Enhancement of thermal conductivity in water-based nanofluids employing TiO2/reduced graphene oxide composites
Enhancement of thermal conductivity in water-based nanofluids employing TiO2/reduced graphene oxide composites
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DOI：
10.1007/s10853-016-0239-3
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发表时间：
2016-07
影响因子：
4.5
通讯作者：
Shanxing Wang;Yunyong Li;Haiyan Zhang;Yingxi Lin;Zhenghui Li;Wenguang Wang;Qibai Wu;Yannan Qian;H. Hong;C. Zhi
中科院分区：
文献类型：
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作者：
Shanxing Wang;Yunyong Li;Haiyan Zhang;Yingxi Lin;Zhenghui Li;Wenguang Wang;Qibai Wu;Yannan Qian;H. Hong;C. Zhi
在这项研究中，通过简单的合成方法，即TiCl4的原位水解，然后固定在还原氧化石墨烯的表面上，制备了由沉积在还原氧化石墨烯表面的分散良好的TiO2纳米粒子（设计为TiO2-G）组成的复合材料。在不添加表面活性剂的条件下，通过超声探头制备了纳米粒子负载量分别为 0.02、0.03、0.05、0.07 和 0.1 wt% 的 TiO2-G/水纳米流体。此外，通过不同的实验方法分析了TiO2-G/水纳米流体的稳定性、zeta电位和热导率。当纳米颗粒负载量为0.02 wt%（0.015 vol%）和0.05 wt%（0.038 vol%）时，TiO2-G/水纳米流体的zeta电位值可分别达到-46.49和-37.44 mV，表现出良好的稳定性。与基液相比，TiO2-G/水纳米流体的导热系数随着TiO2-G复合材料负载量和纳米流体温度的增加而增加，在复合浓度为0.1 wt%（0.078 vol%）时达到最大~33%的增强。因此，TiO2-G/水纳米流体可应用于换热器系统，因为它们具有良好的长期分散稳定性和显着的导热性增强。
In this study, composites consisting of well-dispersed TiO2nanoparticles deposited on the surface of reduced graphene oxide (designed as TiO2-G) were fabricated via a facile synthesis method, namely in situ hydrolysis of TiCl4and subsequently immobilization on the surface of reduced graphene oxide. TiO2-G/water nanofluids with the nanoparticles loading of 0.02, 0.03, 0.05, 0.07, and 0.1 wt% were prepared by ultrasonic probe in the condition without the addition of surfactants. Furthermore, the stability, zeta potential, and thermal conductivity of the TiO2-G/water nanofluids were analyzed by using different experimental methods. With the nanoparticles loading of 0.02 wt% (0.015 vol%) and 0.05 wt% (0.038 vol%), the zeta potential value of TiO2-G/water nanofluids can reach up to −46.49 and −37.44 mV, respectively, exhibiting great stability. Compared to that of the base fluid, the thermal conductivity of TiO2-G/water nanofluids increased with the increase of the loading of TiO2-G composite and the temperature of the nanofluids, and reached a maximum enhancement of ~33 % at a composite concentration of 0.1 wt% (0.078 vol%). Therefore, TiO2-G/water nanofluids can be applied to heat exchanger systems, as they provide a good long-time dispersion stability and a significant thermal conductivity enhancement.