JPH109996A - Control apparatus for flow rate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus by which a flow rate close to a target flow-rate value is obtained by a method in which the target flow-rate amount of the air which flows out from a nozzle is input in advance to a target-flow-rate-amount setting means, a pressure and a flow rate are calculated by a pressure calculation means and a flow-rate calculation means, an actual process amount which is detected by a sensor is compared and computed and the valve travel of every control valve is calculated so as to be output to a valve-travel instruction means. SOLUTION: A flow-rate regulating valve 10 is controlled in such a way that the flow rate of the air which flows into a heater 11 from an air storage device 8 becomes a value which is calculated in advance by a flow-rate calculation means 31. After that, pressure regulating valves 13, 15 are controlled in such a way that an air flow becomes a value in which an exit pressure 18, at the heater 11, detected by pressure sensors 12, 16 and an upstream pressure 19 at a measuring-part nozzle 17 are calculated by a pressure calculation means 2. When the process amount of the upstream pressure 19 at the measuring-part nozzle 17 follows a calculated value, the nozzle-air-outflow amount of the measuring-part nozzle 17 becomes a flow rate which is close to a target value. That is to say, an air target value from the nozzle 17 is calculated by using a calculation expression, and the pressure calculation means 2, the flow-rate calculation means 3 and a valve-travel instruction means 5 are controlled on the basis of the set value of a target-flow-rate setting means 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control device, and more particularly to a flow control device applied to wind tunnel equipment used for aerodynamic research of an aircraft or the like.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional open circuit blow-out type wind tunnel has an air storage 19, a heater 20, a pressure regulating valve 21 and a nozzle 23 connected from the upstream side in the flow direction. The pressure regulation control of 21 has been performed by the pressure sensor 22 which detects the pressure on the upstream side of the nozzle 23 on the outlet side of the pressure regulation valve 21.

[0003]

That is, in the above prior art, the air outflow amount of the nozzle 23 is controlled only by the upstream pressure of the nozzle 23. The reason for this is that the conventional open-circuit blow-out type wind tunnel has a
Since the necessity of controlling with high precision and high responsiveness was not asked, control of only the nozzle upstream pressure was sufficient. However, as the flow control in the wind tunnel has become more sophisticated, it has been impossible to accurately follow the target air outflow amount in an attempt to control the time-varying air flow rate by controlling only the nozzle upstream pressure. Bad control. In addition, when the response is improved, there is a problem that the pressure at the time of rising at the upstream of the measurement section nozzle overshoots. Therefore, an object of the present invention is to provide a flow control device that accurately follows a target air outflow amount without sacrificing responsiveness, and in particular, to provide a flow control device applied to wind tunnel equipment.

[0004]

In order to achieve the above technical object, the present invention provides a target flow rate setting means 1 for inputting and setting a target flow rate as shown in FIG. The pressure calculating means 2 and the flow rate calculating means 3 for calculating the pressure and the flow rate, and the valve opening is calculated from the calculation result and the input value of the sensor 4 converted into the engineering value, and the valve opening command signal and the opening to the display section 6 are calculated. Valve opening degree indicating means 5 for outputting a display signal to valve 7
We propose a flow control device composed of

According to this invention, the pressure and flow rate to be controlled by the pressure calculation means 2 and the flow rate calculation means 3 are calculated by inputting the target flow rate of air flowing out of the nozzle to the target flow rate setting means in advance. . Next, the calculated result is compared with the actual process amount detected by the sensor 4 to calculate the valve opening of each control valve, and when each control valve is operated, a flow rate close to the target flow value is obtained. Can be.
Note that the engineering value conversion refers to converting an electrical signal (for example, an analog signal) detected by the sensor into, for example, a digital value for calculation by a calculation device. The process amount indicates a pressure flow rate actually detected by the sensor. This is provided to distinguish it from the precomputed pressure and flow values to be controlled.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only. FIG. 2 shows a configuration diagram of a wind tunnel facility incorporating the flow control device according to the embodiment of the present invention. In FIG. 2, a first pressure sensor 12 disposed so as to be able to detect the pressure at the outlet side of the air storage unit 8, the flow control valve (flow control valve) 10, and the heater 11 from the upstream side in the air flow direction; Pressure sensor 1
2 is branched into two branches at the downstream side of the detection position, and the nozzle 14 for discharging air to the first branch line 30 through the first pressure regulating valve 13 regulated by the first pressure sensor 12. Are connected. On the other hand, a measuring part nozzle 17 is connected to the second branch pipe line 31 via a second pressure regulating valve 15 regulated by a second pressure sensor 16, and the pressure regulation of the pressure regulating valve 15 is performed. A pressure sensor 16 for performing control is provided so as to detect a pressure on the upstream side of the nozzle 17 on the outlet side of the pressure regulating valve 15.

