Preparation system and preparation method of nanofluid

Abstract

The embodiment of the invention relates to the technical field of nanofluid preparation, in particular to a nanofluid preparation system and a nanofluid preparation method, which are used for mixing metal nanoparticles with alkali metal to form a nanofluid. The preparation system comprises: a mixing container configured to form a mixing chamber; the first feeding pipeline is used for adding metal nanoparticles into the mixing cavity; the second feeding pipeline is used for adding liquid alkali metal into the mixing cavity; the sealed container is arranged to form a sealed cavity and used for containing the metal nanoparticles, and the metal nanoparticles are coated with the solid alkali metal so as to form an integrated piece with the solid alkali metal; and the discharging pipeline is connected with the sealed container and is arranged to be detachably connected with the first feeding pipeline. According to the embodiment of the invention, the sealed container and the discharging pipeline are arranged, so that the nanoparticles can be coated by the solid alkali metal in the glove box by utilizing the sealed container to form an integrated piece, and then the integrated piece enters the mixing cavity through the first feeding pipeline.

Description

Technical Field

[0001] The present application relates to the technical field of nanofluid preparation, and in particular to a nanofluid preparation system and a nanofluid preparation method. Background Art

[0002] Compared with previous nuclear energy systems, the fourth-generation nuclear energy system is required to show higher reliability, higher safety and higher economy. Among them, the sodium-cooled fast reactor, one of the fourth-generation nuclear energy systems, mainly uses liquid metallic sodium as a coolant. Although metallic sodium has excellent heat transfer performance, neutron economy and material compatibility as a coolant, the chemical activity of metallic sodium is relatively high, which also brings constraints to the development of sodium-cooled fast reactors. For example, if there is a breach in the cooling main pipeline or the heat exchanger breaks, when the leaked metallic sodium contacts the oxygen or water in the environment, a violent sodium fire or sodium-water reaction will occur, thereby releasing a large amount of heat.

[0003] In order to mitigate the above-mentioned reactive accidents, sodium-based nanofluids with better heat transfer performance and lower chemical activity can be used to replace traditional metallic sodium coolants. However, the preparation effect of sodium-based nanofluids is not ideal at present. Summary of the invention

[0004] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0005] The inventors of the present application have found that the prepared nanofluid has an inaccurate ratio problem. The inventors of the present application have further found that this is because the nanoparticles have a large specific surface area. When the nanoparticles are sent to a container to mix with the solid alkali metal, the nanoparticles will be adsorbed on the inner wall of the container or pipeline in contact with them, so that the nanoparticles actually mixed with the liquid alkali metal cannot meet the ratio requirements.

[0006] In view of the above technical problems, the embodiments of the present application provide a nanofluid preparation system and a nanofluid preparation method for mixing metal nanoparticles with alkali metals to form a nanofluid.

[0007] In the first aspect, an embodiment of the present application provides a nanofluid preparation system, comprising: a mixing container, the mixing container is configured to form a mixing chamber; a first feed pipeline, used to add metal nanoparticles into the mixing chamber; a second feed pipeline, used to add liquid alkali metal into the mixing chamber; a sealed container, the sealed container is configured to form a sealed chamber, used to accommodate metal nanoparticles, wherein the metal nanoparticles are coated with solid alkali metals to form an integral part with the solid alkali metal; a discharge pipeline, connected to the sealed container, the discharge pipeline is configured to be detachably connected to the first feed pipeline, when the discharge pipeline is disassembled from the first feed pipeline, the sealed chamber and the mixing chamber can be sealed respectively; when the discharge pipeline is connected to the first feed pipeline, the sealed chamber can be connected to the mixing chamber, so that the integral part in the sealed container can enter the mixing chamber via the discharge pipeline and the first feed pipeline in sequence.

[0008] The inventor of the present application has found that in the related art, metal nanoparticles are directly added to the mixing chamber of the mixing container using the first feeding pipeline of the nanofluid preparation system. Since the metal nanoparticles have a large specific surface area, when the metal nanoparticles are directly fed into the mixing chamber via the first feeding pipeline, the metal nanoparticles will be adsorbed on all surfaces that can be contacted during the feeding process, thereby causing an inaccurate ratio of the metal nanoparticles to the alkali metal.

[0009] The embodiment of the present application provides a sealed container and a discharge pipeline, and enables the sealed container and the discharge pipeline to be detachably sealed and connected with the first feed pipeline, so that the sealed container and the discharge pipeline can be removed from the first feed pipeline, so that the nanoparticles are coated with solid alkali metals to form an integrated part and placed in the sealed container in the glove box, and then the sealed container and the discharge pipeline are taken out of the glove box, and the discharge pipeline is sealed and connected with the first feed pipeline, so that the integrated part formed by the solid alkali metal coating can enter the mixing chamber through the first feed pipeline. In the process of the integrated part entering the mixing chamber through the discharge pipeline and the first feed pipeline, it is helpful to avoid the metal nanoparticles from being adsorbed on the inner wall of the mixing container or pipeline, and thus it is helpful to avoid the situation where the ratio of metal nanoparticles and alkali metals is inaccurate.

