Microchannel Heat Sinks (MCHS) can dissipate large amounts of heat in a compact area making them a main choice for managing heat in space-limited applications. Recently, with the help of 3D metal printing, it became easy to fabricate various designs of MCHS with internal complex designs. This study, compare the thermo-hydraulic performance of three bifurcation based MCHS designs, with the traditional straight MCHS. Single-phase cooling of surfaces with high heat fluxes of 200 kW/m and 400 kW/m, was numerically analyzed. The model is validated with the literature. The MCHS designs under study included: a standard smooth microchannel (Case A), a channel with a single extended bifurcation (Case B), multiple inline bifurcations (Case C), and a design employing stepwise bifurcations (Case D). Case A served as the reference case for comparison. Results showed that incorporating bifurcations substantially enhances the MCHS's heat removal efficiency. Specifically, the increment in Nusselt number for Cases B, C, and D compared to case A were 1.78, 1.6, and 1.55, respectively at heat flux of 200 kW/m and Reynolds of 200. Moreover, MCHS designs with bifurcations significantly improved temperature uniformity, achieving the best temperature uniformity of 7.7 °C at a Reynolds number of 700 under a 400 kW/m heat flux.

中文翻译：

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内部分叉微通道散热器各种设计的热工水力性能

微通道散热器 (MCHS) 可以在紧凑的区域内散发大量热量，使其成为空间有限应用中管理热量的主要选择。最近，在3D金属打印的帮助下，可以轻松制造具有内部复杂设计的MCHS的各种设计。本研究将基于三个分叉的 MCHS 设计与传统的直 MCHS 的热工水力性能进行了比较。对 200 kW/m 和 400 kW/m 高热通量表面的单相冷却进行了数值分析。该模型通过文献进行了验证。正在研究的 MCHS 设计包括：标准光滑微通道（案例 A）、具有单个扩展分叉的通道（案例 B）、多个内联分叉（案例 C）以及采用逐步分叉的设计（案例 D）。案例A作为参考案例进行比较。结果表明，合并分叉大大提高了 MCHS 的散热效率。具体而言，在热通量为 200 kW/m 且雷诺数为 200 时，与情况 A 相比，情况 B、C 和 D 的努塞尔数增量分别为 1.78、1.6 和 1.55。此外，具有分岔的 MCHS 设计显着改善了温度均匀性，在 400 kW/m 热通量下，雷诺数 700 时实现 7.7 °C 的最佳温度均匀性。