A method for controlling and evaluating the content of non-condensable gas in a high-temperature heat pipe

Abstract

This invention belongs to the field of heat pipe technology, specifically relating to a method for controlling and online evaluating the content of non-condensable gases in high-temperature heat pipes. The invention includes the following steps: S1, deep cleaning of materials to eliminate non-condensable gases and other impurities dissolved or adsorbed from the end caps, shell, wick, and filling tube; S2, process cleaning to ensure that no new contaminants are introduced during assembly and welding; S3, heat pipe purification and venting to complete the injection of the working fluid and the final purification and venting within the heat pipe; S4, long-term surface barrier to prevent helium and hydrogen from permeating into the heat pipe. This invention addresses the entire process from materials, manufacturing, filling, and testing, achieving proactive and precise control and quantitative evaluation of non-condensable gas content from three dimensions: source control, process elimination, and online evaluation. This improves the long-term reliability and performance consistency of heat pipes under various complex environments.

Description

Technical Field

[0001] This invention belongs to the field of heat pipe technology, specifically relating to a method for controlling and online evaluating the content of non-condensable gases in high-temperature heat pipes. Background Technology

[0002] Heat pipes rely on the phase change flow of their internal working fluid for efficient heat transfer. This process involves several crucial physical processes, including working fluid phase change-vapor flow and liquid reflux. The presence of non-condensable gases significantly impacts these processes, leading to poor temperature uniformity, degraded heat transfer performance, and startup failure. In high-temperature heat pipes, non-condensable gases primarily originate from the following sources: (1) The material itself: the impurities or adsorbed gases carried by the heat pipe shell, end cap, filling tube, wick, working fluid and other materials decompose or release non-condensable gases at high temperature.

[0003] (2) Manufacturing process: Non-condensable gases or pollutants introduced or generated during pipe welding, working fluid filling and other processes.

[0004] (3) Test application environment: Some gases with low atomic number, such as hydrogen and helium, can easily enter the heat pipe through the permeation mechanism. Therefore, when the heat pipe is tested or applied in these special gas environments, non-condensable gases that have permeated through the pipe wall will gradually accumulate inside.

[0005] A set of active non-condensable gas control technologies and quantitative evaluation methods that run through the entire process of materials, manufacturing, filling, testing and application is needed to reduce the content of non-condensable gases inside the heat pipe and avoid the deterioration of heat transfer in the heat pipe. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a method for controlling and evaluating the content of non-condensable gases in high-temperature heat pipes online. This method addresses the entire process of materials, manufacturing, filling, testing, and application, and achieves proactive, precise control and quantitative evaluation of non-condensable gas content from three dimensions: source control, process elimination, and online evaluation. This improves the long-term reliability and performance consistency of heat pipes in various complex environments.

[0007] The technical solution adopted in this invention is as follows: A method for controlling non-condensable gases in a high-temperature heat pipe includes the following steps: S1. Deep cleaning of materials eliminates non-condensable gases and other impurities from the source, including the dissolution and adsorption of end caps, tube shells, liquid suction cores, and filling tubes. S2. Clean process treatment to ensure that no new contaminants are introduced during assembly and welding; S3, Heat pipe purification and exhaust, completes the working fluid injection and the final purification and exhaust in the heat pipe; S4. Long-lasting surface barrier to prevent helium and hydrogen from penetrating into the heat pipe.

[0008] The deep cleaning of the material includes the following steps: S101, Chemical Cleaning Immerse all materials in an alkaline cleaning solution for 10-15 minutes to remove surface oil and dirt; After removal, rinse with deionized water, then immerse in acidic cleaning solution for 10-20 minutes to further remove oxides and impurities; After being removed, rinsed again with deionized water, and then placed in a vacuum oven to dry at around 100°C for 1-2 hours; S102, Pre-degassing After cleaning and drying, the material is placed in a dedicated high-temperature vacuum degassing furnace, and a vacuum is drawn to ensure that the pressure inside the furnace is <1×10⁻⁶. -3 Pa; The furnace temperature was raised to 650-700℃ at a heating rate of 6-10℃ / min and held at this temperature for 4-6 hours. During this process, the furnace pressure first increased and then decreased as the material was degassed and a vacuum was continuously applied, eventually stabilizing at ≤5×10⁻⁶. - 4 Pa; When the furnace temperature is cooled to ≤100℃, the material is removed by breaking the cavity.

