Snow blowing method using thin ice snowflakes

Abstract

To provide a snow blowing method using thin-ice snowflakes which can simultaneously adjust both a production amount and snow quality per unit time of artificial snow during a production stage in an environmental test where the artificial snow is blown onto a test specimen using airflow in a wind tunnel, can supply the required amount continuously and easily on-site, and can perform a precise test.SOLUTION: A snow blowing method using thin-ice snowflakes that utilizes airflow in a wind tunnel 16, includes the steps of: setting a production amount and snow quality per unit time of artificial snow composed of thin-ice snowflakes according to an environmental test utilizing snow blowing onto a test specimen; producing thin ice snowflakes with a predetermined production amount and snow quality per unit time at a level above an outlet 316 of the wind tunnel 16; making the produced thin-ice snowflakes S naturally fall into the wind tunnel 16 or between the outlet 316 of the wind tunnel 16 and the test specimen; and blowing the thin-ice snowflakes that naturally fall toward the test specimen by utilizing the airflow from the upstream side of the test specimen toward the test specimen.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for flying snow using thin ice and snow flakes, and more specifically, to a method for flying snow using thin ice and snow flakes that allows the amount of artificial snow produced and the quality of the snow to be adjusted all at once during the production stage, and that allows the required amount to be continuously and easily supplied on site at that time, and generally allows for precise testing. [Background technology]

[0002] 2. Description of the Related Art Conventionally, environmental tests have been carried out for various purposes in which air currents generated in a wind tunnel are blown against a test specimen to simulate running conditions. One of these is an environmental test in which artificial snow is carried by an air current and blown or falls toward a test specimen, such as a stationary vehicle, to evaluate the effect of snow on the test specimen. They are divided into different types depending on the artificial snow used.

[0003] For example, Patent Document 1 discloses a snowstorm generating system that uses artificial snow made of crushed ice particles. In this snowstorm generating system, ice pieces made by an ice maker are crushed by an ice crusher to become ice particles of a specified size, which are then pressure-fed by the airflow through a snow supply pipe, branched by a distributor into a number of branch pipes, and in each branch pipe, the snow is made into wet snow with a specified moisture content by a snow-wet device, and reaches the blowout nozzle. The snow blown out from the blowout nozzle's outlet is carried by the airflow and flows as a snowstorm along the direction of the airflow, and the snowstorm hits a diffusion surface that is outside the blowout port and is arranged at a specified position forward in the direction of the airflow so as to face the blowout port. The diffusion surface is made of a material that is difficult for snow to adhere to and has a conical shape with its top oriented toward the blowout port, so that the snowstorm does not adhere to the diffusion surface, but is guided along the diffusion surface and diffuses outward in all four directions, and the fluctuation in diffusion characteristics over time due to adhesion to the diffusion surface can be suppressed. Such a snowstorm generating system makes it possible to some extent to spread the snowstorm to a desired spreading area.

[0004] On the other hand, Patent Document 2 discloses a snowmaking system that utilizes snow crystals. This crystal snowfall system is divided into upper and lower spaces by a horizontally extending partition, and has a crystal snow production section in the upper part and a crystal snowfall section in the lower part. The crystal snow production section is located between an upper roller and a lower roller, at least one of which can be rotated. The system has a rotary aeration membrane device equipped with an endless mesh membrane body, and a crystal snow falling body near the lower roller whose tip edge is spaced apart from the outer surface of the mesh membrane body, and crystal snow is produced on the outer surface of the mesh membrane body using moist air containing water vapor at or above ice saturation below freezing point, the crystal snow falling section has a wet snow making device that wets the crystal snow produced by the crystal snow making section while it is falling, and a temperature and humidity adjustment device that adjusts the temperature and humidity within the space of the crystal snow falling section, and the partition is a number of rollers arranged at a predetermined interval with their outer peripheral surfaces facing each other in parallel and rotatable in a direction toward the narrowest part between adjacent rollers from above, and is arranged in the space above the narrowest part so as to be able to receive the falling snow crystals, and each roller constitutes a rotating brush with bristles attached on its outer peripheral surface, and at the narrowest part between adjacent rollers, the brushes overlap each other to form a partition.

[0005] According to this crystal snowfall system, in the upper part of the space divided into upper and lower parts by a horizontally extending partition, frost-like crystal snow is generated on the outer surface of the mesh-like membrane body by moist air containing water vapor above the ice saturation level at below freezing point while the rotary aeration membrane device is rotating, and the crystal snow generated on the outer surface of the mesh-like membrane body can be dropped by the crystal snow dropper near the lower roller. In this case, depending on the rotation speed of the rotary aeration membrane device and the distance between the outer surface of the mesh-like membrane body and the tip edge of the crystal snow dropper, the generated crystal snow may fall off in the form of large snowflakes when it is dropped by the crystal snow dropper. The large snowflakes are received in the space above the narrowest part between the adjacent rollers, and the adjacent rollers rotate in a direction toward the narrowest part between the adjacent rollers, so that the large snowflakes pass through the narrowest part and are guided downward, but at that time, the large snowflakes are repelled by the tip of the rotating brush, and the large snowflakes are broken into small snowflakes without breaking the crystals themselves. At the same time, at the narrowest part between adjacent rollers, the brushes overlap to form a partition, which prevents the rising air currents from reaching the upper part of the space by raising the temperature of the lower space in order to wet the snow crystals during snowfall.This means that the rising air currents do not interfere with snowfall and do not hinder the growth of crystals in the snow-making section, making it possible to wet the snow crystals as they fall while preventing them from breaking down into large snowflakes.