[0010] In a second aspect, an embodiment of the present application provides a method for preparing a nanofluid, and the preparation method adopts the preparation system of the first aspect of the present application to prepare the nanofluid.

[0011] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0013] Figure 1 Schematic diagram of the structure of a nanofluid preparation system according to an embodiment of the present application.

[0014] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the mixing container of the preparation system is shown.

[0015] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0016] Description of reference numerals:

[0017] 11. mixing container; 111. mixing chamber; 112. mixing body; 113. mixing cover; 114. stirring through hole;

[0018] 121, first feed pipeline; 122, second feed pipeline; 123, discharge pipeline; 124, first vacuum and gas charging pipeline; 125, second vacuum and gas charging pipeline; 1261, first delivery pipeline; 1262, second delivery pipeline; 1263, third delivery pipeline; 127, vacuum pump connecting pipeline; 128, first feed valve; 129, second feed valve;

[0019] 13. Sealed container; 131. Sealed chamber; 132. Air intake pipeline;

[0020] 141. vacuum pump; 142. gas storage container; 15. stirring assembly; 151. stirring member; 152. driving member; 153. magnetic sealing member;

[0021] 16. Cooling parts;

[0022] 17. Alkali metal storage containers;

[0023] 18. Weighing device;

[0024] 19. Ultrasonic device; 191. Ultrasonic container; 192. Ultrasonic generating element;

[0025] 21. Nanofluid storage container;

[0026] 22. Nanofluid transport container;

[0027] 23. Adjust the valve. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0029] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0030] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the common meanings understood by persons with ordinary skills in the field to which this application belongs.

[0031] In the description of the embodiments of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] The embodiments of the present application provide a nanofluid preparation system for mixing metal nanoparticles with alkali metals to form a nanofluid.

[0033] In some embodiments, Figure 1 As shown, the preparation system may include a mixing container 11, a first feed line 121, a second feed line 122, a sealed container 13 and a discharge line 123. The mixing container 11 is configured to form a mixing chamber 111. The first feed line 121 is used to add metal nanoparticles to the mixing chamber 111. The second feed line 122 is used to add liquid alkali metal to the mixing chamber 111. The sealed container 13 is configured to form a sealed chamber 131 for accommodating metal nanoparticles. The metal nanoparticles are coated with solid alkali metal to form an integral part with the solid alkali metal.

[0034] See also Figure 2The discharge pipeline 123 is connected to the sealed container 13 and is configured to be detachably connected to the first feed pipeline 121. When the discharge pipeline 123 is disassembled from the first feed pipeline 121, the sealed chamber 131 and the mixing chamber 111 can be sealed respectively; when the discharge pipeline 123 is connected to the first feed pipeline 121, the sealed chamber 131 can be communicated with the mixing chamber 111, so that the integrated part in the sealed container 13 can enter the mixing chamber 111 via the discharge pipeline 123 and the first feed pipeline 121 in sequence.

[0035] In the embodiment of the present application, a sealed container 13 and a discharge pipeline 123 are provided, and the sealed container 13 and the discharge pipeline 123 can be detachably sealed and connected with the first feed pipeline 121, so that the sealed container 13 and the discharge pipeline 123 can be removed from the first feed pipeline 121, so that the nanoparticles coated with solid alkali metals to form an integrated part are placed in the sealed container 13 in the glove box, and then the sealed container 13 and the discharge pipeline 123 are taken out of the glove box, and the discharge pipeline 123 is sealed and connected with the first feed pipeline 121, so that the integrated part formed by the solid alkali metal coating can enter the mixing chamber 111 through the first feed pipeline 121. In the process of the integrated part entering the mixing chamber 111 through the discharge pipeline 123 and the first feed pipeline 121, it is helpful to avoid the metal nanoparticles from being adsorbed on the inner wall of the mixing container 11 or the pipeline, and further helps to avoid the situation where the ratio of the metal nanoparticles and the alkali metal is inaccurate.

[0036] In some embodiments, the material of the metal nanoparticles may be one or more transition metals with a melting point greater than or equal to 900° C. and relatively high interatomic strength. For example, the metal nanoparticles may be titanium nanoparticles, manganese nanoparticles, etc. The alkali metal in the embodiment of the present application may be metallic sodium.

