High-Performance Microchannel Flow Boiling Enhanced by Dual-Bionic Micro/Nano-Structures.

Microchannel flow boiling has emerged as a highly promising electronic cooling technology. However, its practical application is suffering from the lack of effective control over bubble dynamics, especially bubble departure processes. Here, we have proposed a dual-bionic micro/nano-structured surface to mediate bubble departure for enhancement of flow boiling performance in microchannels, drawing inspiration from the micro-ratchets on the peristome surface of Nepenthes alata and the wedge-like beak of a phalarope. The microchannel heat sink with bionic micro/nano-structures demonstrates significant improvement in thermo-hydrodynamic performance, and achieves the critical heat flux of 366.5 W·cm-2 and heat transfer coefficient of 11.8 W·cm-2·K-1 at 600 kg·m-2·s-1, indicating respective increase of 82.5% and 103.2% compared to its smooth counterpart. This gain stems from a dual mechanism that the bionic architecture first enables spontaneous migration of nucleated bubbles from the micro-ratchet root to the tip under an interfacial energy gradient, and subsequently promotes bubble departure from the ratchet tip through the net force of buoyancy and drag. The present strategy exhibits superior cooling capacity over conventional air/water-based methods in dissipating heat from a commercial CPU under full power. The present dual-bionic design holds great potential for addressing the demanding cooling requirements of high-power electronics.