[0006] However, the above-mentioned snowstorm generating system and snowfall system have the following technical problems. First, in the above-mentioned snowstorm generation system, the amount of artificial snow produced and the adjustment of the snow quality by the moisture content are complicated, and it is difficult to conduct precise tests. More specifically, flake ice pieces are produced by spraying water on a cooling surface to form a thin ice layer, which is then peeled off. Except in special cases where the flake ice pieces are used as sherbet pieces with a high moisture content, it is difficult to use the flake ice pieces as they are for testing. The flake ice pieces are crushed by an ice crusher and then transported by the transport air flowing through the transport pipe. The transport pipe's blowing nozzles are usually installed in the wind tunnel, with multiple nozzles at each level, and are routed into the wind tunnel. During this time, the ice is crushed into ice particles of a specified size by the ice crusher, and the crushed ice particles are melted to turn into wet snow. As a result, the arrangement of multiple transport pipes inside the wind tunnel disrupts the airflow inside the wind tunnel, making it difficult to conduct precise testing. In addition, when transporting ice particles with a high moisture content, the ice particles may stick to each other or to the inner surface of the transport pipes, causing the pipes to become clogged, which may hinder smooth testing. Furthermore, artificial snow made from ice particles is significantly different from natural snow in terms of adhesion and bulk density, and adjusting the production amount and moisture content of the artificial snow used in the tests requires individual adjustments: adjusting the production amount at the flake ice production stage, adjusting the size of the ice particles at the flake ice crushing stage, and adjusting the degree of melting of the ice particles at the wet snow stage. It is difficult to flexibly adjust the production amount and moisture content of the artificial snow all at once.

[0007] Secondly, because the snowfall system uses snow crystals, unlike the ice particles used in the snowstorm generation system, the snow quality, particularly the adhesion and bulk density, is not far from natural snow, but the snow crystal production equipment is large-scale, and it is technically difficult to continuously supply the amount needed for environmental testing, for example, testing in which snow crystals are blown toward a stationary vehicle by air currents generated in a wind tunnel, on the spot at that time. Also, it is technically difficult to balance the production amount and size of snow crystals. [Patent Document 1] Patent Publication No. 2015-143583 [Patent Document 2] Patent Publication No. 2018-115794 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] In view of the above technical problems, the object of the present invention is to provide a method of flying thin snow flakes in environmental testing in which artificial snow is carried by the air currents in a wind tunnel toward a test specimen, which allows the amount of artificial snow produced and the snow quality to be adjusted all at once at the production stage, and the required amount can be easily and continuously supplied on site at that time, and generally allows for precise testing. [Means for solving the problem]

[0009] In order to achieve the above object, the method of the present invention for blowing snow using thin ice and snowflakes by utilizing airflow in a wind tunnel comprises the following steps: A step of setting the amount of artificial snow made of thin snow flakes produced per hour and the quality of snow according to an environmental test using snow blown onto a test specimen; producing thin snow flakes at a predetermined production rate and with a predetermined snow quality per hour at a level above the outlet of the wind tunnel; Allowing the produced thin snowflakes to fall naturally into a wind tunnel or between the wind tunnel outlet and a test piece; A step of making thin snowflakes that fall naturally fly toward the test specimen by being carried by an air current that flows from the upstream side of the test specimen toward the test specimen; The configuration has the following features.

[0010] According to the method of flying snow using thin ice and snow flakes having the above configuration, in an environmental test in which artificial snow is carried by air currents in a wind tunnel toward a test specimen, the amount of artificial snow made of thin ice and snow flakes produced per hour and the snow quality are set according to the environmental test using the flying snow toward the test specimen, thin ice and snow flakes of a predetermined amount per hour and of a predetermined snow quality are produced at a level above the wind tunnel outlet, and the produced thin ice and snow flakes are allowed to fall naturally into the wind tunnel or between the wind tunnel outlet and the test specimen. Because the snow is thin ice and snow flakes, there is no need to transport flake-shaped ice pieces by the transport air flowing in the transport pipe, and there is no need to provide a plurality of transport pipe blowout nozzles for each level in the wind tunnel and route them to the wind tunnel, as in the conventional method, and ice pieces of a predetermined size are crushed by an ice crusher in the middle of the transport pipe. There is no need to crush the ice into particles and then melt the crushed ice particles to turn it into wet snow, and the amount of artificial snow produced and the quality of the snow can be adjusted all at once during the production stage. On the other hand, with crystalline snow, as in the past, it was technically difficult to continuously supply the amount needed for environmental testing, such as testing in which a blizzard of snow is blown toward a stationary vehicle by carrying it on the air currents generated in a wind tunnel. However, with this method, the naturally falling thin snow flakes are carried by the air currents flowing toward the test specimen from the upstream side of the test specimen, and the required amount can be easily supplied continuously on the spot. Overall, the snow quality is closer to natural snow than artificial snow made from ice particles, and air current turbulence caused by the placement of a transport pipe in a wind tunnel is avoided, and it becomes possible to conduct precise tests where artificial snow made from crystalline snow was limited to snowfall tests. Here, snow quality is defined in a broad sense, and refers to size (minor diameter x major diameter x thickness), shape, and moisture content.

[0011] Also, a step of allowing the produced thin ice snowflake to fall naturally between the outlet of the wind tunnel and the test piece; It is preferable to have a step of causing thin ice and snow flakes to fall naturally from above the test specimen, carried by the air current flowing from the upstream side of the test specimen toward the test specimen. In addition, the thin ice snowflakes that were produced are allowed to fall naturally into the wind tunnel. It is preferable to have a step of blowing the naturally falling thin snowflakes as a snowstorm towards the test specimen by carrying them on an air current flowing towards an outlet in the wind tunnel. In the snowfall stage, the airflow heading toward the test specimen from the upstream side thereof may be directed diagonally upward from a dedicated airflow outlet for snowfall that is provided separately from the air outlet, so that thin, naturally falling snow flakes are carried by the diagonally upward airflow, causing them to fall from above the test specimen.

