Header Shape Effect on the Inlet Velocity Distribution in Cross-Flow Double-Layered Microchannel Heat Sinks

Stefano Savino,Carlo Nonino

doi:10.3390/fluids7010007

Abstract

Counter-flow double-layered microchannel heat sinks are very effective for thermal control of electronic components; however, they require rather complicated headers and flow maldistribution can also play a negative role. The cross-flow configuration allows a much simpler header design and the thermal performance becomes similar to that provided by the counter-flow arrangement if the velocity distribution in the microchannels is not uniform. The aim of this work is to show the possibility of achieving a favorable flow distribution in the microchannels of a cross-flow double-layered heat sink with an adequate header design and the aid of additional elements such as full or partial height baffles made of solid or porous materials. Turbulent RANS numerical simulations of the flow field in headers are carried out with the commercial code ANSYS Fluent. The flow in the microchannel layers is modeled as that in a porous material, whose properties are derived from pressure drop data obtained using an in-house FEM code. It is demonstrated that, with an appropriate baffle selection, inlet headers of cross-flow microchannel heat sinks yield velocity distributions very close to those that would allow optimal hotspot management in electronic devices.

Highlights

Velocity Distribution in Cross-FlowThe increasing performance of electronic components requires the dissipation of increasing amounts of heat generated and, the adoption of more and more efficient, but still small, cooling systems
The objective of this work is to obtain an adequate maldistribution in the headers of cross-flow DL-microchannel heat sinks (MCHS) to reduce the intensity of the hotspot and, in turn, to limit the thermal resistance
Results of numerical simulations are shown in terms of flow maldistribution in the 50 microchannels pertaining to the top and bottom layers of the heat sink

Summary

Introduction

The increasing performance of electronic components requires the dissipation of increasing amounts of heat generated and, the adoption of more and more efficient, but still small, cooling systems. In this context, the use of liquid-cooled microchannel heat sinks (MCHS) has long been established. More than twenty years ago, Vafai and Zhu [4] designed a double-layered microchannel heat sink (DL-MCHS) for electronic cooling with a counter-current flow arrangement. It has been demonstrated that double-layered microchannel heat sinks allow to obtain interesting performances in terms of reduction of thermal resistance and control of hotspots. Hung et al [7,8] took into account the effect of thermal properties of different substrate materials and optimized the geometric

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Conclusion