Bubble growth dynamics on different fin structures during nucleate boiling

Enhancing the magnitude of heat transfer is critical for improving thermal management in high-performance applications. This study experimentally investigates the effects of different fin structures—simple, coated, dimpled, and holed—on boiling heat transfer performance under varying subcooling conditions. Boiling curves indicate that fins with artificial nucleation sites significantly enhance heat transfer, reducing wall temperatures at the same heat flux. The fin with a hole exhibits the best performance, shifting the boiling curve to lower temperatures by approximately 5 °C. Bubble departure frequency increases with wall temperature, with the holed fin showing the highest departure rate due to its increased surface area and nucleation sites. Bubble growth rate analysis reveals rapid initial growth followed by a slower mass transfer-driven phase, with the holed fin facilitating the fastest growth. Bubble departure diameter increases with wall temperature and decreases with subcooling, with the holed fin producing the largest bubbles. Contact angle measurements show that wettability improves as liquid temperature increases, reducing surface tension and facilitating vapor removal. Overall, the holed fin demonstrates the most effective boiling characteristics, making it an optimal design for enhanced heat transfer applications. These findings provide valuable insights into surface engineering strategies for improving boiling efficiency in industrial and engineering applications.