[0012] It is also preferable to have a step of simulating natural wind on the test specimen by the air current flowing from the upstream side of the test specimen toward the test specimen after the snow has accumulated on the test specimen. In addition, the step of producing the thin ice snowflakes may preferably involve spraying water on the cooling surface to form a thin ice layer, peeling off the formed thin ice layer, and allowing it to fall naturally as it is. In addition, it is preferable to adjust the cooling surface temperature and / or water spray temperature, the amount of water sprayed per hour, and the peeling speed of the thin ice layer to produce a specified amount of thin ice snowflakes per hour and of a specified snow quality.

[0013] Furthermore, it is preferable to have a step of adjusting the temperature of the air flow in the wind tunnel in accordance with the moisture content of the artificial snow required for the environmental test utilizing snow blown onto the test specimen. Furthermore, it is preferable to have a step of setting the speed of the airflow in the wind tunnel in accordance with the flow rate of the naturally falling snowflakes so as to prevent the snowflakes from accumulating in the wind tunnel. In addition, the thickness of the snowflakes may be between 0.1 and 0.2 mm, and the length between 1 and 20 mm. In addition, as an environmental test that utilizes snow flying onto a test specimen, depending on whether it is a snowstorm simulation test for a running simulation vehicle, a snowfall simulation test for a traffic jam simulation vehicle, or a natural wind simulation test for a snow-covered vehicle, it is preferable to have a step of positioning the height at which the thin snowflakes start to fall naturally above the tunnel and the test specimen, adjusting the natural fall position between the tunnel and the test specimen, and adjusting the airflow speed inside the wind tunnel. BEST MODE FOR CARRYING OUT THEINVENTION

[0014] An embodiment of a snow flying system used in the snow flying method using thin snow flakes of the present invention will be described in detail below with reference to the drawings. As shown in Figures 1 and 2, the flying snow system 10 uses artificial snow consisting of thin snow flakes, and is configured to simulate flying snow by having the artificial snow carried by an air current behind it, and to move toward the test specimen, the vehicle V. For this purpose, the system has a wind tunnel facility and a thin snow flake manufacturing device 18. In particular, when continuously supplying the required amount of flying snow having a specified snow quality, the main influencing factors of which are the size and moisture content of the thin snow flakes, toward vehicle V, it is required to rapidly supply the thin snow flakes to be used as artificial snow while they are being produced during testing under specified temperature and humidity control so that the snow can be spread throughout the entire height of vehicle V and, in some cases, the desired flying snow concentration distribution can be achieved along the height of vehicle V.

[0015] In general, the snow flying system 10 generates an airflow MF toward the vehicle V in the wind tunnel 16, while producing artificial snow in the form of thin snowflakes using the thin snowflake manufacturing device 18, and causes the falling thin snowflakes to fly toward the vehicle V, simulating a snowstorm while the vehicle is moving.

[0016] The wind tunnel 16 is an open-type circulation type, and is formed in a generally rectangular shape in a plan view, and includes an (open-type) measurement chamber 300 in which the vehicle V to be measured is placed, and first to fourth bent trunks 302, 304, 306, 308 (bent portions). The airflow MF generated by blower 25 passes through second diffusion drum 310, third bent drum 306, fourth bent drum 308, flow straightening drum 312, and contraction drum 314, and flows into measurement chamber 300 through outlet 316 opening into measurement chamber 300. Through measurement chamber 300, outlet 316 and receiving port 317 are arranged opposite each other, and the air flows through receiving port 317, first bent drum 302, and second bent drum 304 in that order. The airflow MF blown by blower 25 first has its overall wind speed (dynamic pressure) reduced and its pressure (static pressure) increased in the intermediate body, and then passes through contraction body 314, allowing the airflow MF to be blown out from outlet 316 into measurement chamber 300 at a volume (wind speed) sufficient for measurement. As a variant, a dedicated snowfall airflow outlet (not shown) that can be opened and closed can be provided above the outlet 316 of the wind tunnel 16, separate from the outlet 316, and the airflow generated in the wind tunnel 16 can be bypassed and blown diagonally upward from the dedicated snowfall airflow outlet, and the thin snow flakes that are produced between the outlet 316 of the wind tunnel 16 and the vehicle V and allowed to fall naturally can be carried by this airflow, causing snow to fall from above on the vehicle V. More specifically, a bypass duct (not shown) is provided upstream of the straightening tunnel 312, and the tip of the bypass duct is made into an outlet exclusively for snowfall airflow. The position of the outlet exclusively for snowfall airflow need not be limited to the top of the outlet 316 of the wind tunnel 16, but may be on the left, right, or bottom depending on the situation. To switch between blowing air from the outlet 316 of the wind tunnel 16 or the dedicated snowfall airflow outlet, dampers are provided upstream of the straightening tunnel 312 and at the inlet of the bypassed duct, and each damper switches the airflow by opening and closing in the opposite direction. Each damper can be adjusted to be fully open / closed or to an intermediate opening (to adjust the air volume distribution).

[0017] As a result, as will be explained later, the thin snowflakes are carried by the air current MF from behind them within the measurement chamber 300 and are supplied as flying snow toward the vehicle V, and by adjusting the wind speed of the air current MF with the blower 25, it is possible to simulate a moving vehicle V even though the vehicle V is stationary. In addition, in the case of the recirculating wind tunnel 16 for snowfall testing, a separate snow repair device 38 is provided downstream of the vehicle V to separate and collect the snow after the test. In any case, in order to separate the snow by the gravitational fall of the snow or the inertial effect, an area is provided downstream of the vehicle V where the airflow MF is not straightened.

