An ultra-low temperature surface frosting test device and a test method

Abstract

This invention discloses an ultra-low temperature surface frost testing device and method, belonging to the technical field of testing equipment. The ultra-low temperature surface frost testing device includes an atomizing section, a frosting section, and a collection component. The frosting section has a frosting cavity, and a test component is disposed within the frosting cavity. The test component has a channel for the flow of a first medium. The atomizing section is connected to the frosting section and is used to discharge atomized medium into the frosting cavity. The collection component is located within the frosting cavity and positioned on the side of the test component near the atomizing section, and is used to collect the flow information of the atomized medium. The collection component can detect the flow information of the atomized medium, facilitating the observation and study of frost phenomena on the surface of the test component at ultra-low temperatures (below -100℃) under conditions of external hot air flow, and determining the relationship between the specifications of the atomized medium, the first medium, and the test component and the frost phenomenon. This is beneficial for studying the frost phenomenon in precoolers of aircraft or spacecraft, ensuring the safe use of precoolers.

Description

Technical Field

[0001] This invention relates to the field of testing equipment technology, and in particular to an ultra-low temperature surface frosting testing device and testing method. Background Technology

[0002] Intensive precooling is an important means of addressing the thrust gap problem faced by combined-propellant aircraft. Precoolers are an important technical approach to intensive precooling technology, and are typically designed as lightweight, efficient, and compact heat exchangers.

[0003] Frosting is a common phenomenon in the heat exchange pipes of microtube precoolers. Current research on frost formation on cryogenic surfaces is limited to studies conducted under natural convection conditions (room temperature with no wind). Due to technological limitations, it is impossible to study frost formation on the surfaces of cryogenic components under conditions of external hot air flow. Therefore, there is an urgent need for a device capable of measuring frost formation on the surfaces of cryogenic components under conditions of external hot air flow. Summary of the Invention

[0004] In view of the shortcomings of the above-mentioned related technologies, this application provides an ultra-low temperature surface frosting test device and test method to solve the above-mentioned technical problems.

[0005] This application provides an ultra-low temperature surface frost testing device, which includes an atomizing section, a frosting section, and a collecting element. The frosting section has a frosting cavity and a test element is disposed therein. The test element has a channel for flowing a first medium. The atomizing section is connected to the frosting section and is used to discharge atomized medium into the frosting cavity. The collecting element is located in the frosting cavity and is disposed on the side of the test element near the atomizing section, and is used to collect the flow information of the atomized medium.

[0006] To achieve the above and other related objectives, this application provides a testing method for the aforementioned ultra-low temperature surface frosting testing device, comprising:

[0007] The test piece was installed on the frosting section of the ultra-low temperature surface frosting test device;

[0008] Turn on the atomization section of the ultra-low temperature surface frosting test device so that the atomization section can pass the atomization medium into the frosting chamber and obtain the flow information of the atomization medium;

[0009] Under the condition that the flow information of the atomizing medium meets the preset conditions, the first medium is introduced into the test piece to reduce the surface temperature of the test piece, and the temperature of the atomizing medium is greater than the temperature of the first medium.

[0010] The technical solution adopted in this invention can achieve the following beneficial effects: The tester introduces an atomizing medium into the atomizing section, and the atomizing medium is atomized within the atomizing chamber. The atomizing medium can be pure water or a mixture thereof. The tester introduces a first medium into the test piece to lower its surface temperature. The first medium can be liquid nitrogen, etc., and the temperature of liquid nitrogen can be below -100℃. The temperature of the atomizing medium is higher than the temperature of the first medium. The atomizing medium is then introduced into the frosting chamber to cause frosting to form on the surface of the test piece. A data acquisition unit is used to collect the flow information of the atomizing medium. The flow information can be one or more of the temperature, flow rate, humidity, etc., of the atomizing medium, without limitation. The data acquisition unit can detect the flow information of the atomized medium, which facilitates the observation and study of the frosting phenomenon on the surface of the test piece at ultra-low temperatures (below -100℃) under conditions of external hot air flow, as well as the determination of the relationship between the atomized medium, the primary medium, and the specifications of the test piece and the frosting phenomenon. Compared with existing natural convection conditions, this is beneficial for the study of frosting phenomena in the precoolers of aircraft or spacecraft, to ensure the safe use of the precoolers and improve the power level of the spacecraft.

[0011] In addition, the acquisition unit can collect and determine the state of the atomized medium. After the state of the atomized medium stabilizes, the tester can discharge the first medium into the test unit to avoid the test unit being affected by the unstable external temperature, so as to obtain stable and reliable test results of the atomization phenomenon. Attached Figure Description

[0012] 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.

