Icing device and icing method

Abstract

To provide an icing device and icing method for accurately controlling growth of ice when an ice layer is formed on a sample.SOLUTION: In an icing device 1, a spraying unit 21 sprays misty water particles into a test chamber 7, while a sample temperature detection section 3 detects temperature of a sample SP arranged inside the test chamber 7 in an environment at a temperature lower than a freezing point. In the icing device 1, at least one of a position of the spraying unit 21, a spraying amount of water particles by the spraying unit 21, and temperature of the test chamber 7 can be adjusted based on a detection result of the sample temperature detection section 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an icing device and an icing method for forming an ice layer on a test specimen in a room that can be adjusted to a low-temperature environment below freezing. [Background technology]

[0002] Conventionally, there has been known an icing device that forms an ice layer on an object to be iced, which is placed in a room adjusted to a low-temperature environment below the freezing point. This type of icing device is disclosed in Patent Document 1 and Patent Document 2.

[0003] The devices disclosed in Patent Document 1 and Patent Document 2 are both configured to inject water particles into a room (into a chamber in Patent Document 1, and into a wind tunnel room in Patent Document 2) that is adjusted to a predetermined temperature below freezing, and to freeze the water particles on the object to be iced, thereby forming an ice layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-516995 [Patent Document 2] Japanese Utility Model Application Publication No. 02-103245 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when forming an ice layer on an object to be iced, it may be necessary to control the growth of the ice. For example, when forming a transparent ice layer on an object to be iced, it is necessary to control the growth of the ice so that air that inhibits the transparency of the ice layer is not trapped in the ice layer. There is a problem that the growth of the ice cannot be precisely controlled when forming an ice layer on the object to be iced by simply adjusting the temperature of the room in which the object to be iced is placed to a predetermined temperature as in the techniques disclosed in Patent Documents 1 and 2.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide an icing device and an icing method that are capable of precisely controlling the growth of ice when forming an ice layer on a test specimen. [Means for solving the problem]

[0007] According to one aspect of the present invention, an icing device is an apparatus for forming an ice layer on a specimen in a room that can be adjusted to a low-temperature environment below freezing. The icing device includes a spray unit that sprays mist-like water particles into the room, and a specimen temperature detection unit that detects the temperature of the specimen. At least one of the position of the spray unit, the amount of the water particles sprayed by the spray unit, and the temperature inside the room can be adjusted based on the detection result of the specimen temperature detection unit.

[0008] According to this icing device, the spray unit sprays mist-like water particles into a room in which a test specimen is placed. When the room is adjusted to a low-temperature environment below freezing, the water particles sprayed from the spray unit float in the room adjusted to a low-temperature environment below freezing and freeze on the test specimen. The freezing of the water particles on the test specimen forms an ice layer on the test specimen.

[0009] In the icing device, when forming an ice layer on a specimen, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature in the room can be adjusted based on the result of detection of the specimen temperature by the specimen temperature detection unit. The position of the spray unit and the temperature in the room affect the temperature of the water particles when they float in the room and reach the specimen. In addition, the amount of water particles sprayed by the spray unit affects the amount of water particles that reach the specimen. By adjusting these influencing factors based on the detection result of the specimen temperature, it becomes possible to precisely control the temperature of the specimen. Since the temperature of the specimen is an ice growth influencing factor that affects the growth of ice when an ice layer is formed on the specimen, the growth of ice on the specimen can be precisely controlled by precisely controlling the temperature of the specimen.

[0010] The icing device may further include an air conditioning unit that adjusts the temperature inside the room, and the air conditioning unit adjusts the temperature inside the room before the water particles are sprayed from the spray unit so that the temperature of the specimen is lower than a target temperature of the specimen during the spraying of the water particles from the spray unit.

[0011] In this embodiment, the temperature of the specimen is adjusted to a temperature lower than the target temperature before the spray unit starts spraying the water particles, thereby accelerating the freezing of the water particles on the specimen at the initial stage when the spray unit starts spraying the water particles and an ice layer is formed on the specimen.

[0012] In the above-mentioned icing device, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room can be adjusted so that the temperature of the test specimen is maintained within a temperature range of -1°C or more and 0°C or less while the water particles are being sprayed from the spray unit.

[0013] In this embodiment, at least one of the influencing factors, the position of the spray unit, the amount of water particles sprayed by the spray unit, and the room temperature, is adjusted so that the temperature of the specimen is maintained within a temperature range of -1°C or more and 0°C or less while the water particles are being sprayed from the spray unit. Such adjustment of the influencing factors is particularly effective when forming a transparent ice layer on the specimen. By adjusting the temperature of the specimen to -1°C or more and 0°C or less, it is possible to prevent air and the like that inhibits the transparency of the ice layer from being trapped in the ice layer. As a result, a transparent and homogeneous ice layer can be formed on the specimen.

[0014] In the above-mentioned icing device, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room can be adjusted so that the temperature of the test specimen is maintained at a target temperature that is set according to the location where the ice layer is formed on the test specimen while the water particles are being sprayed from the spray unit.

[0015] In the test specimen, for example, the growth rate of ice when forming an ice layer differs between the upper surface facing upward and the lower surface facing downward. When forming an ice layer on the upper surface of the test specimen, the phenomenon of water particles reaching the upper surface dripping off is unlikely to occur. On the other hand, when forming an ice layer on the lower surface of the test specimen, the phenomenon of water particles reaching the lower surface dripping off is likely to occur. For this reason, the growth rate of ice is slower on the lower surface of the test specimen than on the upper surface. In consideration of the difference in the growth rate of ice depending on the ice layer formation part of such a test specimen, at least one of the influencing factors of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room is adjusted so that the temperature of the test specimen is maintained at a target temperature according to the ice layer formation part. This makes it possible to precisely control the growth of ice when forming an ice layer depending on the ice layer formation part of the test specimen.

[0016] In the above icing device, the spray unit is configured to spray water particles having an average particle size less than a predetermined value as the water particles.

