With the development of computer technology and the application of artificial intelligence, electronic chips are becoming increasingly miniaturized and integrated, leading to a rapid increase in their volumetric heating power, thus affecting their normal operation. To address this problem, a heat sink with an array of finned porous microjets was designed, and HFE-7100, which has good thermal stability and electrical insulation, was selected as the cooling medium. Through a combination of numerical simulations and experimental research, the influence of factors such as the longitudinal aspect ratio of the slotted fins, inlet subcooling, inlet volumetric flow rate, and jet Reynolds number on the heat transfer process of microjet boiling was investigated. The results showed that the optimized structure with an aspect ratio of 0.5 met the requirements of chip cooling and had a better cooling effect. In the single-phase convection heat transfer stage, under the same working condition, the inlet subcooling degree had little effect on heat transfer, and increasing the volume flow rate or jet Reynolds number could strengthen the convection heat transfer, and the maximum heat transfer coefficient could reach 15724.40 W/(m²·K). However, in the jet boiling stage, the heat flux corresponding to the onset of nucleate boiling (ONB), and it decreased with a decrease in the inlet subcooling degree. Increasing the inlet volume flow rate or jet Reynolds number inhibited the occurrence of boiling, thus weakening the heat transfer. However, compared with the single-phase convective heat transfer stage, the heat transfer coefficient increased by 20.6%.

During the working process of concentrated solar cells, most of the light energy is converted into heat energy, which leads to increase in device temperature, shortening in life and decrease in photoelectric conversion efficiency. Therefore, it is necessary to develop efficient cooling devices to effectively dissipate the heat to keep sufficiently low temperature of the solar cells. Jet cooling technology has the characteristics of high heat transfer coefficient and uniform distribution of temperature. Perfect cooling performance of microjet cooler can be obtained when using nanofluid as the cooling medium. Silicon carbide nanofluids were prepared by using dispersion method, while a heat sink coupled with impingent jet and microchannel structure was designed in this work. The heat transfer and flow characteristics of the heat sink with silicon carbide nanofluids and water as cooling medium were studied numerically. It is observed that the concentrating solar cell can work efficiently and stably after shinning concentrating light for 1800 times, when the silicon carbide nanofluid was employed as cooling medium. Compared with water, the silicon carbide nanofluid can reduce the surface temperature by 7 ℃ and increase the heat transfer coefficient by 12.2%. The numerical results provide a reliable theoretical basis and data support for the further study of microjet cooler.

The heat generated during the operation of concentrated solar cells has negative impact on them. As a necessary component in the working process of concentrated solar cells, heat dissipation devices play an important role in ensuring the long-term safe, stable, and efficient operation of solar cells under concentrated conditions. The use of nanofluids for cooling is an effective way. A micro jet coupled micro rib channel heat sink was constructed in this work, with nanofluid as the cooling medium. Turbulent heat transfer and flow characteristics of the heat sink were studied using a combination of numerical simulation and experimental research methods. Through numerical simulation, the cooling effects of SiC, Al₂O₃, SiO₂, TiO₂ nanofluids and water as cooling media were compared and discussed. Finally, the SiC-W nanofluid with the optimal cooling performance was selected for the experiment. It is experimentally shown that the SiC-W nanofluids have the several advantages as compared with water, with an increase in thermal conductivity of about 10.2%, an increase in average heat transfer coefficient of about 6.7% and an increase in pressure loss of no more than 1% of water. This study demonstrates the superior heat transfer performance and application value of the SiC-W nanofluids.