[0013] Figure 1 This is a schematic diagram of the structure of an ultra-low temperature surface frosting test device shown in an exemplary embodiment of this application;

[0014] Figure 2 This is a simplified structural diagram of an ultra-low temperature surface frosting testing device shown in an exemplary embodiment of this application;

[0015] Figure 3 This is a schematic diagram of the structure of the frosting section shown in an exemplary embodiment of this application;

[0016] Figure 4 This is a cross-sectional schematic diagram of a frosted section shown in an exemplary embodiment of this application;

[0017] Figure 5 yes Figure 4 Enlarged view of point a in the image;

[0018] Figure 6 This is a schematic diagram of the structure of the test piece and the protective cover shown in an exemplary embodiment of this application;

[0019] Figure 7 This is a cross-sectional schematic diagram of an ultra-low temperature surface frosting test device shown in an exemplary embodiment of this application;

[0020] Figure 8 This is a cross-sectional schematic diagram of the atomizing section shown in an exemplary embodiment of this application.

[0021] Figure 9 This is a flowchart illustrating a test method in an exemplary embodiment of this application.

[0022] In the figure: 1. Ultra-low temperature surface frosting test device; 110. Frosting section; 111. Frosting chamber; 112. Test piece; 1121. Channel; 113. Shell; 1131. Through hole; 1132. Injection hole; 114. Protective cover; 115. Mounting piece; 1151. Mounting cavity; 116. Slide rail structure; 117. Observation structure; 120. Atomization section; 121. Heating device; 122. Atomization device; 123. Pipeline; 1231. Valve body; 130. Collection piece; 140. Stabilization section; 141. Connecting cavity; 151. First tank; 152. Second tank; 153. First box; 161. First flange; 162. Second flange. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] Intensive precooling achieves efficient engine cooling through rapid heat exchange, addressing a core issue in aircraft propulsion. However, the heat exchange pipes of microtube precoolers are prone to frost formation. Research on this phenomenon remains limited to studies of frost formation on conventional low-temperature surfaces under natural convection conditions (room temperature with no wind). Current testing equipment cannot study frost formation under conditions of external hot air flow.

[0026] Frosting is a physical process in which water vapor sublimates or condenses on a solid surface and then freezes to form a frost layer when moist air comes into contact with a cold surface at low temperatures. Therefore, factors such as temperature and the flow rate of moist air affect the frosting effect. Thus, there is an urgent need for a device that can measure the frosting phenomenon under conditions of external hot air flow, so as to facilitate the research on the frosting of ultra-low temperature solid surfaces.

[0027] This application provides an ultra-low temperature surface frosting testing device 1. Please refer to [link / reference]. Figure 1 as well as Figure 2 The ultra-low temperature surface frosting test device 1 may include a frosting section 110, an atomizing section 120, and a collection element 130. The atomizing section 120 and the frosting section 110 are interconnected, and the collection element 130 is disposed in the frosting section 110.

[0028] Please see Figure 1 as well as Figure 2 The atomizing section 120 is connected to the frosting section 110 and is used to discharge the atomizing medium into the frosting chamber 111. Exemplarily, the atomizing medium can be humid air, etc., and is not limited thereto. Exemplarily, the atomizing section 120 is provided with an atomizing device 122, such as an atomizing nozzle or piezoelectric ceramic, which can atomize water into water vapor, and the water vapor mixes with hot air to form the atomizing medium. The frosting section 110 has a frosting chamber 111, which is connected to the atomizing chamber.

[0029] Please see Figure 2 and Figure 3 The frosting section 110 has a frosting cavity 111, and a test piece 112 is provided in the frosting section 110. The test piece 112 is disposed inside the frosting cavity 111, and the test piece 112 can be a thin round tube or other tube structure. Please continue reading. Figure 4 as well as Figure 5The test piece 112 is located within the frosting chamber 111, and has a channel 1121 for circulating a first medium. Exemplarily, the atomizing medium flows to the atomizing section 120, where it is atomized within the atomizing chamber. The atomizing medium can be pure water or a mixture thereof. The first medium is introduced into the test piece 112 to lower its surface temperature. The first medium can be liquid nitrogen, and its temperature can be below -100°C. The temperature of the atomizing medium can be higher than the temperature of the first medium. The atomizing medium is introduced into the frosting chamber 111 to cause frosting on the surface of the test piece 112. Furthermore, the test piece 112 can be interconnected with a first tank 151, which contains the first medium and discharges it into the test piece 112. Alternatively, the test piece 112 can also be connected to a pump body for pumping in the first medium; this is not limited.

[0030] In some other embodiments, the test piece 112 is detachably disposed in the frosting section 110. Furthermore, various test pieces 112 of different specifications can be fixed in the frosting section 110 to measure the relationship between the frosting phenomenon and the specifications of the test piece 112.