[0017] In this embodiment, when forming an ice layer on the test specimen, ultra-fine water particles with an average particle size less than a predetermined value are sprayed from the spray unit. This makes it easy to suspend the water particles in the chamber and to bring the water particles closer to a supercooled state. This contributes to the formation of a homogeneous ice layer on the test specimen.

[0018] The icing device may further include a pressure pump that supplies pressurized water to the spray unit to cause the spray unit to spray the water particles. The pressure pump supplies pressurized water to the spray unit so that the spray pressure of the water particles is kept constant during the spraying of the water particles from the spray unit.

[0019] In this embodiment, the water pressure when spraying water particles from the spray unit is kept constant, so that water particles with a substantially constant average particle size can be sprayed. This makes it possible to stabilize the temperature of the water particles when they reach the test specimen after floating in the room while being sprayed from the spray unit. This contributes to the formation of a homogeneous ice layer on the test specimen.

[0020] An icing method according to another aspect of the present invention is a method for forming an ice layer on a specimen in a room that can be adjusted to a low-temperature environment below freezing. This icing method includes a spraying step of spraying mist-like water particles into the room with a spray unit while detecting the temperature of the specimen with a specimen temperature detection unit, and in the spraying step, at least one of the position of the spray unit, the amount of the water particles sprayed by the spray unit, and the temperature inside the room is adjusted based on the detection result of the specimen temperature detection unit.

[0021] According to this icing method, in the spraying step, a spray unit sprays mist-like water particles into a room in which the specimen is placed. As a result, an ice layer is formed on the specimen by freezing the water particles on the specimen. Furthermore, in the spraying step, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature in the room is adjusted based on the result of detection of the specimen temperature by the specimen temperature detection unit. This makes it possible to precisely control the temperature of the specimen, which is an ice growth influencing factor that affects the growth of ice when an ice layer is formed on the specimen. By precisely controlling the temperature of the specimen in this way, the growth of ice on the specimen can be precisely controlled.

[0022] The above-mentioned icing method may include, as a preliminary step before the spraying step, a pre-cooling step of adjusting the temperature inside the room so that the temperature of the specimen is lower than a target temperature of the specimen in the spraying step.

[0023] In this embodiment, in the pre-cooling step prior to the spraying step, the temperature of the specimen is adjusted to a temperature lower than the target temperature, which can promote freezing of the water particles on the specimen in the initial stage when the spray unit starts spraying the water particles and an ice layer is formed on the specimen.

[0024] In the above-mentioned icing method, in the spraying process, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room is adjusted so that the temperature of the test specimen is maintained within a temperature range of -1°C or more and 0°C or less.

[0025] In this embodiment, the temperature of the specimen is adjusted to between -1°C and 0°C in the spraying process, which makes it possible to prevent air and other substances that would impair the transparency of the ice layer from being trapped in the ice layer, thereby forming a transparent and homogeneous ice layer on the specimen.

[0026] In the above-mentioned icing method, in the spraying process, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room is adjusted so that the temperature of the test specimen is maintained at a target temperature corresponding to the location where the ice layer is formed on the test specimen.

[0027] In this embodiment, taking into consideration that the ice growth rate differs depending on the ice layer formation location on the specimen, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the room temperature is adjusted so that the temperature of the specimen is maintained at a target temperature corresponding to the ice layer formation location. This makes it possible to precisely control the growth of ice when forming an ice layer depending on the ice layer formation location on the specimen.

[0028] In the above icing method, in the spraying step, water particles having an average particle size less than a predetermined value are sprayed by the spray unit.

[0029] In this embodiment, in the spraying step, ultra-fine water particles having an average particle size less than a predetermined value are sprayed from the spray unit. This makes it easy to suspend the water particles in the chamber and to bring the water particles closer to a supercooled state. This contributes to the formation of a homogeneous ice layer on the test specimen.

[0030] In the above icing method, in the spraying step, the spray pressure of the water particles from the spray unit is kept constant.

[0031] In this embodiment, the water pressure when spraying water particles from the spray unit is kept constant, so that water particles with a substantially constant average particle size can be sprayed. This makes it possible to stabilize the temperature of the water particles when they reach the test specimen after floating in the room while being sprayed from the spray unit. This contributes to the formation of a homogeneous ice layer on the test specimen. Effect of the Invention

[0032] As described above, according to the present invention, it is possible to provide an icing device and an icing method that are capable of precisely controlling the growth of ice when forming an ice layer on a test specimen. [Brief description of the drawings]

[0033] [Figure 1] 1 is a diagram illustrating a schematic configuration of an icing device according to an embodiment of the present invention. [Diagram 2] 1 is a perspective view showing a configuration of a unit support provided in an icing device. FIG. [Diagram 3] 4 is a flowchart illustrating an icing method implemented using the icing device. [Figure 4] FIG. 13 is a diagram illustrating a main portion of a modified example of the icing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, an icing device and an icing method according to the present embodiment will be described with reference to the drawings.

[0035] The icing device and the icing method according to the present embodiment are applicable to a test device and a test method for forming an ice layer on a test specimen in a room that can be adjusted to a low-temperature environment below freezing and performing a test. Examples of such tests include an icing test using aircraft-mounted equipment as a test specimen, an icing test for evaluating the effectiveness of a hydrophobic coating agent that prevents ice formation on aircraft structures, an icing test for evaluating the resistance of a vehicle structure such as an automobile against ice formation, and an icing test for evaluating the resistance of power transmission equipment such as a power transmission line against ice formation. The icing test for aircraft-mounted equipment is specified in Section 24 Category C of RTCA / DO-160G. In this icing test, it is required that a transparent ice layer be formed on the test specimen. In addition, examples of the test specimen include main wings and tails mounted on the aircraft body, landing gear for supporting the aircraft body on the ground, and pitot tubes used to measure airspeed. In the following, the icing device and the icing method according to the present embodiment will be described using an aircraft-mounted equipment as an example of a test specimen.

[0036] [About the ice attachment device] The icing device 1 shown in Fig. 1 is a device for forming an ice layer on a specimen SP in a test chamber 7. The test chamber 7 is an example of a room whose environment is adjusted to allow ice to form on the specimen SP.

