JPS60227146A - Testing device for smoke diffusion model - Google Patents

Abstract

PURPOSE:To easily set the roughness of the surface of the geographic model and to reproduce accurately turbulence of an air flow and a wind speed distribution by forming a geographically equivalent member of an elastic material which deforms with external force and restores itself freely. CONSTITUTION:Numbers of geographically equivalent members 22 corresponding to actual ground bodies are arranged dispersedly on the surface of the geographic model 4 along which air containing tracer gas blown out of a chimney model 2 flows, and a necessary roughness setting surface is formed. Then, the geographically equivalent members 32 are flexible tubes formed of a silicone rubber to fluororubber material as an elastic material which has gas resistance and endures compression and traction. Then when a model test is taken on gas diffusion condition, the geographically equivalent members 22 are arranged on the model 4 and necessary roughness is set. In this case, the geographically equivalent members are formed of the elastic material which deforms with external force and restores itself freely, so the roughness setting is facilitated and turbulence of an air flow and a wind speed distribution are reproduced accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for testing, using a model, the state of diffusion of gas discharged from chimneys and buildings.

[Conventional technology]

In recent years, with the development of industry, the prevention of air pollution caused by exhaust gases emitted from power plants, chemical factories, etc. has become a pressing issue. In order to establish such air pollution countermeasures, it is necessary to qualitatively understand the diffusion status of these polluted exhaust gases in the atmosphere and on the ground surface, and to analyze the location conditions.

It is necessary to obtain data to determine the most effective and economical installation point, height, exhaust gas emission rate, etc. of chimneys depending on the size and other factors.

As a means of obtaining such data, there are calculation methods,
There are two methods: practical tests and model tests.

Calculation methods such as Sutton's theoretical formula, board formula, and the British Met Office's empirical formula have been published, but none of them take into account the influence of topography. In addition, there are recent cases in which the influence of topography on these equations has been determined through numerical analysis using a computer, but all of these require experimental verification.

Field testing methods can only be tested after the actual chimney has been constructed, and testing in a wide area with complex topography would be extremely costly and labor intensive.

Furthermore, it is difficult to freely select the height of the chimney, wind direction, etc., and data can only be obtained at - points.

In contrast to the above-mentioned methods based on calculations and field tests, methods based on model tests using wind tunnels take into account the effects of topography, allow for free selection of chimney height, wind direction, etc. In addition to being able to obtain materials, the cost and labor required are both low.

Conventional model testing involves discharging gas from a chimney model in a wind tunnel and observing with the naked eye the diffusion of the gas on a topographic model.

[Problem that the invention seeks to solve]

However, using a model to accurately reproduce the airflow turbulence or wind speed distribution induced by structures on the actual topographic surface, natural forests such as mountains, etc. requires a great deal of effort and expense. There is a problem that

In addition, as a means of reproducing the roughness conditions of the ground surface caused by conventional features, methods such as placing sponges, wood chips, etc. on the surface of the model, or applying adhesive and scattering sand grains on top of it have been carried out. However, when installing various measurement sensors, sampling jigs, etc. on topographic models, the weight of workers and tools is added to the surface of the model, so the durability of sponges, wood chips, sand grains, etc. on the surface of the model may be affected. Some of them become scarce and deteriorate or become obsolete during repeated experiments, and there is also the problem that the reproducibility of the roughness conditions of the model surface is poor.

The present invention aims to solve these problems by easily and accurately reproducing airflow turbulence and wind speed distribution caused by roughness conditions caused by features on the actual ground surface on a terrain model. Another object of the present invention is to provide a diffusion-free model testing device that improves the durability of a model that reproduces roughness conditions.

[Means for solving problems]

For this reason, the non-diffusion model test device of the present invention includes a topographical model placed in a wind tunnel and a tracer gas discharge means for discharging tracer gas into the wind tunnel, In order to set the surface of the above-mentioned topographical model as a required roughness setting surface, a large number of features corresponding to the same roughness setting surface are distributed in the "force-discharging topographical model" 2, and the same feature is It is characterized in that the corresponding member is made of an elastic material that can be freely deformed and restored by external force.

