Snowfall Test Method

Abstract

This invention provides a snowfall test method using artificial snow made from thin ice flakes. [Solution] [Claim 1] A thin ice and snowflake manufacturing apparatus is provided between a constricted flow duct and a stationary vehicle, the apparatus having an outlet at its lower end for allowing thin ice and snowflakes generated by peeling off a thin ice layer to fall naturally, and an airflow generating device is provided between the outlet and the constricted flow duct that can adjust the direction of the airflow toward the thin ice and snowflakes falling by gravity from the outlet so that snow falls and accumulates from directly above the stationary vehicle, A snowfall test method characterized by comprising the steps of: adjusting the direction of the airflow generated by an airflow generator while directing thin ice and snowflakes from directly above a stationary vehicle, without directing airflow from the aforementioned flow-contraction tunnel toward the stationary vehicle, thereby causing snow accumulation.

Description

Technical Field

[0001] The present invention relates to a snowfall test method, and more particularly to a snowfall test method using artificial snow made of thin ice and snow flakes for snowfall.

Background Art

[0002] Conventionally, environmental tests in a mode simulating a running state have been conducted for various purposes by blowing a jet air flow generated in a wind tunnel toward a test specimen. As one of them, there is an environmental test for evaluating the influence of snow on a test specimen by placing artificial snow on a jet air flow and causing the artificial snow to fly or snow toward the test specimen, for example, a stationary vehicle. It is classified into types according to the artificial snow used.

[0003] For example, Patent Document 1 discloses a snowstorm generation system using artificial snow of crushed ice particles. In this snowstorm generation system, ice pieces made by an ice maker are crushed by a crusher to become ice particles of a predetermined particle size, are pressure-fed by an air flow through a snow supply pipe, are branched into a plurality of branch pipes by a distribution device, and in each branch pipe, are made into wet snow having a predetermined moisture content by a wet snow device and reach a blowout nozzle. The snow blown out from the blowout port of the blowout nozzle rides on the air flow and flows as a snowstorm along the traveling direction of the air flow. The snowstorm hits a diffusion surface arranged to face the blowout port at a predetermined position in front of the traveling direction of the air flow outside the blowout port. The diffusion surface is formed in a conical shape made of a material having poor adhesion to snow and with its top approaching the blowout port so as to have poor adhesion to snow. Therefore, the snowstorm is guided along the diffusion surface without adhering to the diffusion surface, diffuses outward in all directions, and can suppress fluctuations in diffusion characteristics over time associated with adhesion to the diffusion surface. According to such a snowstorm generation system, it is possible to some extent to diffuse the snowstorm into a desired diffusion area.

[0004] On the other hand, Patent Document 2 discloses a snowfall system using crystal snow. This crystalline snowfall system is located in a space divided vertically by a horizontally extending partition, with a crystalline snow production section in the upper part and a crystalline snowfall section in the lower part. The crystalline snow production section consists of an upper roller and a lower roller, at least one of which is rotatable. The device comprises a rotating ventilation membrane device with an endlessly stretched mesh-like membrane, and a crystalline snow shedding body whose leading edge is spaced apart from the outer surface of the mesh-like membrane near the lower roller. Below freezing point, crystalline snow is generated on the outer surface of the mesh-like membrane by moist air containing water vapor above ice saturation. The crystalline snow falling section includes a wet snow making device that wets the crystalline snow produced by the crystalline snow production section during snowfall, and a temperature and humidity control device that adjusts the temperature and humidity within the space of the crystalline snow falling section. The partition consists of a plurality of rollers arranged at predetermined intervals with their outer surfaces facing each other parallel to one another, and rotatable in a direction toward the narrowest part between adjacent rollers from above. The space above the narrowest part consists of a plurality of rollers arranged to receive the shedding crystalline snow. Each roller constitutes a rotating brush with bristles implanted on its outer surface, and the partition is formed when the brushes of the adjacent rollers overlap at the narrowest part between them.