[0037] 1, an air-conditioning room 8 is provided on the side of a test room 7 in which a specimen SP to be tested is placed, and is separated from the test room 7 by a partition wall 71. The partition wall 71 is provided with an air outlet 711 and an air inlet 712.

[0038] The icing device 1 is equipped with an air conditioning unit 6 that conditions the air flowing in the air conditioning chamber 8. The air conditioning unit 6 adjusts the temperature of the air in the air conditioning chamber 8 by heating or cooling the air in the air conditioning chamber 8. The air whose temperature has been adjusted by the air conditioning unit 6 is blown out from the air outlet 711 into the test chamber 7. In this way, temperature-adjusted air is supplied into the test chamber 7. By blowing air out from the air conditioning chamber 8 into the test chamber 7, the air in the test chamber 7 is sucked into the air conditioning chamber 8 from the air inlet 712. In this way, the temperature of the air in the test chamber 7 is adjusted by repeatedly circulating the air between the air conditioning chamber 8 and the test chamber 7. In other words, the air conditioning unit 6 can adjust the temperature in the test chamber 7 by supplying temperature-adjusted air into the test chamber 7.

[0039] The temperature inside the test chamber 7 is detected by the room temperature detection unit 72. The room temperature detection unit 72 is configured, for example, by a temperature sensor. The room temperature detection unit 72 is provided near the air outlet 711 inside the test chamber 7, and detects the temperature of the air near the air outlet 711. The temperature inside the test chamber 7 is adjusted to a temperature below freezing, for example, between -10°C and -1°C.

[0040] The icing device 1 provides an environment in which an ice layer is formed on the specimen SP in a test chamber 7 that can be adjusted to a low temperature environment below the freezing point. The icing device 1 includes a sprayer 2, a specimen temperature detection unit 3, a unit support 4, and a blower 5.

[0041] The sprayer 2 is a mechanism for spraying mist-like water particles into the test chamber 7. The number of sprayers 2 to be installed is determined according to the area of ​​the test chamber 7, the size of the test specimen SP, or the position of the ice layer formation site on the test specimen SP, and may be one, or two or more. The sprayer 2 includes a spray unit 21, a pressure pump 22, a filter 23, a supply pipe 24, a tank 25, and a water temperature regulator 26.

[0042] The spray unit 21 is disposed in the test chamber 7. The spray unit 21 has one or more spray nozzles 211. The spray unit 21 sprays mist-like water particles from the spray nozzle 211. In this embodiment, the spray unit 21 has the multiple spray nozzles 211.

[0043] The water particles sprayed from the spray unit 21 are cooled to a supercooled state or a state close to being supercooled by floating in the test chamber 7, which is adjusted to a low-temperature environment below the freezing point. The water particles floating in the test chamber 7 freeze on the specimen SP when they reach the specimen SP. This freezing of the water particles on the specimen SP forms an ice layer on the specimen SP.

[0044] The tank 25 and the water temperature regulator 26 are disposed outside the test chamber 7. The tank 25 stores water, and the water is supplied to the spray unit 21. The water temperature regulator 26 adjusts the temperature of the water in the tank 25. In other words, the water temperature regulator 26 adjusts the temperature of the water in the tank 25, thereby making it possible to adjust the temperature of the water particles sprayed from the spray unit 21. The temperature of the water in the tank 25 is adjusted to, for example, between 0°C and 40°C. It is to be noted that the water temperature regulator 26 may be omitted and water particles at room temperature (25°C) may be sprayed from the spray unit 21.

[0045] The pressure pump 22 is disposed outside the test chamber 7. A plurality of pressure pumps 22 are provided corresponding to the plurality of spray nozzles 211 in the spray unit 21. In other words, the number of pressure pumps 22 provided is the same as the number of spray nozzles 211 in the spray unit 21. Each pressure pump 22 pressurizes the water in the tank 25 and supplies it to each spray nozzle 211 of the spray unit 21.

[0046] Each pressure pump 22 and each spray nozzle 211 in the spray unit 21 are connected by a supply pipe 24. Water pressurized by each pressure pump 22 flows through the supply pipe 24 and is supplied to each spray nozzle 211. At least the portion of the supply pipe 24 that is routed inside the test chamber 7 is covered with a heat insulating material. This makes it possible to prevent the water flowing through the supply pipe 24 from freezing.

[0047] The filter 23 is disposed outside the test chamber 7. The filter 23 collects foreign matter contained in the water flowing through the supply pipe 24. This makes it possible to prevent the water containing foreign matter from being supplied to the spray nozzle 211 in the spray unit 21.

[0048] The spray unit 21 sprays water particles from each spray nozzle 211 by being supplied with pressurized water from each pressure pump 22. In a configuration in which a pressure pump 22 is provided corresponding to each of the multiple spray nozzles 211, the number of spray nozzles 211 spraying water particles can be adjusted by adjusting the number of times the pressure pump 22 is operated. In this way, the amount of water particles sprayed by the spray unit 21 can be adjusted by adjusting the number of spray nozzles 211 spraying water particles according to the number of times the pressure pump 22 is operated.

[0049] In the above example, a configuration in which a plurality of pressurizing pumps 22 are provided corresponding to the plurality of spray nozzles 211, respectively, has been described, but the present invention is not limited to this configuration. For example, a single pressurizing pump 22 may be provided, and the pressurizing pump 22 and each spray nozzle 211 in the spray unit 21 may be connected by a supply pipe 24 provided with an on-off valve. In this case, the amount of water particles sprayed by the spray unit 21 can be adjusted by adjusting the number of spray nozzles 211 spraying water particles according to the number of on-off valves to be opened while the pressurizing pump 22 is in operation.

[0050] The water injection pressure of the water particles injected from the spray unit 21 is adjusted by the water supply pressure to the spray nozzle 211 by the pressure pump 22. The water injection pressure when the water particles are injected from the spray unit 21 affects the average particle size of the water particles. In other words, as the water injection pressure of the water particles by the spray unit 21 increases, the average particle size of the water particles decreases. The average particle size of the water particles injected from the spray unit 21 is set to, for example, 12 μm or more and 25 μm or less.

