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

Abstract

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.