Selected porous-ribs design for performance improvement in double-layered microchannel heat sinks

• Published in: International journal of thermal sciences Vol. 137; pp. 616 - 626
• Main Authors: Li, Xian-Yang, Wang, Shuo-Lin, Wang, Xiao-Dong, Wang, Tian-Hu
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 01.03.2019
• Subjects: Double-layered; Microchannel heat sink; Numerical; Overall thermal resistance; Porous ribs; Pressure drop; Double-layered; Overall thermal resistance; Numerical; Microchannel heat sink; Porous ribs; Pressure drop
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2018.12.029

Microchannel heat sinks have provided an efficient solution in the thermal management of high-power density devices. In general, however, they cannot exhibit high thermal performance and lower pressure drop simultaneously. In this work, an improved design of microchannel heat sinks possessing a combination of high thermal performance and low pressure drop is proposed, where the superiority of double-layered concept and the advantage of porous-ribs design are taken into account. In the improved design, two layers of rectangular channels are stacked one atop another with porous ribs utilized in the upper layer while solid ribs employed in the lower layer. The thermal performance and the flow characteristics of the improved design are numerically studied using a three-dimensional solid-fluid conjugate model. Four other heat sinks with different structure (solid-ribs single-layered, porous-ribs single-layered, solid-ribs double-layered, and porous-ribs double-layered) are designed for performance comparison. The results demonstrate that the improved design yields the lowest thermal resistance and the best temperature uniformity on the bottom wall among all the five designs whether at an identical Reynolds number or at a fixed pumping power. The appropriate combination of better thermal conductivity of solid ribs and lower pressure drop of porous ribs in a double-layered heat sink is responsible for the performance improvement. •An improved double-layered microchannel heat sink is proposed.•Porous ribs are employed in the upper layer with solid ribs in the lower layer.•Thermal performance and pumping power both reduce for the improved design.