A new working medium for heat pipe with unpowered heat dissipation function

Abstract

The application discloses a novel heat pipe working medium with unpowered heat dissipation function, and particularly relates to the field of energy-saving heat exchange materials. The heat pipe working medium is prepared by mixing normal pentane, anhydrous ethanol and a composite additive according to a volume ratio, and the filling ratio of the working medium in a vacuum pipe shell is 8-80%. During preparation, the heat pipe working medium is filled into the pipe shell under vacuum condition and sealed, and the pressure in the pipe is not higher than 0.8 kPa. A reinforced heat transfer coating formed by emulsifying, spraying and ladder curing of sodium silicate, tung oil and sodium benzoate is arranged on the inner wall of the pipe shell. The working medium is environmentally friendly and non-corrosive, and can realize high-efficiency heat dissipation under the condition of no external power, and has high heat dissipation power. The application has high heat dissipation efficiency, is environmentally friendly, and is suitable for passive energy-saving heat exchange of various building walls, industrialized aquaculture ponds, plant factories, data center servers, photovoltaic power generation and other devices which have heat generation and need heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of energy-saving heat exchange materials, and in particular to a novel heat pipe working fluid with non-powered heat dissipation function. Background Technology

[0002] In practical applications of heat pipe materials, water, ethanol, acetone, alkanes, and their halogenated derivatives remain the mainstream choices. Dichloromethane is a typical example; by introducing two chlorine atoms to replace hydrogen atoms in the methane molecule, it not only increases the molecular weight and significantly enhances dispersion forces, thus raising the boiling point. Furthermore, since methane is a nonpolar molecule while dichloromethane is a polar molecule, this transformation also strengthens the intermolecular orientation forces. Under these combined effects, dichloromethane reaches a boiling point of 39.6℃, giving it a significant advantage in low-temperature heat pipes. However, a single chlorine atom can destroy tens of thousands of ozone molecules, causing severe environmental damage—a major drawback of this type of molecule.

[0003] Observations of alkane compounds reveal that when the carbon chain length reaches five carbon atoms, i.e., n-pentane, the molecule exhibits strong deformability. Furthermore, due to the asynchronous movement of electrons and protons within the electron cloud, relative displacement occurs, generating an instantaneous dipole moment and inducing an instantaneous dipole moment in another n-pentane molecule. The interaction between these instantaneous dipole moments is influenced by various factors, resulting in n-pentane molecules being liquid at room temperature and pressure with a low boiling point. However, using only n-pentane as a heat pipe working fluid limits its application range. Especially at high temperatures, n-pentane may evaporate rapidly, leading to a decrease in heat pipe performance. Simultaneously, although n-pentane possesses a certain thermal conductivity, it is likely lower than some commonly used heat pipe working fluids such as water and liquid ammonia, thus affecting the heat transfer efficiency of the heat pipe. Considering the relatively weak intermolecular forces in n-pentane, additional refrigeration is required in the condenser section for effective circulation, increasing system energy consumption. A brief overview of existing technologies in this field is as follows: Patent 202510721427.9 discloses a method for preparing a novel heat pipe sintered core powder and its application in heat pipes. Addressing the heat dissipation requirements of ultra-thin electronic devices, the invention employs a gradient coupling process of displacement-reduction synergistic reaction. Using spherical copper powder as raw material, silver crystal nuclei are constructed through surface activation, modification, and silver ammonia solution reaction. Then, morphology is controlled by tannic acid, ascorbic acid reduction, and high-temperature aging to prepare island-shaped silver-coated copper composite powder. This powder is filled into a high-conductivity oxygen-free copper tube and sintered at high temperature to form a liquid-absorbing core. The resulting heat pipe thickness can be controlled below 0.7 mm, exhibiting excellent capillary properties, adsorption capacity, and processing stability. This effectively solves the problems of abnormal grain growth and easy flattening defects in copper tubes during traditional heat pipe sintering.

[0004] Patent 201910732876.8 discloses a novel method for preparing a high-throughput heat exchange tube. To improve the insufficient thermal conductivity of traditional heat exchange tubes, a composite electrodeposition solution containing copper sulfate pentahydrate, graphene sheets, sodium polydisulfide diethane sulfonate, and chloride ions is prepared. After acid washing the surface of the heat exchange tube, a cathode rotating pulse electrodeposition process is used to form a uniform and dense graphene and copper-based composite deposition layer on the surface of the base tube. This method is suitable for various heat exchange, heat dissipation, and cooling equipment and has the advantages of efficient and controllable process, good bonding strength, and good thermal stability.