[0037] In some embodiments, the size of the metal nanoparticles may be less than 100 nm, such as 50 nm. In some embodiments, the ratio of the mass of the metal nanoparticles to the total mass of the metal nanoparticles and the alkali metal may be in the range of 0.1 wt% to 10 wt%.

[0038] In some embodiments, the one-piece may be in the shape of a rod.

[0039] In some embodiments, the discharge pipeline 123 and the first feed pipeline 121 may be connected via a quick-release joint. The quick-release joint may be threaded.

[0040] In some embodiments, the preparation system may further include a mold. The liquid alkali metal mixed with the metal nanoparticles is poured into the mold and cooled to obtain an integral part. After obtaining the integral part, the integral part may be transferred to a sealed container 13 in a glove box filled with an inert gas for sealed storage.

[0041] The mold may be a rod-shaped mold.

[0042] In some embodiments, the inner wall of the mold may be formed with a non-wetting coating to prevent the integral part from adhering to the inner wall of the mold. The material of the non-wetting coating may be aluminum oxide or polytetrafluoroethylene.

[0043] In some embodiments, the inner diameter of the mold is smaller than the inner diameters of the discharge pipeline 123 and the first feed pipeline 121. This helps to avoid the problem that the integrated part is not easy to pass through the pipeline into the mixing chamber 111 due to its large size.

[0044] The size of the integral piece may be in the range of 10-20 mm, for example 10 mm,

[0045] In some embodiments, the preparation system may further include a first feed valve 128, a second feed valve 129, and a first vacuum and gas charging pipeline 124. The first feed valve 128 may be disposed on the first feed pipeline 121. The second feed valve 129 may be disposed on the discharge pipeline 123. The first vacuum and gas charging pipeline 124 is connected to the first feed pipeline 121 or the discharge pipeline 123, so that when the discharge pipeline 123 is connected to the first feed pipeline 121, the pipeline between the first feed valve 128 and the second feed valve 129 can be evacuated and filled with inert gas.

[0046] The embodiments of the present application can control the opening or closing of the first feed valve 128 and the second feed valve 129 to isolate or seal the sealed chamber 131 and the mixing chamber 111, which is relatively convenient; the first vacuum and inflation pipeline 124 is used to evacuate the pipeline between the first feed valve 128 and the second feed valve 129 and fill it with inert gas, which is beneficial for evacuating the pipeline between the first feed valve 128 and the second feed valve 129 after the discharge pipeline 123 is sealed and connected to the first feed pipeline 121, so as to avoid the introduction of air in the process of the integrated component entering the mixing chamber 111.

[0047] In some embodiments, if the sealed chamber 131 needs to be disconnected from the mixing chamber 111, the first feed valve 128 and the second feed valve 129 can be closed first, and then the discharge pipeline 123 and the first feed pipeline 121 can be disassembled. If the sealed chamber 131 needs to be connected to the mixing chamber 111, the discharge pipeline 123 and the first feed pipeline 121 can be connected first, and then the first vacuum and inflation pipeline 124 can be used to evacuate the pipeline between the first feed valve 128 and the second feed valve 129, and then the first feed valve 128 and the second feed valve 129 can be opened after evacuation.

[0048] In some embodiments, the operation of evacuating the pipeline between the first feed valve 128 and the second feed valve 129 and filling it with inert gas using the first vacuum and inflation pipeline 124 can be repeated multiple times, for example, 4 times, to ensure that the air in the pipeline can be fully discharged.

[0049] In some embodiments, the preparation system may include an air inlet line 132, and the sealed container 13 is further provided with an air inlet for connection with the air inlet line 132. The air inlet line 132 is used to provide air pressure to drive the integrated part smoothly from the sealed cavity 131 into the mixing container 11, so as to prevent the integrated part from falling only by gravity and possibly getting stuck in the pipeline.

[0050] After the discharge pipeline 123 is connected to the first feed pipeline 121, and the pipeline between the first feed valve 128 and the second feed valve 129 is evacuated and filled with inert gas by the first vacuum and inflation pipeline 124, the first feed valve 128 and the second feed valve 129 can be opened, and then gas is injected into the sealed cavity 131 through the intake pipeline 132. The gas is used to blow the integrated part from the sealed cavity 131 into the discharge pipeline 123, and enter the mixing container 11 through the first feed pipeline 121.

[0051] In some embodiments, the mixing container 11 may include a mixing body 112 and a mixing cover 113. The mixing cover 113 may be used to seal the mixing body 112 to form a mixing chamber 111.

[0052] In some embodiments, the discharge pipeline 123 can be disposed at the bottom of the sealed container 13. The first feed pipeline 121 can be disposed on the mixing cover 113 of the mixing container 11. The discharge pipeline 123 and the first feed pipeline 121 can both extend vertically so that the integrated component can smoothly fall into the mixing chamber 111 under the action of gravity and gas pressure.