[0051] The spray unit 21 is desirably configured to spray water particles (so-called "dry mist") having an average particle size less than a predetermined value (e.g., 16 μm) from the spray nozzle 211. These water particles are ultrafine water particles having an average particle size less than a predetermined value, so that the water particles can be easily suspended in the test chamber 7 and can be easily brought close to a supercooled state. This contributes to the formation of a homogeneous ice layer on the specimen SP.

[0052] The specimen temperature detection unit 3 detects the temperature of the specimen SP. The specimen temperature detection unit 3 is configured with a temperature sensor such as a thermocouple. The specimen temperature detection unit 3 is attached to the surface of the specimen SP and detects the surface temperature of the specimen SP. The specimen temperature detection unit 3 may be configured to detect the surface temperature of the specimen SP in a non-contact manner using infrared rays or the like.

[0053] The blower 5 is disposed in the test chamber 7. The blower 5 generates wind at a predetermined wind speed. The wind generated by the blower 5 can move the water particles sprayed from the spray unit 21 and suspended in the test chamber 7 toward the specimen SP. Note that the installation of the blower 5 may be omitted.

[0054] The unit support 4 is configured to support the spray unit 21 in the test chamber 7. Furthermore, the unit support 4 is configured to allow adjustment of the relative position of the spray unit 21 with respect to the specimen SP. As shown in FIG. 2, the unit support 4 includes a unit support portion 41, a rail 42, four support members 43, a first support frame 44, and two second support frames 45.

[0055] The four support members 43 are erected on the floor surface of the test chamber 7 so as to extend in the vertical direction. The first support frame 44 is a member formed in a rectangular frame shape, and is fixed to the upper ends of the four support members 43 in a horizontal position. The two second support frames 45 are members extending in a first horizontal direction H1, and are respectively connected to the vertical middle parts of the two support members 43 so as to face each other in a second horizontal direction H2 perpendicular to the first horizontal direction H1.

[0056] The rail 42 is a member extending in the second horizontal direction H2, and is supported by the first support frame 44 or the two second support frames 45. The rail 42 is movable in the first horizontal direction H1 along the first support frame 44 or the two second support frames 45. The unit support part 41 is a member that supports the spray unit 21, and is attached to the rail 42 in a state in which the spray unit 21 is supported. The unit support part 41 is movable in the second horizontal direction H2 along the rail 42.

[0057] In the unit support 4, the rail 42 is moved in the first horizontal direction H1 along the first support frame 44 or the two second support frames 45, and the unit support part 41 supporting the spray unit 21 is moved in the second horizontal direction H2 along the rail 42. This allows the relative position of the spray unit 21 to be adjusted in the horizontal direction with respect to the specimen SP. Furthermore, by changing the support of the rail 42 between the first support frame 44 and the second support frame 45, the relative position of the spray unit 21 to the specimen SP can be adjusted in the vertical direction. Note that the second support frame 45 may be omitted in the unit support 4, and the first support frame 44 supporting the rail 42 may be moved in the vertical direction along the four support members 43. In this case, the relative position of the spray unit 21 to the specimen SP can be adjusted in the vertical direction by moving the first support frame 44 in the vertical direction.

[0058] The configuration of the unit support 4 is not limited to the above configuration, as long as it is capable of supporting the spray unit 21 and adjusting the relative position of the spray unit 21 with respect to the specimen SP in the vertical and horizontal directions.

[0059] In icing device 1, when forming an ice layer on specimen SP, it is possible to adjust at least one of the position of spray unit 21, the amount of water particles sprayed by spray unit 21, and the temperature in test chamber 7 based on the detection result of the temperature of specimen SP by specimen temperature detection unit 3. Specifically, in icing device 1, the relative position of spray unit 21 with respect to specimen SP is adjusted by unit support 4. Also, the amount of water particles sprayed by spray unit 21 is adjusted by adjusting the number of spray nozzles 211 that spray water particles according to the number of operations of pressure pump 22. Furthermore, the temperature in test chamber 7 is adjusted according to the supply of temperature-adjusted air by air conditioning unit 6 into test chamber 7.

[0060] The position of the spray unit 21 and the temperature in the test chamber 7 affect the temperature of the water particles when they float in the test chamber 7 and reach the specimen SP. In addition, the amount of water particles sprayed by the spray unit 21 affects the amount of water particles that reach the specimen SP. By adjusting these influencing factors based on the detection result of the temperature of the specimen SP by the specimen temperature detection unit 3, it becomes possible to precisely control the temperature of the specimen SP. Since the temperature of the specimen SP is an ice growth influencing factor that affects the growth of ice when an ice layer is formed on the specimen SP, the growth of ice on the specimen SP can be precisely controlled by precisely controlling the temperature of the specimen SP.

[0061] The position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7 are all influencing factors that affect the temperature of the specimen SP. In the following description, at least one of the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7 may be collectively referred to as the "specimen temperature influencing factors."

[0062] In icing device 1, it is desirable to maintain the water pressure at which the water particles are sprayed from spray unit 21 at a constant level. As described above, the water pressure at which the water particles are sprayed is adjusted by the water pressure supplied to spray nozzle 211 by pressure pump 22. By maintaining the water pressure at which the water particles are sprayed from spray unit 21 at a constant level, water particles with a substantially constant average particle size can be sprayed. This makes it possible to stabilize the temperature of the water particles when they float in test chamber 7 and reach specimen SP during spraying from spray unit 21. This contributes to the formation of a homogeneous ice layer on specimen SP.