[0005] In this type of crystalline snowfall system, in the upper part of a space divided vertically by a horizontally extending partition, humid air containing water vapor above ice saturation at below freezing point generates frost-like crystalline snow on the outer surface of a mesh-like membrane during the rotation of the rotating ventilated membrane device. Near the lower roller, the crystalline snow generated on the outer surface of the mesh-like membrane can be removed by a crystalline snow removal device. In this case, depending on the rotation speed of the rotating ventilated membrane device and the distance between the outer surface of the mesh-like membrane and the leading edge of the crystalline snow removal device, the generated crystalline snow may be removed by the crystalline snow removal device in the form of large snow flakes. The large snow flakes are received in the space above the narrowest point between adjacent rollers, and as the adjacent rollers rotate toward the narrowest point between them, the large snow flakes are guided downwards through the narrowest point. At this time, the large snow flakes are flicked away by the tip of the rotating brush, and the large snow flakes are broken down into smaller snow flakes without the crystals themselves being destroyed. In addition, at the narrowest point between adjacent rollers, the brushes overlap, forming a partition. This prevents the rising airflow from reaching the upper part of the space by raising the temperature in the lower space to wet the crystalline snow during snowfall. This prevents the snowfall from being obstructed by the rising airflow and does not hinder the growth of crystals in the snowmaking section. Thus, it is possible to wet the crystalline snow during snowfall while preventing the formation of large snow flakes.

[0006] However, the blizzard generation system and snowfall system described above have the following technical problems. Firstly, both the blizzard generation system and the snowfall system described above are designed specifically for blizzard generation and snowfall, respectively, and are not capable of handling various environmental tests that utilize artificial snowfall. More specifically, in tests involving supplying artificial snow to a test specimen, such as a vehicle, in addition to blowing artificial snow onto a stationary vehicle simulating movement using airflow from a wind tunnel to create a blizzard, as mentioned above, there are also tests that involve snow falling from directly above onto a stationary vehicle to allow it to accumulate, or snow falling from an angle onto a vehicle moving at walking speed in traffic to allow it to accumulate, and after snow has accumulated on the vehicle, heat dissipation evaluation tests such as snow melting / refreezing are conducted by simulating natural wind. In this case, snow accumulation on a vehicle from directly above or at an angle differs from that caused by blizzards in terms of the variation in the contact area with the vehicle due to the adhesion of snowflakes before accumulation, and the degree of adhesion to the vehicle. In particular, artificial snow made from ice particles cannot simulate snow accumulation caused by natural snowfall. More specifically, crushed ice particles have a higher hardness and different adhesion properties compared to natural snow, making it difficult to accurately evaluate the adhesion of snow to a test specimen. There is a need for a single environmental testing facility that can accomplish the various snow environment tests described above.

[0007] Secondly, while the snowmaking system described above utilizes crystalline snow, and therefore its snow quality, particularly its adhesion, is not far removed from natural snow, unlike the thin ice and snowflakes in the blizzard generation system described above, the crystalline snow production equipment is large-scale, making it technically difficult to continuously supply the necessary amount of snow on-site at the time required for environmental tests, such as tests where blizzards are blown onto stationary vehicles using airflow generated in a wind tunnel. [Patent Document 1] Japanese Patent Publication No. 2015-143583 [Patent Document 2] Japanese Patent Publication No. 2018-115794 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0008] In view of the above technical problems, the object of the present invention is to provide a snowfall test method using artificial snow made from thin ice and snowflakes. [Means for solving the problem]

[0009] To achieve the above objectives, the snowfall test method of the present invention is: The process involves installing a thin ice and snowflake manufacturing apparatus between a constricted flow duct and a stationary vehicle, the apparatus having an outlet at its lower end for allowing thin ice and snowflakes generated by peeling off a thin ice layer to fall naturally, and installing an airflow generating apparatus between the outlet and the constricted flow duct that can adjust the direction of the airflow directed towards the thin ice and snowflakes falling by gravity from the outlet so that snow falls and accumulates from directly above the stationary vehicle, The system is configured to allow snow to accumulate by adjusting the direction of the airflow generated by the airflow generator while causing thin ice and snowflakes to fall from directly above the stationary vehicle, without directing airflow from the aforementioned constricted flow tunnel toward the stationary vehicle.

[0010] Furthermore, in the snow accumulation stage, there is a step in which airflow is directed from the constricted flow tunnel toward a stationary vehicle, and the stationary vehicle is used to simulate the driving speed during traffic congestion. Furthermore, the system may include a step of adjusting the direction of the airflow from the airflow generator toward the stationary vehicle according to the airflow velocity from the constricted flow tunnel. Furthermore, after the snow accumulation stage is completed, there may be a step in which airflow is directed from the constricted flow tunnel toward the stationary vehicle to simulate natural wind. [Best Mode for Carrying Out the Invention]