[0009] The cleaning process includes the following steps: S201, Pipe Fitting Assembly Transfer all materials to a clean workbench in a cleanroom of at least Class 1000 cleanroom. The assembly of the tube shell and the liquid suction core, as well as the preliminary assembly and positioning of the end cap, tube shell and filling tube are carried out. S202, Pipe Fitting Welding The pre-assembled pipe fittings are transferred to a vacuum electron beam welding machine; Maintain a vacuum level of ≤1×10⁻⁶ in the welding chamber. -3 Pa, vacuum electron beam welding is performed on the end cap and the shell, and the end cap and the filling tube.

[0010] The heat pipe purification exhaust includes the following steps: S301, Vacuum heating degassing Connect one end of the assembled and welded heat pipe filling tube to the vacuum system, and place the other end inside the heating furnace; Start the vacuum pump unit and evacuate the heat pipe to a vacuum level of ≤1×10⁻⁶. -3 Pa; Start the heating furnace, preset the heating curve, and adopt a stepped heating and degassing process. In the first stage, the temperature is raised to 200℃ and held for 2 hours to remove any adsorbed moisture and initially remove non-condensable gases from the interior. The second stage involves heating to 650℃ and holding for 4 hours for deep degassing. Throughout this process, the vacuum level should be better than 1×10⁻⁶. - 3 Pa; The third stage involves cooling the temperature back to 200°C in preparation for subsequent purification and filling of the working fluid. S302, working fluid purification and filling Before filling the working fluid, vacuum distillation or cold trap capture is used to filter the fluid through a multi-layer stainless steel wire mesh filter to purify the working fluid and improve its purity. The purified working fluid is injected into the heat pipe through a metering container; S303, hot steam exhaust After the working fluid is injected, the heating furnace is rapidly heated to 650°C to heat the heat pipe evaporation section, causing the working fluid in the evaporation section to evaporate violently and generate steam. The furnace temperature is maintained at 650℃ for 5 minutes, allowing the working fluid steam to purge the non-condensable gas remaining in the tube cavity to the top of the condensation section, and then extract it through a vacuum pump. The filling tube is then sealed and welded.

[0011] The long-term surface barrier includes the following steps: The outer surface of the finished heat pipe is roughened by sandblasting; Subsequently, a dense alumina coating with a thickness of 50-150 μm is prepared on the outer surface of the heat pipe to block the penetration of small molecule gases.

[0012] A method for online assessment of non-condensable gas content in high-temperature heat pipes includes the following steps: S1, Heat pipe cold start The heat pipe evaporation section is heated, and the working fluid in the evaporation section gradually melts and begins to evaporate to produce steam. As the temperature of the working fluid steam in the evaporation section rises, the working fluid steam will go through three flow pattern stages: "free molecular flow - transition flow - continuous flow", and finally form a continuous steam flow. S2, during the heat pipe start-up phase, the partial pressure of non-condensable gases in the initial state is obtained; S3, the steady-state stage of the heat pipe, further obtains the partial pressure of non-condensable gas in the initial state.

[0013] In step S1, initially, the heat pipe vapor chamber is occupied by non-condensable gas, and the partial pressure of the non-condensable gas is... The volume occupied is The initial average temperature is During startup, the temperature at which steam transitions from a transitional flow to a continuous flow is defined as the continuous steam flow transition temperature. .

[0014] In S2, the steam temperature at which the steam in the evaporation section begins to advance is defined as the heat pipe start-up temperature. When the temperature of the continuous steam flow in the evaporation section reaches the heat pipe start-up temperature At that time, the partial pressure of non-condensable gases With the saturation pressure of the continuous steam flow at this time Equal; according to the ideal gas law, the volume occupied by the non-condensable gas at this time is equal. and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : The saturation pressure of the continuous steam flow From the start-up temperature The query returned the results.