[0018] Next, as shown in Figures 2 to 4, the thin ice snowflake manufacturing device 18 has a water spray spray 24 that sprays water toward the inner surface 56 of the fixed hollow cylinder 20, a blade 28 whose tip 26 is spaced a predetermined distance from the inner surface 56, and a rotational drive means 30 that rotates the water spray spray 24 and the blade 28 concentrically with the fixed hollow cylinder 20, and the water spray spray 24 and the blade 28 are spaced a predetermined angular distance θ from each other in the circumferential direction of the fixed hollow cylinder 20, and an outlet 32 ​​is provided at the lower end through which the thin ice snowflakes S generated by peeling off the thin ice layer L formed on the inner surface 56 with the blade 28 fall naturally.

[0019] The thin ice and snowflake manufacturing device 18 is fixed to the ceiling of a stand (not shown), and the thin ice and snowflakes made by the thin ice and snowflake manufacturing device 18 fall into the wind tunnel 16 or the measurement chamber 300 through an opening provided on the underside of the stand. The thin snowflake manufacturing device 18 can be moved between the flow straightening cavern 312 and the stationary vehicle V depending on the content of the environmental test using flying snow on the stationary vehicle V. For example, when the airflow from the upstream side of the stationary vehicle V toward the stationary vehicle V is directed diagonally upward from a dedicated snowfall airflow outlet, and the naturally falling thin ice and snow flakes are placed on the diagonally upward airflow to make them fall from above the stationary vehicle V, the thin ice and snow flakes produced can be positioned between the outlet 316 of the wind tunnel 16 and the stationary vehicle V at a position where they can fall naturally as they are; when the airflow is placed on the airflow flowing toward the outlet 316 within the wind tunnel 16 and the naturally falling thin ice and snow flakes are blown as blizzard toward the stationary vehicle V, the thin ice and snow flakes produced can be positioned at a position where they can fall naturally as they are into the wind tunnel 16. In addition, the airflow MF in the wind tunnel 16 can be used not only to simulate the running of a stationary vehicle V, but also in tests to simulate natural wind on a stationary vehicle V by airflow flowing toward the outlet 316 in the wind tunnel 16 after snow has accumulated on the stationary vehicle V. When it is desired to change the height of snow accumulation on a stationary vehicle V, particularly when testing while placing the vehicle on top of a dynamo roller and rotating the tires, the vehicle position is limited and the snow accumulation height position cannot be adjusted by moving the vehicle itself back and forth, so it is effective to make the thin ice snowflake manufacturing device 18 itself movable. To allow the thin ice snowflake manufacturing device 18 to move between the flow straightening tunnel 312 and the stationary vehicle V, the thin ice snowflake manufacturing device 18 may be hung or mounted on the ceiling of a frame so that the frame can move in the extension direction of the wind tunnel 16, or the thin ice snowflake manufacturing device 18 may be fitted to rails installed on the ceiling of the test room so that it can be moved. By mounting the thin ice snowflake manufacturing device 18 on rails installed on the ceiling of the test room so that it can move in the airflow direction of the wind tunnel 16 and in directions perpendicular to the airflow direction (including up, down, left and right), the snow accretion area can be changed up, down, left and right. As a modified example, a stand may be constructed to surround the outlet 316 of the wind tunnel 16, the thin ice snowflake device 18 may be installed on the stand, and the stand may be constructed as a mobile stand with casters on the lower part.

[0020] The fixed hollow cylinder 20 has an inner cylinder 22 on whose inner surface a thin ice layer L is formed, and an outer cylinder 23 surrounding the inner cylinder 22. The inner cylinder 22 and the outer cylinder 23 are made of steel, and a hollow section 21 is provided between the inner cylinder 22 and the outer cylinder 23. A refrigerant is supplied to the hollow section 21 from the refrigerator section 74 via pipes 76, 78, and the inner peripheral surface 56 of the inner cylinder 22 is cooled to a predetermined temperature by the refrigerant, so that it functions as a cooling surface for spraying water. The outer peripheral surface of the fixed hollow cylinder 20 is covered with a cylindrical protective cover (not shown). The fixed hollow cylinder 20 has an outlet 32 ​​at its lower end 42 through which thin ice snowflakes S generated by peeling off the thin ice layer L formed on the inner surface 56 of the inner cylinder 22 with a blade 28 fall naturally.

[0021] The connecting rod 40 is arranged horizontally so as to cross the space within the fixed hollow cylinder 20 through the center of the fixed hollow cylinder 20, and a connecting rod rotating mechanism 44 is provided at each end 42. A pair of blades 28-watering spray sprays 24 are provided via support arms 46 near each end 42 of the connecting rod rotating mechanism 44 toward the center of the fixed hollow cylinder 20, and the connecting rod rotating mechanism 44 rotates the connecting rod 40 around the center of the fixed hollow cylinder 20, thereby making each pair of blades 28-watering spray sprays 24 movable in the circumferential direction of the fixed hollow cylinder 20. The level of the connecting rod 40 relative to the fixed hollow cylinder 20 may be determined appropriately, but as will be described later, the upper part of the fixed hollow cylinder 20 is preferable in terms of the installation mode of the connecting rod rotation mechanism 44.

