Hail production method for aircraft impact testing

Abstract

The hail production method for aircraft impact test of the present application is suitable for the test of the atmospheric detection equipment on board using the start-up wind tunnel device, which comprises the following steps: preparing a metal mold, producing a mixed water solution, and placing the mixed water solution into the metal mold and cooling to form an ice ball; starting the refrigeration equipment and the spraying equipment in the wind tunnel device to set the environmental parameters of the test area of the wind tunnel device according to the test requirements; placing the ice ball in the spraying equipment and starting to make the ice ball in a rotating or rotating state, and spraying supercooled water droplets to the ice ball in a dynamic state through the spraying equipment to form an ice layer on the surface of the ice ball, and alternately placing the ice ball with a secondary ice layer in a plurality of cloud field environments adjusted according to the test requirements to finally form simulated hail with transparent layers and opaque layers alternately, and storing the simulated hail in a refrigerator at-30 DEG C, thereby improving the authenticity and accuracy of the test.

Description

Technical Field

[0001] This invention belongs to the technical field of experimental hail production methods, and particularly relates to a hail production method for aircraft impact tests. Background Technology

[0002] Aircraft often encounter hail during takeoff, flight, and landing. Hail impacts can damage external equipment such as atmospheric data probes, affecting normal operation. To verify the ability of various aircraft equipment to withstand hail environments, preliminary hail environment adaptability requirements have been proposed both domestically and internationally, and dedicated hail impact testing systems are under construction to evaluate the equipment's resistance to hail impacts.

[0003] Currently, there are similar devices used for hail impact testing of photovoltaic panels, such as ASTM F320 "Standard Test Method for Resistance to Hail Impact of Transparent Housings in Aerospace", CN219736764U "A Hail Impact Test Apparatus for Photovoltaic Modules" and CN109031466A "A Hail Simulator". However, these devices have low hail speeds and cannot simulate the alternating transparent and opaque structure of real hail in nature. They are not suitable for simulating hail impact testing of aircraft in wind tunnels, resulting in reduced test efficiency.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing hail for aircraft impact tests, solving the technical problem that hail-based aircraft impact tests are inefficient due to the use of hail in existing technologies. The technical solution of this invention has many beneficial effects, as described below: A method for creating hailstones for aircraft impact tests, applicable to airborne atmospheric detection equipment using a wind tunnel setup, the method comprising: S101: Prepare a metal mold, the size of which is adapted to the size of the hailstones used in the test; S102: Prepare a mixed aqueous solution, wherein softened deionized water is heated to boiling and then cooled, and after cooling, standard medical degreased cotton fibers are added and stirred evenly to form the mixed aqueous solution; S103: A mixed aqueous solution is placed into a metal mold and cooled to form ice balls; S104: Start the cooling and spraying equipment inside the wind tunnel and set the environmental parameters of the test area of ​​the wind tunnel according to the test requirements: S105: The ice ball is placed in a spraying device and started, and the ice ball is rotated or turned. Supercooled water droplets are sprayed onto the ice ball in a dynamic state through the spraying device to form an ice layer on the surface of the ice ball. S106: Adjust the temperature of the cloud field to below -8℃ using the refrigeration equipment, and adjust the spray droplet parameters of the spray equipment according to the atmospheric environment requirements of the test; restart the spray equipment to spray supercooled water droplets onto the ice ball in a dynamic state, and form a new ice layer on the ice layer and / or the surface of the ice ball. S107: Ice balls that form secondary ice layers are alternately placed in various cloud and fog environments adjusted according to experimental requirements, eventually forming simulated hail with alternating transparent and opaque layers. The simulated hail is stored in a freezer at -30°C.

[0006] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: This method artificially simulates hail using a spraying technique. A spray system atomizes softened deionized water in a low-temperature environment, forming supercooled water droplets. By adjusting the water and air pressure at the nozzles, it simulates cloud and fog environments with varying droplet sizes, temperatures, and water contents. When the cloud and fog field is set to have a low temperature and high water content, transparent ice layers form to simulate hail, while when the cloud and fog field is set to have a high temperature and low water content, opaque frost layers form to simulate hail. The alternation of cloud and fog fields simulates the hail structure in nature, characterized by alternating transparent and opaque layers. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a flowchart illustrating the method of the present invention. Detailed Implementation

[0009] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0010] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0011] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0012] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that aspects can be practiced without these specific details. To enable those skilled in the art to better understand the invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0013] In nature, real hailstones are usually composed of alternating transparent and opaque layers. Hailstones first form an opaque ice nucleus by colliding with supercooled water and freezing. As the hailstones tumble up and down in the hail cloud, when the ice nucleus collides with large supercooled water droplets with higher temperatures, it forms a pure, bubble-free, transparent ice layer. When it collides with ice crystals or small supercooled water droplets with lower temperatures, it forms an opaque ice layer with more impurities and bubbles.

[0014] Existing simulated hail is mainly used for hail impact verification of photovoltaic modules and is difficult to directly apply to the requirements of hail impact tests on aircraft. The main problems with simulated hail are: 1) Current methods for creating simulated hail involve filling a spherical mold with water and freezing it to create an ice ball, which cannot simulate the alternating transparent and opaque layers of real hailstones in nature; 2) It cannot realistically simulate hail intensity, affecting the effectiveness of hail impact tests. To address these problems, this invention provides... Figure 1 The hailstone preparation method shown is applicable to airborne atmospheric sounding equipment tested using a wind tunnel. The hailstone preparation method includes... S101: Prepare a metal mold. The size of the metal mold is adapted to the size of the hailstones used in the test. Specifically, the metal mold is either a honeycomb structure or a single molded unit. If the metal mold is a honeycomb structure, the size of the single molded unit is 5mm to 20mm. Alternatively, the size of the single molded unit of the high-precision metal mold is 5mm to 20mm.