[0015] The start-up temperature The heat flux density of the evaporation section at this time q Average temperature of the evaporation section wall and wall-vapor thermal resistance R By reverse deduction, we obtain: In S3, When the heat pipe reaches steady-state operation, the working fluid vapor occupies most of the heat pipe area, while the non-condensable gas only occupies the top of the condensation section. There is a large temperature gradient between the vapor and non-condensable gas regions, and a clear temperature interface exists between them. The vapor temperature at this interface is the continuous vapor flow transition temperature. ; Based on the transition temperature interface of the continuous steam flow, the steam region and the non-condensable gas region are divided, and the average steam temperature at this point is determined. Obtain the steam saturation pressure at this time The partial pressure of the non-condensable gas at this point can be obtained based on pressure balance. Furthermore, based on the ideal gas law, the volume occupied by the non-condensable gas at this point... and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : In S3, the heat pipe is in a steady-state operation phase, with a high steam temperature and a small steam pressure drop, meaning the steam temperature inside the heat pipe is basically uniform. Therefore, the average wall temperature of the heat pipe's adiabatic section is considered to be... With average steam temperature They are basically equal: The beneficial effects of this invention are: (1) The present invention provides a method for controlling non-condensable gases in a high-temperature heat pipe and an online evaluation method for non-condensable gas content, which systematically eliminates non-condensable gases: targeted measures are proposed for each link from materials to testing and application, forming a closed-loop control, which significantly reduces the initial non-condensable gas content in the heat pipe and the possibility of non-condensable gas increasing during subsequent operation, thereby improving the performance stability and reliability of heat pipe products.

[0016] (2) The present invention provides a method for controlling non-condensable gases in a high-temperature heat pipe and an online evaluation method for non-condensable gas content. The evaluation methods are intuitive and practical: the two non-condensable gas evaluation methods can be monitored online using only conventional temperature test data, which is convenient to implement and can realize rapid evaluation of non-condensable gases.

[0017] (3) The present invention provides a method for controlling non-condensable gas in a high-temperature heat pipe and an online evaluation method for non-condensable gas content, which guides process optimization: the measures applied in the control technology can be directly used to optimize process parameters (such as degassing temperature, time, vacuum degree, baking curve, etc.) to achieve closed-loop improvement of the process.

[0018] (4) The present invention provides a method for controlling non-condensable gases in high-temperature heat pipes and an online evaluation method for non-condensable gas content. It addresses the entire process of materials, manufacturing, filling, testing and application, and achieves active and precise control and quantitative evaluation of non-condensable gas content from three dimensions: source control, process elimination and online evaluation. This improves the long-term working reliability and performance consistency of heat pipes in various complex environments and has good application prospects and transformation potential. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in describing the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments recorded in the present invention. Those skilled in the art can derive other drawings from the following drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of a high-temperature heat pipe structure provided by the present invention; Figure 2 Flowchart of the high-temperature heat pipe non-condensable gas control method provided by the present invention; Figure 3 This is a schematic diagram of the steam flow pattern transformation during the heat pipe startup phase in this invention; Figure 4 This is a schematic diagram illustrating the principle of the online assessment method for the content of non-condensable gases inside a heat pipe in this invention.

[0021] Explanation of reference numerals in the attached figures: 1-End cap, 2-Tube shell, 3-Liquid suction core, 4-Liquid filling tube, 5-Weld joint. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., refer to the orientation or positional relationship shown in the accompanying drawings, and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figure 1 As shown, the high-temperature heat pipe structure involved in this invention mainly consists of an end cap 1, a shell 2, a liquid wick 3, and a filling tube 4, etc., and is filled with a liquid metal working fluid, such as potassium. There are a total of 4 welding points 5 involved in the high-temperature heat pipe, including 2 between the end cap 1 and the shell 2, 1 between the end cap 1 and the filling tube 4, and 1 on the filling tube 4 itself.

[0026] like Figure 2 As shown, the present invention provides a method for controlling non-condensable gases in a high-temperature heat pipe, including deep cleaning of materials, process cleaning treatment, heat pipe exhaust purification, and long-term surface barrier, specifically including the following steps: S1. Deep cleaning of materials aims to eliminate non-condensable gases and other impurities from the source, including those dissolved or adsorbed by the end cap 1, tube shell 2, suction core 3, and filling tube 4. Specific operating steps are as follows: S101, Chemical Cleaning Immerse all materials in an alkaline cleaning solution for 10-15 minutes to remove surface oil and dirt; After removal, rinse with deionized water, then immerse in acidic cleaning solution for 10-20 minutes to further remove oxides and impurities; After removal, rinse again with deionized water, then place in a vacuum oven and dry at around 100℃ for 1-2 hours.