[0011] Embodiments of the snow environment testing equipment including the snowfall system of the present invention will be described in detail below with reference to the drawings. As shown in Figure 1, the snow environment testing facility 10 utilizes artificial snow made of thin ice and snowflakes, and is configured to simulate snowflake flying by using an airflow from behind the artificial snow to move towards the test subject, vehicle V. For this purpose, the snowfall system includes a thin ice and snowflake manufacturing device 18 and an airflow generating device 100, and also includes a wind tunnel and, if applicable, a driving simulation facility including a dynamo roller. In particular, when continuously supplying a required amount of snow with a predetermined snow quality, where the size and moisture content of the thin ice fragments are the main influencing factors, toward vehicle V, it is necessary to manufacture and rapidly supply a group of thin ice fragments to be used as artificial snow immediately before the test, under predetermined temperature and humidity control, so that the snow can spread across the entire height of vehicle V and, if necessary, achieve a desired snow fragment concentration distribution in the height direction of vehicle V.

[0012] In general terms, the snow environment testing facility 10 generates an airflow MF towards the vehicle V inside the wind tunnel 16, produces thin ice snowflakes using a thin ice snowflake manufacturing device 18, and uses the airflow generated diagonally upward towards the vehicle V by the airflow generator 100 to blow the falling thin ice snowflakes diagonally upward, causing them to fall onto the vehicle V.

[0013] The wind tunnel 16 is an open-type recirculating wind tunnel, and is formed in a roughly rectangular shape in plan view, comprising an open-type measurement chamber 300 in which the vehicle V to be measured is placed, and four bent sections 302, 304, 306, and 308 (bent sections). The airflow MF generated by the blower 25 flows through the second diffusion cylinder 310, the third bending cylinder 306, the fourth bending cylinder 308, the straightening cylinder 312, and the constriction cavity 314, and into the measurement chamber 300 through the outlet 316 that opens into the measurement chamber 300. The outlet 316 and the receiving port 317 are positioned opposite each other in the measurement chamber 300, and the airflow flows in the order of receiving port 317, the first bending cylinder 302, and the second bending cylinder 304. The airflow MF blown by the blower 25 first reduces the overall airflow velocity (dynamic pressure) and increases the pressure (static pressure) in the intermediate section. Then, by passing it through the constricted flow tunnel 314, an airflow MF with a sufficient volume (velocity) for measurement can be blown out from the outlet 316 into the measurement chamber 300.

[0014] As a result, as will be explained later, thin ice and snowflakes are supplied as flying snow towards the vehicle V within the measurement chamber 300, carried by the airflow MF from behind it, and by adjusting the wind speed of the airflow MF with the blower 25, it is possible to simulate a moving vehicle V even though the vehicle V is stationary. Furthermore, in the case of the recirculating wind tunnel 16 used for snowfall testing, a separate snow repair device 38 is provided downstream of the vehicle V to separate and recover the snow after the test. In any case, a region is deliberately provided downstream of the vehicle V where the airflow MF is not rectified in order to separate the snow through gravity or inertial effect.

[0015] Next, as shown in Figures 2 to 4, the thin ice snowflake manufacturing apparatus 18 includes a water spray spray 24 that sprays water toward the inner circumferential surface 56 of a fixed hollow cylinder 20, a blade 28 whose tip 26 is separated from the inner circumferential surface 56 by a predetermined distance, and a rotational driving means 30 that rotates the water spray spray 24 and the blade 28 concentrically with the fixed hollow cylinder 20. The water spray spray 24 and the blade 28 are separated from each other by a predetermined angular distance θ in the circumferential direction of the fixed hollow cylinder 20, and an outlet 32 ​​is provided at the lower end to allow the thin ice snowflakes S generated by peeling off the thin ice layer L formed on the inner circumferential surface 56 with the blade 28 to fall naturally.