[0031] Please see Figure 2 The data acquisition element 130 is located inside the frosting chamber 111. The data acquisition element 130 can be a sensor and is positioned on the side of the test piece 112 near the atomization section 120. It is used to collect flow information of the atomized medium. The flow information can be one or more of the following: temperature, flow rate, humidity, etc., of the atomized medium, without limitation. The data acquisition element 130 can detect the flow information of the atomized medium, facilitating the observation and study of frosting phenomena on the surface of the test piece 112 at ultra-low temperatures (below -100℃) under conditions of external hot air flow. It also helps determine the relationship between the specifications of the atomized medium, the first medium, and the test piece 112 and the frosting phenomenon. This is beneficial for studying the frosting phenomenon in precoolers of aircraft or spacecraft, ensuring the safe use of precoolers and improving the power level of the spacecraft. The data acquisition element 130 can collect and determine the state of the atomized medium, ensuring that the test personnel discharge the first medium into the test piece 112 after the state of the atomized medium has stabilized, avoiding the influence of unstable external temperatures on the frosting results.

[0032] Of course, the atomizing section 120 and the frosting section 110 can be made of heat insulation material, which can reduce the interference of the external environment on the test results and improve the accuracy of the test results.

[0033] Please see Figure 4The frosting section 110 may have a housing 113, which may be made of heat-insulating material, including but not limited to ceramic material or multi-layer heat-insulating material. The multi-layer heat-insulating material may be composed of alternating layers of reflective screens (such as aluminum foil, aluminized film) and spacer layers (such as fiberglass mesh, polyester fiber felt). A frosting cavity 111 is formed within the housing 113, and the test piece 112 is located within the frosting cavity 111. Furthermore, the test piece 112 may be positioned in the center of the frosting cavity 111, meaning that while the atomizing medium is discharged into the frosting cavity 111, the atomizing medium can contact the surface of the test piece 112 from all sides, preventing uneven frosting of the test piece 112 and interference with the test results. The opposite ends of the test piece 112 extend beyond the housing 113, and these opposite ends can extend and be vented with a first medium, which can reduce the surface temperature of the test piece 112. The housing 113 and the test piece 112 are sealed together. Furthermore, the housing 113 is provided with a sealing element, including but not limited to rubber gaskets, polytetrafluoroethylene gaskets, etc. The sealing element can contact the periphery of the test piece 112 to achieve a seal. The sealed fit can prevent the atomized medium at the gaps from leaking, reduce the loss of the atomized medium, and improve the effect of the frosting phenomenon.

[0034] For further information, please refer to [link / reference]. Figure 1 as well as Figure 4 The frosting section 110 may also include a mounting element 115, which is installed within the housing 113. Please refer to [further details]. Figure 4 and Figure 5 The mounting component 115 has a mounting cavity 1151. The test piece 112 is fixed to the mounting component 115 and extends into the mounting cavity 1151. The mounting component 115 can be connected to a pump body or liquid nitrogen tank, etc., to receive the first medium and discharge it into the channel 1121. The mounting cavity 1151 and the channel 1121 are connected, and the mounting component 115 is used to discharge the first medium into the channel 1121. Of course, this allows the mounting component 115 to be adapted to test pieces 112 of different specifications, so that all kinds of test pieces 112 can receive the first medium stably and ensure the consistency of test conditions. At the same time, the mounting cavity 1151 of the mounting component 115 can buffer the first medium, so that the first medium undergoes a certain degree of uniform flow in the mounting cavity 1151 before entering the channel 1121, avoiding uneven flow during the process, ensuring that the first medium can act more evenly on the test piece 112, and improving the accuracy of the test.

[0035] In addition, please see Figure 1 and Figure 6The ultra-low temperature surface frosting test device 1 may include a first flange 161 and a second flange 162. The housing 113 may have a first mounting hole and a second mounting hole, which are coaxial. The first flange 161 is installed in the first mounting hole, and the second flange 162 is installed in the second mounting hole. A mounting member 115 can be disposed in the first flange 161 and / or the second flange 162. The opposite ends of the test piece 112 can be respectively embedded in the mounting member 115 of the first flange 161 and the mounting member 115 of the second flange 162, so that the first medium is discharged from the mounting member 115 of the first flange 161 into the test piece 112, and then from the test piece 112 into the mounting member 115 of the second flange 162, and discharged outside the ultra-low temperature surface frosting test device 1, so that the first medium can exchange heat with the test piece 112 efficiently. Mounting component 115 can have a sealing function, and both the first flange 161 and the second flange 162 are mutually sealed with the test piece 112, so that the test piece 112 is completely fixed while the frosting chamber 111 is sealed to prevent the external environment from interfering with the test piece 112.

