Abstract Droplet evaporation offers high heat rejection rates and is widely used in the form of spray cooling or dropwise cooling of various heat dissipating devices. However, due to the limiting heat flux removal capacity of conventional fluids, such as water, these cannot be used in thermal management of high heat flux devices. In this research, the evaporation of silver (Ag)-graphene (GNP) hybrid nanofluid droplet and its residue effects on the evaporation of following Ag-GNP hybrid nanofluid droplet, due to its synergistic thermal properties, is experimentally investigated for various mixing ratios, from MR-1 (0.1(Ag):0.9(GNP)) to MR-5 (0.9(Ag):0.1(GNP)), and different residue sizes. A theoretical model is also proposed for hybrid nanofluid droplet evaporation and semi-empirical relations are developed to estimate the hybrid nanofluid droplet spreading over its residue surface. The results show a substantial increase in the droplet evaporation rate with increasing residue size and decreasing mixing ratio. MR-1 hybrid nanofluid droplet gives the highest evaporation rate (up to 370%) on its highly wetted residue surface, while the evaporation rate significantly drops moving from MR-2 to MR-5 hybrid nanofluid droplets on their partially wetted residue surfaces. Moreover, the evaporation rate substantially increases (up to 240%) with increasing residue size for MR-1 hybrid nanofluid droplet resting on its residue surface, however, the effect of residue size on droplet evaporation rate considerably diminishes moving from MR-2 to MR-5 hybrid nanofluid droplets resting on their respective residues.

中文翻译：

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不同混合比下银-石墨烯杂化纳米流体液滴在其多孔残留物表面的蒸发和润湿行为

摘要 液滴蒸发具有较高的排热率，广泛用于各种散热装置的喷雾冷却或滴状冷却。然而，由于传统流体（例如水）的热通量去除能力有限，因此这些流体不能用于高热通量设备的热管理。在这项研究中，银（Ag）-石墨烯（GNP）杂化纳米流体液滴的蒸发及其对后续Ag-GNP杂化纳米流体液滴蒸发的残留影响，由于其协同热性能，在各种混合比例下进行了实验研究，从 MR-1 (0.1(Ag):0.9(GNP)) 到 MR-5 (0.9(Ag):0.1(GNP))，以及不同的残基大小。还提出了混合纳米流体液滴蒸发的理论模型，并开发了半经验关系来估计混合纳米流体液滴在其残留物表面上的扩散。结果表明，随着残留物尺寸的增加和混合比的降低，液滴蒸发率显着增加。MR-1 混合纳米流体液滴在其高度润湿的残留物表面上提供最高的蒸发率（高达 370%），而蒸发率在其部分润湿的残留物表面上从 MR-2 移动到 MR-5 混合纳米流体液滴时显着下降。此外，随着停留在其残留物表面的 MR-1 混合纳米流体液滴的残留物尺寸增加，蒸发率显着增加（高达 240%），然而，