[0005] Therefore, this invention proposes a novel heat pipe working fluid with non-powered heat dissipation function. Summary of the Invention

[0006] The main objective of this invention is to provide a novel heat pipe working fluid with non-powered heat dissipation function, which can effectively solve the problems of existing working fluids in terms of environmental protection, thermal conductivity and cycle efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A novel heat pipe working fluid with non-powered heat dissipation function is disclosed. The working fluid is a mixed solution containing n-pentane, anhydrous ethanol, and composite additives, wherein the volume fraction of n-pentane is 50%-96%, the volume fraction of anhydrous ethanol is 4%-50%, and the volume fraction of composite additives is 0-2%. The heat pipe includes a sealed shell, the interior of which is a vacuum cavity filled with the working fluid.

[0008] Preferably, the volume ratio of n-pentane to anhydrous ethanol is 19:1-2:1.

[0009] Preferably, the working fluid fills 8-80% of the vacuum cavity.

[0010] Preferably, the composite additive is added at a ratio of 0-2% of the total volume.

[0011] A method for preparing a heat pipe with non-powered heat dissipation function includes the following steps: S1: Measure n-pentane and anhydrous ethanol, mix them evenly at room temperature to obtain the heat pipe working fluid; S2: Seal the tube shell to the vacuum system and evacuate its internal cavity; S3: Under vacuum conditions, the heat pipe working fluid prepared in step S1 is filled into the cavity of the tube shell, and after reaching the predetermined filling ratio, it is sealed to obtain a heat pipe without power heat dissipation function.

[0012] Preferably, in step S2, the vacuum is evacuated until the pressure inside the cavity does not exceed 0.8 kPa.

[0013] Preferably, the inner wall of the tube shell in step S2 is provided with a heat transfer enhancement coating, which is formed by emulsifying, spraying and step-curing sodium silicate, tung oil and sodium benzoate.

[0014] Preferably, the preparation of the enhanced heat transfer coating includes the following steps: A1: Take 70-85 parts of sodium silicate, add 15-30 parts of tung oil for emulsification, add 10-25 parts of sodium benzoate powder and deionized water, and stir continuously to obtain a slurry; A2: The inner wall of the pipe shell is sandblasted, cleaned, and dried. The slurry is then applied to the inner wall using a spray gun. After surface drying at room temperature, it is cured by step-by-step heating to form a coating.

[0015] Preferably, the stepped temperature curing in step A2 involves holding at 80-100℃ for 1-2 hours, holding at 150-180℃ for 2-3 hours, and curing at 180-200℃ for 1-2 hours.

[0016] Preferably, deionized water is selected as the solvent, and the amount of each component added by mass percentage is as follows: sodium tetraborate 0.1-1.0 parts, sodium dihydrogen phosphate 0.1-1.5 parts, sodium molybdate 0.05-0.8 parts, methylbenzotriazole 0.02-0.3 parts, sodium benzoate 0.1-1.2 parts, and the balance is deionized water. First, add measured deionized water to the reaction vessel, turn on the mechanical stirrer, and control the stirring speed at 300-600 r / min. While continuously stirring, add the ingredients in steps according to their solubility from high to low. First, add sodium tetraborate and stir continuously for 3-5 minutes until completely dissolved. Then, add sodium dihydrogen phosphate and continue stirring for 3-5 minutes until the system is clear and transparent. Next, add sodium molybdate and keep the stirring rate constant, stirring for 2-4 minutes until fully dissolved. Then, add methylbenzotriazole. Since this component has relatively low solubility in water, appropriately extend the stirring time to 5-10 minutes to ensure that it is completely dissolved and uniformly dispersed. Finally, add sodium benzoate and continue stirring for 8-15 minutes to ensure that all additives reach saturated solubility equilibrium in water without local agglomeration, thus obtaining a stable and homogeneous aqueous solution of composite additives.