[0036] In one embodiment, the outer diameter of the test piece 112 is 1mm-5mm, such as 1mm, 2mm, or 5mm, and is not limited. The outer diameter of the test piece 112 should not be too large or too small. If the outer diameter of the test piece 112 is too large, the large outer diameter will rapidly absorb cold energy, potentially causing the temperature of the medium inside the pipe to change too rapidly, resulting in excessively severe frost formation. Furthermore, an excessively large surface area leads to uneven reaction, affecting the recording of test results. If the outer diameter of the test piece 112 is too small, the small outer diameter pipe 123 has a small surface area, resulting in low heat exchange efficiency with the external cold source, leading to slow heating and cooling rates of the medium inside the pipe, making it difficult to quickly reach the critical temperature required for frost formation. A test piece 112 with a suitable outer diameter can balance the reaction effect and improve the test results.

[0037] In another embodiment, the wall thickness of the test piece 112 is 40μm-60μm, such as 40μm, 50μm, or 60μm, and is not limited. The wall thickness of the test piece 112 should not be too thick or too thin. If the wall thickness is too thick, the internal and external temperatures of the test piece 112 will be difficult to quickly reach the critical temperature required for frosting, delaying the initiation of the frosting phenomenon and failing to accurately reflect the initial conditions of the reaction. Conversely, if the wall thickness of the test piece 112 is too thin, the thermal resistance of the test piece 112 is extremely low, resulting in excessively rapid heat transfer. This causes the temperature of the medium inside the tube to be greatly affected by minute fluctuations in the atomizing medium or the first medium, easily leading to excessively low instantaneous cooling, overly violent frosting, and an inability to maintain stable frosting conditions, resulting in poor test repeatability. A suitable wall thickness of the test piece 112 ensures rapid frosting while avoiding the impact of minute fluctuations in the atomizing medium or the first medium, thus improving the test reliability of the ultra-low temperature surface frosting test device 1.

[0038] Of course, in other cases, the ultra-low temperature surface frosting test device 1 can also detect the frosting reaction on the inner surface of the test piece 112. When detecting the frosting reaction on the inner surface of the test piece 112, the size of the test piece 112 can be set large enough for observation and recording, which will not be elaborated here.

[0039] In the initial stage of operation, existing pumps may pump unstable airflow. This is because the internal airflow of the pump body and its connected pipes changes suddenly, potentially causing backflow. This backflow interferes with the delivery airflow, creating an unstable pulse flow. See the embodiments in this application for details. Figure 4 as well as Figure 6 The frosting section 110 can also be equipped with a protective cover 114, which is movably installed on the housing 113 to switch between a blocked position and an open position. When the protective cover 114 is in the blocked position, it is located on the side of the test piece 112 near the atomizing section 120. With the protective cover 114 installed on the side of the test piece 112 near the atomizing section 120 (i.e., the windward side), the atomizing medium will be discharged from the atomizing section 120 towards the test piece 112. The protective cover 114 effectively blocks the atomizing medium, preventing it from frosting on the surface of the test piece 112 before it stabilizes. Simultaneously, it also prevents the atomizing medium from directly blowing onto the side of the test piece 112 near the atomizing section 120, avoiding uneven frosting on the test piece 112 and poor test repeatability. When the protective cover 114 is in the open position, it is separated from the test piece 112, and is removed from the side of the test piece 112 closest to the atomizing section 120. Once the tester can observe or detect that the atomized medium has stabilized, the protective cover 114 is removed to conduct the frosting test. The protective cover 114 serves both to improve test results and repeatability, and to prevent interference with subsequent tests, thus enhancing the reliability of the frosting test.

[0040] In a more specific implementation, please refer to Figure 4 as well as Figure 5The housing 113 has a through hole 1131, through which a channel 1121 passes. A protective cover 114 is movably installed at the through hole 1131 and can selectively extend or retract into the housing 113. When the protective cover 114 is in the blocked position, it moves into the frosting chamber 111 and is positioned over the test piece 112. The protective cover 114 enters the frosting chamber 111 and covers the test piece 112. The atomizing medium is discharged from the atomizing section 120 towards the test piece 112. The protective cover 114 effectively blocks the atomizing medium, preventing it from frosting on the surface of the test piece 112 before it stabilizes. When the protective cover 114 is in the open position, it moves out of the housing 113. The through hole 1131 on the housing 113 allows the protective cover 114 to pass through, and it can retract out of the housing 113, completely exposing the test piece 112 to the frosting chamber 111 for convenient operation or testing. This allows the protective cover 114 to be completely removed, which helps reduce the interference of the protective cover 114 with subsequent test results.