[0022] The connecting rod rotation mechanisms 44 provided at the respective ends 42 are common to both ends, so only one of them will be described. The connecting rod rotation mechanism 44 generally includes a pair of tires 48I, 48O arranged on either side of the connecting rod 40, a vertical rotating shaft 50 that supports each of the pair of tires 48I, 48O rotatably around the center of the tire 48, a rotating shaft support portion 52 that supports the vertical rotating shaft 50, and a drive motor 30 that drives and rotates the tire 48. The pair of tires 48I, 48O are provided on the inner peripheral surface 56 side and the outer peripheral surface 58 side of the inner tube 22 of the fixed hollow cylinder 20, respectively, and are arranged to fit into the circumferential grooves 60 provided on the inner peripheral surface 56 side and the circumferential grooves 60 provided on the outer peripheral surface 58 side, and the pair of tires 48I, 48O are arranged to sandwich the fixed hollow cylinder 20. The distance between the pair of tires 48I, 48O, i.e., the length of the rectangular member (described later), may be determined from the viewpoint that the connecting rod 40, and thus the two sets of blades 28-watering spray sprays 24, can be smoothly rotated in the circumferential direction of the fixed hollow cylinder 20 by the connecting rod rotation mechanism 44. The tires 48 are preferably made of ordinary rubber having elasticity with shock absorption and deformability. More specifically, the width w of the circumferential groove 60 is set according to the width of the tire 48, and is preferably slightly wider than the width of the tire 48 so that the tire 48 is free to rotate around its center, and the depth d of the circumferential groove 60 is preferably determined from the viewpoint of being able to support the connecting rod 40 and the two sets of blades 28 - water spray sprayers 24 by a total of four tires 48.

[0023] The rotating shaft support part 52 is, for example, a rectangular member having a central support part for each tire 48 at each of the four corners, and is arranged so as to straddle the upper peripheral surface of the fixed hollow cylinder 20 from above the fixed hollow cylinder 20 from inside to outside, and is connected to the corresponding end part 42 of the connecting rod 40 on the inner peripheral surface 56 side. As a result, the connecting rod 40 and the rotating shaft support part 52, and thus each tire 48 supported by the rotating shaft support part 52, can move as a unit. The drive motor 30 may be, for example, a drive motor, which is directly connected to the vertical rotating shaft 50 of one of the four tires 48, forming the rotation driving tire 48, and the other tires 48 forming the driven tires 48. The drive motor 30 may be provided on one of the tires 48 on one side of the pair of connecting rod rotating mechanisms 44, and the remaining seven tires 48 may be formed as driven tires 48. In this case, the driven tire 48 is free to rotate with respect to the corresponding vertical rotating shaft 50, and the drive tire 48 is connected to the vertical rotating shaft 50 that is rotationally driven by the drive motor 30, for example, via a reduction mechanism (not shown).

[0024] With the above configuration, while the connecting rod rotation mechanism 44 supports the connecting rod 40 and the rotating shaft support part 52, and thus the tire 48 supported by the rotating shaft support part 52, the drive motor 30 rotates the connecting rod 40, and thus the two sets of blades 28 - water sprinkling spray sprays 24, in the circumferential direction of the fixed hollow cylinder 20.As will be described later, the water sprinkling spray sprays 24 spray water onto the inner surface 56 of the inner tube 22 of the fixed hollow cylinder 20, while the thin ice layer L formed on the inner surface 56 is peeled off as thin ice snowflakes by the blades 28.

[0025] Each support arm 46 is preferably made of metal like the connecting rod 40, is provided perpendicular to the connecting rod 40, and both ends are bent toward the inner peripheral surface 56. The bending angle α of the end of the support arm 46 is about 110°. The connection position and bending angle of the support arm 46 with respect to the connecting rod 40 may be set appropriately. The water sprinkling spray 24 and the blade 28 are spaced from each other at a predetermined angular interval θ in the circumferential direction of the fixed hollow cylinder 20, and the predetermined angular interval θ can be set appropriately since the thin ice layer L formed on the cooling surface by the water sprinkled by the water sprinkling spray 24 will not be peeled off by the blade 28 until it reaches a certain thickness.

[0026] Each sprinkling spray 24 is disposed on the lagging side in the rotational direction of the nearest blade 28. The installation height of the sprinkling spray 24 is preferably set at approximately the middle position of the height of the inner circumferential surface 56 so that the spray range can cover the entire height of the inner circumferential surface 56 of the inner tube 22 of the fixed hollow cylinder 20. The spray pressure of the mist water sprayed from the sprinkling spray 24 is preferably about 0.05 to 0.2 MPa.

[0027] The water sprinkler spray 24 can be attached to the support arm 46 in such a way that the distance from the water sprinkler spray 24 to the inner peripheral surface 56 of the inner cylinder 22 and the direction in which the water is sprayed from the water sprinkler spray 24 can be adjusted.

[0028] The blades 28 attached to the respective tip portions of the support arms 46 are made of metallic rectangular plates having a length equal to the height length of the inner tube 22 of the fixed hollow cylinder 20, and as described above, are provided so as to form a predetermined inclination angle α with respect to the tangent direction of the rotation direction. A gap adjustment bolt 29 is attached to the end portion of the blades 28 on the support arm 46 side for adjusting the gap between the tip portion 27 of the blades 28 and the inner peripheral surface 56 of the inner tube 22 of the fixed hollow cylinder 20. The gap between the tip portion of the blades 28 and the inner peripheral surface 56 of the inner tube 22 of the fixed hollow cylinder 20 is preferably about 0.1 to 0.2 mm. Due to manufacturing errors in the inner surface 56 of the inner tube 22 of the hollow cylinder 20, the minimum clearance between the inner surface 56 and the tip 27 of the blade 28 is approximately limited to 0.1 mm. However, this also depends on the thickness of the thin ice layer L formed on the inner surface 56, but if it exceeds 0.2 mm, it becomes difficult to obtain thin ice snowflakes with the desired snow quality, such as moisture content. Regarding the relationship between the spacing and the size of the detached snow flakes, it has been confirmed that within this range, the effect on the size of the snow flakes, particularly the thickness, is small, and that the size and moisture content (water content) of the snow flakes are important parameters in relation to the refrigerant temperature and / or water spray temperature, flow rate, and the number of rotations of the connecting rod 40.