[0017] Preferably, the components of the above-mentioned composite additive work synergistically to improve the safety performance of the working fluid from multiple dimensions. The specific mechanisms of action are as follows: 1. Sodium tetraborate can decompose and melt when heated, forming a continuous and dense glassy isolation layer that covers the surface of the working fluid and contact materials, isolating oxygen and blocking heat transfer. Its decomposition process is a strongly endothermic reaction, which can absorb a large amount of heat from the system, rapidly reduce the local temperature of the working fluid, and inhibit thermal runaway; 2. Sodium dihydrogen phosphate can catalyze and promote the rapid formation of a stable and dense carbonized layer in the working fluid during heating and combustion, effectively blocking flame spread and heat and mass transfer, while adjusting the pH value of the system to maintain the long-term stability of the working fluid; 3. Sodium molybdate can capture active free radicals in the combustion chain reaction in the gas phase and condensed phase, interrupt the combustion chain process, achieve gas phase flame suppression, and form a passivation protective film on the metal surface, which has both flame suppression and corrosion inhibition effects, improving the operational safety of the working fluid; 4. Methylbenzotriazole can inhibit the electrochemical corrosion of the metal matrix, reduce the decomposition and aging of the working fluid caused by metal catalysis, stabilize the working fluid components, and avoid local overheating and abnormal decomposition; 5. Sodium benzoate, as a system stabilizer, improves the solubility and dispersibility of each additive in water, prevents component separation and stratification, and ensures the continuous performance of the synergistic effect of the composite additives.

[0018] Preferably, the application includes using the heat pipe as a passive energy-saving heat exchange device in various building cold storage walls, factory breeding ponds, plant factories, data center servers, photovoltaic inverter power generation, or other related scenarios where heat is generated and needs to be dissipated.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. With the heat pipe charge rate set to 80%, the heat source temperature maintained at 50℃, and the ambient temperature maintained at 40℃, this working fluid can efficiently achieve rapid, non-powered heat dissipation of the heat source within 1 minute, with a heat dissipation power of 51270W / m. 2 This demonstrates excellent thermal conductivity and heat dissipation performance. Furthermore, both increases in heat source temperature and decreases in ambient temperature enhance the heat dissipation power of the heat pipe. This invention selects n-pentane and anhydrous ethanol, both with extremely low global warming potential, and incorporates composite additives as working fluids to achieve an environmentally friendly design.

[0020] 2. The introduction of alcohol into the working fluid of the present invention enhances the polarity of the heat pipe working fluid and optimizes the phase change cycle dynamics between the evaporation and condensation sections. Compared with a single n-pentane working fluid, the heat pipe working fluid of the present invention has more sufficient reflux in the condensation section, effectively avoiding the local drying phenomenon that may occur at high temperatures, improving the long-term stability and reliability of the heat pipe operation, and achieving more efficient heat transport and dissipation.

[0021] 3. This invention provides an enhanced heat transfer coating. By compounding tung oil and sodium benzoate into a sodium silicate matrix and then performing a stepped curing process, a stable, dense, and strongly adhesive hydrophilic coating is formed on the inner wall of the heat pipe. This coating effectively increases the number of vaporization nuclei, strengthens capillary action, improves the evaporation and reflux efficiency of the working fluid, and enhances the overall heat transfer performance of the heat pipe. Attached Figure Description

[0022] Figure 1 A schematic diagram of the process for preparing a novel heat pipe working fluid with non-powered heat dissipation function for this invention; Figure 2 This is a schematic diagram of the temperature-time curves of embodiments and comparative examples of the present invention at a heat source temperature of 90°C; Figure 3 This is a schematic diagram of the temperature-time curves of embodiments and comparative examples of the present invention at a heat source temperature of 70°C; Figure 4 This is a schematic diagram of the temperature-time curves of embodiments and comparative examples of the present invention at a heat source temperature of 60°C; Figure 5 This is a schematic diagram of the temperature-time curves of embodiments and comparative examples of the present invention at a heat source temperature of 50°C; Figure 6 This is a schematic diagram showing the curves of different filling ratios at an ambient temperature of 40°C for embodiments and comparative examples of the present invention. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise range thresholds, and these range thresholds should be understood to include values ​​close to these range thresholds. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0024] The following is in conjunction with the appendix Figure 1-5 This specification provides a detailed description of a novel heat pipe working fluid with non-powered heat dissipation function, as provided in the embodiments of this specification.

[0025] Figure 1 The diagram shows the working fluid of a novel heat pipe without powered heat dissipation and the preparation steps of the heat pipe. The specific implementation steps are as follows.

