Enhancement of pool-boiling heat transfer using nanostructured surfaces on aluminum and copper

Enhanced pool-boiling critical heat fluxes (CHF) at reduced wall superheat on nanostructured substrates are reported. Nanostructured surfaces were realized using a low temperature process, microreactor-assisted-nanomaterial-deposition. Using this technique we deposited ZnO nanostructures on Al and Cu substrates. We observed pool-boiling CHF of 82.5 W/cm2 with water as fluid for ZnO on Al versus a CHF of 23.2 W/cm2 on bare Al surface with a wall superheat reduction of 25–38 °C. These CHF values on ZnO surfaces correspond to a heat transfer coefficient of ∼23,000 W/m2 K. We discuss our data and compare the behavior with conventional boiling theory.