[0029] The water temperature and amount of water adjustment device 61 is provided to adjust the temperature and flow rate of water supplied to the water sprinkler nozzle 24, and has a water tank 62, a heater 64 for heating the water in the water tank 62, a pipe 66 for connecting the water tank 62 and the water sprinkler nozzle 24, and a liquid feed pump 68 provided in the middle of the pipe 66, and the control panel 70 controls the heater 64 and the liquid feed pump 68 through the control line 54 to adjust the water temperature and the water amount, and the water whose water temperature and water amount have been adjusted is supplied to the water sprinkler nozzle 24 through the pipe 66. The water supplied to the thin ice snowflake manufacturing device 18 may be tap water, and the water temperature is 5 to 25°C. As described above, the liquid feed pump 68 supplies water from the water tank 62 to the water sprinkler nozzle 24 through the pipe 66, and the amount of water sprinkled per hour from the water sprinkler nozzle 24 to the inner peripheral surface 56 can be adjusted. The refrigerant temperature adjustment device 72 is provided to adjust the temperature of the refrigerant supplied into the hollow cylinder 20, and has a normal refrigerator section 74 including a condenser (not shown) and an inverter-controlled compressor (not shown), a return pipe 76 that returns the refrigerant from an evaporator (not shown) provided in the hollow cylinder 20 to the refrigerator section 74 via an evaporation pressure adjustment valve 80, and a supply pipe 78 that supplies the refrigerant to the evaporator via an expansion valve 82. The control panel 70 controls the refrigerator section 74 and the evaporation pressure adjustment valve 80 through the control line 54, and controls the temperature and flow rate of the refrigerant supplied into the hollow cylinder 20, so that the refrigerant with the adjusted temperature and flow rate is supplied to the evaporator in the hollow cylinder 20, cools the cooling surface to a predetermined temperature, and the heated refrigerant returns to the refrigerator section 74.

[0030] The control panel 70 controls the drive motor 30 through the control line 54 to adjust the rotation speed of the connecting rod 40, thereby adjusting the amount of water received by the cooling surface per unit area per unit time on the inner surface 56 of the inner cylinder 22, which is the cooling surface, and the speed at which the thin ice layer L formed on the cooling surface is peeled off. With the above configuration, the water temperature and water volume are adjusted by the water temperature and volume adjustment device 61 according to the desired size, moisture content (water content) of the thin ice snowflakes and the desired amount of snow production or snow making per hour, while the refrigerant temperature adjustment device 72 adjusts the refrigerant temperature, while the drive motor 30 is controlled to adjust the speed at which the thin ice layer L is peeled off. The desired size of the thin snowflakes varies depending on the content and conditions of the environmental test, but the thickness is 0.1 to 0.2 mm and the length is 1 to 20 mm, both of which are determined from the perspective of being able to fly the snow toward the test specimen by utilizing the airflow from the upstream side of the test specimen.

[0031] The operation method of the flying snow system 10 having the above configuration will now be described. The temperature inside the measurement room 300 in which the thin ice snowflake manufacturing device 18 is installed should be kept below 5°C, preferably below 3°C.

[0032] First, the desired size of the thin snowflakes and the desired production amount per hour (snowfall amount) are set according to the test purpose of the snow environment test, and the airflow speed of the airflow MF in the wind tunnel 16 is set according to the running speed of the vehicle V to be simulated. In this case, it is preferable to adjust the temperature of the airflow in the wind tunnel according to the moisture content of the artificial snow required for the environmental test using snow blown onto the vehicle V. As an environmental test using blown snow on vehicle V, depending on whether it is a snowstorm simulation test for a moving model vehicle, a snowfall simulation test for a traffic jam model vehicle, or a natural wind simulation test for a snow-covered vehicle, the height at which the thin ice snowflakes start to fall naturally is positioned above the flow straightening tunnel 312 and the stationary vehicle V, the natural fall position is adjusted between the flow straightening tunnel 312 and the stationary vehicle V, and the airflow speed inside the wind tunnel is adjusted. Figure 2 shows a case where the thin ice snowflake manufacturing device 18 is installed between the outlet 316 of the wind tunnel 16 and the stationary vehicle V for a snowstorm simulation test for a moving model vehicle. The size and level of the outlet 316 of the contraction cavity 314 may be selected depending on the height of the vehicle V or the area of ​​the vehicle V on which snow is desired to accumulate. In the case of a snowfall simulation test, the dampers provided at the upstream position of the straightening cavity 312 and at the bypassed duct inlet are opened while the damper at the bypassed duct inlet side is closed, so that the airflow generated in the wind tunnel 16 is bypassed from the dedicated snowfall airflow outlet provided above the outlet 316 of the wind tunnel 16 and blown diagonally upward from a dedicated snowfall airflow outlet provided separately from the outlet 316, and the thin snowflakes produced between the outlet 316 of the wind tunnel 16 and the vehicle V and allowed to fall naturally are carried by this airflow, causing snow to fall from above on the vehicle V. In the case of a snowstorm simulation test, the damper at the bypassed duct inlet side is closed while the damper at the upstream position of the straightening cavity 312 is opened so that the airflow blows out only from the outlet 316 of the wind tunnel 16. Next, based on the desired size of the thin snowflakes and the desired production amount per hour (amount of snowfall), the control panel 70 controls the water temperature and amount of water adjustment device 61, the refrigerant temperature adjustment device 72 and the drive motor 30 to adjust the temperature and flow rate of the water supplied to the sprinkler nozzle 24, the refrigerant temperature, and the rotational speed of the connecting rod 40. More specifically, by operating the refrigerator section 74, a refrigerant is supplied to the fixed hollow cylinder 20 via pipes 76, 78 to set the temperature of the inner surface 56 of the inner tube 22 of the fixed hollow cylinder 20 to -10°C to -20°C, and the amount of water sprayed from the water sprinkling spray 24 and the rotational speed of the connecting rod 40 are set according to the size of the snow flakes and the production amount.