[0041] Furthermore, the housing 113 is equipped with a motor, which can drive the protective cover 114 to switch between an open position and a blocked position. Additionally, the frosting chamber 111 is equipped with sensors, such as flow rate sensors, pressure sensors, or temperature sensors, which can acquire test signals such as the flow of the atomized medium within the frosting chamber 111 or the surface temperature of the test piece 112. The sensors can transmit test signals for acquisition and use by the control module of the ultra-low temperature surface frosting testing device 1. When the surface temperature of the test piece 112 reaches a preset temperature, the control module can control the motor to drive the protective cover 114 to the open position. The preset temperature can be less than or equal to -100℃, such as -110℃ or -100℃. Furthermore, the control module can also control the flow rates of the atomized medium and the first medium, which helps to improve the degree of automation and reduce manual operation steps.

[0042] In addition, please see Figure 4 as well as Figure 6 The housing 113 is further provided with a slide rail structure 116, which is slidably connected to the protective cover 114. The slide rail structure 116 guides the protective cover 114, allowing it to be stably removed or placed into the frosting chamber 111. Furthermore, either the slide rail structure 116 or the protective cover 114 is provided with a limiting structure, which abuts against the other or the housing 113 to limit the protective cover 114 and prevent it from moving excessively.

[0043] Of course, in other cases, the protective cover 114 can be rotatably positioned within the frosting chamber 111, with the protective cover 114 positioned on the side of the test piece 112 closest to the atomizing section 120. When the protective cover 114 is in the shielded position, its surface intersects the flow direction of the atomizing medium, thus blocking the atomizing medium and preventing frost formation on the surface of the test piece 112 before it stabilizes. When the protective cover 114 is in the shielded position, its surface is parallel to the flow direction of the atomizing medium, and it does not obstruct the atomizing medium, allowing for frosting testing.

[0044] Preferably, please refer to Figure 6 The protective cover 114 extends parallel to or collinear with the test piece 112. The cross-section of the protective cover 114 is arc-shaped. The length and specific shape of the arc are not limited; the cross-section of the protective cover 114 can be a quarter-circle arc, a semi-circle arc, or other types of arcs, which will not be elaborated here. The center of the arc is located on the side of the protective cover 114 closer to the test piece 112. For example, the protective cover 114 can be a semi-tubular structure, extending in the same direction as the test piece 112, with an arc-shaped cross-section and the center of the arc biased towards the test piece 112. The protective cover 114 can wrap the test piece 112 inside the arc near the center, so that the flowing atomized medium is guided or blocked by the arc surface before contacting the test piece 112, avoiding the unstable medium from directly impacting the test piece 112, thereby providing protection.

[0045] Of course, in other cases, the protective cover 114 can also be a planar structure or other irregular structure, and the protective cover 114 can also play a blocking role, which will not be elaborated on.

[0046] The device may contain air or residual humid air from the previous test, which can cause frosting before the atomizing medium is introduced, severely interfering with the experimental results. Please refer to the embodiments in this application. Figure 5The housing 113 also has an injection hole 1132, which can be circular or square, etc., without limitation. The injection hole 1132 is located on the side of the protective cover 114 closest to the test piece 112, and is suitable for injecting a protective medium. The protective medium can be nitrogen, which is stable and inexpensive. The injection hole 1132 allows the injection of the protective medium to displace air, preventing airflow around the test piece 112 and preventing water in the air from frosting before the atomizing medium is introduced, thus reducing the influencing factors of the test and improving the stability of the test results. Furthermore, in the initial stage of the test, when the flow rate or pressure of the atomizing medium is uneven, the continuous injection of the protective medium into the injection hole 1132 provides protection around the test piece 112, preventing unstable atomizing medium from directly contacting the test piece 112 and causing unstable frosting. This helps improve the controllability of the test and the reliability of the test results.

[0047] In the embodiments of this application, please refer to Figure 7 The ultra-low temperature surface frosting test device 1 also includes a stabilizing section 140, which has a connecting cavity 141 connecting the atomizing section 120 and the frosting section 110. The cross-sectional area of ​​the connecting cavity 141 is larger than that of the frosting cavity 111. In other words, the stabilizing section 140 between the atomizing section 120 and the frosting section 110 has a connecting cavity 141, and the cross-sectional area of ​​the connecting cavity 141 is larger than that of the frosting cavity 111 along the direction from the atomizing section 120 to the frosting section 110. Due to the larger cross-sectional area of ​​the connecting cavity 141, the flow rate of the atomized medium gradually slows down after flowing into the stabilizing section 140. The stabilizing section 140 acts as a buffer for the atomized medium, making its flow rate and volume more uniform and avoiding imbalances. Furthermore, discharging the atomized medium into the frosting section 110 further improves test stability and prevents unreproducible test results due to unstable flow rates of the atomized medium.