[0027] S102, Pre-degassing After cleaning and drying, the material is placed in a dedicated high-temperature vacuum degassing furnace, and a vacuum is drawn to ensure that the pressure inside the furnace is <1×10⁻⁶. -3 Pa; The furnace temperature is raised to 650-700℃ (50-100℃ higher than the maximum operating temperature of the heat pipe) at a heating rate of 6-10℃ / min, and then held at this temperature for 4-6 hours. During this process, as the material is degassed and a vacuum is continuously applied, the furnace pressure first rises and then falls, eventually stabilizing at ≤5×10⁻⁶. -4 Pa; When the furnace temperature is cooled to ≤100℃, the material is removed by breaking the cavity.

[0028] S2. Process cleaning is designed to ensure that no new contaminants are introduced during assembly and welding. Specific operating steps are as follows: S201, Pipe Fitting Assembly Transfer all materials to a clean workbench in a cleanroom of at least Class 1000 cleanroom. The assembly of the tube shell 2 and the liquid suction core 3 was carried out, as well as the preliminary assembly and positioning of the end cap 1, tube shell 2 and filling tube 4.

[0029] S202, Pipe Fitting Welding The pre-assembled pipe fittings are transferred to a vacuum electron beam welding machine; Maintain a vacuum level of ≤1×10⁻⁶ in the welding chamber. -3 Pa, vacuum electron beam welding is performed on end cap 1 and tube shell 2, and end cap 1 and filling tube 4.

[0030] S3, Heat Pipe Purification and Exhaust, aims to complete the working fluid injection and the final purification and exhaust within the heat pipe. The specific operating steps are as follows: S301, Vacuum heating degassing Connect one end of the assembled and welded heat pipe filling tube 4 to the vacuum system and place the other end inside the heating furnace; Start the vacuum pump unit and evacuate the heat pipe to a vacuum level of ≤1×10⁻⁶. -3 Pa; Start the heating furnace, preset the heating curve, and adopt a stepped heating and degassing process. In the first stage, the temperature is raised to 200℃ and held for 2 hours to remove any adsorbed moisture and initially remove non-condensable gases from the interior. The second stage involves heating to 650℃ and holding for 4 hours for deep degassing. Throughout this process, the vacuum level should be better than 1×10⁻⁶.- 3 Pa; The third stage involves cooling the temperature back to 200°C in preparation for subsequent purification and filling of the working fluid.

[0031] S302, working fluid purification and filling Before filling the working fluid, vacuum distillation or cold trap capture methods are used, or the fluid is filtered through a multi-layer stainless steel wire mesh filter to purify the working fluid and improve its purity. The purified working fluid is injected into the heat pipe through a metering container.

[0032] S303, hot steam exhaust After the working fluid is injected, the heating furnace is rapidly heated to 650°C to heat the heat pipe evaporation section, causing the working fluid in the evaporation section to evaporate violently and generate steam. The furnace temperature was maintained at 650℃ for 5 minutes, allowing the working fluid steam to purge the non-condensable gas remaining in the tube cavity to the top of the condensation section and extract it through a vacuum pump. Then, the filling tube 4 was sealed and welded.

[0033] S4. Long-term surface barrier design to prevent gases such as helium and hydrogen from permeating into the heat pipe. Specific operating steps are as follows: S401, Surface Coating Treatment The outer surface of the finished heat pipe is roughened by sandblasting; Subsequently, a dense alumina coating with a thickness of 50-150 μm is prepared on the outer surface of the heat pipe to block the penetration of small molecule gases.

[0034] It should be noted that for long-term surface barrier, materials with lower permeability can also be directly selected as heat pipe materials, such as nickel-based high-temperature alloys like Inconel 625. Compared to stainless steel, it can effectively slow down hydrogen permeation and damage, reducing the risk of permeation from the material's inherent nature.