[0016] The snowmaking device, a thin ice snowflake generating device 18, is installed between the constricted flow tunnel 314 and the stationary vehicle V, as shown in Figure 2, so that the generated thin ice snowflakes fall naturally from the discharge port 32 and land in front of the constricted flow tunnel 314. The height of the discharge port 32 is preferably above the top of the straightening flow tunnel 312. As a variation, the thin ice and snowflake manufacturing device 18 may be made movable between the constricted flow tunnel 314 and the stationary vehicle V according to the airflow velocity that simulates the vehicle's travel speed. When it is desired to change the snowfall position on a stationary vehicle V, especially when the vehicle is placed on top of a dynamo roller and the tires are rotating during testing, the vehicle's position is limited, and the snowfall position cannot be adjusted by moving the vehicle itself forward or backward. Therefore, it is effective to make the thin ice and snowflake generating device 18 itself movable. In this case, it may be used in conjunction with adjusting the direction of the airflow J generated diagonally upward toward the vehicle V by the airflow generator 100 described later. In order to make the thin ice and snowflake manufacturing device 18 movable between the constricted flow hole 314 and the stationary vehicle V, the thin ice and snowflake manufacturing device 18 is provided by hanging or mounting it on the ceiling part of the gantry, and the entire gantry is made movable in the extending direction of the wind tunnel 16, or the thin ice and snowflake manufacturing device 18 may be fitted onto rails provided on the ceiling of the test chamber to make it movable. By providing rails on the ceiling of the test chamber so that the thin ice and snowflake manufacturing device 18 can move in the air flow direction of the wind tunnel 16 and in the direction perpendicular to the air flow direction (vertical or horizontal), the snow landing area can be made variable in the vertical and horizontal directions. Also, particularly in the case of a test (water content adjustment) where the temperature of the test chamber is high and melting of the snow during falling is not excessive, the thin ice and snowflake manufacturing device 18 may be moved in the vertical direction, or in order to avoid physical interference between the thin ice and snowflake manufacturing device 18 and other test equipment, it may be moved in the vertical and horizontal directions in order to be stored on the left and right above the wind tunnel 16.

[0017] 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 part 21 is provided between the inner cylinder 22 and the outer cylinder 23. Refrigerant is supplied from a refrigerator 74 to the hollow part 21 via pipes 76, 78 so that the inner peripheral surface 56 of the inner cylinder 22 is cooled to a predetermined temperature by the refrigerant. The outer peripheral surface of the fixed hollow cylinder 20 is covered with a cylindrical protective cover (not shown). The fixed hollow cylinder 20 is provided at its lower end part 42 with a discharge port 32 for allowing the thin ice and snowflakes S generated by peeling off the thin ice layer L formed on the inner peripheral surface 56 by the blade 28 to fall naturally.

[0018] The connecting rod 40 is horizontally provided so as to cross the space inside the fixed hollow cylinder 20 through the center of the fixed hollow cylinder 20, and connecting rod rotation mechanisms 44 are provided at each end part 42. Near the center of the fixed hollow cylinder 20 at each end part 42 of the connecting rod rotation mechanism 44, a pair of blades 28 - water spray nozzles 24 are provided via support arms 46. By the connecting rod rotation mechanism 44, the connecting rod 40 rotates around the center of the fixed hollow cylinder 20, and thus each pair of blades 28 - water spray nozzles 24 is configured to be movable in the circumferential direction of the fixed hollow cylinder 20. The level of the connecting rod 40 with respect to the fixed hollow cylinder 20 may be determined as appropriate. However, as will be described later, from the installation aspect of the connecting rod rotating mechanism 44, the upper part of the fixed hollow cylinder 20 is preferable.

[0019] Since the connecting rod rotating mechanisms 44 provided at each end 42 are common, one of them will be described. The connecting rod rotating mechanism 44 generally includes a pair of tires 48I and 48O arranged on both sides with the connecting rod 40 as a boundary, a vertical rotating shaft 50 that rotatably supports each of the pair of tires 48I and 48O around the center of the tire 48, a rotating shaft support portion 52 that supports the vertical rotating shaft 50, and a rotation driving portion 54 that rotationally drives the tire 48. The pair of tires 48I and 48O are provided on the inner peripheral surface 56 side and the outer peripheral surface 58 side of the fixed hollow cylinder 20, respectively, and are fitted into the circumferential groove 60 provided on the inner peripheral surface 56 side and the circumferential groove 60 provided on the outer peripheral surface 58 side, and are arranged so as to sandwich the fixed hollow cylinder 20 by the pair of tires 48I and 48O. The interval between the pair of tires 48I and 48O, that is, the length of the rectangular member (described later) may be determined from the viewpoint that the connecting rod rotating mechanism 44 allows the connecting rod 40, and thus the two sets of blades 28 - water spray nozzles 24 to rotate smoothly in the circumferential direction of the fixed hollow cylinder 20. The tire 48 is 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 can rotate freely around the center. The depth d of the circumferential groove 60 is preferably determined from the viewpoint that the four tires 48 in total can support the connecting rod 40 and the two sets of blades 28 - water spray nozzles 24.