FIG. 3 is a control block diagram for controlling such an embodiment. Target flow rate setting means 1 for inputting and setting a target flow rate, pressure calculating means 2 for calculating pressure and flow rate from the set values, and The point that the flow rate calculation means 3 and the display unit 6 are provided is the same as that of FIG. 1, but the sensor 4 includes the first and second pressure sensors 12 and 16 as described above.
The flow control valve 10 and the first pressure control valve 1
Valve opening indicating circuit 10 corresponding to third and second pressure regulating valves 15
A, 13A and 15A are provided, and the valve opening degree indicating circuit 10 is provided.
In A, the valve opening is calculated from the calculation result of the flow rate calculating means 3 and a valve opening command signal and an opening display signal to the display unit 6 are output. In the valve opening degree indicating circuits 13A and 15A, the pressure sensors 13 and 15 corresponding to the calculation results of the pressure calculating means 2 are provided.
Is calculated from the digitally converted pressure detection value,
It outputs a valve opening command signal and an opening degree display signal to the display unit 6. Note that, for example, the cv value range of the flow control valve 10 is 0 to 350,
The cv value range of the first pressure regulating valve 13 is 0 to 1300, and the cv value range of the second pressure regulating valve 15 is 0 to 650. The throat area of the air discharge nozzle 14 is 29.5 × 10 ^-4 m.
^2. Throat area of measuring part nozzle 17 is 0.0531m ²
Is set to

Next, the operation based on the embodiment will be described. As described above, the flow regulating valve 10 is controlled and sent to the heater 11 side so that the flow rate of the air flowing from the air storage 8 to the heater 11 becomes a value calculated by the flow rate calculating means 3 in advance. After being heated by the heater 11, the air flow becomes a value calculated by the pressure calculating means based on the outlet pressure 18 of the heater 11 and the upstream pressure 19 of the measuring unit nozzle 17 detected by the pressure sensors 13 and 15. The pressure control valves 13 and 15 are controlled. The adjustment range of the valve opening is 0 to 100%. If the process amount of the upstream pressure 9 of the measurement unit nozzle 17 follows the calculated value, the nozzle air outflow amount mp of the measurement unit nozzle 17 is calculated by the following equation 1), so that a flow rate close to the target value can be obtained. it can. mp = (A · φ · Pp) / (R · T ₀ ) ^1/2 ... 1) A: Area of nozzle throat of measurement section φ: Constant Pp: Nozzle upstream pressure of measurement section nozzle 17 R: Air gas constant T ₀ : Air temperature

[0009] Next, Table 1 shows a target upstream pressure value PPs of the measurement nozzle 17, a target pressure Pcs at the outlet of the heater 11, a target air value flowing out of the measurement nozzle 17 (input value m of the measurement air amount), and An equation for calculating a target value F _AS of the air inflow amount of the heater 11 is shown. Pressure calculation means 2 for calculating pressure and flow rate from the set values of target flow rate setting means 1 based on this equation
And the flow rate calculating means 3 and the valve opening degree indicating means 5 are controlled.

[0010]

[Table 1]

Next, using the embodiment of FIGS. 2 and 3, control is performed with target values at respective control points calculated from the time-varying air target values flowing out of the measurement section nozzle 17 by the calculation formula in Table 1. As a result, the upstream pressure 9 of the measuring section nozzle 17 becomes
It is possible to follow the target value as shown in FIG. 5, and as a result,
It has been confirmed that the target nozzle air outflow amount can be obtained by the above-described calculation formula.

[0012]

As described above, in the conventional control method described in the section of the prior art, the response time is twice or more, and when the response is improved, the pressure overshoot occurs at the time of start-up. The disadvantages can be said to be controllably improved by the present invention. In addition, as shown in the above embodiment, by introducing the flow control device of the present invention into wind tunnel equipment, it is possible to obtain the air outflow amount at the measuring section with high accuracy and high responsiveness.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a flow control device according to a basic embodiment of the present invention.

FIG. 2 is a configuration diagram of a wind tunnel facility to which the flow control device of the present invention is applied.

FIG. 3 is a configuration diagram of a flow rate control device according to an embodiment of the present invention incorporated in the device of FIG. 2;

FIG. 4 is a configuration diagram of a conventional wind tunnel facility.

FIG. 5 is a graph illustrating a control result using the control device of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 8 Air storage device 9 Measurement section nozzle upstream pressure 10 Flow control valve 11 Heater 12 First pressure sensor 14 Atmospheric discharge nozzle 15 Pressure control valve 16 Pressure sensor 17 Measurement section nozzle

Claims (1)

[Claims] 1. A target flow rate setting means for inputting and setting a target outflow amount, a pressure and flow rate calculating means for calculating a pressure and a flow rate from the set values, a calculation result based on the calculation means and a digital conversion, for example. Calculate the valve opening from the sensor input value converted into the engineering value of
And a valve opening instruction means for outputting a valve opening command signal and an opening display signal to a display unit.