[0063] In addition, in the icing device 1, the specimen temperature influence factor is adjusted so that the temperature of the specimen SP is maintained at a predetermined target temperature within a temperature range of -1°C or more and 0°C or less during the spraying of water particles from the spray unit 21. At this time, at least one of the following adjustments is performed first: adjusting the position of the spray unit 21 by the unit support 4, and adjusting the amount of water particles sprayed by the spray unit 21 according to the number of spray nozzles 211 that spray the water particles. If the temperature of the specimen SP is not maintained at the target temperature by these adjustments, the temperature in the test chamber 7 is adjusted by the air conditioning unit 6. Among the adjustments of the specimen temperature influence factor, the adjustment of the position of the spray unit 21 and the adjustment of the amount of water particles sprayed by the spray unit 21 are performed before the spraying of the water particles, and the adjustment of the temperature in the test chamber 7 is performed during the spraying of the water particles. Alternatively, the adjustment of the position of the spray unit 21 may be performed before the spraying of the water particles, and the adjustment of the amount of water particles sprayed by the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed during the spraying of the water particles. In addition, the adjustment of the amount of water particles sprayed by the spray unit 21 may be performed before the water particles are sprayed, and the adjustment of the position of the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are sprayed. In addition, the adjustment of the position of the spray unit 21, the adjustment of the amount of water particles sprayed by the spray unit 21, and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are sprayed.

[0064] Specifically, when the temperature of the specimen SP detected by the specimen temperature detection unit 3 is higher than the target temperature, the position of the spray unit 21 is adjusted by the unit support 4 so that the spray unit 21 moves away from the specimen SP. As a result, the distance that the water particles sprayed from the spray unit 21 float before reaching the specimen SP becomes longer, so that the temperature of the water particles when they reach the specimen SP becomes lower. As a result, the temperature of the specimen SP can be brought closer to the target temperature. In addition, the amount of water particles sprayed by the spray unit 21 is adjusted to be reduced. As a result, the amount of water particles with a temperature higher than the target temperature that reach the specimen SP becomes smaller. As a result, the temperature of the specimen SP can be brought closer to the target temperature. In addition, the temperature in the test chamber 7 is adjusted by the air conditioning unit 6 so that the temperature is lowered. As a result, the temperature of the water particles floating in the test chamber 7 becomes lower. As a result, the temperature of the water particles when they reach the specimen SP also becomes lower, so that the temperature of the specimen SP can be brought closer to the target temperature.

[0065] On the other hand, when the temperature of the specimen SP detected by the specimen temperature detection unit 3 is lower than the target temperature, the position of the spray unit 21 is adjusted by the unit support 4 so that the spray unit 21 approaches the specimen SP. As a result, the distance that the water particles sprayed from the spray unit 21 travel before reaching the specimen SP is shortened, and the temperature of the water particles when they reach the specimen SP is increased. As a result, the temperature of the specimen SP can be brought closer to the target temperature. In addition, the amount of water particles sprayed by the spray unit 21 is adjusted to be increased. As a result, the amount of water particles with a temperature higher than the target temperature that reach the specimen SP is increased. As a result, the temperature of the specimen SP can be brought closer to the target temperature. In addition, the temperature in the test chamber 7 is adjusted by the air conditioning unit 6 so that the temperature is increased. As a result, the temperature of the water particles floating in the test chamber 7 is increased. As a result, the temperature of the water particles when they reach the specimen SP is also increased, and the temperature of the specimen SP can be brought closer to the target temperature.

[0066] Adjusting the specimen temperature influence factors so that the temperature of the specimen SP is maintained at a target temperature between -1°C and 0°C is particularly effective when forming a transparent ice layer on the specimen SP. By adjusting the temperature of the specimen SP to between -1°C and 0°C, it is possible to prevent air and other substances that impair the transparency of the ice layer from being trapped in the ice layer. This makes it possible to form a transparent and homogenous ice layer on the specimen SP.

[0067] In the specimen SP, for example, the growth rate of ice when forming an ice layer differs between the upper surface facing upward and the lower surface facing downward. When an ice layer is formed on the upper surface of the specimen SP, the phenomenon of water particles reaching the upper surface dripping off is unlikely to occur. On the other hand, when an ice layer is formed on the lower surface of the specimen SP, the phenomenon of water particles reaching the lower surface dripping off is likely to occur. For this reason, the growth rate of ice is slower on the lower surface of the specimen SP than on the upper surface.

[0068] It is preferable that the icing device 1 is configured in consideration of the fact that the growth rate of ice differs depending on the ice layer formation portion of the specimen SP. In other words, in the icing device 1, at least one of the specimen temperature influence factors, the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7, is adjusted so that the temperature of the specimen SP is maintained at a target temperature set according to the ice layer formation portion of the specimen SP while the water particles are being sprayed from the spray unit 21. In this case, as for the adjustment of the specimen temperature influence factors, the adjustment of the position of the spray unit 21 and the adjustment of the amount of water particles sprayed by the spray unit 21 are performed before the spraying of the water particles, and the adjustment of the temperature in the test chamber 7 is performed while the water particles are being sprayed. Alternatively, the adjustment of the position of the spray unit 21 may be performed before the spraying of the water particles, and the adjustment of the amount of water particles sprayed by the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are being sprayed. In addition, the adjustment of the amount of water particles sprayed by the spray unit 21 may be performed before the water particles are sprayed, and the adjustment of the position of the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are sprayed. In addition, the adjustment of the position of the spray unit 21, the adjustment of the amount of water particles sprayed by the spray unit 21, and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are sprayed.

[0069] The target temperature when the lower surface of the specimen SP is not a target for ice layer formation is set as the "first target temperature", and the target temperature when the lower surface of the specimen SP is included as a target for ice layer formation is set as the "second target temperature". In this case, the second target temperature is set to a value lower than the first target temperature. That is, in the icing device 1, when the lower surface of the specimen SP is not a target for ice layer formation, the specimen temperature influence factor is adjusted so that the temperature of the specimen SP is maintained at the first target temperature. On the other hand, when the lower surface of the specimen SP is included as a target for ice layer formation and the entire surface of the specimen SP is a target for ice layer formation, the specimen temperature influence factor is adjusted so that the temperature of at least the lower surface of the specimen SP is maintained at a second target temperature lower than the first target temperature. This makes it possible to precisely control the growth of ice when forming an ice layer according to the ice layer formation site of the specimen SP. The specimen temperature detection unit 3 may be configured to detect the temperature of a surface of the specimen SP other than the lower surface, or may be configured to detect the temperature of the lower surface of the specimen SP. The specimen temperature detection unit 3 may be configured to change the target position of temperature detection on the specimen SP depending on the location of the specimen SP where an ice layer is to be formed. For example, when the lower surface of the specimen SP is not a target for ice layer formation, the specimen temperature detection unit 3 detects the temperature of a surface of the specimen SP other than the lower surface. On the other hand, when the entire surface of the specimen SP is a target for ice layer formation, the specimen temperature detection unit 3 detects the temperature of the lower surface of the specimen SP.

