Krishnamurthy S, Bhattacharya P, Phelan P E, Prasher R S
Department of Mechanical & Aerospace Engineering, Arizona State University, Building ECG, Room 346, Tempe, 85287-6106, USA.
Nano Lett. 2006 Mar;6(3):419-23. doi: 10.1021/nl0522532.
Thermal conductivity enhancement in nanofluids, which are liquids containing suspended nanoparticles, has been attributed to localized convection arising from the nanoparticles' Brownian motion. Because convection and mass transfer are similar processes, the objective here is to visualize dye diffusion in nanofluids. It is observed that dye diffuses faster in nanofluids compared to that in water, with a peak enhancement at a nanoparticle volume fraction, phi, of 0.5%. A possible change in the slope of thermal conductivity enhancement at that same phi signifies that convection becomes less important at higher phi. The enhanced mass transfer in nanofluids can be utilized to improve diffusion in microfluidic devices.
纳米流体（即含有悬浮纳米颗粒的液体）的热导率增强归因于纳米颗粒布朗运动引起的局部对流。由于对流和传质是相似的过程，此处的目标是观察染料在纳米流体中的扩散情况。据观察，与在水中相比，染料在纳米流体中的扩散速度更快，在纳米颗粒体积分数φ为0.5%时增强效果达到峰值。在相同的φ下，热导率增强斜率的可能变化表明，在较高的φ下对流变得不那么重要。纳米流体中增强的传质可用于改善微流控设备中的扩散。