[0020] The rotating shaft support portion 52 is, for example, a rectangular member having a central support portion for each tire 48 at each of its four corners, positioned above the fixed hollow cylinder 20 so as to straddle the upper circumferential surface of the fixed hollow cylinder 20 both internally and externally, and connected to the corresponding end 42 of the connecting rod 40 on the inner circumferential surface 56 side. As a result, the connecting rod 40, the rotating shaft support portion 52, and thus each tire 48 supported by the rotating shaft support portion 52 are movable as a single unit. The rotation drive unit 54 may be, for example, a drive motor, and is directly connected to the vertical rotation shaft 50 of one of the four tires 48, making it the rotation drive tire 48, while the other tires 48 are configured as driven tires 48. Alternatively, the rotation drive unit 54 may be provided on one of the tires 48 on one side of the pair of connecting rod rotation mechanisms 44, with the remaining seven tires 48 being driven tires 48. In this case, the driven tires 48 are free to rotate relative to their corresponding vertical rotation shafts 50, while the drive tires 48 are preferably connected to the vertical rotation shafts 50, which are rotationally driven by the rotation drive unit 54, via, for example, a reduction mechanism (not shown).

[0021] With the above configuration, the connecting rod 40 and the rotating shaft support part 52 are supported by the connecting rod rotation mechanism 44, and thus the tire 48 supported by the rotating shaft support part 52 is supported. The rotation drive unit 54 causes the connecting rod 40 and thus the two sets of blades 28-water spray 24 to rotate in the circumferential direction of the fixed hollow cylinder 20. As will be explained later, the water spray 24 sprays water onto the inner circumferential surface 56 of the fixed hollow cylinder 20, and the blades 28 peel off the thin ice layer L formed on the inner circumferential surface 56 as thin ice and snow fragments.

[0022] Each support arm 46, like the connecting rod 40, is preferably made of metal, is positioned perpendicular to the connecting rod 40, and both ends are bent toward the inner circumferential surface 56. The bending angle α of the tip of the support arm 46 is set to approximately 110°. The connection position and bending angle of the support arm 46 relative to the connecting rod 40 can be set as appropriate. The water spray 24 and blade 28 are positioned at a predetermined angular distance θ from each other in the circumferential direction of the fixed hollow cylinder 20. The predetermined angular distance θ can be set appropriately so that the thin ice layer L formed on the cooling surface by the water sprayed by the water spray 24 is not peeled off by the blade 28 until it reaches a certain thickness.

[0023] Each water spray nozzle 24 is positioned on the side of the rotational lag of the nearest blade 28. The installation height of the water spray nozzle 24 is preferably approximately in the middle of the height of the inner circumferential surface 56 of the fixed hollow cylinder 20 so that the spray range can cover the entire height of the inner circumferential surface 56. The spray pressure of the mist of water ejected from the water spray nozzle 24 is preferably about 0.05 to 0.2 MPa.

[0024] The water spray nozzle 24 allows for adjustment of the distance from the water spray nozzle 24 to the inner surface 56 of the inner cylinder 22, and the direction of water spray from the water spray nozzle 24, depending on how it is attached to the support arm 46.

[0025] The blades 28 attached to the ends of each support arm 46 are made of rectangular metal plates having a length equivalent to the height of the inner cylinder 22 of the fixed hollow cylinder 20, and are positioned to form a predetermined inclination angle α with respect to the tangential direction in the rotational direction. A spacing adjustment bolt 29 is attached to the support arm 46 side end of the blade 28 to adjust the distance between the tip of the blade 28 and the inner circumferential surface 56 of the fixed hollow cylinder 20. The distance between the tip 27 of the blade 28 and the inner circumferential surface 56 of the inner cylinder 22 of the fixed hollow cylinder 20 is preferably about 0.1 to 0.2 mm. Due to manufacturing tolerances of the inner circumferential surface 56 of the inner cylinder 22 of the hollow cylinder 20, the minimum clearance between the inner circumferential surface 56 and the tip 27 of the blade 28 is approximately 0.1 mm, while depending on the thickness of the thin ice layer L formed on the inner circumferential surface 56, if it exceeds 0.2 mm, it becomes difficult to obtain thin ice snow fragments of the desired snow quality, such as moisture content. Regarding the relationship between the spacing and the size of the detached thin ice and snowflakes, within this range, the effect on the size of the thin ice and snowflakes, especially their thickness, is small. It has been confirmed that the size of the thin ice and snowflakes is determined by the refrigerant temperature and / or spray water temperature, flow rate, and the rotation speed of the connecting rod 40.

