Enhanced boiling heat transfer with copper oxide hierarchical surfaces

We experimentally investigated the enhancement in critical heat flux (CHF) during pool boiling on copper oxide (CuO) hierarchical surfaces, where surface roughness at multiple length scales is presented. On the surface with the highest surface roughness factor of 13.3, a CHF of ≈250 W/cm² and heat transfer coefficient of ≈8×10⁴ W/m² K, were achieved. A good agreement between our developed model and experimental results supports the idea that roughness-amplified surface forces are responsible for CHF enhancement on structured surfaces. The work promises enhanced heat removal capability using hierarchically-structured surfaces for high heat flux thermal management.