Abstract TiO2-water nanofluids are prepared by a two-step method, and the stabilities of nanofluids are studied by sedimentation observation method and transmittance method respectively. Related experimental system for studying the heat transfer characteristics of CPU cooled by nanofluids is established, and the reliability of the experimental system is researched. The heat transfer and flow characteristics of CPU cooled by TiO2-water nanofluids are experimentally investigated. The effects of half spherical bulges arrangement modes (aligned and staggered arrangement) on the heat transfer enhancement of CPU are discussed. It is found that the surface temperatures of CPU cooled by nanofluids with aligned arrangement and staggered arrangement can be reduced by 10.5% and 12.5% at best compared with base fluid respectively. Also, the effects of nanoparticle mass fractions (ω = 0.1%, 0.2%, 0.3%, 0.4% and 0.5%) and Reynolds numbers (Re = 98, 185, 274, 323, 365, 400, 478, and 548) on the thermo-hydraulic performances are analyzed. It is found that nanofluids with ω = 0.4% show the best heat transfer performance, and the arrangement model and nanoparticle mass fraction have little effect on the resistance coefficient at high Reynolds number (Re > 365). Lastly, the comprehensive performances of nanofluids in the CPU are investigated.

中文翻译：

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半球形凸起对TiO 2 -水纳米流体冷却CPU传热特性的影响

摘要 采用两步法制备TiO2-水纳米流体，分别采用沉降观察法和透射法研究纳米流体的稳定性。建立了研究纳米流体冷却CPU传热特性的相关实验系统，并对实验系统的可靠性进行了研究。实验研究了由TiO2-水纳米流体冷却的CPU的传热和流动特性。讨论了半球形凸起排列方式（对齐和交错排列）对CPU传热增强的影响。结果表明，与基液相比，排列排列和交错排列的纳米流体冷却的CPU表面温度分别最多可降低10.5%和12.5%。还，纳米粒子质量分数（ω = 0.1%、0.2%、0.3%、0.4% 和 0.5%）和雷诺数（Re = 98、185、274、323、365、400、478 和 548）对热力学的影响- 分析液压性能。发现ω = 0.4%的纳米流体表现出最好的传热性能，并且排列模型和纳米颗粒质量分数在高雷诺数（Re > 365）下对阻力系数的影响很小。最后，研究了纳米流体在 CPU 中的综合性能。并且排列模型和纳米颗粒质量分数对高雷诺数（Re> 365）的阻力系数影响不大。最后，研究了纳米流体在 CPU 中的综合性能。并且排列模型和纳米颗粒质量分数对高雷诺数（Re> 365）的阻力系数影响不大。最后，研究了纳米流体在 CPU 中的综合性能。