[For production]

According to the above-described non-diffusion model testing device of the present invention, roughness conditions caused by features on the ground surface that cause airflow turbulence can be easily reproduced by arranging members corresponding to the features on the model surface. On the other hand, the feature-equivalent member is made of elastic material and has a shape #i.
Therefore, it can be freely restored against deformation caused by external forces.
This provides durability.

〔Example〕

Below, a non-diffusion model testing device as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a perspective view thereof, Fig. 2 is a perspective view showing a part of the topographic model, and Fig. 3 is a perspective view of the terrain model. FIG. 4 is a perspective view of the feature-equivalent member, and FIG. 4 is a side view showing the attached state of the feature-equivalent member, and FIGS. 5 to 7 show modified examples of the feature-equivalent member, and FIG. Side view, No. 6
The figure is a side view showing how the device is attached to the topographic model, FIG. 7 is a plan view showing how it is attached to the topographic model, FIG. 8 is a side view showing the model rotation mechanism of this device, and FIG. 9 is a side view showing how the device is attached to the topographic model. 10 is a perspective view showing the tracer gas concentration measuring mechanism of the present device, and FIG. 10 is a graph showing tracer gas concentration characteristics at measurement points.

As shown in Fig. 1, a chimney model 2. A house model 3 and a terrain model 4 are installed on the upper surface of a base plate 5 arranged on a wind tunnel floor surface 7.

Furthermore, a blower (fan) 15 that sends air into the wind tunnel 1 is installed at the windward end of the wind tunnel 1 via airflow control materials 16 and 17 to reproduce actual airflow conditions such as wind turbulence. The airflow control material 1G is constructed by arranging rods or plates in a lattice shape within the cross section of the flow path in the wind tunnel j, and the airflow control material 17 is composed of a plate-like member placed on the wind tunnel floor 7 at right angles to the airflow. It can be placed horizontally like this.

On the other hand, the tracer gas discharge means A provided outside the wind tunnel 1 includes a tracer gas cylinder 18 that stores a tracer gas that has been mixed and adjusted to a predetermined force concentration in advance, and a tracer gas that measures the flow rate of the tracer gas flowing out from the tracer gas cylinder 18. a gas flow meter 19; a tracer gas passage 20 connecting the chimney model 2 and the tracer gas cylinder 18;
It is comprised of a flow rate adjustment valve 21 that adjusts the amount of tracer gas in the tracer gas cylinder 18, and the tracer gas is discharged from the chimney model 2 at an appropriate flow rate by this tracer gas discharge means A.

Further, on the surface of the topographical model 4 along which the airflow containing the tracer gas discharged from the chimney model 2 flows, a large number of feature-equivalent members 22 corresponding to the features at the edge of the forest are distributed and arranged.
A desired roughness setting surface is formed.

As shown in FIGS. 3 and 4, this feature-equivalent member 22 is a flexible circular tube made of a silicone-based or fluorine-based rubber material, which is an elastic material that has load-bearing properties and is resistant to compression and tension. A notch 22a is formed below it.

Then, the feature-equivalent member 22 is inserted into the hole 41 formed in the plate 4a constituting the topographical model 4, and is inserted into the notch 22a.
It is fixed to the topographic model 4 by pouring adhesive 221) into it.

The height and diameter of the feature-equivalent member 22 are set according to the roughness desired to be reproduced on the topographical model 4, and in order to increase the roughness, as shown in Figs. 2.5 to 7, The upper part of the feature-equivalent member 22 may be cut into a teacup-like shape with an appropriate width, or the upper part of the feature-equivalent member 22 may be cut into a teacup-like shape, or the upper part of the feature-equivalent member 22 may be cut into pieces of the board 11 stacked on top of each other as shown in FIG.
It is also possible to arrange the feature-equivalent member 22 and set the required roughness.