[0026] Preparation Example 1 This invention provides a method for preparing an aqueous solution of a composite additive, as detailed below: Using deionized water as the solvent, the following components were added by mass percentage: 0.5 parts sodium tetraborate, 0.8 parts sodium dihydrogen phosphate, 0.4 parts sodium molybdate, 0.15 parts methylbenzotriazole, 0.6 parts sodium benzoate, with the remainder being deionized water; During preparation, first add measured deionized water to the reaction vessel, turn on the mechanical stirrer, and control the stirring speed at 450 r / min. Under continuous stirring, add the ingredients in steps according to their solubility from high to low. First, add sodium tetraborate and stir continuously for 4 minutes until completely dissolved. Then, add sodium dihydrogen phosphate and continue stirring for 4 minutes until the system is clear and transparent. Next, add sodium molybdate and keep the stirring rate constant, stirring for 3 minutes until fully dissolved. Then, add methylbenzotriazole. Since this component has relatively low solubility in water, the stirring time is appropriately extended to 8 minutes to ensure that it is completely dissolved and uniformly dispersed. Finally, add sodium benzoate and continue stirring for 11 minutes to ensure that all additives reach saturated solubility equilibrium in water without local agglomeration, thus obtaining a stable and homogeneous aqueous solution of composite additives.

[0027] Example 1 A method for preparing a novel heat pipe working fluid with non-powered heat dissipation function, the specific implementation steps of which are as follows: A novel heat pipe working fluid with non-powered heat dissipation function is composed of a mixed solution of n-pentane and anhydrous ethanol. The volume fraction of n-pentane is 50%, and the volume fraction of anhydrous ethanol is 50%. n-pentane and anhydrous ethanol are weighed according to a volume ratio of 19:1-2:1. The aqueous solution of the composite additive obtained in Preparation Example 1 is added to the above basic heat pipe working fluid at a ratio of 1 wt%. The mixture is stirred until homogeneous at room temperature to obtain the heat pipe working fluid.

[0028] A copper tube with a wall thickness of 0.8 mm and an inner diameter of 8 mm was selected as the tube shell. 80 parts sodium silicate and 20 parts tung oil were mixed and emulsified, and 15 parts sodium benzoate powder and an appropriate amount of deionized water were added, stirring until a uniform slurry was formed. After sandblasting the inner wall of the copper tube, it was cleaned and dried. The slurry was then evenly coated onto the inner wall of the tube shell using a spraying process. After surface drying at room temperature, a stepped curing process was performed: first, holding at 90℃ for 1.5 hours, then at 160℃ for 2.5 hours, and finally curing at 190℃ for 1.5 hours to form a dense coating. The coating was then cleaned with anhydrous ethanol and dried. The tube shell was connected to a vacuum system, and a vacuum was drawn until the internal pressure reached 0.8 kPa. Under vacuum conditions, the heat pipe working fluid was filled into the tube shell at a filling ratio of 10%, and then the tube shell was sealed to obtain the heat pipe.

[0029] Example 2 A method for preparing a novel heat pipe working fluid with non-powered heat dissipation function, the specific implementation steps of which are as follows: A novel heat pipe working fluid with non-powered heat dissipation function is composed of a mixed solution of n-pentane and anhydrous ethanol. The volume fraction of n-pentane is 96%, and the volume fraction of anhydrous ethanol is 4%. n-pentane and anhydrous ethanol are weighed at a volume ratio of 2:1. The aqueous solution of the composite additive obtained in Preparation Example 1 is added to the above basic heat pipe working fluid at a ratio of 1 wt%. The mixture is stirred until homogeneous at room temperature to obtain the heat pipe working fluid.

[0030] A copper tube with a wall thickness of 0.8 mm and an inner diameter of 8 mm was selected as the tube shell. 70 parts sodium silicate and 15 parts tung oil were mixed and emulsified, and 10 parts sodium benzoate powder and an appropriate amount of deionized water were added. The mixture was stirred until a uniform slurry was formed. After sandblasting the inner wall of the copper tube, it was cleaned and dried. The slurry was then evenly coated onto the inner wall of the tube shell using a spraying process. After surface drying at room temperature, a stepped curing process was performed: first, the tube was kept at 80℃ for 1 hour, then at 150℃ for 2 hours, and finally cured at 180℃ for 1 hour to form a dense coating. The coating was then cleaned with anhydrous ethanol and dried. The tube shell was connected to a vacuum system, and a vacuum was drawn until the internal pressure reached 0.8 kPa. Under vacuum conditions, the heat pipe working fluid was filled into the tube shell at a filling ratio of 10%, and then the tube shell was sealed to obtain the heat pipe.