[0026] A water temperature and flow rate adjustment device 61 is provided to adjust the temperature and flow rate of the water supplied to the watering nozzle 24. It includes a water tank 62, a heating heater 64 for heating the water in the water tank 62, piping 66 connecting the water tank 62 and the watering nozzle 24, and a liquid transfer pump 68 installed in the middle of the piping 66. A control panel 70 controls the heating heater 64 and the liquid transfer pump 68 to adjust the water temperature and flow rate, so that the water with adjusted temperature and flow rate is supplied to the watering nozzle 24 via the piping 66. Tap water can be supplied to the thin ice snow flake manufacturing device 18, and the water temperature should be between 5 and 25°C. The refrigerant temperature control device 72 is provided to adjust the temperature of the refrigerant supplied into the hollow cylinder 20 and includes a normal refrigeration unit 74 which includes a condenser (not shown) and an inverter-controlled compressor (not shown), a return pipe 76 which returns the refrigerant from an evaporator (not shown) located inside the hollow cylinder 20 to the refrigeration unit 74 via an evaporation pressure regulating valve 80, and a supply pipe 78 which supplies the refrigerant toward the evaporator via an expansion valve 82. The control panel 70 controls the refrigeration unit 74 and the evaporation pressure regulating valve 80, controlling the temperature and flow rate of the refrigerant supplied into the hollow cylinder 20, so that the refrigerant with adjusted temperature and flow rate is supplied to the evaporator inside the hollow cylinder 20, cooling the cooling surface 22 to a predetermined temperature, and the heated refrigerant returns to the refrigeration unit 74.

[0027] The control panel 70 controls the drive motor 54 and adjusts the rotation speed of the connecting rod 40, thereby adjusting the speed at which water is supplied to the cooling surface 22 and the speed at which the thin ice layer L formed on the cooling surface 22 is peeled off. With the above configuration, the water temperature and water flow rate are adjusted by the water temperature and water flow rate adjustment device 60 according to the desired size of thin ice snowflakes and the desired production amount (snowfall amount) per hour, while the refrigerant temperature is adjusted by the refrigerant temperature adjustment device 72, and the speed at which the thin ice layer L is peeled off is adjusted by controlling the drive motor 54.

[0028] The airflow generator 100 is installed outside the height range reached by the airflow MF that flows from inside the wind tunnel 16 toward the stationary vehicle V. It comprises an airflow generation drive source 102, an airflow discharge nozzle 104 that blows out the airflow J generated by the airflow generation drive source 102, and an airflow transport pipe 106 that connects the airflow generation drive source 102 and the airflow discharge nozzle 104. The airflow discharge nozzle 104 is installed above the top of the outlet 316 of the constricted flow tunnel 314 and below the level of the discharge port 32. This prevents the airflow J generated by the airflow generator 100 diagonally upward toward the vehicle V from being deflected by the airflow MF generated from inside the wind tunnel 16. The airflow generation drive source 102 may be, for example, a blower, and the airflow outlet nozzle 104 may be a plurality of nozzles, all positioned at the same level, or it may be a single nozzle with a horizontally elongated opening. As a variation, multiple airflow generators 100 may be provided and installed at the same level.

[0029] The operation method of the snow environment testing facility 10 having the above configuration will now be described. The temperature inside the measurement chamber 300 where the thin ice snowflake manufacturing device 18 is installed should be kept at 5°C or lower, preferably at 3°C ​​or lower.

[0030] First, the desired size of thin ice flakes and the desired production rate (snowfall) per hour are set according to the purpose of the snow environment test. Depending on the height of the stationary vehicle V, the size and level of the outlet 316 of the constricted flow cavity 314 may be selected, or the angle at which the airflow is directed diagonally upward in the airflow outlet nozzle 104 may be selected. Next, based on the set desired size of thin ice snowflakes and the desired production rate (snowfall) per hour, the control panel 70 controls the water temperature and flow rate adjustment device 60, the refrigerant temperature adjustment device 72, and the drive motor 54 to adjust the temperature and flow rate of the water supplied to the water spray nozzle 24, the refrigerant temperature, and the rotation speed of the connecting rod 40. More specifically, the refrigerator 74 is activated to supply refrigerant to the fixed hollow cylinder 20 via pipes 76 and 78, raising the temperature of the inner surface of the fixed hollow cylinder 20 to -10 to -20°C, while the amount of water sprayed from the water sprayer 24 and the rotation speed of the connecting rod 40 are set according to the size and amount of thin ice and snow fragments produced.