[0070] When adjusting the specimen temperature influence factor when the entire surface of the specimen SP is to be the target for ice layer formation, the amount of water particles sprayed by the spray unit 21 may be adjusted in consideration of the ice growth rate on each surface of the specimen SP so that the amount of water particles reaching the upper surface of the specimen SP is less than that reaching the lower surface. This allows an ice layer of uniform thickness to be formed over the entire surface of the specimen SP.

[0071] In addition, in the icing device 1, the temperature in the test chamber 7 may be adjusted by the air conditioning unit 6 before the spraying of water particles from the spray unit 21 so that the temperature of the specimen SP becomes the target temperature of the specimen SP during the spraying of water particles from the spray unit 21. This can promote freezing of the water particles on the specimen SP in the initial stage when the spraying of water particles by the spray unit 21 starts and an ice layer is formed on the specimen SP. Alternatively, the temperature in the test chamber 7 may be adjusted by the air conditioning unit 6 before the spraying of water particles from the spray unit 21 so that the temperature of the specimen SP becomes a temperature (pre-cooling temperature) lower than the target temperature of the specimen SP during the spraying of water particles from the spray unit 21. This can promote freezing of the water particles on the specimen SP in the initial stage when the spraying of water particles by the spray unit 21 starts and an ice layer is formed on the specimen SP.

[0072] [How to apply ice] Next, an icing method for forming an ice layer on the specimen SP in the test chamber 7 that can be adjusted to a low-temperature environment below freezing will be described with reference to the flowchart of Fig. 3. Each step of this icing method is performed using the icing device 1 described above.

[0073] A specimen SP is placed in the test chamber 7, a specimen temperature detection unit 3 is attached to the specimen SP, and a unit support 4 supporting the spray unit 21 is placed at a predetermined position so that the spray unit 21 is separated from the specimen SP by a predetermined distance. In addition, a pre-cooling temperature of the specimen SP and a target temperature according to the portion of the specimen SP where an ice layer is to be formed are set.

[0074] In addition, the operating conditions of the sprayer 2 are also set in advance. Specifically, the water injection pressure for injecting water particles having a desired average particle size from the spray unit 21, that is, the water supply pressure from the pressure pump 22 to the spray nozzle 211, is set in advance. At this time, when water particles having an average particle size less than a predetermined value (for example, 16 μm) are injected from the spray unit 21, the water temperature regulator 26 adjusts the temperature of the water in the tank 25 so that the temperature of the water particles injected from the spray unit 21 is, for example, room temperature (25° C.). As described above, water particles (dry mist) having an average particle size less than a predetermined value are water particles that easily float in the test chamber 7 and easily approach a supercooled state. For this reason, it is not necessary to set the temperature of the water particles injected from the spray unit 21 to a low temperature near 0° C., and it is sufficient to adjust it to a room temperature of, for example, 25° C.

[0075] The temperature inside the test chamber 7 is adjusted to a temperature below freezing, for example, between −10° C. and −1° C., by the air conditioning unit 6. Such temperature adjustment inside the test chamber 7 by the air conditioning unit 6 may be performed before or after placing the specimen SP in the test chamber 7.

[0076] Before the spray unit 21 sprays water particles, the temperature in the test chamber 7 is adjusted by the air conditioning unit 6 so that the temperature of the specimen SP reaches the pre-cooling temperature (step S1, pre-cooling step). During such adjustment of the temperature in the test chamber 7, it is determined based on the detection result of the specimen temperature detection unit 3 whether the temperature of the specimen SP has reached the pre-cooling temperature (step S2).

[0077] When the temperature of the specimen SP reaches the pre-cooling temperature (YES in step S2), spraying of water particles from the spray unit 21 starts (step S3). In the initial stage in which the spray unit 21 starts spraying water particles and an ice layer is formed on the specimen SP, the temperature of the specimen SP is at the pre-cooling temperature, so freezing of the water particles on the specimen SP is promoted.

[0078] Furthermore, the water pressure of the water particles is kept constant while the water particles are being sprayed from the spray unit 21. This allows water particles with a substantially constant average particle size to be sprayed from the spray unit 21. This allows the temperature of the water particles to be stabilized when they float in the test chamber 7 and reach the specimen SP while the water particles are being sprayed from the spray unit 21. The water particles sprayed from the spray unit 21 are cooled to a supercooled state or a state close to being supercooled by floating in the test chamber 7, which is adjusted to a low-temperature environment below freezing.

[0079] During the spraying of water particles from the spray unit 21, at least one of the specimen temperature influencing factors, i.e., the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7, is adjusted based on the detection result of the specimen temperature detection unit 3 so that the temperature of the specimen SP is maintained at a predetermined target temperature within a temperature range of -1°C or more and 0°C or less (step S4). At this time, the specimen temperature influencing factor is adjusted so that the temperature of the specimen SP is maintained at a target temperature set according to the ice layer formation portion of the specimen SP. This makes it possible to prevent air, which inhibits the transparency of the ice layer, from being trapped in the ice layer. Therefore, a transparent and homogeneous ice layer can be formed on the specimen SP.

[0080] Among the adjustments of the specimen temperature influence factors, the adjustment of the position of the spray unit 21 and the adjustment of the amount of water particles sprayed by the spray unit 21 are performed before the spraying of the water particles, and the adjustment of the temperature in the test chamber 7 is performed while the water particles are being sprayed. Alternatively, the adjustment of the position of the spray unit 21 may be performed before the spraying of the water particles, and the adjustment of the amount of water particles sprayed by the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are being sprayed. Also, the adjustment of the amount of water particles sprayed by the spray unit 21 may be performed before the spraying of the water particles, and the adjustment of the position of the spray unit 21 and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are being sprayed. Also, the adjustment of the position of the spray unit 21, the adjustment of the amount of water particles sprayed by the spray unit 21, and the adjustment of the temperature in the test chamber 7 may be performed while the water particles are being sprayed.