In addition, when cutting the upper part of the feature equivalent member 22 into a tea cup shape, for example, when reproducing a mountain forest, the width of the cut is widened to reduce fluctuations caused by wind force, and when reproducing grass, fruit trees, etc. It is possible to add a wind effect by narrowing the cutting width and increasing fluctuations caused by the wind.

In addition, numeral 23 in FIG. 1 is a plurality of gas sampling holes opened on the topographical model 4, 58 is a tape impregnated with a color-changing reagent that changes color in response to tracer gas, and 59 is a mark of the state of discoloration of the tape. Shows a still camera for recording.

As shown in FIGS. 1 and 8, the base plate 5 is placed on the wind tunnel floor 7 via the soft drive bearing 6, and a rotating shaft 8 is attached to the lower part of the base plate 5. By connecting the boot 9-10 attached to the lower end of the drive source 8 and the boot 9-9 that can be attached to the rotating shaft of the drive source (motor) 11 with the power transmission heald 14, the base plate 5 can be moved to the rotating shaft by the drive source 11. It is rotated around 8. Note that as the drive source 11, a pulse motor, a linear motor, or the like is used.

Also, data recorders and disks that record actual wind direction fluctuation data (or data obtained by calculation).

A recording device 12 such as a paper tape is connected to a drive source 11 via an amplification/conversion device 13, and this amplification/conversion device 1
3 performs amplification, time axis conversion 9 frequency conversion, etc. based on the output signal from the recording device 12, and then inputs the appropriately converted signal to the drive source 11 to operate the drive source 11.

@9 As shown in Figure 9, the tracer residue amount detector B detects the tracer gas absorption liquid layer 24 and the tracer gas absorption liquid M2.
4 and thin tubes 25 and 26 inserted into the
The capillary 25 is immersed in the tracer gas absorption liquid 27 in the tracer gas absorption liquid layer 24, while the capillary 26 is not immersed.

The gas sampling hole 23 opening into the wind tunnel 1 is connected to the thin tube 25 through a sampling tube 28 and connected to the tracer gas amount detector B, and the tracer gas amount detector B is connected to the thin tube 26. It is connected to the capillary tube 3 ( ) in the sampling gas amount detector C by a tube 29 .

The sampling gas amount detector C includes thin tubes 30, 20a to 3.
gas suction tubes 31 to 36 each having a different diameter and predetermined volume are interposed between these thin tubes 30.30a to 30f, and these gas suction tubes 30. 31 to 36 are arranged in the vertical direction and communicated through thin tubes 30, 30a to 30f, respectively. and,
The sampling gas amount detector C is filled with water up to the position of the thin tube 30.

Note that the tracer gas amount detector B and the sampling gas amount detector C are provided for each of the plurality of gas sampling holes 23.

The sampling gas suction means includes a header 37 that communicates with the capillary tube 30F via a solenoid valve 42, and a suction pump 38a that is connected to the header 37 via a pipe 38b.

On the other hand, each of the thin tubes 30a to 3 old has a water level detection end 39.
a to 39f are attached, and these water level detection ends 39a to
39f are connected to the converters 40a to 40f, respectively, and the water level detection ends 39a to 39f and the converters 40a to 4
The water level in the sampling gas amount detector C is detected by 0f.

Further, a concentration detection end 41 is attached to the tracer gas absorption liquid 27 portion in the tracer gas absorption liquid layer 24, and this concentration detection end 41 is connected to the converter 43 via a signal cable 57. The concentration of the tracer gas dissolved in the tracer gas absorption liquid 27 is detected by the converter 43.

