Lattice Boltzmann modeling and analysis of electric field-enhanced nanofluid evaporation and vapor release via bubble–particle dynamics

Nanofluids, which exhibit strong solar absorption and high photothermal conversion efficiency, can significantly improve the performance of solar steam generation. Applying an electric field is expected to further enhance evaporation. Although experimental studies have demonstrated the enhancement effect of electric fields, the underlying mechanisms governing electric field-assisted nanofluid steam generation remain insufficiently understood. In particular, how electric fields regulate particle motion and vapor release has not been fully elucidated. In this study, a lattice Boltzmann model for nanofluid evaporation under an electric field is developed, revealing the electric field-driven bubble nucleation and coalescence, as well as the upward migration of bubble–particle complexes followed by vapor release. The results demonstrate that the electric field accelerates bubble nucleation, coalescence, and ascent, thereby increasing the bubble release frequency. Meanwhile, an electric field lowers the nucleation energy barrier on nanoparticle surfaces and increases the number of effective nucleation sites, enabling bubbles to form rapidly in the early stages and detach promptly. Specifically, as the electric potential increases from 0 to 0.1, the bubble detachment diameter decreases by 18.5%, the rise velocity increases by 231.1%, and the bubble coalescence rate increases by 27.9%. Collectively, these effects enhance steam generation from the nanofluid. These findings provide a theoretical basis for designing and optimizing solar steam generation systems.