[0053] The inner diameters of the discharge pipeline 123 and the first feed pipeline 121 and the diameters of the first feed valve 128 and the second feed valve 129 can be greater than the preset value, so that the integral part in the sealed container 13 can smoothly fall into the mixing chamber 111. In some embodiments, the preset value can be, for example, 25 mm. In some embodiments, the inner diameters of the discharge pipeline 123 and the first feed pipeline 121 and the diameters of the first feed valve 128 and the second feed valve 129 can be, for example, 30 mm.

[0054] In some embodiments, the preparation system may further include a stirring assembly 15. The stirring assembly 15 may be disposed in the mixing container 11, and is used to mechanically stir the material in the mixing chamber 111. The embodiment of the present application utilizes the stirring assembly 15 to mechanically stir the material in the mixing chamber 111, which is conducive to uniformly dispersing the metal nanoparticles in the mixing chamber 111 in the liquid alkali metal.

[0055] In some embodiments, the mixing container 11 may include a stirring through hole 114. The stirring assembly 15 may include a stirring member 151, a driving member 152, and a magnetic seal 153. The stirring member 151 enters the mixing container 11 from the stirring through hole 114. The driving member 152 may be disposed outside the mixing container 11 to drive the stirring member 151 to rotate. The magnetic seal 153 may be disposed outside the mixing container 11 to seal between the stirring member 151 and the stirring through hole 114 of the mixing container 11.

[0056] In the embodiment of the present application, the driving member 152 drives the stirring member 151 to rotate so as to stir the material in the mixing container 11; a magnetic seal 153 is provided between the stirring member 151 and the stirring through hole 114 of the mixing container 11, so as to ensure that the preparation system can operate for a long time in a high temperature environment, avoid problems such as alkali metal leakage caused by poor sealing between the stirring member 151 and the stirring through hole 114 of the mixing container 11, and at the same time avoid introducing new impurities into the mixing container 11.

[0057] In some embodiments, the stirring through hole 114 may be disposed on the mixing cover 113. In some embodiments, the magnetic seal 153 may be a magnetic sealing ring.

[0058] In some embodiments, the preparation system may further include a cooling element 16 for cooling the magnetic seal 153 , so as to ensure the sealing effect of the magnetic seal 153 .

[0059] In some embodiments, the cooling member 16 may be a cooling jacket that is cooled using oil cooling.

[0060] In some embodiments, the preparation system may further include an alkali metal storage container 17 and a second vacuum and gas charging pipeline 125. The alkali metal storage container 17 may be used to provide liquid alkali metal. The second vacuum and gas charging pipeline 125 may be used to evacuate the alkali metal storage container 17 and fill it with inert gas, so as to drive the liquid alkali metal from the alkali metal storage container 17 into the mixing container 11 via the second feed pipeline 122 by gas pressure.

[0061] The embodiment of the present application realizes the injection of liquid alkali metal from the alkali metal storage container 17 into the mixing container 11 via the second feed pipeline 122 in a gas pressure-driven manner through the second vacuum and inflation pipeline 125. This ensures that the process of the liquid alkali metal entering the mixing container 11 is carried out in an environment filled with inert gas to ensure the purity of the liquid alkali metal. At the same time, the use of gas pressure-driven method does not require the provision of an additional driving device, which is conducive to simplifying the structure of the preparation system.

[0062] In some embodiments, the preparation system may further include a vacuum pump 141, a gas storage container 142, and a vacuum pump connecting line 127. The gas storage container 142 may be used to store an inert gas. The second vacuum and gas charging line 125 may be connected to the gas storage container 142 and the vacuum pump connecting line 127, respectively. The vacuum pump 141 may be used to pump the inert gas in the gas storage container 142 to the first vacuum and gas charging line 124 and the second vacuum and gas charging line 125 via the vacuum pump connecting line 127.

[0063] In some embodiments, the preparation system may further include a heating element. The heating element may be used to heat the liquid alkali metal in the alkali metal storage container to prevent the liquid alkali metal from solidifying. Exemplarily, the liquid alkali metal in the alkali metal storage container may be in the range of 220-300°C.

[0064] In some embodiments, the preparation system may further include a weighing device 18. The weighing device 18 may be used to weigh the alkali metal storage container 17 and / or the mixing container 11, so as to determine the weight of the liquid alkali metal entering the mixing container 11. The embodiment of the present application uses the weighing device 18 to determine the weight of the liquid alkali metal entering the mixing container 11, so that the weight of the metal nanoparticles in the prepared nanofluid and the weight of the liquid alkali metal can meet the ratio requirements.