[0033] The mist water sprayed from the water sprinkling spray 24 rotating counterclockwise together with the support arm 46 toward the inner circumferential surface 56 of the inner tube 22 of the fixed hollow cylinder 20 instantly freezes when it comes into contact with the inner circumferential surface 56 of the inner tube 22 of the fixed hollow cylinder 20, forming a thin ice layer L. The thin ice layer L formed on the inner circumferential surface 56 of the inner tube 22 of the fixed hollow cylinder 20 is peeled off by the blade 28 rotating counterclockwise together with the support arm 46, becoming thin ice snowflakes. The countless peeled off thin ice snowflakes fall from the discharge port 32.

[0034] According to the snow flying method using thin ice and snowflakes S having the above-mentioned configuration, in an environmental test in which artificial snow is carried by the air current MF in the wind tunnel 16 toward a test specimen, the hourly production amount and snow quality of artificial snow consisting of thin ice and snowflakes S are set according to the environmental test using the flying snow toward the test specimen, and thin ice and snowflakes S of a predetermined production amount and predetermined snow quality per hour are produced at a level above the outlet 316 of the wind tunnel 16, and the produced thin ice and snowflakes S are allowed to fall naturally into the wind tunnel 16 or between the outlet 316 of the wind tunnel 16 and the test specimen. As a result, since the thin ice and snowflakes S are thin, there is no need to transport the flake-shaped ice pieces by the transport air flowing in the transport pipe after crushing them with an ice crusher, and there is no need to provide multiple nozzles for the transport pipe within the wind tunnel 16 at the same level for each level in the wind tunnel 16 and route them to the inside of the wind tunnel 16, and there is no need to transport the thin ice and snowflakes S from the middle of the transport pipe, as in the conventional method. Therefore, there is no need to crush the ice into ice particles of a specified size using an ice crusher and then melt the crushed ice particles to turn them into wet snow, and the amount of artificial snow produced and the quality of the snow can be adjusted all at once during the production stage. On the other hand, with crystalline snow, as in the past, it was technically difficult to continuously supply the amount needed for environmental tests, such as tests in which snow is blown toward a stationary vehicle by carrying it on the air currents generated in the wind tunnel 16. However, with this method, the naturally falling thin snowflakes S are carried on the air currents flowing toward the test specimen from the upstream side of the test specimen, and are made to fly toward the test specimen, so the required amount can be easily supplied continuously on the spot. Overall, the snow quality is closer to natural snow than artificial snow made from ice particles, and air current turbulence caused by the placement of a transport pipe in the wind tunnel 16 is avoided, and it becomes possible to conduct precise tests whereas with crystalline snow, artificial snow was limited to snowfall tests.

[0035] In particular, in the case of a test to evaluate the actual snowfall intensity on a vehicle, the airflow speed of the airflow MF generated in the wind tunnel 16 is set according to the traveling speed simulated by the stationary vehicle V, and the amount of thin ice snowflakes produced per hour by the thin ice snowflake manufacturing device 18 is set according to the set airflow speed and the actual snowfall intensity to be reproduced. Here, snowfall intensity refers to the water depth (mm / h) equal to the weight of snow accumulated per unit area on the ground surface per unit time, and actual snowfall intensity refers to the snowfall intensity when it falls to the ground, for example when snow is blown by the wind onto power lines, and the wind speed is taken into account, which can be several tens of times greater than the snowfall intensity in some cases.In order to evaluate the actual snowfall intensity, it is necessary to simulate the snowfall intensity by setting the desired amount of snow production or the desired amount of snow made, while simulating the wind speed using the airflow MF from the wind tunnel 16. As described above, using the wind tunnel equipment, it is possible to produce thin snow flakes on the spot, let them fall naturally, and have them carried by the air current behind them and fly toward the test specimen. Therefore, by adjusting the falling position of the thin snow flakes and combining it with the air current, it is possible to use a single wind tunnel equipment to perform various snow environment tests such as simulating snowfall and blizzards.

[0036] Although the embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications and changes without departing from the scope of the present invention. For example, in this embodiment, when snow falls on a stationary vehicle V, the airflow MF generated in the wind tunnel 16 is bypassed diagonally upward from the outlet 316. However, instead of bypassing the airflow MF generated in the wind tunnel 16 diagonally upward from the outlet, an airflow generating device may be provided above the outlet 316 to generate an airflow diagonally upward and between the outlet 316 and the stationary vehicle V, and the naturally falling thin snowflakes may be carried by this airflow, thereby causing snow to fall on the stationary vehicle V. In addition to bypassing the airflow MF generated in the wind tunnel, an airflow generating device may also be used in parallel. For example, in this embodiment, as shown in Fig. 2, the thin ice snowflake manufacturing device 18 has been described as being installed between the outlet 316 of the flow contraction cavity 314 and the stationary vehicle V, but it is not limited thereto, and as long as the countless thin ice snowflakes S manufactured by the thin ice snowflake manufacturing device 18 do not accumulate in the wind tunnel 16 when they naturally fall, but can be reliably blown away by the airflow MF generated in the wind tunnel 16, it may be installed above the flow contraction cavity 314. In this case, it is preferable to set the speed of the airflow MF in the wind tunnel 16 according to the natural falling flow rate of the thin ice snowflakes so that the thin ice snowflakes that naturally fall in the wind tunnel 16 do not accumulate. [Brief description of the drawings]