[0031] The mist of water sprayed from the water sprayer 24, which rotates counterclockwise with the support arm 46, toward the inner surface of the fixed hollow cylinder 20, instantly freezes upon contact with the inner surface of the fixed hollow cylinder 20, forming a thin layer of ice L. The thin layer of ice L formed on the inner surface of the fixed hollow cylinder 20 is peeled off by the blade 28, which rotates counterclockwise with the support arm 46, into thin ice and snow fragments. The countless peeled-off thin ice and snow fragments fall into the measurement chamber 300 from the discharge port 32.

[0032] Next, without flowing the airflow MF inside the wind tunnel 16, the airflow generator 100 directs an airflow J diagonally upward towards the stationary vehicle V, towards the thin ice and snowflakes S falling by gravity from the outlet 32, between the outlet 32 ​​and the constricted flow tunnel 314, so that snow falls from directly above the stationary vehicle V, causing snow to accumulate on the stationary vehicle V. If the distance between the thin ice and snowflake manufacturing device 18 and the stationary vehicle V is long, the upward diagonal direction of the airflow outlet nozzle 104 from the airflow generator 100 should be reduced accordingly, while the airflow rate should be increased according to the amount of thin ice and snowflakes produced per hour from the thin ice and snowflake manufacturing device 18 and / or the size of the thin ice and snowflakes. The airflow rate can be adjusted by adjusting the size of the opening of the airflow outlet nozzle 104 and / or the airflow velocity. Alternatively, if the amount of thin ice and snowflakes produced per hour and the amount of thin ice and snowflakes falling are small, it may be possible to increase the airflow rate without reducing the upward diagonal orientation of the airflow nozzle 104. Furthermore, the distance between the thin ice and snowflake manufacturing device 18 and the stationary vehicle V can be adjusted by moving the thin ice and snowflake manufacturing device 18 toward the stationary vehicle V. If moving the thin ice and snowflake manufacturing device 18 alone, or adjusting the diagonal upward direction of the airflow nozzle 104 alone, is insufficient, the movement of the thin ice and snowflake manufacturing device 18 and the adjustment of the diagonal upward direction of the airflow nozzle 104 can be combined.

[0033] As an alternative snow environment test, during the snow accumulation phase on the stationary vehicle V described above, an airflow MF may be flowed from the constricted flow tunnel 314 toward the stationary vehicle V, thereby simulating the driving speed during traffic congestion using the stationary vehicle V. In this case, it is preferable to set the airflow velocity of the airflow MF in the wind tunnel 16 according to the driving speed of the vehicle V being simulated, or to adjust the direction of the airflow J from the airflow generator 100 toward the stationary vehicle V according to the airflow velocity from the constricted flow tunnel 314. In summary, snow accumulation on a vehicle from directly above or at an angle differs from that caused by blizzards in terms of the variation in contact area with the vehicle due to the adhesion of snowflakes before accumulation, and the degree of adhesion to the vehicle. By using artificial snow made from thin ice fragments to simulate snow accumulation, it becomes possible to perform an evaluation that more closely resembles that of natural snow.

[0034] Furthermore, for conducting another snow environment test, after the snow accumulation stage on the stationary vehicle V described above is completed, a natural wind can be simulated by flowing an airflow MF from the constricted flow tunnel 314 toward the stationary vehicle V. This makes it possible to conduct heat dissipation evaluation tests, such as snow melting and snow refreezing, by simulating natural wind conditions after snow has accumulated on the vehicle.

[0035] With the snowmaking system having the above configuration, the thin ice snow fragment manufacturing device 18 is installed between the flow condensation cavity and the stationary vehicle V, and the water spray spray 24 and blade 28 are rotated concentrically with the fixed hollow cylinder 20 by the rotational drive means 30. By spraying water with the water spray spray 24 toward the inner cooling surface of the fixed hollow cylinder 20, a thin ice layer is formed on the inner cooling surface, and the thin ice layer is peeled off by the blade 28, which is spaced at a predetermined angular interval from the water spray spray 24 in the circumferential direction of the fixed hollow cylinder 20, thereby generating thin ice snow fragments, which can then be allowed to fall naturally from the discharge port 32 at the lower end.