[0081] During the spraying of water particles from the spray unit 21, it is determined whether or not the target spraying time has elapsed (step S5). If the target spraying time has elapsed (YES in step S5), the spraying of water particles from the spray unit 21 is stopped (step S6). Note that the period from step S3, in which the spraying of water particles from the spray unit 21 is started, to step S6, in which the spraying of water particles from the spray unit 21 is stopped, corresponds to the spraying process.

[0082] When the spray unit 21 stops spraying the water particles, the thickness of the ice layer formed on the specimen SP is measured by a thickness gauge. For example, an ultrasonic thickness gauge can be used as this thickness gauge. The ultrasonic thickness gauge is configured to calculate the thickness of the ice layer by measuring the propagation time when ultrasonic waves output from a probe in contact with the surface of the ice layer are reflected by the specimen SP and return. The ultrasonic thickness gauge can measure the thickness of the ice layer on the specimen SP non-destructively.

[0083] Based on the measurement result of the thickness gauge, it is determined whether the thickness of the ice layer on the specimen SP has reached the target thickness (step S7). If the thickness of the ice layer on the specimen SP has not reached the target thickness (NO in step S7), the processes from step S3 to step S7 are repeated.

[0084] If the thickness of the ice layer on the specimen SP reaches the target thickness (YES in step S7), the temperature in the test chamber 7 is adjusted by the air conditioning unit 6 so that the temperature of the specimen SP becomes the specified sub-freezing operating test temperature (step S8).

[0085] When the temperature of the specimen SP is maintained at the operation test temperature, an operation test of the specimen SP on which the ice layer has formed is started (step S9). Then, it is determined whether the operation test of the specimen SP has been completed (step S10), and when a predetermined condition is satisfied, the operation test is terminated.

[0086] While the icing device and icing method according to the embodiment of the present invention have been described above, the present invention is not limited thereto, and for example, the following modified embodiments can be adopted.

[0087] In the above embodiment, the icing device 1 and the icing method are described when applied to an icing test in which a transparent ice layer is formed on an aircraft-mounted device as a test specimen, but the present invention is not limited to this. The present invention is also applicable to ice layer formation for performing icing tests to evaluate the effectiveness of a hydrophobic coating agent that prevents ice formation on aircraft structures, icing tests to evaluate the resistance of vehicle structures such as automobiles to ice formation, and icing tests to evaluate the resistance of power transmission facilities such as power lines to ice formation.

[0088] In the above embodiment, a configuration has been described in which the temperature of the specimen SP is adjusted to the pre-cooling temperature before the spray unit 21 sprays water particles, but the configuration is not limited to this. The icing device 1 may be configured to omit the adjustment of the temperature of the specimen SP to the pre-cooling temperature, and to start spraying water particles from the spray unit 21 when the temperature of the specimen SP is maintained at the target temperature.

[0089] In the above embodiment, a configuration has been described in which water particles (dry mist) having an average particle size less than a predetermined value (e.g., 16 μm) are sprayed from the spray unit 21, but the present invention is not limited to such a configuration. The spray unit 21 may be configured to spray water particles having an average particle size equal to or greater than the predetermined value, so long as the water particles are capable of floating in the test chamber 7.

[0090] In the above embodiment, a configuration has been described in which the water jet pressure of the water particles is kept constant during the spraying of the water particles from the spray unit 21, but the present invention is not limited to such a configuration. The spray unit 21 may be configured to be capable of adjusting the amount of water particles sprayed by adjusting the water jet pressure of the water particles. In this case, the amount of water particles sprayed by the spray unit 21 can be adjusted by adjusting the water jet pressure of the water particles instead of adjusting the number of spray nozzles 211 that spray the water particles.

[0091] In the above embodiment, a configuration has been described in which the position of the spray unit 21 is adjusted by changing the position of the unit support part 41 in the unit support 4 to move the spray unit 21, but the present invention is not limited to such a configuration. Instead of this, or in addition to this, the position of the spray unit 21 may be adjusted by moving the unit support 4 itself.

[0092] In the above embodiment, a configuration has been described in which at least one of the specimen temperature influence factors, the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7, is adjusted based on the detection result of the temperature of the specimen SP by one specimen temperature detection unit 3, but the present invention is not limited to such a configuration. For example, a plurality of specimen temperature detection units 3 may be provided, and the temperature of the specimen SP may be detected by these specimen temperature detection units 3. In this case, at least one of the specimen temperature influence factors, the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7, is adjusted based on a representative value such as a maximum value, a minimum value, or an average value of the detection results of the plurality of specimen temperature detection units 3. Alternatively, at least one of the specimen temperature influence factors, the position of the spray unit 21, the amount of water particles sprayed by the spray unit 21, and the temperature in the test chamber 7, may be adjusted based on each detection result of the plurality of specimen temperature detection units 3.

[0093] In the above embodiment, the configuration in which water particles are sprayed from one spray unit 21 to form an ice layer on the specimen SP has been described, but the present invention is not limited to such a configuration. For example, as shown in FIG. 4, the icing device 1 may be configured such that one sprayer 2 includes multiple spray units 21A and 21B and multiple specimen temperature detectors 3A and 3B according to the ice layer formation site on the specimen SP. Specifically, the icing device 1 includes a first spray unit 21A for forming an ice layer on a surface other than the lower surface of the specimen SP, and a second spray unit 21B for forming an ice layer on the lower surface of the specimen SP. Furthermore, the icing device 1 includes a first specimen temperature detector 3A for detecting the temperature of the surface other than the lower surface of the specimen SP, and a second specimen temperature detector 3B for detecting the temperature of the lower surface of the specimen SP.