Furthermore, the converter 43 of the concentration detection end 4J. Water level detection end 39
The converter 40a-4Of, solenoid valve 42 and suction pump 38a of a-39F are connected to the signal cable 4f3.4, respectively.
Control data acquisition device 44 via 7° 48 and 49
and an arithmetic and control computer 45 is connected to the data acquisition device 44 via a signal cable 50, and these solenoid valves 42. When the output signal from the tracer gas amount detector B reaches a predetermined value or more, the data acquisition device 44, the computer 45, etc. stop the suction of the sampling gas through the corresponding sampling pipe 28, that is, the sampling gas suction means. A control means is configured.

Furthermore, Figure 10 is a graph showing the tracer gas concentration characteristics at the measurement point, where the vertical axis shows the absorption liquid concentration and the horizontal axis shows the sampling gas suction amount. In the concentration measurable region, 4 indicates the concentration saturation region.

In addition, the solid line F in the figure indicates the tracer gas concentration characteristics at an arbitrary measurement point, and the symbols 61 to G7 indicate the sampling gas suction amount that can be set in this example. It shows the sampling gas suction amount that reaches the measurable area.

In other words, the sampling gas suction means is connected to the tracer gas absorption liquid 27 measured by the tracer gas amount detector B.
At the same time when the concentration of .

In the non-diffusion model testing apparatus of the present invention configured as described above, when performing a model test in a situation where gas diffuses, first, the feature-equivalent member 22 is placed on the topographical model 4 and the required roughness is Set the degree. In addition, if necessary, the feature equivalent member 2
Adjust the roughness to the desired roughness by making 2 into a tea cup shape or adjusting the slits.

Then, the tape 58 is impregnated with a color changing reagent consisting of an alcoholic solution of an indicator that changes color with ammonia, such as bromo thymol blue, and starch paste.
= $1, and paste this tape 58 on the top surface of the terrain model 4 as shown in the figure.

On the other hand, the wind direction data output from the recording device 12 is subjected to time axis conversion and frequency conversion by the converter 13 and inputted to the drive source (motor) 11, thereby creating the chimney model 2.
A base plate 5 on which a house model 3 and a terrain model 4 are placed is driven to rotate at a predetermined angular velocity.

Note that this rotational drive is performed by applying the rotational driving force of the drive source 11 to the pulley 9. Belt 14. This is done by transmitting the signal to the rotating shaft 8 of the base plate 5 via the pulley 10.

Next, the tracer gas flow rate adjustment valve 21 is opened, and the flow rate adjustment valve 21 is adjusted to a predetermined flow rate while monitoring the tracer gas flow meter 19. Thereby, the test ammonia mixed gas as a tracer gas is discharged from the tracer gas cylinder 18 through the passage 20 and into the wind tunnel 1 from the chimney model 2.

Then, airflow control members 16 and 17 are placed inside the wind tunnel 1, and air is blown into the wind tunnel 1 by rotating the blower (fan) 15 at a predetermined rotation speed.

In this way, the blower 15 is rotated, the airflow control material], the combination of 6+17 is determined, and the base plate 5 is rotated so that predetermined actual airflow conditions (wind speed, wind speed distribution, turbulence, etc.) are achieved. As a result, the actual airflow that changes from time to time depending on the terrain is reproduced on the terrain model 4, and the tracer gas discharged from the chimney model 2 is diffused in the same way as in the actual situation.

When the tracer gas diffused in this way comes into contact with the tape 58 impregnated with the above-mentioned color-changing reagent, the color-changing reagent changes color from orange-yellow to yellow-green to indigo. It is possible to know the diffusion situation on the ground of the mixed gas discharged from the chimney model 2.

Note that the method for impregnating the tape 58 with the color-changing reagent is as follows.
The surface may be sprayed with a sprayer, or the entire tape 58 may be immersed in the color changing reagent solution. Further, the amount of impregnation may be determined depending on the time period indicating the state of discoloration. For example, if the maintenance time is to be lengthened, the amount may be increased, and if the maintenance time is to be shortened, the amount may be decreased.

In addition, by observing with the naked eye or the still camera 59 how the discolored region expands with the passage of time (usually about 1 to 2 minutes), it is possible to qualitatively estimate the mixed gas concentration distribution on the surface of the model. be able to.

