Spreading-splashing transition of nanofluid droplets on a smooth flat surface

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:606

Article

Aksoy, Y. T.¹  Eneren, P.¹  Koos, E.²  Vetrano, M. R.¹ 

[1] Katholieke Univ Leuven, Dept Mech Engn, Div Appl Mech & Energy Convers TME, B-3001 Leuven, Belgium

[2] Katholieke Univ Leuven, Dept Chem Engn, Soft Matter Rheol & Technol SMaRT, B-3001 Leuven, Belgium

关键词: Droplet splashing;    Nanofluid splashing;    Lamella spreading velocity;    Droplet impact;    Nanofluid viscosity;   

DOI  :  10.1016/j.jcis.2021.07.157

来源: Elsevier

【 摘 要 】

Hypothesis: Even a small fraction of nanoparticles in fluids affects the splashing behavior of a droplet upon impact on a smooth surface. Experiments: Nanofluid drop impact onto a smooth sapphire substrate is experimentally investigated over wide ranges of Reynolds (10(2) < Re < 10(4)) and Weber (50 < We < 500) numbers for three nanofluid mass concentrations (0.01%, 0.1%, 1%) using high-speed photography. Nanofluids are prepared by diluting a commercial Al2O3-water nanofluid in aqueous glycerol solutions without dispersants. In total, 30 samples are prepared and 1799 data points are acquired. Every sample is experimentally characterized prior to droplet impact measurements in terms of stability, density, viscosity, and surface tension to demonstrate the observed outcomes on the We-Re maps. Each droplet impact condition is repeated at least 3 times to ensure good repeatability. Findings: The non-monotonic behavior of the spreading-to-splashing transition remains the same for nanofluids. However, nanofluids influence this boundary by promoting splashing at low Reynolds numbers. We explain this behavior by increased lamella spreading speed and lift during the lamella spreading stage. Finally, we develop an empirical correlation which describes the splashing threshold dependency on nanoparticle concentration for the first time. (C) 2021 Elsevier Inc. All rights reserved.

【 授权许可】

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