[0065] In some embodiments, the weighing device 18 may be a high-precision electronic scale.

[0066] In some embodiments, the preparation system may further include an ultrasonic device 19. The ultrasonic device 19 may be used to receive the material from the mixing container 11 to perform ultrasonic treatment on the material. The embodiment of the present application utilizes the ultrasonic device 19 to perform ultrasonic treatment on the material received from the mixing container 11, so that the metal nanoparticles can be more evenly dispersed in the liquid alkali metal.

[0067] In some embodiments, the ultrasonic device 19 may include an ultrasonic container 191 and an ultrasonic generator 192. The ultrasonic container 191 may be in fluid communication with the mixing container 11. The ultrasonic generator 192 may be disposed in the ultrasonic container 191 to perform ultrasonic treatment on the material in the ultrasonic container 191.

[0068] The embodiment of the present application configures the ultrasonic device 19 to include an ultrasonic container 191 and an ultrasonic generator 192, so that the material in the mixing container 11 can be introduced into the ultrasonic container 191 for ultrasonic treatment instead of being ultrasonically treated in the mixing container 11, thereby avoiding the deterioration of the sealing of the mixing container 11 due to ultrasound.

[0069] In some embodiments, the preparation system may further include a first material delivery pipeline 1261 and a plurality of regulating valves 23. The first material delivery pipeline 1261 may be used to connect the ultrasonic container 191 to the mixing body 112 of the mixing container 11. A plurality of regulating valves 23 may be provided on the first material delivery pipeline 1261 to control the on-off of the first material delivery pipeline 1261.

[0070] In some embodiments, the preparation system may further include a control device, which may be used to determine the working parameters of the ultrasonic generator 192 according to the melting point of the metal nanoparticles and the temperature of the material in the ultrasonic container 191 .

[0071] The embodiment of the present application uses a control device to determine the working parameters of the ultrasonic generator 192 to prevent ultrasound from causing a significant increase in fluid temperature, causing the nanoparticles to melt and form an alloy with sodium, thereby causing the performance of the nanofluid to deteriorate. At the same time, it prevents the local temperature of the nanofluid from being too high, thereby causing alkali metal boiling or flashing, etc., which brings safety hazards.

[0072] In some embodiments, the working parameters of the ultrasonic generator 192 may include the ultrasonic time of the ultrasonic wave emitted by the ultrasonic generator 192 and the power of the ultrasonic generator 192. In some embodiments, the control device may set the ultrasonic time to not exceed a preset time to avoid the phenomenon of alkali metal boiling or flashing due to excessive local temperature of the nanofluid.

[0073] Usually, the ultrasonic frequency emitted by the ultrasonic generator 192 is fixed. In some embodiments, the ultrasonic device 19 may include multiple ultrasonic generators 192 with different ultrasonic frequencies, and the control device may also select an ultrasonic generator 192 with a suitable ultrasonic frequency according to the melting point of the metal nanoparticles and the temperature of the material in the ultrasonic container 191.

[0074] In some embodiments, the preparation system may further include a second material delivery pipeline 1262 and a nanofluid storage container 21. The second material delivery pipeline 1262 is used to connect the ultrasound container 191 with the nanofluid storage container 21. The nanofluid storage container 21 is used to store the nanofluid obtained after the ultrasound treatment.

[0075] In some embodiments, the preparation system may further include a third material delivery pipeline 1263 and a nanofluid transport container 22. The third material delivery pipeline 1263 is used to connect the nanofluid storage container 21 to the nanofluid transport container 22. The nanofluid transport container 22 is used to store the nanofluid to be transported in the nanofluid storage container 21.

[0076] In some embodiments, the second material delivery pipeline 1262 and the third material delivery pipeline 1263 may be provided with regulating valves 23 respectively, which are used to control the on-off of the second material delivery pipeline 1262 and the third material delivery pipeline 1263 respectively.

[0077] The embodiment of the present application also provides a method for preparing a nanofluid, which is used to mix metal nanoparticles with alkali metals to form a nanofluid. The preparation method uses the preparation system of any embodiment of the present application to prepare the nanofluid.

[0078] In some embodiments, the preparation method includes steps S1 to S3.

[0079] S1. The metal nanoparticles are coated with a solid alkali metal to form an integral body with the solid alkali metal.

[0080] S2. Add liquid alkali metal into the mixing container 11, add the integrated component into the sealed container 13, connect the discharge pipeline 123 with the first feed pipeline 121, and add the integrated component into the mixing container 11 through the discharge pipeline 123 and the first feed pipeline 121.

[0081] S3, uniformly mixing the integral member with liquid alkali metal to form a nanofluid.