[0036] Here, without flowing airflow from the constricted tunnel 314 toward the stationary vehicle V, an airflow generator 100 installed between the outlet 32 ​​and the constricted tunnel 314 is used to flow airflow J diagonally upward toward the stationary vehicle V toward the thin ice and snow fragments falling by gravity from the outlet 32. By adjusting the direction and / or flow rate of the airflow generated by the airflow generator 100, it is possible to simulate snowfall and accumulation from directly above the stationary vehicle V, or, during the snow accumulation stage, flow airflow MF from the constricted tunnel 314 toward the stationary vehicle V, simulating the speed of traffic congestion using the stationary vehicle, causing snow to fly diagonally toward the stationary vehicle V and accumulate, or, after the snow accumulation stage is completed, flow airflow MF from the constricted tunnel 314 toward the stationary vehicle V to simulate natural wind and conduct heat dissipation tests. In short, it is possible to conduct various environmental tests related to snowfall using artificial snow made from thin ice and snow fragments using a single environmental test facility.

[0037] Although embodiments of the present invention have been described in detail above, various modifications and changes are possible for those skilled in the art without departing from the scope of the present invention. For example, in this embodiment, with respect to the airflow generator 100, it has been described that the orientation of the airflow nozzle 104 itself can be adjusted, but the invention is not limited to this. The airflow nozzle 104 itself may be fixed, and the installation angle of the airflow generator 100 may be adjusted to tilt upward toward the airflow nozzle 104, or the orientation of the airflow nozzle 104 itself may be adjustable, and the installation angle of the airflow generator 100 may be adjusted to tilt upward toward the airflow nozzle 104. [Brief explanation of the drawing]

[0038] [Figure 1] This is an overall configuration diagram of a snow environment testing facility according to an embodiment of the present invention. [Figure 2] This is a partial diagram showing the snowfall conditions on a stationary vehicle V of a snow environment testing facility according to an embodiment of the present invention. [Figure 3] This is a schematic side view showing a thin ice and snowflake manufacturing apparatus 18 of a snow environment testing facility according to an embodiment of the present invention. [Figure 4] This is a schematic plan view showing a thin ice and snowflake manufacturing apparatus 18 of a snow environment testing facility according to an embodiment of the present invention. [Explanation of Symbols]

[0039] S Thin ice flakes MF airflow J Airflow V Stationary Vehicles θ predetermined angular interval α blade tilt angle w width of the circumferential groove 60 d Depth of the circumferential groove 60 L Thin ice layer 10. Snow Environment Testing Facility 11 Wind tunnel equipment 16 Wind tunnel 18. Thin ice and snowflake manufacturing device 20 Fixed hollow cylinder 21 Hollow part 24 Watering spray 27 Tip 28 blades 29 Fixing bolts 30 Rotary drive means 32 Outlet 40 connecting rods 42 End 44. Rotating rod mechanism 46 Support Arm 48 tires 50 Vertical Rotating Shaft 52 Rotating shaft support section 54 Rotary drive unit 56 Inner surface 58 Outer surface 60 Circumferential grooves 61 Water temperature water adjustment device 62 water tanks 64 Heating 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 100 Airflow Generator 102 Airflow generation drive source 104 Airflow Nozzle 106 Airflow conveying pipe 300 Measurement room 302, 304, 306, 308 Bent torso 310 Second Diffusion Body 306 Third Bent Torso 308 Fourth Bent Torso 312 Rectifier Cylinder 314 Flow-constricting tunnel 316 Air outlet 317 Receiving Port

Claims

1. The process involves installing a thin ice and snowflake manufacturing apparatus between a constricted flow duct and a stationary vehicle, the apparatus having an outlet at its lower end for allowing thin ice and snowflakes generated by peeling off a thin ice layer to fall naturally, and installing an airflow generating apparatus between the outlet and the constricted flow duct that can adjust the direction of the airflow directed towards the thin ice and snowflakes falling by gravity from the outlet so that snow falls and accumulates from directly above the stationary vehicle, A snowfall test method characterized by comprising the steps of: adjusting the direction of the airflow generated by an airflow generator while directing thin ice and snowflakes from directly above a stationary vehicle, without directing airflow from the aforementioned flow-contraction tunnel toward the stationary vehicle, thereby causing snow accumulation.

2. In the aforementioned snow accumulation stage, there is a step in which airflow is directed from the constricted flow tunnel toward a stationary vehicle, and the stationary vehicle is used to simulate the driving speed during traffic congestion. Furthermore, the snowfall test method according to claim 1, further comprising the step of adjusting the direction of the airflow from the airflow generator toward the stationary vehicle according to the airflow velocity from the constriction tunnel.

3. Furthermore, the snowfall test method according to claim 1, further comprising a step of simulating natural wind by flowing air from the constricted flow tunnel toward a stationary vehicle after the snow accumulation stage is completed.

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