Murshed S M Sohel, de Castro C A Nieto
Centro de Ciências Moleculares e Materiais, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
J Nanosci Nanotechnol. 2011 Apr;11(4):3427-33. doi: 10.1166/jnn.2011.3745.
This paper reports an experimental investigation on the spreading characteristics of nanofluid droplets impinging on aluminum substrate under the influence of several key factors such as nanoparticle volume fraction, substrate temperature, and the Weber number. Sample nanofluid used is prepared by dispersing several volumetric concentrations (1 to 5%) of titanium dioxide nanoparticles in ethylene glycol. The entire dynamic process of each droplet collision with the substrate surface and the spreading phenomena is captured by using a high speed camera and then the transient spreading diameter and height of droplet are determined. It is found that the higher the concentration of nanoparticles the larger the spreading diameter of nanofluid droplet. As the surface temperature increases, the overall spreading diameter and height of nanofluid droplet significantly decreases and increases, respectively. At larger Weber number, the final spreading of the nanofluid droplet is also found to be larger than that of lower Weber number. Present results demonstrate that spreading characteristics of nanofluid droplets impacting onto solid surface are greatly influenced by each of the aforementioned factors.
本文报道了一项关于纳米流体液滴在纳米颗粒体积分数、基底温度和韦伯数等几个关键因素影响下撞击铝基底时的铺展特性的实验研究。所使用的样品纳米流体是通过将几种体积浓度（1%至5%）的二氧化钛纳米颗粒分散在乙二醇中制备而成的。利用高速摄像机捕捉每个液滴与基底表面碰撞的整个动态过程以及铺展现象，然后确定液滴的瞬态铺展直径和高度。研究发现，纳米颗粒浓度越高，纳米流体液滴的铺展直径越大。随着表面温度升高，纳米流体液滴的整体铺展直径显著减小，而高度则分别显著增大。在较大的韦伯数下，还发现纳米流体液滴的最终铺展比韦伯数较低时更大。目前的结果表明，上述每个因素都对纳米流体液滴撞击固体表面时的铺展特性有很大影响。