[0015] S102: Prepare a mixed aqueous solution, wherein softened deionized water is heated to boiling and then cooled. After cooling, standard medical degreased cotton fibers are added and stirred evenly to form a mixed aqueous solution. The purpose of adding degreased cotton fiber threads is to increase the strength of the final hailstone. Specifically, the standard medical degreased cotton fiber content is 30%, and the mass percentage of standard medical degreased cotton fiber in the mixed aqueous solution is 14%-16%.

[0016] S103: The mixed aqueous solution is placed into a metal mold and cooled. Specifically, the mixed aqueous solution is injected into the expansion hole reserved on the top of the metal mold and placed in a freezer. The temperature is set to -20℃ and kept for 3 hours to form ice balls with a size of 5mm to 20mm. S104: Start the cooling and spraying equipment in the wind tunnel device, and set the environmental parameters of the test area of ​​the wind tunnel device (the test area is a section of the wind tunnel device). Generally, the temperature of the cloud field is 0℃~-8℃. Based on the cloud field with a water droplet size of 20μm and a water content of 2g / m³, set the nozzle water pressure and air pressure.

[0017] S105: The ice puck is placed in a spraying device and activated, causing it to rotate or spin. Supercooled water droplets are sprayed onto the dynamic ice puck through the spraying device to form an ice layer on its surface. The supercooled water adheres to the rotating ice puck, forming a new ice layer. Simultaneously, thanks to the cotton fibers, the ice layer formed by the rotating ice puck is less prone to cracking, breaking, or detaching from the puck, exhibiting strong adhesion.

[0018] S106: Adjust the temperature of the cloud field to below -8℃ using a cooling device, and adjust the spray droplet parameters of the spraying equipment according to the atmospheric environment requirements of the test. For example, adjust the spray droplet parameters to 20μm and the water content to 1g / m³, and restart the spraying equipment to spray supercooled water droplets onto the ice ball in a dynamic state, and form a new ice layer on the ice layer and / or the surface of the ice ball. By forming multiple ice layers on the ice ball, the real hail is simulated. S107: Considering the size and shape variations of hail in real environments, to approximate real hail as closely as possible, ice balls with secondary ice layers are alternately placed in various cloud and fog environments adjusted according to experimental requirements, ultimately forming simulated hail with alternating transparent and opaque layers. The overall structure of the simulated hail is extremely close to that of natural hail. The simulated hail is stored in a freezer at -30°C. Specifically, it is alternately placed in cloud and fog environments with high temperature and high water content and cloud and fog environments with low temperature and low water content, so that the ice balls in step 6 form simulated hail with alternating transparent and opaque layers. Generally, the high temperature and high water content cloud and fog environment is at least -8°C and 2g / m³ water content, and the low temperature and low water content environment is at least -20°C and 0.8g / m³ water content.

[0019] The resulting simulated hail, with alternating transparent and opaque layers, more realistically mimics the hail structure found in nature. The addition of fine degreased cotton fibers further simulates the intensity of natural hail. Using the hail provided in this application in a wind tunnel can improve the effectiveness of hail impact tests on aircraft.

[0020] The product provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the invention claims.

Claims

1. A method for producing hail for aircraft impact tests, wherein the produced hail is suitable for testing with airborne atmospheric detection equipment using a wind tunnel device, characterized in that, The hail-making method includes, S101: Prepare a metal mold, the size of which is adapted to the size of the hailstones used in the test; S102: Prepare a mixed aqueous solution, wherein softened deionized water is heated to boiling and then cooled, and after cooling, standard medical degreased cotton fibers are added and stirred evenly to form the mixed aqueous solution; S103: A mixed aqueous solution is placed into a metal mold and cooled to form ice balls; S104: Start the cooling and spraying equipment in the wind tunnel and set the environmental parameters of the test area of ​​the wind tunnel according to the test requirements. Among them, the temperature of the cloud field is 0℃~-8℃, the water droplet size is 20μm and the water content is 2g / m³. S105: The ice ball is placed in a spraying device and started, and the ice ball is rotated or turned. Supercooled water droplets are sprayed onto the ice ball in a dynamic state through the spraying device to form an ice layer on the surface of the ice ball. S106: Adjust the temperature of the cloud field to below -8℃ using a refrigeration device, and adjust the spray droplet parameters of the spraying equipment according to the atmospheric environment requirements of the test; restart the spraying equipment to spray supercooled water droplets onto the ice ball in a dynamic state, and form a new ice layer on the ice layer and / or the surface of the ice ball. The spray droplet parameters are selected to be 20μm and the water content is 1g / m³. S107: Ice balls that form secondary ice layers are alternately placed in various cloud and fog environments adjusted according to experimental requirements, eventually forming simulated hail with alternating transparent and opaque layers. The simulated hail is stored in a freezer at -30°C.

2. The hail-making method according to claim 1, characterized in that, In S101, the metal mold is either a honeycomb structure or a single mold.

3. The hail-making method according to claim 2, characterized in that, When the metal mold is a honeycomb structure, the size of a single structure is 5mm to 20mm, or the size of a single metal mold when it is formed is 5mm to 20mm.

4. The hail-making method according to claim 1, characterized in that, The standard medical absorbent cotton fiber accounts for 14%-16% of the mass of the mixed aqueous solution.

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