Université de Neuchâtel, Institut de Physique, Laboratoire de chimie physique des surfaces, Rue Emile-Argand 11, 2009-Neuchâtel, Switzerland.
Langmuir. 2010 Jan 19;26(2):663-70. doi: 10.1021/la9022757.
Nanofluids (colloidal suspensions of nanoparticles) have been reported to display significantly enhanced thermal conductivities relative to those of conventional heat transfer fluids, also at low concentrations well below 1% per volume (Putnam, S. A., et at. J. Appl. Phys. 2006, 99, 084308; Liu, M.-S. L., et al. Int. J. Heat Mass Transfer. 2006, 49; Patel, H. E., et al. Appl. Phys. Lett. 2003, 83, 2931-2933). The purpose of this paper is to evaluate the effect of the particle size, concentration, stabilization method and particle clustering on the thermal conductivity of gold nanofluids. We synthesized spherical gold nanoparticles of different size (from 2 to 45 nm) and prepared stable gold colloids in the range of volume fraction of 0.00025-1%. The colloids were inspected by UV-visible spectroscopy, transmission electron microscope (TEM) and dynamic light scattering (DLS). The thermal conductivity has been measured by the transient hot-wire method (THW) and the steady state parallel plate method (GAP method). Despite a significant search in parameter space no significant anomalous enhancement of thermal conductivity was observed. The highest enhancement in thermal conductivity is 1.4% for 40 nm sized gold particles stabilized by EGMUDE (triethyleneglycolmono-11-mercaptoundecylether) and suspended in water with a particle-concentration of 0.11 vol%.
纳米流体（纳米粒子的胶体悬浮液）被报道显示出比传统传热流体显著增强的热导率，即使在低于 1%体积浓度的情况下也是如此（Putnam，S. A.等人，J. Appl. Phys. 2006，99，084308；Liu，M.-S. L.等人，Int. J. Heat Mass Transfer. 2006，49；Patel，H. E.等人，Appl. Phys. Lett. 2003，83，2931-2933）。本文旨在评估粒径、浓度、稳定化方法和颗粒团聚对金纳米流体热导率的影响。我们合成了不同尺寸（2-45nm）的球形金纳米粒子，并制备了体积分数在 0.00025-1%范围内的稳定金胶体。通过紫外-可见光谱、透射电子显微镜（TEM）和动态光散射（DLS）对胶体进行了检查。通过瞬态热线法（THW）和稳态平行板法（GAP 法）测量了热导率。尽管在参数空间中进行了大量搜索，但没有观察到热导率的显著异常增强。热导率的最高增强是 40nm 尺寸的金颗粒在 EGMUDE（三甘醇单-11-巯基十一烷醚）稳定下的增强，悬浮在水中的颗粒浓度为 0.11 体积%，增强了 1.4%。