[0082] In the embodiment of the present application, the nanoparticles are coated with solid alkali metal to form an integrated part and placed in a sealed container 13 in a glove box, and then the sealed container 13 and the discharge pipeline 123 are taken out of the glove box, and the discharge pipeline 123 is sealedly connected with the first feed pipeline 121, so that the integrated part formed by the solid alkali metal coating can enter the mixing chamber 111 through the first feed pipeline 121. In the process of the integrated part entering the mixing chamber 111 through the discharge pipeline 123 and the first feed pipeline 121, it is helpful to avoid the metal nanoparticles from being adsorbed on the inner wall of the mixing container 11 or the pipeline, and further helps to avoid the situation where the ratio of the metal nanoparticles and the alkali metal is inaccurate.

[0083] In some embodiments, step S1 includes: under an inert atmosphere, weighing a solid alkali metal (e.g., 20-30 g) and a target weight of metal nanoparticles in a glove box filled with inert gas, heating the solid alkali metal into a liquid, pouring the metal nanoparticles into the liquid alkali metal to mix, and then pouring the liquid alkali metal mixed with the metal nanoparticles into a rod-shaped mold for cooling to obtain an integral part. After obtaining the integral part, the integral part can be transferred to a sealed container 13 in a glove box filled with inert gas for sealed storage.

[0084] It is easy to understand that the total amount of the solid alkali metal added in step S1 and the liquid alkali metal added to the mixing container 11 in step S2 is the content of the alkali metal in the nanofluid.

[0085] In some embodiments, the cross-sectional size of the integrated part made in step S1 is smaller than the inner diameter of the discharge pipeline 123 and the first feed pipeline 121, and smaller than the diameter of the first feed valve 128 and the second feed valve 129, so as to avoid the integrated part from sticking to the pipeline or valve, making it difficult to enter the mixing container 11 smoothly.

[0086] In some embodiments, in step S3, under atmospheric environment, the sealed container 13 is connected to the first feed pipeline 121 through the discharge pipeline 123; the discharge pipeline 123 and the first feed pipeline 121 are evacuated, and then an inert gas is injected into the discharge pipeline 123 and the first feed pipeline 121; the discharge pipeline 123 and the first feed pipeline 121 are connected, so that the integrated part in the sealed container 13 enters the mixing container 11 via the discharge pipeline 123 and the first feed pipeline 121.

[0087] In some embodiments, step S3 includes: after the integral piece is added into the mixing container 11 , waiting for a first preset time to allow the alkali metal in the integral piece to completely melt; and then, mechanically stirring the material in the mixing container 11 using the stirring piece 151 .

[0088] The method provided in the embodiment of the present application waits for a first preset time to allow the alkali metal in the integral part to completely melt, and then uses the stirring member 151 to mechanically stir the material in the mixing container 11, so as to prevent the stirring member 151 from throwing the integral part to the inner wall of the mixing container 11 and adhering to the inner wall when the alkali metal is not completely melted, thereby hindering the full dispersion of the metal nanoparticles in the liquid alkali metal.

[0089] In some embodiments, when the stirring member 151 is first started, the speed of the stirring member 151 should not be too high, for example, the speed of the stirring member 151 is less than 100 rpm. If the speed of the stirring member 151 is relatively high, the metal nanoparticles are more likely to be thrown onto the inner wall of the mixing chamber 111 during the stirring process.

[0090] In some embodiments, before charging the alkali metal into the alkali metal storage container 17 for the first time, the alkali metal storage container 17 may be evacuated and filled with an inert gas so that the water and oxygen content in the alkali metal storage container 17 does not exceed 50 ppm.

[0091] When the stirring member 151 is used to mechanically stir the materials in the mixing container 11, the driving member 152 can be controlled to start the stirring member 151 at a first speed, and the stirring member 151 can be rotated at the first speed for a first preset time; then the stirring member 151 is rotated at a second speed for a second preset time, and then the stirring member 151 is rotated at a third speed for a third preset time; finally, the stirring member 151 is rotated at a fourth speed for a fourth preset time. The first speed, the second speed, the third speed, and the fourth speed increase in sequence.

[0092] The method provided in the embodiment of the present application sequentially controls the stirring member 151 to rotate at different rotation speeds for different preset time periods, which is beneficial for enabling the metal nanoparticles to be fully dispersed in the liquid alkali metal.

[0093] In such an embodiment, the material in the mixing container 11 can be mechanically stirred by the stirring member 151 in the following manner. When the material enters the mixing chamber 111 and waits for the alkali metal to be fully melted (for example, wait for 15 minutes), the driving member 152 is controlled to start the stirring member 151 at a speed less than 100 rpm, and after 3 minutes, the speed of the stirring member 151 is increased to 100 rpm and stably operated for 15 minutes; after stably operating for 15 minutes, the speed of the stirring member 151 is increased to 250 rpm and stably operated for 15 minutes; after stably operating for 15 minutes again, the speed of the stirring member 151 is continued to be increased to 400 rpm and continuously operated for 12. During the above stirring process, the stirring temperature can be maintained in the range of 250-300°C.