[0094] The following describes the adjustment of specimen temperature influence factors in the icing device 1 configured as above, when the entire surface of the specimen SP is the target for ice layer formation. At least one of the position of the first spray unit 21A and the amount of water particles sprayed by the first spray unit 21A is adjusted based on the detection result of the first specimen temperature detection unit 3A so that the temperature of the surface of the specimen SP other than the lower surface is maintained at a first target temperature. At least one of the position of the second spray unit 21B and the amount of water particles sprayed by the second spray unit 21B is adjusted based on the detection result of the second specimen temperature detection unit 3B so that the temperature of the lower surface of the specimen SP is maintained at a second target temperature lower than the first target temperature. This allows a homogeneous ice layer to be formed on the entire surface of the specimen SP.

[0095] In the above embodiment, a configuration has been described in which icing device 1 includes blower 5 disposed in test chamber 7, but the present invention is not limited to such a configuration. Installation of blower 5 in test chamber 7 may be omitted. [Explanation of symbols]

[0096] 1. Icing device 2 spray machine 21 Spray unit 22 Pressure pump 3. Test piece temperature detection section 6. Air Conditioning Section 7. Test Room SP specimen

Claims

1. An ice forming apparatus for forming an ice layer on a test specimen brought into a room that can be adjusted to a low temperature environment below freezing, comprising: A spray unit that sprays mist-like water particles into the room; A specimen temperature detection unit that detects the temperature of the specimen; An air conditioning unit that adjusts the temperature inside the room, The air conditioning unit is configured to adjust the temperature inside the room based on the detection result of the temperature of the specimen by the specimen temperature detection unit while the water particles are being sprayed from the spray unit, so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range below 0°C and ice forms on the specimen.

2. An ice forming apparatus for forming an ice layer on a test specimen in a room that can be adjusted to a low temperature environment below freezing, A spray unit that sprays mist-like water particles into the room; A specimen temperature detection unit that detects the temperature of the specimen; An air conditioning unit that adjusts the temperature inside the room, The air conditioning unit is The temperature inside the chamber is adjusted based on the detection result of the specimen temperature detection unit during the spraying of the water particles from the spray unit so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range of 0° C. or less and ice forms on the specimen, An ice formation device configured to adjust the temperature inside the room so that the temperature of the specimen is lower than the target temperature before the water particles are sprayed from the spray unit.

3. The icing device according to claim 1 or 2, wherein the temperature range is from -1°C to 0°C.

4. 4. The icing device according to claim 1, wherein the spray unit sprays water particles having an average particle size less than a predetermined value as the water particles.

5. The ice forming device according to claim 4 , wherein the average particle size is 12 μm or more and 25 μm or less.

6. a pressure pump that supplies pressurized water to the spray unit to cause the water particles to be sprayed from the spray unit; The icing device according to any one of claims 1 to 5, wherein the pressure pump supplies pressurized water to the spray unit so that the spray pressure of the water particles is maintained constant during the spraying of the water particles from the spray unit.

7. A method for forming an ice layer on a specimen brought into a room that can be adjusted to a low temperature environment below freezing, comprising: A spraying step of spraying mist-like water particles into the chamber by a spray unit while detecting the temperature of the specimen by a specimen temperature detection unit, In the spraying process, while the water particles are being sprayed from the spray unit, the temperature inside the room is adjusted based on the detection result of the temperature of the specimen by the specimen temperature detection unit so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range below 0°C, thereby forming ice on the specimen.

8. A method for forming an ice layer on a specimen in a room that can be adjusted to a low temperature environment below freezing, comprising: A spraying step of spraying mist-like water particles into the chamber by a spray unit while detecting the temperature of the specimen by a specimen temperature detection unit, In the spraying step, adjusting a position of the spray unit based on a detection result of the specimen temperature detection unit so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range; If the detection result is higher than the target temperature, adjusting the position of the spray unit to move away from the specimen; If the detection result is lower than the target temperature, the position of the spray unit is adjusted to be closer to the specimen.

9. A method for forming an ice layer on a specimen in a room that can be adjusted to a low temperature environment below freezing, comprising: A spraying step of spraying mist-like water particles into the chamber by a spray unit while detecting the temperature of the specimen by a specimen temperature detection unit, In the spraying step, Based on the detection result of the specimen temperature detection unit, an amount of the water particles sprayed by the spray unit is adjusted so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range; If the detection result is higher than the target temperature, adjusting the spray amount of the water particles by the spray unit to be smaller; When the detection result is lower than the target temperature, the amount of the water particles sprayed by the spray unit is adjusted to be larger.

10. A method for forming an ice layer on a test specimen in a room that can be adjusted to a low temperature environment below freezing, comprising: A spraying step of spraying mist-like water particles into the chamber by a spray unit while detecting the temperature of the specimen by a specimen temperature detection unit, In the spraying step, during the spraying of the water particles from the spray unit, the temperature in the room is adjusted based on the detection result of the specimen temperature detection unit so that the temperature of the specimen is maintained at a target temperature within a predetermined temperature range of 0° C. or less and ice forms on the specimen; An icing method comprising, as a preliminary cooling step prior to the spraying step, a pre-cooling step of adjusting the temperature inside the room so that the temperature of the specimen is lower than the target temperature of the specimen in the spraying step.

11. The icing method according to any one of claims 7 to 10, wherein the temperature range is from -1°C to 0°C.

12. 10. The icing method of claim 8 or 9, wherein in the spraying process, at least one of the position of the spray unit, the amount of water particles sprayed by the spray unit, and the temperature inside the room is adjusted so that the temperature of the specimen is maintained at a target temperature corresponding to the ice layer formation location on the specimen while the water particles are being sprayed from the spray unit.

13. The icing method according to any one of claims 7 to 12, wherein in the spraying step, water particles having an average particle size less than a predetermined value are sprayed by the spray unit as the water particles.

14. The ice formation method according to claim 13, wherein the average particle size is 12 μm or more and 25 μm or less.

15. The icing method according to any one of claims 7 to 14, wherein in the spraying step, a spray pressure of the water particles from the spray unit is kept constant.

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