Optimization of Dynamic Wetting and Heat Transfer in High-Power Electronics Cooling: Influence of Impact Parameters, Wettability Distribution and Power input

In the pursuit of high-power electronics, effective solutions for thermal management play a crucial role in the performance and lifespan of devices. Droplet train cooling (directing a series of droplets sequentially onto a heated surface) is one way to remove the heat from powerful electronic devices. This cooling technique harnesses the principles of phase-change heat transfer, and has the capacity to handle high heat fluxes. Here, we investigate how the effectiveness of droplet train cooling of heated surfaces can be augmented by using wettability-patterned surfaces. The target surface has superhydrophilic (SHPL) islands laid as a regular array in a superhydrophobic background (SHPB). This configuration serves a dual purpose, preventing flooding (a problem associated with drop train impact on superhydrophilic surfaces) while ensuring efficient evaporative cooling. In the present work, we investigate the effect of droplet train parameters, such as the flow rate and Weber number on the cooling efficiency, which naturally increases with rising flow rate of the cooling fluid (water). We also study the effect of wettability on the cooling efficiency by varying the SHPL island diameter and pitch. The cooling efficiency increases with SHPL island diameter due to more solid-liquid contact area and with increasing pitch due to quicker drainage of the pooled water from the surface. Furthermore, we optimize the design of the wettability-patterned surface and achieve a high cooling efficiency. The current work advances our knowledge of liquid impingement cooling for wettability-modified surfaces with the potential to improve the cooling performance of power electronic devices.