[0094] In some embodiments, step S2 further includes: heating the liquid alkali metal to a temperature range of 220-300° C. in the alkali metal storage container 17 ; and increasing the gas pressure of the alkali metal storage container 17 to inject a predetermined amount of liquid alkali metal from the alkali metal storage container 17 into the mixing container 11 .

[0095] In some embodiments, step S3 further includes: performing ultrasonic treatment on the mixed fluid to form a nanofluid.

[0096] In some embodiments, the frequency, duration and power of the ultrasonic treatment are determined according to the melting point of the metal nanoparticles and the temperature of the mixed fluid in the ultrasonic container 191. The embodiment of the present application determines the frequency, duration and power of the ultrasonic treatment according to the melting point of the metal nanoparticles and the temperature of the mixed fluid in the ultrasonic container 191, so as to prevent the ultrasound from causing a significant increase in the fluid temperature, causing the nanoparticles to melt and form an alloy with sodium, thereby causing the performance of the nanofluid to deteriorate; at the same time, it prevents the local temperature of the nanofluid from being too high, thereby causing the alkali metal to boil or flash, etc., which brings safety hazards.

[0097] In some embodiments, the melting point of the metal nanoparticles is higher than 900°C, the temperature of the mixed fluid in the ultrasonic container 191 is 220-300°C, and during the ultrasonic treatment, the ultrasonic frequency of the ultrasonic wave emitted by the ultrasonic generator 192 can be less than or equal to 20kHz, the power of the ultrasonic generator 192 can be less than or equal to 400W, and the ultrasonic time can be less than 3 minutes. Exemplarily, the ultrasonic frequency of the ultrasonic wave emitted by the ultrasonic generator 192 can be 19.5kHz, and the power of the ultrasonic generator 192 can be 400W. During the ultrasonic treatment, the heat generated by the ultrasonic wave is relatively large. By setting the ultrasonic frequency to 19.5kHz and the power to 400W, the heat generated by the ultrasonic wave can be relatively small, and the temperature of the nanofluid is also low, so as to prevent the metal nanoparticles from melting and forming an alloy with the liquid alkali metal, and at the same time prevent the local temperature of the nanofluid from being too high, so as to cause the alkali metal to boil or flash, etc., which brings safety hazards.

[0098] The preparation system and preparation method of the embodiment of the present application uniformly disperse the nanoparticles added to the liquid alkali metal in sequence through mechanical stirring and ultrasonic treatment, and the prepared nanofluid has good uniformity.

[0099] The preparation system and preparation method of the embodiments of the present application are suitable for the preparation of kilogram-level sodium-based nanofluids.

[0100] The kilogram-level sodium-based nanofluid preparation system and preparation method of the embodiment of the present application can be used to carry out various performance tests of sodium-based nanofluids in terms of suspension stability, thermal stability, etc., so as to determine the influence of different preparation processes on the performance of sodium-based nanofluids, and provide verification data for the subsequent design of the preparation process and preparation system of engineering-level sodium-based nanofluid coolants.

[0101] The method for preparing nanofluids according to the embodiments of the present application is described below in conjunction with specific embodiments.

[0102] (1) When the alkali metal storage container 17 is charged with sodium for the first time, the alkali metal storage container 17, the mixing container 11, the ultrasonic container 191 and other related equipment and connecting pipes need to be evacuated and replaced with argon. When the water and oxygen impurity contents are both lower than 50ppm, the sodium charging operation can be carried out.

[0103] (2) The alkali metal in the alkali metal storage container 17 is heated to 250°C.

[0104] (3) In a glove box, a high-precision scale is used to quantitatively weigh target transition metal element nanoparticles and a small amount of solid metallic sodium. After the solid metallic sodium is heated into a liquid, the nanoparticles are poured into the liquid sodium for mixing.

[0105] (4) The liquid sodium containing nanoparticles mixed in step (3) is introduced into a mold, and after cooling, a thin rod-shaped integral sample with a diameter of about 10 mm is formed.

[0106] (5) Add the liquid sodium prepared in step (2) into the mixing container 11 in a quantitative manner.

[0107] (6) Place the one-piece sample prefabricated in step (4) into a sealed container 13.

[0108] (7) Install the sealed container 13 containing the one-piece sample in step (6) into the first feed pipe 121.

[0109] (8) The pipeline between the sealed container 13 and the mixing container 11 is evacuated and replaced with argon. After repeating this process 4 times, the pressure of this section of the pipeline is supplemented to normal pressure.