Further, as a tracer gas to be mixed with air and discharged from the chimney model 2, sulfur dioxide gas is added to the alkaline gas such as ammonia described in the above embodiment.

Acidic gases such as hydrogen chloride can also be used.

Next, if you want to quantitatively determine the concentration distribution of the tracer gas in the discoloration range of the tape 58, remove the tape 58,
The actual airflow is reproduced on the terrain model 4 in the same manner as the method described above, and the tracer gas discharged from the chimney model 2 is diffused in the same manner as in the actual case.

Then, the distribution of the diffused tracer gas on the topographical model 4 reaches a steady state after a certain period of time. After that,
When the electromagnetic valve 42 is opened and the suction pump 38a is operated, the water in the sampling gas amount detector C is gradually discharged downward. As a result, the water level in the thin tube 30 at the top of the sampling gas amount detector C is lowered to the gas suction tube 31.
, gradually move downward with the thin tube 30a.

Along with this, the pressure inside the detector C decreases, the pressure within the tracer gas absorption liquid layer 24 communicating with the detector C via the tube 29 also decreases, and the gas is removed from the gas sampling hole 23 through the sampling tube 28 into the wind tunnel. The tracer gas in 1 is sucked into detector C. In this case, the sampling gas suction amount can be set at will up to the water level of the thin tubes 30a to 30f, and the sampling gas suction amount at that time is equal to the cumulative capacity of the gas suction cylinders 31 to 36 located above the water level. .

In such a sampling gas suction process, the concentration of the tracer gas absorption liquid 27 increases with the passage of time, that is, as the sampling gas suction amount increases, and the concentration detection end
The concentration signal from 11 is input to the computer 45 every moment, and the computer 45 determines whether the concentration has reached the measurable range or not. If the water level has not reached the water level, suction continues, but if the water level has reached the water level, the solenoid valve 42 is closed to stop the suction in the thin tubes (30a to 30f) at the bottom of the member where the current water level is located. This control is performed at the time when the signal from the water level detection terminals (39a to 39f) is first picked up after reaching the concentration measurable region I-.

For example, the gas suction tube 33 of the sampling gas amount detector C
When the water level reaches the measurable area while the water level is within the water level, the water level further falls to the thin tube 30c and the water level detection end 39
c and its converter 40c generate a signal, the solenoid valve 42 is closed, and suction of the sampling gas at that measurement point is stopped. If this state is shown in Figure 4,
GO is the cumulative suction amount up to the middle of the gas suction tube 33 (member 3
G3 is the cumulative suction amount up to the gas suction cylinder 32 (the total volume of members 30, 31, .30a, and 32), G
4 is the cumulative suction amount up to the gas suction tube 33 (members 30, 31
, 30a, and 32.33), and suction stops at G4.

In this way, the sampling gas suction amount suitable for the tracer gas concentration at each measurement point can be set for each measurement point. In other words, at the measurement point in the high concentration area, the upper thin tube 30
The suction operation stops at point a, but at measurement points in the low concentration region, the suction operation continues up to the lowest tube 3Of.

When the water level drops to the part of the thin tube 30f, a signal is generated from the water level detection end 39f and the converter 40f, and at this point, the suction pump 38a is stopped and the suction operation is completed. Note that since the amount of suction differs at each measurement point, the measurement data is made dimensionless by the amount of suction at each measurement point to perform a relative comparison.

According to this example, in a model test, it is possible to reproduce the actual airflow characteristics where the wind direction fluctuates greatly, and at each measurement point when measuring the diffusion area (concentration situation) of gas discharged from a chimney, etc. Only the amount of sampling gas that can be accurately measured according to its concentration is sucked in, so even if the concentration range to be measured is extremely wide, the gas diffusion area can be measured quickly and accurately at low cost. It ends with what you do.