[0031] Example 3 A method for preparing a novel heat pipe working fluid with non-powered heat dissipation function, the specific implementation steps of which are as follows: A novel heat pipe working fluid with non-powered heat dissipation function is composed of a mixed solution of n-pentane and anhydrous ethanol. The volume fraction of n-pentane is 60%, and the volume fraction of anhydrous ethanol is 40%. n-pentane and anhydrous ethanol are weighed at a volume ratio of 10:1. The aqueous solution of the composite additive obtained in Preparation Example 1 is added to the above basic heat pipe working fluid at a ratio of 2 wt%. The mixture is stirred until homogeneous at room temperature to obtain the heat pipe working fluid.

[0032] A copper tube with a wall thickness of 0.8 mm and an inner diameter of 8 mm was selected as the tube shell. 80 parts sodium silicate and 20 parts tung oil were mixed and emulsified, and 15 parts sodium benzoate powder and an appropriate amount of deionized water were added, stirring until a uniform slurry was formed. After sandblasting the inner wall of the copper tube, it was cleaned and dried. The slurry was then evenly coated onto the inner wall of the tube shell using a spraying process. After surface drying at room temperature, a stepped curing process was performed: first, holding at 90℃ for 1.5 hours, then at 160℃ for 2.5 hours, and finally curing at 190℃ for 1.5 hours to form a dense coating. The coating was then cleaned with anhydrous ethanol and dried. The tube shell was connected to a vacuum system, and a vacuum was drawn until the internal pressure reached 0.8 kPa. Under vacuum conditions, the heat pipe working fluid was filled into the tube shell at a filling ratio of 10%, and then the tube shell was sealed to obtain the heat pipe.

[0033] Comparative Example 1 Using a copper tube of the same size but without filling it with working fluid, and only evacuating it to 0.8 kPa, the remaining steps are the same as in Example 1.

[0034] Comparative Example 2 Without inserting any pipes, the system serves as a reference for natural heat dissipation, and the remaining steps are the same as in Example 1.

[0035] The products prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to the following performance tests: The heat pipes described in Examples 1-3 and Comparative Examples 1-2 were selected. All were copper tubes with an inner diameter of 8mm, a wall thickness of 0.8mm, and a height of 1.8m. Internal treatment and working fluid filling were performed according to the respective examples and comparative examples. Three identical thermos cups were used, each filled with an equal amount of hot water as a heat source. Insulation cotton was wrapped around the mouths of all cups to ensure a uniform heat dissipation vent diameter of 10mm, guaranteeing consistent heat dissipation conditions.

[0036] The experimental group was fitted with heat pipes filled with the heat pipe working fluid of the present invention. The copper pipe group was fitted with copper pipes of the same size but without the working fluid, and only evacuated to 0.8 kPa to eliminate the influence of the thermal conductivity of the copper pipe itself and the vacuum environment. The blank group was not fitted with any pipes and served as a natural heat dissipation benchmark.

[0037] The ambient temperature was set and stabilized at 40℃. Equal amounts of hot water were poured into three insulated cups, setting initial temperatures of 50℃, 60℃, 70℃, and 90℃ respectively to simulate different operating temperature conditions. When the water temperature reached the set value, the corresponding heat pipe or empty copper tube was quickly inserted into the heat source; this was recorded as the experimental start time t0=0. The data recording system was simultaneously activated to monitor and record the temperature changes of the three heat sources over 90 minutes, with a data acquisition interval of 15 minutes. The heat pipe working fluid was primarily 66.7% n-pentane and 33.3% anhydrous ethanol, with a filling ratio set at 40%. Analysis of the heat source temperature decrease curve over time was performed as follows: Figure 2-5 .

[0038] Anhydrous pentane and ethanol in a volume ratio of 95:5 were added to the heat pipe at four different filling ratios of 8%, 15%, 20%, and 40%. Performance was tested under the same operating conditions, and the results are as follows: Figure 6 As shown in the figure, the experimental results indicate that when the working fluid filling ratio of the heat pipe is 15%, the water temperature drops rapidly by 4.6℃ within 1 minute, exhibiting the fastest cooling. This demonstrates that the optimal filling ratio of the n-pentane-anhydrous ethanol mixture as the working fluid for the heat pipe is approximately 15%.

[0039] from Figure 2-5 As can be seen, when using a heat pipe with n-pentane and anhydrous ethanol as the heat pipe working fluid, the temperature of the heat source drops significantly faster than that of the control group with an empty copper pipe and natural heat dissipation. This indicates that the heat pipe working fluid effectively accelerates the transfer and dissipation of heat in the heat pipe.