[0035] A schematic diagram of the normal operation principle of a heat pipe is shown below. Figure 3 As shown. When the heat pipe is in its initial state, the working fluid inside the wick is in a solidified state, and the vapor chamber is in a high vacuum state, as... Figure 3 As shown in stage (I); when the heat pipe evaporator section is heated, the working fluid in the evaporator section gradually melts and begins to evaporate to produce steam, as... Figure 3 As shown in stage (II), as the temperature of the working fluid steam in the evaporation section increases, the working fluid steam will go through three flow pattern stages: "free molecular flow - transition flow - continuous flow", eventually forming a continuous steam flow, as shown in the diagram. Figure 3 As shown in stage (III); under the pressure difference between the evaporation and condensation sections, the continuous steam flow begins to advance towards the condensation section, causing the temperature along the heat pipe to rise. Finally, the heat pipe enters steady-state operation, as shown... Figure 3The intermediate stage (IV) is shown. The temperature at which steam transitions from a transition flow to a continuous flow is defined as the continuous steam flow transition temperature. This is also an important basis for online assessment of noncondensable gas content.

[0036] When non-condensable gases are present within the heat pipe, the operating state of the heat pipe changes. Another aspect of this invention provides a method for online evaluation of the non-condensable gas content in high-temperature heat pipes, such as... Figure 4 As shown, the main steps include: S1 Heat Pipe Cold Start In the initial state, such as Figure 4 As shown in the intermediate stage (I), the heat pipe vapor chamber is occupied by non-condensable gas, at which point the partial pressure of the non-condensable gas is... The volume occupied is The initial average temperature is .

[0037] A startup test was conducted on the high-temperature heat pipe, and its wall temperature was monitored. The evaporation section of the heat pipe was heated, and the working fluid in the evaporation section gradually melted and began to evaporate to produce steam. As the temperature of the working fluid steam in the evaporation section increased, the working fluid steam went through three flow pattern stages: "free molecular flow - transition flow - continuous flow," eventually forming a continuous steam flow. At this point, due to the presence of non-condensable gases, the continuous steam flow could not advance towards the condensation section.

[0038] S2 Heat Pipe Start-up Temperature Analysis As heat is continuously input into the evaporation section, the steam pressure and temperature in the evaporation section area continue to rise. When the pressure of the continuous steam flow further increases and exceeds the partial pressure of the non-condensable gas, the continuous steam flow begins to advance into the condensation section.

[0039] The steam temperature at which the steam begins to propagate in the evaporation section is defined as the heat pipe start-up temperature. ,like Figure 4 As shown in the middle stage (II), when the temperature of the continuous steam flow in the evaporation section reaches the heat pipe start-up temperature... At that time, the partial pressure of non-condensable gases With the saturation pressure of the continuous steam flow at this time Equal, saturation pressure of continuous steam flow It can be determined by the start-up temperature The query yielded the result. Further, based on the ideal gas law, the volume occupied by the non-condensable gas at this point... and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : (1) S3 Heat Pipe Steady-State Stage Zoning Analysis As the temperature and pressure of the working fluid steam continue to increase, the continuous steam flow is advanced to the condensation section, pushing the non-condensable gas to the top of the condensation section and compressing it.

[0040] like Figure 4 As shown in stage (III), when the heat pipe reaches steady-state operation, the working fluid vapor occupies most of the heat pipe area, while the non-condensable gas only occupies the top of the condensation section. There is a large temperature gradient between the vapor and non-condensable gas regions, and there is a clear temperature interface between the two. The vapor temperature at this interface is the continuous vapor flow transition temperature. .

[0041] Based on the transition temperature interface of the continuous steam flow, the steam region and the non-condensable gas region are divided, and the average steam temperature at this point is determined. Obtain the steam saturation pressure at this time The partial pressure of the non-condensable gas at this point can be obtained based on pressure balance. Furthermore, based on the ideal gas law, the volume occupied by the non-condensable gas at this point... and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : (2) It should be noted that the temperature measured during the test is the heat pipe wall temperature, which needs to be further converted to steam temperature. For the temperature analysis of the S2 heat pipe during the start-up phase, the steam temperature within the evaporation section is required, which can be obtained from the heat flux density of the evaporation section at that time. q Average temperature of the evaporation section wall and wall-vapor thermal resistance R By working backwards, the steam temperature within the evaporation section can be obtained, which is the heat pipe start-up temperature. : (3) For the steady-state phase analysis of the S3 heat pipe, the heat pipe is in a steady-state operation phase, with a high vapor temperature and a small vapor pressure drop, meaning the vapor temperature inside the heat pipe is basically uniform. Generally, the average wall temperature of the heat pipe's adiabatic section is considered to be... With average steam temperature They are basically equal: (4) As can be seen, the present invention provides an online assessment method for the non-condensable gas content of a high-temperature heat pipe, including a heat pipe start-up stage temperature analysis method based on the continuous vapor flow transformation mechanism and a heat pipe steady-state stage zonal analysis method. Based on conventional test data, the non-condensable gas content inside the heat pipe can be rapidly assessed online, obtaining the internal non-condensable gas partial pressure under the initial state (i.e., cold state) of the heat pipe. .