[0037] [Figure 1] 1 is an overall configuration diagram of a snow flying system according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a partial view showing snowfall on a stationary vehicle V of the snow-flying system according to the embodiment of the present invention. [Diagram 3] FIG. 1 is a schematic side view showing a thin ice snowflake manufacturing device 18 of a flying snow system according to an embodiment of the present invention. [Figure 4] FIG. 1 is a schematic plan view showing a thin ice snowflake manufacturing device 18 of a flying snow system according to an embodiment of the present invention. [Explanation of symbols]

[0038] S Thin ice snowflake MF Airflow J Airflow V Stationary vehicle θ Predetermined angle interval α Blade inclination angle w Width of circumferential groove 60 d Depth of circumferential groove 60 L Thin ice layer 10 Snow Flying System 11 Wind tunnel equipment 16 Wind tunnel 18 Thin ice snowflake manufacturing device 20 Fixed hollow cylinder 21 Hollow part 24 Watering Spray 27 Tip 28 Blades 30 Drive motor 32 Outlet 40 Connecting rod 42 End 44 Connecting rod rotation mechanism 46 Support Arm 48 Tires 50 Vertical rotating shaft 52 Rotating shaft support 54 Control Line 56 Inner surface 58 Outer surface 60 Circumferential Groove 61 Water temperature water adjustment device 62 Water Tank 64 Heater 66 Piping 68 Liquid transfer pump 70 Control Panel 72 Refrigerant temperature adjustment device 74 Refrigerator part 76 Return pipe 78 Supply pipe 80 Flow control valve 300 Measurement room 302, 304, 306, 308 Bent Torso 310 Second diffuser 306 3rd bent trunk 308 4th bent trunk 312 Straightening Torso 314 Contraction Body 316 Air Outlet 317 Reception

Claims

1. A step of setting the amount of artificial snow made of thin snow flakes produced per hour and the quality of snow according to an environmental test using snow blown onto a test specimen; producing thin snow flakes at a predetermined production rate and with a predetermined snow quality per hour at a level above the outlet of the wind tunnel; Allowing the produced thin snowflakes to fall naturally into a wind tunnel or between the wind tunnel outlet and a test piece; A step of making thin snowflakes that fall naturally fly toward the test specimen by being carried by an air current that flows from the upstream side of the test specimen toward the test specimen; A method for blowing snow using thin ice and snow flakes by utilizing air currents in a wind tunnel, comprising:

2. Allowing the produced thin snowflake to fall naturally between the outlet of the wind tunnel and the test piece; 2. A method for blowing snow using thin snow flakes by utilizing the air flow in a wind tunnel as described in claim 1, comprising the step of causing naturally falling thin snow flakes to fall from above the test specimen, by being carried by the air flow from the upstream side of the test specimen toward the test specimen.

3. 3. A method for causing thin snow flakes to fly by utilizing air currents in a wind tunnel as described in claim 2, wherein the snowfall step involves directing the air current from the upstream side of the test specimen toward the test specimen diagonally upward from a dedicated air current outlet for snowfall that is provided separately from the outlet, so that the thin snow flakes that fall naturally are made to fall from above the test specimen by being carried by the diagonally upward air current.

4. The step of letting the thin ice snowflakes that were produced fall naturally into the wind tunnel; 2. A method for blowing thin snow flakes that fall naturally on the air flow flowing toward the outlet in the wind tunnel, as a snowstorm, toward a test specimen, comprising the steps of: entraining the thin snow flakes on the air flow flowing toward the outlet in the wind tunnel, as a snowstorm;

5. 5. A method for blowing snow using thin snow flakes by utilizing airflow in a wind tunnel as described in any one of claims 2 to 4, comprising a step of simulating natural wind on the test specimen by using the airflow flowing from the upstream side of the test specimen toward the test specimen after the snow has accumulated on the test specimen.

6. 2. The method for producing thin ice and snow flakes by utilizing air currents in a wind tunnel as described in claim 1, wherein the step of producing the thin ice and snow flakes comprises spraying water on a cooling surface to form a thin ice layer, peeling off the formed thin ice layer, and allowing it to fall naturally as it is.

7. A method for producing thin ice snow flakes of a specified quality and in a specified amount per hour by adjusting the cooling surface temperature and / or water spray temperature, the amount of water sprayed per hour, and the peeling speed of the thin ice layer, according to claim 6.

8. 2. The method for blowing snow using thin snow flakes by utilizing airflow in a wind tunnel as described in claim 1, further comprising a step of adjusting the temperature of the airflow in the wind tunnel according to the moisture content of the artificial snow required for environmental testing using blown snow on a test specimen.

9. 5. A method for blowing snow by using air currents in a wind tunnel as described in claim 4, comprising a step of setting the speed of the air currents in the wind tunnel according to the flow rate of the naturally falling snowflakes so that the thin snowflakes do not accumulate in the wind tunnel.

10. 2. A method for making snow fly using thin snow flakes by utilizing air currents in a wind tunnel as claimed in claim 1, wherein the thickness of the thin snow flakes is 0.1 to 0.2 mm, and the length is 1 to 20 mm.

11. 2. A method for blowing snow using thin snow flakes by utilizing airflow in a wind tunnel as described in claim 1, comprising the steps of: positioning the height at which the thin snow flakes start to fall naturally above the tunnel and the test specimen, adjusting the position of the free fall between the tunnel and the test specimen, and adjusting the airflow speed in the wind tunnel, depending on whether the environmental test using blown snow on the test specimen is a snowstorm simulation test for a running simulation vehicle, a snowfall simulation test for a traffic jam simulation vehicle, or a natural wind simulation test for a snow-covered vehicle.

Images