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CN-122012033-A - Preparation method of microfluidic phase-change cooling liquid

CN122012033ACN 122012033 ACN122012033 ACN 122012033ACN-122012033-A

Abstract

The invention discloses a preparation method of microfluidic phase-change cooling liquid, and belongs to the technical field of advanced thermal management material preparation. According to the method, a specific microfluidic flow and functional fluid are designed, and molten phase change material fluid, shell fluid containing curable resin and heat conducting filler and cooling base fluid which is insoluble in a shell are pumped into a microfluidic chip respectively. In the chip flow channel, the shell fluid is wrapped with the phase change material fluid in situ by virtue of the action of hydrodynamic force and interfacial tension, so that monodisperse core-shell liquid drops are formed and dispersed in the base liquid. And then leading the liquid drops to pass through a solidification area to solidify the shell layer in the flowing process, and directly obtaining a suspension system of the phase-change microcapsule dispersed in the base liquid. The invention realizes the accurate control of the size of the phase-change microcapsule and the thickness of the shell layer, and provides a continuous, efficient and structurally controllable phase-change cooling liquid preparation method.

Inventors

  • ZHOU YUZHI
  • XUE FEI
  • FU CHONG
  • GUAN YOUZHI
  • LI JIALIANG
  • Qi Junhan

Assignees

  • 盛忆镐科技(江苏)有限公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (10)

  1. 1. The preparation method of the microfluidic phase-change cooling liquid is characterized by comprising the following steps of: S1, providing a molten phase change material fluid as a nuclear phase fluid; s2, providing a mixed fluid containing a curable resin and a heat-conducting filler as a shell fluid, wherein the curable resin is photo-curing or thermosetting; s3, providing a cooling liquid which is not compatible with the shell fluid as a continuous phase fluid; s4, respectively and simultaneously introducing the core-phase fluid, the shell-layer fluid and the continuous-phase fluid into a micro-fluidic chip at controllable flow rates Vc, vs and Vf, wherein the flow rates Vc, vs and Vf are mutually independent and adjustable and are used for controlling the size of core-shell liquid drops so that the shell-layer fluid wraps the core-phase fluid to form core-shell liquid drops and is dispersed in the continuous-phase fluid; S5, guiding the fluid containing the core-shell liquid drops to pass through a solidification zone so as to solidify the shell fluid; s6, collecting the suspension containing the solidified phase-change microcapsules flowing out of the solidification area.
  2. 2. The method for preparing a microfluidic phase-change coolant according to claim 1, wherein the step S1 comprises heating and melting an organic material having a phase change temperature of 30 ℃ to 60 ℃ and maintaining the temperature at 10 ℃ to 40 ℃ above the phase change temperature, or adding surface-treated heat-conductive particles having an average particle diameter of 10nm to 200nm and dispersing while maintaining the molten state.
  3. 3. The method for preparing a microfluidic phase-change cooling liquid according to claim 2, wherein the surface-treated heat-conducting particles have a surface treating agent of a silane coupling agent having a C8-C18 alkyl chain, and the treating agent is used in an amount of 0.5% to 3% of the mass of the heat-conducting particles.
  4. 4. The method for preparing a microfluidic phase-change coolant according to claim 1, wherein the step S2 comprises mixing the curable resin with a plate-shaped heat conductive filler having a ratio of radius to thickness of more than 50, which is 5% to 35% by mass of the mixed fluid, followed by defoaming and homogenizing treatment.
  5. 5. The method for preparing a microfluidic phase-change cooling liquid according to claim 1, wherein in the step S4, the flow channel of the microfluidic chip is a flow focusing structure; The flow rates Vc, vs and Vf are 1 mu L/min-Vc-15 mu L/min,2 mu L/min-Vs-50 mu L/min and 50 mu L/min-Vf-800 mu L/min.
  6. 6. The method of preparing a microfluidic phase change coolant according to claim 5, wherein the step S4 is performed while maintaining a constant temperature of a path through which the core phase fluid flows, the constant temperature being 15 ℃ or higher than a phase change temperature of a phase change material in the core phase fluid.
  7. 7. The preparation method of the microfluidic phase-change cooling liquid according to claim 1, wherein in the step S5, the solidification area is a tubular runner connected with an outlet of the microfluidic chip, when the photo-solidification resin is used, an ultraviolet light source with a wavelength of 355nm to 405nm and a light intensity of 10mW/cm2 to 200mW/cm2 is adopted to uniformly irradiate along the length direction of the tubular runner, and when the thermosetting resin is used, the tubular runner is placed in a constant temperature environment of 60 ℃ to 120 ℃.
  8. 8. The method of preparing a microfluidic phase change coolant according to claim 7, wherein in the step S5, a residence time of the core-shell droplets in the solidification zone is controlled to be between 30 seconds and 300 seconds by adjusting a total flow rate of the fluid.
  9. 9. The method for preparing a microfluidic phase-change cooling liquid according to claim 1, wherein the step S6 is followed by the step S7 of adding a dispersant to the collected suspension and stirring at a low speed, wherein the dispersant is polyether-modified silicone oil or a block copolymer, the addition amount of the dispersant is 0.01 to 0.5% of the total mass of the suspension, and the rotation speed of the low-speed stirring is 50 to 300rpm, and the time is 10 to 60 minutes.
  10. 10. The method of preparing a microfluidic phase change coolant according to claim 9, wherein the step S7 is followed by a step S8 of measuring the mass concentration of the phase change microcapsules in the suspension and adjusting the final mass concentration thereof to a target range of 2% to 12% by supplementing the continuous phase fluid.