[0042] It should be noted that the online evaluation method for non-condensable gas content in high-temperature heat pipes provided by this invention can calculate the non-condensable gas content in two operating stages during the heat pipe startup test. The non-condensable gas partial pressure values ​​obtained from the two stages can be compared with each other, further improving the accuracy and reliability of the non-condensable gas content evaluation.

[0043] While those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0044] Furthermore, it should be understood that although the present invention is described according to embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for controlling non-condensable gases in a high-temperature heat pipe, characterized in that, Includes the following steps: S1. Deep cleaning of materials eliminates non-condensable gases and other impurities from the source, including the dissolution and adsorption of end caps, tube shells, liquid suction cores, and filling tubes. S2. Clean process treatment to ensure that no new contaminants are introduced during assembly and welding; S3, Heat pipe purification and exhaust, completes the working fluid injection and the final purification and exhaust in the heat pipe; S4. Long-lasting surface barrier to prevent helium and hydrogen from penetrating into the heat pipe.

2. The method for controlling non-condensable gases in a high-temperature heat pipe according to claim 1, characterized in that, The deep cleaning of the material includes the following steps: S101, Chemical Cleaning Immerse all materials in an alkaline cleaning solution for 10-15 minutes to remove surface oil and dirt; After removal, rinse with deionized water, then immerse in acidic cleaning solution for 10-20 minutes to further remove oxides and impurities; After being removed, rinsed again with deionized water, and then placed in a vacuum oven to dry at around 100°C for 1-2 hours; S102, Pre-degassing After cleaning and drying, the material is placed in a dedicated high-temperature vacuum degassing furnace, and a vacuum is drawn to ensure that the pressure inside the furnace is <1×10⁻⁶. -3 Pa; The furnace temperature was raised to 650-700℃ at a heating rate of 6-10℃ / min and held at this temperature for 4-6 hours. During this process, the furnace pressure first increased and then decreased as the material was degassed and a vacuum was continuously applied, eventually stabilizing at ≤5×10⁻⁶. -4 Pa; When the furnace temperature is cooled to ≤100℃, the material is removed by breaking the cavity.

3. The method for controlling non-condensable gases in a high-temperature heat pipe according to claim 2, characterized in that, The cleaning process includes the following steps: S201, Pipe Fitting Assembly Transfer all materials to a clean workbench in a cleanroom of at least Class 1000 cleanroom. The assembly of the tube shell (2) and the liquid suction core (3) is carried out, as well as the preliminary assembly and positioning of the end cap (1), the tube shell (2) and the filling tube (4); S202, Pipe Fitting Welding The pre-assembled pipe fittings are transferred to a vacuum electron beam welding machine; Maintain a vacuum level of ≤1×10⁻⁶ in the welding chamber. -3 Pa, vacuum electron beam welding is performed on the end cap (1) and the shell (2), and on the end cap (1) and the filling tube (4).

