Molecular Dynamics Study of Boiling and Bubble Nucleation Under Varying Heat Flux and External Forces in Hydrophobic/Hydrophilic Microchannels

This study explores the boiling phenomena of saturated and subcooled water in grooved microchannels using molecular dynamics simulations, focusing on the effects of microchannel material properties and external forces. This study includes two parts. The first part examines slotted grooved microchannels with hydrophilic (iron) and hydrophobic (aluminum) surfaces. Results reveal that aluminum microchannels significantly enhance boiling efficiency, reducing boiling time to 6.21 ns and increasing maximum temperature and velocity to 411 K and 0.00216 Å/fs, respectively, compared to iron. The hydrophobic surface promotes bubble nucleation and improves heat transfer. The second part evaluates the impact of external forces (0.001, 0.002, 0.003, and 0.005 kcal/mol·Å) on boiling dynamics. Increasing the force reduces maximum density to 0.0188 atoms/ų while raising velocity and temperature to 0.00280 Å/fs and 451 K. The center-of-mass displacement increases to 57.1 Å, and Gibbs free-energy decreases to 1.76 kcal/mol, accelerating boiling time to 6.63 ns at the highest force. These findings highlight the crucial roles of hydrophobic surfaces and external forces in optimizing boiling efficiency. The results offer valuable insights for enhancing heat transfer processes in microfluidic systems and developing advanced thermal management technologies.