Experimental Study of the Periodical Electric Field-Enhancing Nanofluid Droplet Evaporation Characteristics on an...

The control and enhancement of droplet evaporation on inclined surfaces are pivotal for industrial thermal processes, including spray cooling and emission control. While substrate inclination is known to enhance the evaporation of a deionized water droplet, its synergistic interplay with two established enhancement techniques, applying external electric fields and doping with nanoparticles, introduces a new regime of droplet dynamics that remains unresolved, hindering optimization. This study systematically decouples the individual and synergistic effects of Al₂O₃/SiO₂ nanoparticles, substrate inclination (0-30°), and electric fields on droplet evaporation dynamics. The results indicate that the electric field can enhance droplet evaporation with a maximum rate of up to 22.7%, while nanoparticles can achieve a peak enhancement rate of 20.8%. The combined application of inclination, an electric field, and nanoparticles achieves a maximum reduction in evaporation time of 40.7%. This synergy also critically alters the characteristic relationship between evaporation time and inclination, exemplified by the elimination of the time peak observed at 10° inclination under individual influences. Critically, the governing evaporation mechanisms on inclined surfaces differ fundamentally from horizontal ones when these enhancements are applied. These findings demonstrate that horizontal surface models cannot be directly extrapolated, thus offering novel insights for designing droplet-based systems on inclined surfaces.