Optimization and comparison of double-layer and double-side micro-channel heat sinks with nanofluid for power electronics cooling

The tendency of increasing power rating and shrinking size of power electronics systems requires advanced thermal management technology. Introduction of micro-channel heat sink into power electronics cooling has significantly improved the cooling performance. In present work, two advanced micro-channel structures, i.e. double-layer (DL) and double-side (sandwich) with water as coolant, are optimized and compared by computational fluid dynamics (CFD) study. The micro-channels are integrated inside the Cu-layer of direct bond copper (DBC). The effects of inlet velocity, inlet temperature, heat flux are investigated during geometry optimization. The major scaling effects including temperature-dependent fluid properties and entrance effect are considered. Based on the optimal geometry, the sandwich structure with counter flow shows a reduction in thermal resistance by 59%, 52% and 53% compared with single-layer (SL), DL with unidirectional flow and DL with counter flow respectively. Water based Al2O3 (with concentration of 1% and 5%) nanofluid is further applied which shows remarkable improvement for wide channels.