〔Effect of the invention〕

As described in detail above, the smoke diffusion model testing device of the present invention includes a topographical model placed in a wind tunnel and a tracer gas discharge means for discharging tracer gas into the wind tunnel. In order to set the surface of the terrain model along which the contained airflow is to follow as the required roughness setting surface, a large number of members corresponding to features forming the same roughness setting surface are distributed on the terrain model and are arranged in the same manner. With a simple configuration in which the feature-equivalent member is made of an elastic material that can be freely deformed and restored by external forces, it is easy to set the roughness of the terrain model surface in smoke diffusion model tests using wind tunnels. This method has the advantage of accurately reproducing airflow turbulence and wind speed distribution caused by roughness conditions caused by features on the actual ground surface, while greatly improving the durability of members corresponding to features.

[Brief explanation of drawings]

The figures show a smoke diffusion model test device as an embodiment of the present invention, in which Fig. 1 is a perspective view thereof, Fig. 2 is a perspective view showing a part of the topographic model, and Fig. 3 is a perspective view of the topographic model. FIG. 4 is a perspective view of the corresponding member, and FIG. 4 is a side view showing the installed state of the feature-equivalent member, and FIGS. 5 to 7 show modified examples of the feature-equivalent member, and FIG. 5 is a side view of the feature-equivalent member. 6 is a side view showing how the device is attached to the topographic model, FIG. 7 is a plan view showing how it is attached to the topographic model, and FIG. 8 is a side view showing the model rotation mechanism of this device. FIG. 5 is a perspective view showing the tracer gas concentration measuring mechanism of the present device, and FIG. 10 is a graph showing tracer gas concentration characteristics at measurement points. 1. Wind tunnel (measurement chamber), 2. Chimney model, 3. House model, 4. Terrain model, 4a.. Board, 4b.. Hole, 5..
Base plate, 6... Bearing for rotational drive, 7... Wind tunnel floor surface,
8...Rotating shaft, 9,10...Pulley, 11...Drive source (motor), 12...Recording device, 13...Amplification/conversion device, 14...Transmission belt, 15...Blower R (fan) ,
16w1? ... Air flow control material, 18. Tracer gas cylinder, 19. Tracer gas flow meter, 20. Tracer gas passage, 21. Flow rate adjustment valve, 22. Feature equivalent member, 22a. Notch, 22b.・Adhesive, 23...Gas sampling hole, 24...Tracer gas absorption liquid layer, 2
5.26...Thin tube, 27...Tracer gas absorption liquid, 28
...Sampling tube, 29...Tube, 30.30a~30
f...Thin tube, 31-36...Gas suction cylinder, 37...Hengoo, 33a...Suction pump, 381)...Piping, 39
a~39f...Water level detection end, 4(la-4OL/converter, 41...Concentration detection end, 42...Solenoid valve, 43...Converter, 44...Control data acquisition device, 45...Calculation) and control computer, 46-50... signal cable, 51...
- Rectifier grating, 52... Contraction part, S3... Opening part, 54.
55... rectifier, 56... wind tunnel exhaust stack, 57... signal cable, 58... tape, 59... still camera,
) ~... Tracer discharge means, B... Tracer gas amount detector, C... Sampling gas amount detector, D... Sampling gas suction means, F... Tracer gas concentration characteristics at any measurement point, GO ~G7... Sampling gas suction means measurable area, M... Concentration saturation area. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 3 220 Figure 4 2b Figure 5 Figure 6 4j) 110 Figure 7

Claims (1)

[Claims] A topographical model placed in a wind tunnel and a tracer gas discharge means for discharging a tracer gas into the wind tunnel are provided, and the surface of the topographical model along which the airflow containing the tracer gas is to be guided is set to a required roughness setting surface. In order to set the same roughness, a large number of feature-equivalent members forming the same roughness setting surface are distributed on the terrain model, and the feature-equivalent members have an elasticity that allows them to be freely deformed and restored by external forces. A smoke diffusion model test device, characterized in that it is formed of.