[0048] In the embodiments of this application, please refer to Figure 3 as well as Figure 4 The frosting section 110 is equipped with an observation structure 117, which corresponds to the test piece 112. The observation structure 117 includes, but is not limited to, an observation window and a camera module. In one case, the observation structure 117 is an observation window, which can be made of transparent material and is located on the cavity wall forming the frosting cavity 111, allowing the tester to observe it with the naked eye. In another case, the observation structure 117 is a camera module that can extend into the frosting cavity 111 to collect the surface frosting of the test piece 112 and transmit the data to the outside via cable or wireless communication, allowing the tester to observe it on a display device. There are no restrictions on this.

[0049] In the embodiments of this application, please refer to Figure 2 as well as Figure 8 The atomizing section 120 may include a heating device 121 and an atomizing device 122. The heating device 121 may be an electric heating device, such as a resistance wire. The atomizing device 122 has an atomizing chamber. The heating device 121 is used to heat the carrier gas and discharge air into the atomizing chamber. The carrier gas may be air or nitrogen, etc. The heating device 121 may be connected to an air pump or gas tank, etc., and can receive the flowing carrier gas. The atomizing device 122 includes, but is not limited to, an atomizing nozzle or piezoelectric ceramic, etc. The atomizing device 122 is used to atomize the second medium in the atomizing chamber. In other words, after the heating device 121 heats the carrier gas, it is sent into the atomizing chamber. The atomizing device 122 then atomizes the second medium in the atomizing chamber. The second medium and the carrier gas mix and exchange heat with each other, and the temperature of the atomized medium rises, causing frost formation on the surface of the test piece 112. At the same time, the hot carrier gas carries the atomized second medium during its flow, allowing it to smoothly enter the frosting chamber 111 and come into contact with the test piece 112. This setup utilizes carrier gas to drive and heat the second medium, ensuring that the atomizing medium has sufficient temperature and power for subsequent frosting. This avoids the impact of uneven temperature distribution of the atomizing medium on the frosting reaction of the test piece 112, thus improving the reliability of the test.

[0050] In one implementation, please refer to Figure 2 The heating device 121 and the atomizing device 122 are connected by a pipe 123, and the pipe 123 is equipped with a valve body 1231, which is used to control the opening of the pipe 123. The valve body 1231 on the pipe 123 can adjust the opening of the pipe 123, thereby controlling the flow rate of the atomizing medium to adjust its effect on the test piece 112 and prevent drastic changes in the surface temperature of the test piece 112. Furthermore, the tester can also adjust the air flow rate and pressure through the valve body 1231, as air provides heat and driving force to the atomizing medium, thus affecting the flow rate and temperature of the atomizing medium. This facilitates the study of the influence of the flow rate and temperature of the atomizing medium on the frosting phenomenon, increasing the applicability of the ultra-low temperature surface frosting test device 1.

[0051] Of course, in some other cases, the atomizing section 120 may include a heat exchanger and an atomizing device. The atomizing device atomizes the second medium, and the atomized second medium mixes with the carrier gas to form the atomized medium. The heat exchanger can exchange heat with the atomized medium. Furthermore, a high-temperature medium is introduced into the inner pipe of the heat exchanger, and the heat of the high-temperature medium is conducted to the atomized medium to increase its temperature. The atomized medium is then driven into the atomizing chamber by a fan, which will not be elaborated here.

[0052] To achieve the above and other related objectives, this application also provides a testing method for the aforementioned ultra-low temperature surface frosting testing device 1. Please refer to [link to relevant documentation]. Figure 9The testing methods include:

[0053] Step S110: Install the test piece onto the frosting section of the ultra-low temperature surface frosting test device.

[0054] The test specimen is installed in the frosting section of the ultra-low temperature surface frosting test device, with at least a portion of the specimen located within the frosting chamber. This allows the subsequent atomizing medium to provide an environment conducive to frosting. Furthermore, a sealant fills and seals the gap between the test specimen and the frosting section to prevent medium leakage from affecting the test environment. The limiting structure between the test specimen and the frosting section also ensures precise alignment, guaranteeing the test specimen is positioned in the preset test location.

[0055] The test specimen is installed in the frosting section of the ultra-low temperature surface frosting test device, placing it in a preset test position. Furthermore, at least a portion of the test specimen is located within the frosting chamber of the frosting section, allowing the subsequent atomizing medium to contact the specimen surface. A first medium is then introduced into a channel within the test specimen, changing its temperature through heat exchange between the first medium and the test specimen. This first medium can be liquid nitrogen, etc. Because the temperature of the atomizing medium is higher than that of the first medium, this temperature difference creates a low-temperature environment on the test specimen surface suitable for the phase change of the atomizing medium, providing the necessary temperature conditions for the subsequent condensation of the atomizing medium into frost on the test specimen surface, ensuring that the frosting phenomenon occurs as expected.