Description

Preparation method of microfluidic phase-change cooling liquid Technical Field The invention relates to the technical field of advanced thermal management material preparation, in particular to a preparation method of microfluidic phase-change cooling liquid. Background With the continuous increase of power density of electronic devices, especially the rapid increase of power demand of data center servers, efficient heat dissipation technology is becoming critical. Traditional air-cooled heat dissipation approaches the heat dissipation limit of the air-cooled heat dissipation device gradually, and liquid cooling technology, particularly phase-change liquid cooling technology which utilizes phase-change latent heat for heat exchange, is widely focused due to higher heat dissipation efficiency. The core of the phase change cooling liquid is that a Phase Change Material (PCM) is dispersed in a stable form in a cooling base liquid, and phase change occurs in an operating temperature range to absorb a large amount of heat. The existing phase-change cooling liquid preparation technology mainly comprises two representative methods, but has certain limitations. The first method is to directly and physically blend solid-solid or solid-liquid phase materials, heat conductive particles and liquid base liquid (for example, the scheme disclosed in chinese patent CN115181550 a). The method has simple process, but the phase change material is in direct contact with the cooling liquid, and under the long-term thermal cycle and fluid shearing action, the problems of leakage, particle agglomeration or poor compatibility with the base liquid and the like of the phase change material are easy to occur, so that the long-term reliability and stability of a cooling system are affected. The second method is to encapsulate the phase change material into microcapsules in advance and then disperse the microcapsules in a base liquid (for example, the scheme disclosed in chinese patent CN118834666 a). Although the encapsulation stability is improved to a certain extent by the method, the preparation of the microcapsule is generally dependent on batch processing technologies such as emulsification, coating, crushing, screening and the like on a macroscopic scale. These processes have difficulty in precisely controlling the size distribution, shell thickness, and structural integrity of the microcapsules, resulting in poor product batch consistency. Meanwhile, the complex multi-step post-treatment process makes the process flow complicated, the energy consumption is higher, and continuous and large-scale production is not easy to realize; therefore, a preparation method of the microfluidic phase-change cooling liquid is provided for solving the problems. Disclosure of Invention In order to overcome the defects in the prior art, the embodiment of the invention provides a preparation method of a microfluidic phase-change cooling liquid, which aims to solve the defects that a phase-change material is easy to leak, the size and the structure of a microcapsule are uncontrollable, the preparation process is complex and discontinuous and the like in the existing phase-change cooling liquid preparation technology. In order to achieve the purpose, the invention provides the following technical scheme that the preparation method of the microfluidic phase-change cooling liquid comprises the following steps: S1, providing a molten phase change material fluid as a nuclear phase fluid, and providing phase change latent heat for a cooling liquid; s2, providing a mixed fluid containing curable resin and a heat-conducting filler as a shell fluid, wherein the curable resin is photo-curing or thermosetting and is used for packaging the nuclear phase fluid and forming a heat-conducting passage; S3, providing a cooling liquid which is not compatible with the shell fluid as a continuous phase fluid and is used as a dispersion medium and a heat transfer working medium; S4, respectively and simultaneously introducing the core-phase fluid, the shell-layer fluid and the continuous-phase fluid into a micro-fluidic chip at controllable flow rates Vc, vs and Vf, wherein the flow rates Vc, vs and Vf are mutually independent and adjustable, and the shell-layer fluid wraps the core-phase fluid to form monodisperse core-shell liquid drops and is dispersed in the continuous-phase fluid by regulating fluid power and interfacial tension; S5, guiding the fluid containing the core-shell liquid drops to pass through a solidification zone, so that the shell fluid undergoes solidification reaction in the flowing process to form a solid shell with complete structure; S6, collecting suspension containing solidified phase-change microcapsules flowing out of the solidification area to serve as the phase-change cooling liquid. Further, the step S1 comprises heating and melting the organic material with the phase change temperature of 30-60 ℃ which is suitable for the heat dissipatio