JPS61118638A - Shear control apparatus - Google Patents

Abstract

PURPOSE:To enable the free setting of a flow speed in an up-and-down direction, by respectively controlling flow speeds in a flow passage, which is divided by dividing plates, by a flow speed control apparatus. CONSTITUTION:Dividing plates 11 are arranged almost parallelly in the upstream side within a measuring body 5 at equal intervals and attached to the wall of the measuring body 5 at both ends thereof. Control plates 13 each having a width slightly narrower than each internal between the dividing plates are attached to the rotary shaft 12 horizontally traversing the measuring body 5 so as to pierce therethrough. When the rotary angle of the rotary shaft is adjusted to change the inclination of the control plates 13, the winds flowing through plural flow passages partitioned in the up-and-down direction by the dividing plates are changed in a throttling degree by the flow amount control apparatus consisting of the rotary shaft 12 and the control plates 13 and a flow speed is controlled. Therefore, the necessary shape of a shear 14 is obtained at the end parts of the dividing plates 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device that completely controls the shear of fluid flowing in a flow path, such as a water tank or a wind tunnel, that is, the flow velocity distribution in a cross section of the flow path.

[Conventional technology]

In order to prevent air pollution caused by exhaust gases emitted from power plants, chemical factories, etc., it is necessary to qualitatively and quantitatively understand the diffusion status of these polluted exhaust gases in the atmosphere and on the ground surface, and to take measures based on location conditions, scale, etc. Accordingly, it is necessary to obtain data to determine the most effective and economical chimney installation location, height, exhaust gas emission rate, etc.

Methods for obtaining such data include calculation methods, on-site testing methods, and model testing methods.

As a calculation method, 3utton
Theoretical formulas, board formulas, and the British Met Office's empirical formulas have been published, but none of them take into account the influence of topography. In addition, there have recently been cases in which the effects of topography on these equations have been determined through numerical analysis using a computer, but all of these require verification through experiments.

The field test method cannot be tested until after the actual chimney has been constructed, and conducting tests in a wide area with complex topography would be extremely costly and labor intensive.

Moreover, the chimney height.

You can freely choose the wind direction, etc. with indoor shoes.

− Data can only be obtained at the location.

Tests using models include qualitative measurements such as ejecting gas from a chimney model and observing the gas diffusion situation with the naked eye, or quantitative measurements such as sucking the gas and measuring its concentration. Is going.

Figure 3 shows an outline of this type of experiment using a wind tunnel.

The wind 2 generated by the blower 1 is once diffused by the diffusion cylinder 3 and then constricted by the contraction cylinder 4, and is discharged into the measurement cylinder 5 as a parallel flow.

Inside the measurement cylinder 5 are a roughness 6 for controlling ground friction, a chimney model 7 for discharging tracer gas, and a building model 8. So-called terrain models such as a ground surface model 9 are arranged.

Although details are omitted, the diffusion of the tracer gas is determined by applying a color-changing reagent to the surface of the ground model 9, or by sucking the gas and determining its concentration.

In tests carried out in this way, the wind acting on the terrain model must be reproduced in the same way as the natural wind. The wind speed of natural wind is almost zero at the ground due to ground friction, slightly higher at higher places, and faster at higher places. This wind speed distribution in the vertical direction is called a shear, and is shown at 10 in the wind tunnel. Although the original shape of the shear changes depending on weather conditions, the shape of the shear 10 within the measurement cylinder 5 determines the diffusion situation and is extremely important in the diffusion test.

[Problem that the invention seeks to solve]

Conventionally, the shape of the shear 10 inside the measuring cylinder 5 is controlled.

The roughness level was 6 only. In other words, in order to give the same shear shape as natural wind to the wind that has been made uniform with contraction flow 4, it is necessary to reduce the wind speed near the ground to zero at an early point with roughness 6, and then wait for the boundary layer to develop. was there. Therefore, it is necessary to make the measuring cylinder 5 longer.
1.The wind is still fast upwards, so to speak.

Only shear shapes that met the "power law" could be obtained.

[Means for solving Problem 11] The present invention is a device for controlling the shear of fluid flowing in a flow path, which comprises a dividing plate arranged horizontally in the flow path and dividing the flow path into a plurality of upper and lower parts; The flow rate adjustment device controls the flow rate in each flow path divided by the dividing plate.

[Effect]

In the apparatus of the present invention, the flow path is divided into a plurality of upper and lower parts by a two-part plate. Moreover, the flow velocity in each divided flow path is controlled by a flow velocity adjusting device.

Therefore, by controlling the flow velocity within each division, it is possible to make a difference in the upward and downward direction of the flow path.

〔Example〕

The present invention will now be described with reference to an embodiment of the apparatus shown in FIGS. 1 and 2, but the structure and function of each member denoted by the same reference numeral as in FIG. 3 is the same, so the explanation will be omitted.

Reference numeral 11 denotes dividing plates, which are arranged substantially horizontally at equal intervals on the upstream side of the measuring cylinder 5 (seven plates in the figure), and are attached to the walls of the measuring cylinder 5 at both ends. Reference numeral 12 denotes a rotating shaft that passes through the measurement barrel 5 horizontally and is attached to a control plate 13 having a width slightly narrower than the interval between the two divided plates 11.

Note that the two rotating shafts 12 are appropriately fixed at an external protrusion of the measuring cylinder 5. In addition, 15 is a guide plate and 1 divided plate 1
1 (or between the dividing plate 11 and the wall) as necessary.

Now, the experiment is similarly conducted in a wind tunnel equipped with the shear control device of the second embodiment.

As shown in FIG. 2, the rotation angles of the two rotation shafts 12 are adjusted to change the inclination of the control plate 13.

In this figure, the inclination angle of the control plate 13 in the upper part of the measurement cylinder 5 is small, and increases as it goes downward.

That is, the degree of constriction of the wind flowing through each of the flow channels divided into upper and lower sections by the 9-part plate 11 is controlled by the flow rate adjusting device consisting of the 1-rotation shaft 12 and the control plate 13, so that the flow rate is controlled. become.

Note that the guide plate 15 is for adjusting the wind disturbed by the control plate 13 into a horizontal flow.

Therefore, in the case of FIG. 2, the shape of the shear 14 along the so-called power law, which is faster as it moves upward in the measuring cylinder 5, is the shape of the dividing plate 1.
It will be obtained at the end of 1.

Further, in a test that requires a shear shape in which the wind speed is slow in the middle part of the measurement cylinder 5, the inclination of the control plate 13 in the middle part may be increased.

In the above embodiment, the two-part plates 11 are arranged at equal intervals, but the intervals may be arbitrarily changed as necessary.

Moreover, it can also be installed in the flow path of an aquarium.

〔effect〕

According to the apparatus of the present invention, since the flow velocity of the fluid in the flow path can be freely set in the vertical direction, it is effective at poles when adjusting the shear such as in a diffusion test.

[Brief explanation of drawings]

FIG. 1 is a diagram of a wind tunnel equipped with the device of the invention. Figure 2 is an enlarged view of the main parts, and Figure 3 is a diagram of a conventional wind tunnel. 5... Measuring cylinder, 11... Dividing plate, 12... Rotating shaft. 13...Control board.

Claims (1)

[Claims] A device for controlling the shear of fluid flowing in a flow path,
A shear characterized by having a dividing plate arranged horizontally in a flow path and dividing the flow path into a plurality of upper and lower parts, and a flow rate adjusting device that controls the flow speed in each flow path divided by the dividing plate. Control device.