[0056] Step S120: Turn on the atomization section of the ultra-low temperature surface frosting test device so that the atomization section can pass the atomization medium into the frosting chamber and obtain the flow information of the atomization medium.

[0057] Turn on the atomization section to start it working and send the atomized medium into the frosting chamber in an atomized form. This allows the atomized medium to enter the frosting chamber smoothly, preparing it for subsequent interaction with the test piece.

[0058] Furthermore, the second medium is introduced into the atomizing device of the atomizing section of the ultra-low temperature surface frosting test device. The atomizing device can be an atomizing nozzle or a piezoelectric ceramic plate, etc., and the second medium can be pure water, etc., without limitation. The atomizing device will activate its own atomization function to process the second medium, breaking it down into fine atomized particles. Simultaneously, the carrier gas can be transferred to the heating device, which can heat the carrier gas at a temperature greater than 100℃, such as 100℃, 110℃, etc., without limitation. The heating device can change the temperature of the atomized medium to meet the expected design. The carrier gas can mix with the second medium in the atomizing chamber of the atomizing section. The carrier gas can be air or nitrogen, etc., without limitation. The atomized second medium can be more evenly distributed in the carrier gas, ensuring that the atomized medium can fully act on the surface of the test piece, providing a suitable reaction environment for the subsequent frosting phenomenon.

[0059] The acquisition unit of the ultra-low temperature surface frosting test device can be configured with one or a combination of infrared sensors, pressure sensors, etc. Flow information can include at least one of the following: temperature, flow rate, and humidity of the atomized medium. The acquisition unit can obtain the specific flow conditions of the atomized medium around the test piece, such as the stability of the atomized medium flow. This also helps to infer the relationship between the parameters of the atomized medium and the frosting phenomenon, facilitating the study of frosting phenomena in aircraft or spacecraft precoolers, ensuring the safe use of precoolers, and improving the level of spacecraft dynamics research.

[0060] Step S130: Under the condition that the flow information of the atomizing medium meets the preset conditions, the first medium is introduced into the test piece to reduce the surface temperature of the test piece. The temperature of the atomizing medium is greater than the temperature of the first medium.

[0061] When the flow information of the atomizing medium meets the preset conditions, the flowability of the atomizing medium has stabilized. For example, the flow rate of the atomizing medium is maintained at a preset value. At this point, the tester introduces the first medium into the test piece. Since the temperature of the atomizing medium is higher than that of the first medium (which can be liquid nitrogen, etc.), the first medium will lower the surface temperature of the test piece through heat exchange, causing a frosting reaction on the surface of the test piece. This operation of introducing the first medium only after the atomizing medium has stabilized avoids fluctuations in test conditions caused by unstable medium conditions, prevents a decrease in test stability, and ensures that the test is conducted in a controlled environment. Alternatively, when the flow information of the atomizing medium meets the preset conditions, the first medium can be directly driven into the test piece via a pump or similar device. This helps improve the stability of the frosting reaction in the ultra-low temperature surface frosting test device.

[0062] According to an optional implementation, before step S110: activating the atomization section of the ultra-low temperature surface frosting test device, the method further includes:

[0063] Step S210: Place the protective cover of the ultra-low temperature surface frost test device on the side of the test piece near the atomization section, and inject the protective medium through the injection hole of the ultra-low temperature surface frost test device.

[0064] The tester places a protective cover over the test piece near the atomization section and simultaneously injects a protective medium through the injection port. This protective medium can be nitrogen or similar gas. The protective medium repels moisture around the test piece, preventing it from interfering with the test results. The protective cover prevents the atomization medium from directly contacting the test piece and also prevents the atomization medium from dispersing the protective medium, thus enhancing its protective capability. The protective medium and the protective cover form a barrier before the atomization medium stabilizes, blocking external moisture from contacting the test piece surface and preventing premature frost formation that could affect the test results.

[0065] According to an optional implementation, after step S130: introducing the first medium into the test piece, the method further includes:

[0066] Step S220: When the surface temperature of the test piece is less than or equal to -100°C, stop injecting the protective medium into the injection hole of the ultra-low temperature surface frost test device, and remove the protective cover of the ultra-low temperature surface frost test device from the side of the test piece near the atomization section.

