Experimental research on cooling performances of radial expanding-channeled heat sinks applied for multiple heat sources

Intrinsic two-phase flow instability using multiple parallel boiling channels hinders the actual implementation of flow boiling cooling techniques in high heat flux and multiple heat source applications. Recently, we proposed a radial expanding-channeled heat sink (ECHS) to realize a high two-phase flow stability under extreme conditions. In the present work, the cooling performances of two heat sinks connected in series or in parallel were investigated with the heat load adjusted individually. The results indicated that when two ECHS were connected in parallel, the inlet flowrate was evenly distributed into the two heat sinks, and their heat transfer performance was identical. At a sudden change in the heat load of one path, the flowrate of the other heat sink may change by 10% to 30% without inducing flow instability or heat deterioration. The thermal resistance for both heat sinks was lower than 0.025 °C/W, and no instability or dry-out was observed as long as the initial flowrate was larger than 0.28 kg/min. With the proposed ECHS, multiple heat sources such as central processing unit, server, rack, etc. can be connected in series or in parallel to construct an integrated cooling system for large-scale data center applications.