4. The method for controlling non-condensable gases in a high-temperature heat pipe according to claim 3, characterized in that, The heat pipe purification exhaust includes the following steps: S301, Vacuum heating degassing Connect one end of the assembled and welded heat pipe filling tube (4) to the vacuum system and place the other end in the heating furnace; Start the vacuum pump unit and evacuate the heat pipe to a vacuum level of ≤1×10⁻⁶. -3 Pa; Start the heating furnace, preset the heating curve, and adopt a stepped heating and degassing process. In the first stage, the temperature is raised to 200℃ and held for 2 hours to remove any adsorbed moisture and initially remove non-condensable gases from the interior. The second stage involves heating to 650℃ and holding for 4 hours for deep degassing. Throughout this process, the vacuum level should be better than 1×10⁻⁶. -3 Pa; The third stage involves cooling the temperature back to 200°C in preparation for subsequent purification and filling of the working fluid. S302, working fluid purification and filling Before filling the working fluid, vacuum distillation or cold trap capture is used to filter the fluid through a multi-layer stainless steel wire mesh filter to purify the working fluid and improve its purity. The purified working fluid is injected into the heat pipe through a metering container; S303, hot steam exhaust After the working fluid is injected, the heating furnace is rapidly heated to 650°C to heat the heat pipe evaporation section, causing the working fluid in the evaporation section to evaporate violently and generate steam. The furnace temperature was maintained at 650℃ for 5 minutes, so that the working fluid steam would purge the non-condensable gas remaining in the tube to the top of the condensation section and extract it through a vacuum pump. Then the filling tube (4) was sealed.

5. The method for controlling non-condensable gases in a high-temperature heat pipe according to claim 4, characterized in that, The long-term surface barrier includes the following steps: The outer surface of the finished heat pipe is roughened by sandblasting; Subsequently, a dense alumina coating with a thickness of 50-150 μm is prepared on the outer surface of the heat pipe to block the penetration of small molecule gases.

6. A method for online evaluation of non-condensable gas content in high-temperature heat pipes, characterized in that, Includes the following steps: S1, Heat pipe cold start The heat pipe evaporation section is heated, and the working fluid in the evaporation section gradually melts and begins to evaporate to produce steam. As the temperature of the working fluid steam in the evaporation section rises, the working fluid steam will go through three flow pattern stages: "free molecular flow - transition flow - continuous flow", and finally form a continuous steam flow. S2, during the heat pipe start-up phase, the partial pressure of non-condensable gases in the initial state is obtained; S3, the steady-state stage of the heat pipe, further obtains the partial pressure of non-condensable gas under the initial state; In step S1, initially, the heat pipe vapor chamber is occupied by non-condensable gas, and the partial pressure of the non-condensable gas is... The volume occupied is The initial average temperature is During startup, the temperature at which steam transitions from a transitional flow to a continuous flow is defined as the continuous steam flow transition temperature. ...

7. The method for online evaluation of non-condensable gas content in high-temperature heat pipes according to claim 6, characterized in that, In S2, the steam temperature at which the steam in the evaporation section begins to advance is defined as the heat pipe start-up temperature. When the temperature of the continuous steam flow in the evaporation section reaches the heat pipe start-up temperature At that time, the partial pressure of non-condensable gases With the saturation pressure of the continuous steam flow at this time Equal; according to the ideal gas law, the volume occupied by the non-condensable gas at this time is equal. and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : ； The saturation pressure of the continuous steam flow From the start-up temperature The query returned the results.

8. The method for online evaluation of non-condensable gas content in high-temperature heat pipes according to claim 7, characterized in that, The start-up temperature The heat flux density of the evaporation section at this time q Average temperature of the evaporation section wall and wall-vapor thermal resistance R By reverse deduction, we obtain: 。 9. The method for online evaluation of non-condensable gas content in high-temperature heat pipes according to claim 8, characterized in that, In S3, When the heat pipe reaches steady-state operation, the working fluid vapor occupies most of the heat pipe area, while the non-condensable gas only occupies the top of the condensation section. There is a large temperature gradient between the vapor and non-condensable gas regions, and a clear temperature interface exists between them. The temperature at this interface is the vapor transition temperature of the continuous vapor flow. ; Based on the transition temperature interface of the continuous steam flow, the steam region and the non-condensable gas region are divided, and the average steam temperature at this point is determined. Obtain the steam saturation pressure at this time The partial pressure of the non-condensable gas at this point can be obtained based on pressure balance. Furthermore, based on the ideal gas law, the volume occupied by the non-condensable gas at this point... and the average temperature of non-condensable gases The partial pressures of noncondensable gases in the initial state are obtained. : 。 10. The method for online evaluation of non-condensable gas content in high-temperature heat pipes according to claim 9, characterized in that, In S3, the heat pipe is in a steady-state operation phase, with a high steam temperature and a small steam pressure drop, meaning the steam temperature inside the heat pipe is basically uniform. Therefore, the average wall temperature of the heat pipe's adiabatic section is considered to be... With average steam temperature They are basically equal: 。

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