[0067] Because it absorbs the cold energy of the first medium, the surface temperature of the test piece will gradually decrease. When the surface temperature of the test piece drops to -100℃ or lower, the injection of protective medium into the injection hole is stopped, and the protective cover is moved away from the side of the test piece closest to the atomization section. At this time, the atomization medium is in a stable state, and the surface of the test piece has reached a low temperature suitable for subsequent tests. This avoids interference from unexpected frost in the early stage and ensures that subsequent tests are carried out in an accurate state. It can precisely control the frost phenomenon corresponding to each test data, that is, it can observe and judge the relationship between the flow information of the atomization medium, the surface temperature of the test piece, and the frost phenomenon, thereby improving the accuracy of the test and ensuring the reliability of the test results.

[0068] Understandably, the surface temperature of the test piece can be obtained by a sensor or an infrared detection device located outside the ultra-low temperature surface frost test device, and there are no restrictions on this.

[0069] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0070] Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for testing surface frosting at ultra-low temperatures, characterized in that, include: The frost section has a frost cavity and a test piece is provided therein. The test piece is installed in the frost cavity and has a channel for the flow of a first medium. Atomizing section, which is connected to the frosting section and is used to discharge atomizing medium into the frosting chamber; A collection element is located inside the frosting chamber and is positioned on the side of the test piece near the atomizing section, and is used to collect the flow information of the atomizing medium; The frosting section has a housing, and the frosting cavity is formed within the housing. The frosting section is also provided with a protective cover, which is movably installed in the housing to switch between a blocked position and an open position. When the protective cover is in the blocked position, it is located on the side of the test piece near the atomizing section. When the protective cover is in the open position, it is removed from the side of the test piece near the atomizing section. The housing also has an injection hole located on the side of the protective cover near the test piece, and the injection hole is suitable for injecting a protective medium.

2. The ultra-low temperature surface frosting testing device according to claim 1, characterized in that, The frosting section also includes a mounting component, which is installed inside the housing. The mounting component has a mounting cavity. The test piece is fixed to the mounting component and extends into the mounting cavity. The mounting cavity is connected to the channel. The mounting component is used to discharge the first medium into the channel. And / or, the outer diameter of the test piece is 1mm-5mm, and the wall thickness of the test piece is 40μm-60μm.

3. The ultra-low temperature surface frosting testing device according to claim 2, characterized in that, The protective cover is parallel or collinear with the extension direction of the test piece, and the cross-section of the protective cover is arc-shaped, with the center of the arc located on the side of the protective cover closer to the test piece. And / or, the housing is provided with a through hole, the channel penetrates the housing, the protective cover is movably installed at the through hole and can selectively extend or extend into the housing, when the protective cover is in the blocked position, the protective cover moves into the frosting cavity and is located on the test piece, when the protective cover is in the open position, the protective cover moves outside the housing.

4. The ultra-low temperature surface frosting testing device according to claim 1, characterized in that, The ultra-low temperature surface frosting test device is also provided with a stabilizing section, which has a connecting cavity that connects the atomizing section and the frosting section, and the cross-sectional area of ​​the connecting cavity is larger than that of the frosting cavity. And / or, the frosting section is provided with an observation structure, and the observation structure is provided in correspondence with the test piece.

5. The ultra-low temperature surface frosting testing device according to claim 1, characterized in that, The atomizing section includes a heating device and an atomizing device. The atomizing device has an atomizing chamber. The heating device is used to heat the carrier gas and discharge the carrier gas into the atomizing chamber. The atomizing device is used to atomize a second medium in the atomizing chamber to mix the second medium with the carrier gas and form the atomized medium.

6. The ultra-low temperature surface frosting testing device according to claim 5, characterized in that, The heating device and the atomizing device are connected by a pipe, and the pipe is equipped with a valve body, which is used to control the opening degree of the pipe.

7. A testing method for the ultra-low temperature surface frosting testing apparatus as described in any one of claims 1-6, characterized in that, The testing method includes: The test piece is installed on the frosting section of the ultra-low temperature surface frosting test device; The atomization section of the ultra-low temperature surface frosting test device is activated so that the atomization section can introduce the atomizing medium into the frosting chamber and obtain the flow information of the atomizing medium. When the flow information of the atomizing medium meets the preset conditions, the first medium is introduced into the test piece to reduce the surface temperature of the test piece, wherein the temperature of the atomizing medium is greater than the temperature of the first medium.

8. The test method according to claim 7, characterized in that, Before opening the atomization section of the ultra-low temperature surface frost test device, the method further includes: placing the protective cover of the ultra-low temperature surface frost test device on the side of the test piece near the atomization section, and injecting a protective medium through the injection hole of the ultra-low temperature surface frost test device. After introducing the first medium into the test piece, the method further includes: when the surface temperature of the test piece is less than or equal to -100°C, stopping the injection of the protective medium into the injection hole of the ultra-low temperature surface frost testing device, and removing the protective cover of the ultra-low temperature surface frost testing device from the side of the test piece near the atomization section.

Images