[0040] Anhydrous pentane and ethanol were tested at different initial heat source temperatures (50℃, 60℃, 70℃, and 90℃) with a volume ratio of 95:5 and a filling ratio of 15% to simulate different working temperature conditions. As the initial temperature increased, the heat pipe heat dissipation effect was better. This is because the evaporation and condensation cycle of the working fluid is more active at high temperatures, thereby accelerating the heat transfer.

[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A heat pipe working fluid with non-powered heat dissipation function, characterized in that, The working fluid is a mixed solution of n-pentane, anhydrous ethanol, and composite additives, wherein the volume fraction of n-pentane is 50-96%, the volume fraction of anhydrous ethanol is 4-50%, and the volume fraction of composite additives is 0%-2%; the heat pipe includes a sealed shell, the interior of which is a vacuum cavity filled with the working fluid.

2. The heat pipe working fluid with non-powered heat dissipation function according to claim 1, characterized in that, The volume ratio of n-pentane to anhydrous ethanol is in the range of 19:1 to 2:

1.

3. The heat pipe working fluid with non-powered heat dissipation function according to claim 1, characterized in that, The working fluid is filled to a ratio of 8-80% in the vacuum chamber.

4. A method for preparing a heat pipe with non-powered heat dissipation function according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Measure n-pentane, anhydrous ethanol, and composite additives and mix them evenly at room temperature to obtain the heat pipe working fluid; S2: Seal the tube shell to the vacuum system and evacuate its internal cavity; S3: Under vacuum conditions, the heat pipe working fluid prepared in step S1 is filled into the cavity of the tube shell, and after reaching the predetermined filling ratio, it is sealed to obtain a heat pipe without power heat dissipation function.

5. The method for preparing the novel environmentally friendly heat pipe according to claim 4, characterized in that, In step S2, a vacuum is drawn until the pressure inside the cavity does not exceed 0.8 kPa.

6. The method for preparing the novel environmentally friendly heat pipe according to claim 4, characterized in that, The preparation method of the composite additive aqueous solution in step S1 is as follows: First, add deionized water to the reaction vessel, turn on the mechanical stirrer, control the stirring speed to 300-600 r / min, and under continuous stirring, first add 0.1-1.0 parts of sodium tetraborate, and continue stirring for 3-5 min until completely dissolved. Then add 0.1-1.5 parts of sodium dihydrogen phosphate, and continue stirring for 3-5 min until the system is clear and transparent. Then add 0.05-0.8 parts of sodium molybdate, keep the stirring rate constant, and stir for 2-4 min until fully dissolved. Next, add 0.02-0.3 parts of methylbenzotriazole, extend the stirring time to 5-10 min, and finally add 0.1-1.2 parts of sodium benzoate, and continue stirring for 8-15 min to obtain a stable and homogeneous composite additive aqueous solution.

7. The method for preparing the novel environmentally friendly heat pipe according to claim 4, characterized in that, In step S2, the inner wall of the tube shell is provided with a heat transfer enhancement coating, which is formed by emulsifying, spraying and step-curing sodium silicate, tung oil and sodium benzoate.

8. The method for preparing the novel environmentally friendly heat pipe according to claim 7, characterized in that, Preparation of the enhanced heat transfer coating Includes the following steps: A1: Take 70-85 parts of sodium silicate, add 15-30 parts of tung oil to emulsify, then add 10-25 parts of sodium benzoate powder and deionized water and stir continuously to obtain a slurry; A2: After sandblasting the inner wall of the pipe shell, cleaning and drying it, the slurry is applied to the inner wall by spraying. After surface drying at room temperature, it is cured by step-by-step heating to form a coating.

9. A heat pipe working fluid with non-powered heat dissipation function according to claim 8, characterized in that, The stepped temperature curing in step A2 involves holding at 80-100℃ for 1-2 hours, holding at 150-180℃ for 2-3 hours, and curing at 180-200℃ for 1-2 hours.

10. The application of a heat pipe working fluid with no powered heat dissipation function according to any one of claims 1-9 in equipment heat dissipation, characterized in that, The applications include using the heat pipe as a passive energy-saving heat exchange device in various building walls, factory-style aquaculture ponds, plant factories, data center servers, photovoltaic power generation, or other scenarios where heat is generated and needs to be dissipated.

Images