[0110] (9) Argon gas is filled into the mixing container 11 so that the gas pressure in the mixing chamber 111 of the mixing container 11 is slightly positive, for example, less than 3 kPa.

[0111] (10) Open the first feed valve 128 and the second feed valve 129 between the sealed container 13 and the mixing container 11 in sequence, and blow the sample into the mixing container 11 by blowing air into the sealed container 13.

[0112] (11) Start the oil cooling system to cool the magnetic sealing ring position of the stirring assembly 15.

[0113] (12) After the integrated sample falls into the mixing container 11, wait for 15 minutes, then start the stirring element 151 at a low speed. After 3 minutes, increase the speed of the stirring element 151 to 100 rpm. After running stably for 15 minutes, increase the speed to 250 rpm. After running stably for another 15 minutes, increase the speed to 400 rpm again and continue running for 12 hours.

[0114] (13) Then, the stirring is stopped, and the liquid metallic sodium in the mixing container 11 is introduced into the ultrasonic container 191 by driving the argon gas pressure.

[0115] (14) The nanoparticles were dispersed secondary in the basic sodium solution for 30 min using an ultrasonic generator with an ultrasonic frequency of 19.5 kHz and a power of 400 W.

[0116] (15) The sodium-based nanofluid dispersed by ultrasonic in step (14) is transferred to the nanofluid storage container 21 again by argon driving, thereby completing the preparation of the sodium-based nanofluid.

[0117] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0118] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A nanofluid preparation system for mixing metal nanoparticles with alkali metals to form a nanofluid, characterized in that: The preparation system comprises: a mixing container, the mixing container being arranged to form a mixing chamber; a first feed pipeline, for adding metal nanoparticles into the mixing chamber; a second feed pipeline for adding liquid alkali metal into the mixing chamber; a sealed container, the sealed container being configured to form a sealed cavity for containing the metal nanoparticles, wherein the metal nanoparticles are coated by a solid alkali metal to form an integral piece with the solid alkali metal; A discharge pipeline is connected to the sealed container, and the discharge pipeline is configured to be detachably connected to the first feed pipeline. When the discharge pipeline is detached from the first feed pipeline, the sealed chamber and the mixing chamber can be sealed respectively; when the discharge pipeline is connected to the first feed pipeline, the sealed chamber can be communicated with the mixing chamber, so that the integrated part in the sealed container can enter the mixing chamber via the discharge pipeline and the first feed pipeline in sequence.

2. The preparation system according to claim 1, characterized in that: Also includes: A first feed valve, disposed on the first feed pipeline; A second feed valve, arranged on the discharge pipeline; The first vacuum and inflation pipeline is connected to the first feed pipeline or the discharge pipeline, so that when the discharge pipeline is connected to the first feed pipeline, the pipeline between the first feed valve and the second feed valve can be evacuated and filled with inert gas.

3. The preparation system according to claim 1, characterized in that: Also includes: A stirring assembly is arranged in the mixing container and is used for mechanically stirring the materials in the mixing chamber.

4. The preparation system according to claim 3, characterized in that: The mixing container includes a stirring through hole; The stirring assembly comprises: A stirring member, entering into the mixing container from the stirring through hole; A driving member, disposed outside the mixing container, for driving the stirring member to rotate; The magnetic sealing member is arranged outside the mixing container and is used for sealing between the stirring member and the stirring through hole of the mixing container.

5. The preparation system according to claim 4, characterized in that: Also includes: A cooling element is used to cool the magnetic sealing element.

6. The preparation system according to claim 1, characterized in that: Also includes: an alkali metal storage container for providing liquid alkali metal; The second vacuum and gas filling pipeline is used to evacuate the alkali metal storage container and fill it with inert gas, so as to use gas pressure to drive the liquid alkali metal from the alkali metal storage container to be injected into the mixing container via the second feed pipeline.

7. The preparation system according to claim 6, characterized in that: Also includes: A weighing device is used to weigh the alkali metal storage container and / or the mixing container so as to determine the weight of the liquid alkali metal entering the mixing container.

8. The preparation system according to claim 1, characterized in that: Also includes: The ultrasonic device is used for receiving the material from the mixing container to perform ultrasonic treatment on the material.

9. The preparation system according to claim 8, characterized in that: The ultrasonic device comprises: an ultrasonic container in fluid communication with the mixing container; The ultrasonic generator is arranged in the ultrasonic container and is used for ultrasonically treating the material in the ultrasonic container.

10. A method for preparing a nanofluid, for mixing metal nanoparticles with alkali metals to form a nanofluid, characterized in that: The preparation method uses the preparation system described in any one of claims 1 to 9 to prepare the nanofluid.

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