross-sectional area target value by the flow rate adjusting valves 12A and 12B is calculated so that the target value and the detected value for the wind speed at the outlet 4 are the same, and the opening degree of the flow rate adjusting valves 12A and 12B is adjusted based on the calculation result. Is done.

  If comprised as mentioned above, there exists a merit in the following points.

  (1) There are few components and the structure is simple.

  As the flow rate variation means, there may be an actuator 14C (compressor 14A or vacuum pump 14B) and a tank (high pressure air storage tank 11A, vacuum tank 11B).

  Since the fluctuation (adjustment) of the wind speed is mainly performed by opening control (control of the opening cross-sectional area) of the flow rate adjusting valves 12A and 12B, the control can be simplified. That is, when the wind speed fluctuates, the pressure regulating valves 12A 'and 12B' need only hold a predetermined pressure.

  (2) The factors that adjust the fluctuation of the wind speed are the opening area of the flow rate adjusting valves 12A and 12B and the pressure value of the tank (high pressure storage tank 11A, vacuum tank 11B), both of which can be used as parameters. A wide adjustment range for wind speed is feasible.

  The wind speed (air flow rate) can be adjusted by the opening degree (opening area) of the flow rate adjustment valves 12A and 12B, and the wind speed (air flow rate) can be determined in combination with the pressure adjustment function. Periodic fluctuations can be easily realized by controlling the opening and closing speeds of the flow rate adjusting valves 12A and 12B. The tank pressure can be changed to an arbitrary value, and the pressure is controlled to be constant during the wind speed fluctuation control.

  In addition, by reducing the main wind speed target value by one amplitude of the variable wind speed and taking over the entire area of the variable wind speed with only the blowout system, the same effect as the control in the two systems including the suction system is achieved while reducing the control target. It can be realized easily. Similarly, the main wind speed target value can be increased by one amplitude of the variable wind speed, and the entire area of the variable wind speed can be handled only by the suction system.

  The steady flow rate and the wind speed of the mainstream air are adjusted by controlling the rotation speed of the fan 2.

  In addition, the present invention is applied to a circulating wind tunnel as a general wind tunnel, but can also be applied to an Eiffel wind tunnel that does not circulate the air volume.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the wind speed adjusting device of the reflow type wind tunnel equipment which is 1st Embodiment based on this invention. It is a figure which shows schematic structure of the wind speed adjusting device of the reflow type wind tunnel equipment which is the 2nd Embodiment which concerns on this invention. It is a figure which shows schematic structure of the wind speed adjusting device of the reflow type wind tunnel equipment which is the 3rd Embodiment which concerns on this invention. It is explanatory drawing of the setting method of the pressure target value of the auxiliary air source (high pressure air reservoir, vacuum tank) which adjusts wind speed fluctuation | variation control. It is explanatory drawing of the setting method of the cross-sectional area target value of the flow regulating valve which adjusts wind speed fluctuation | variation control. It is explanatory drawing of the setting method of the cross-sectional area target value of the flow regulating valve which adjusts wind speed fluctuation | variation control. It is a figure which shows schematic structure of one Embodiment of the wind speed adjustment apparatus of a reflow type wind tunnel installation in the case of carrying out control calculation automatically of the fluctuating target value. It is a control block diagram of the apparatus shown in FIG. It is a figure which shows schematic structure of the conventional recirculation type wind tunnel equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Suction port 2 Fan 3 Air passage 4 Outlet 5 Measuring part 6 Corner vane 7 Commutation wire net 8 Rectification grid 9 Air cooling device 11A High pressure air tank 11B Vacuum tank 12A, 12B Flow rate adjustment valve 12A ', 12B' Pressure adjustment valve 13A , 13B Connection passage 14A Compressor 14B Vacuum pump 21A, 21B Pressure detector 22A, 22B Flow rate adjustment valve opening detector 22A ', 22B' Pressure adjustment valve opening detector 31 Measurement chamber 32 Pulsation prevention port

Claims (4)

In a wind speed adjusting device for a recirculation type wind tunnel facility that forcibly circulates air in a blower through a substantially continuous air passage, and blows out the air through a blow outlet to a measurement unit,
A flow rate varying means for forcibly varying the flow rate of the air flowing through the air passage is provided;
The flow rate variation means blows air from the outside to the steady flow main flow air flowing through the blow passage by the blower, or sucks out a part of the air from the main flow air to the outside through the blow passage. A wind speed adjusting device for a recirculation type wind tunnel facility, characterized by forcibly changing the flow rate of flowing air. The flow rate varying means has a high-pressure reservoir that stores compressed air that is blown into the air passage, and a flow rate adjusting means that adjusts the amount of air that is blown from the high-pressure reservoir into the air passage.
2. The wind speed adjusting device for a recirculation type wind tunnel facility according to claim 1, wherein a flow rate of air blown through the blowout port to the measuring unit is increased with respect to a steady flow rate of the mainstream air. The flow rate varying means has a vacuum tank in a negative pressure state for sucking air from the air passage, and a flow rate adjusting means for adjusting the amount of air sucked from the air passage into the vacuum tank,
2. The wind speed adjusting device for a recirculation type wind tunnel facility according to claim 1, wherein a flow rate of air blown through the blowout port to the measurement unit is reduced with respect to a steady flow rate of the mainstream air. The air volume variation means is
A first flow rate variation means having a high pressure reservoir for storing compressed air to be blown into the blower passage, and a flow rate adjusting means for adjusting the amount of air blown from the high pressure reservoir to the blower passage;
The flow rate varying means includes a second flow rate varying means having a vacuum chamber in a negative pressure state for sucking air from the air blowing path, and a flow rate adjusting means for adjusting the amount of air sucked into the vacuum tank from the air blowing path. ,
2. The wind speed adjusting device for a recirculation type wind tunnel facility according to claim 1, wherein the flow rate of air blown through the blowout port to the measuring unit is increased or decreased with respect to the steady flow rate of the mainstream air.

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