The convective cooling associated with Microchannel heat sink (MCHS) devices for electronic components with high power density is a recent topic of cutting-edge research. However, thermal improvement with minimum degradation in hydrodynamic characteristic by extending the effective heat transfer area of different walls of MCHS is still a major challenge. In this regard, the heat transfer enhancement and fluid flow behavior of MCHS with protrusions, dimples and their different wall, geometric and design combinations are numerically studied in the present study. The wall configurations considered for the present analysis includes: Base wall protrusions/dimples (BWP/D), Side wall protrusions/dimples (SWP/D) and all walls protrusions/dimples (AWP/D). While for design configurations, the (AWP/D-Aligned), (AWP/D-staggered) and all wall protrusions and dimples mix (AWPD-Mix) cases are considered. The governing equations are discretized and solved across the computational domain using commercial computational fluid dynamics code with three-dimensional conjugate laminar flow model. The numerical model is then validated with experiment and theory in the literature and reasonable agreement in the results of average Nusselt number (Nu_avg) and apparent friction factor (f_app) are observed. The effect of geometric parameters i.e. protrusion/dimple’s diameter (D_fr = 200 - 230 μm) and Pitch (S_fr = 400 - 1200 μm), operating parameters i.e. Reynolds number (Re = 100–1000) and Heat flux (q_w = 50–100 W/cm²) on the heat transfer and fluid flow characteristics are examined to provide a better physical understanding of the energy management. The results indicate that the addition of protrusions/dimples to different walls of MCHS significantly improves the heat transfer with reasonable increase in pressure drop. The fluid flow pattern with the addition of the protrusions/dimples to different walls is improved through better mixing and lower pumping power augmentation to transport the same heat load than Straight MCHS. The favorable configuration along with geometric and operating parameters in terms of better thermal and hydrodynamic performance is suggested based on thermal enhancement factors (ƞ) and entropy generation rates (\( {\dot{\mathrm{S}}}_{\mathrm{gen}} \)). Among the proposed wall configurations, AWP demonstrates superior thermal performance by resulting in maximum improvement of 82% in ƞ compared to BWP configuration. When compared to the straight MCHS, AWP-aligned MCHS achieved maximum enhancement of 115% in Nu_avg at the cost of 152% higher f_app at same operating conditions of Re = 1000 and q_w = 100 W/cm² for design configurations. Furthermore, the outcomes of this study is expected to provide some important guidelines for the future experiments on such MCHS devices for energy saving and management.

中文翻译：

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具有凸起/凹痕的不同壁/设计配置的微通道散热器中传热增强和流体流动特性的数值研究

与具有高功率密度的电子组件的微通道散热器（MCHS）装置相关的对流冷却是前沿研究的最新主题。然而，通过扩展MCHS不同壁的有效传热面积，以最小的水动力特性退化进行热改进仍然是一个主要挑战。在这方面，本研究对带有凸起，凹坑及其不同壁，几何形状和设计组合的MCHS的传热增强和流体流动行为进行了数值研究。本分析考虑的墙配置包括：底墙突起/凹痕（BWP / D），侧壁突起/凹痕（SWP / D）和所有墙突起/凹痕（AWP / D）。对于设计配置，（AWP / D对齐）（AWP / D交错）和所有墙体突起和凹痕混合（AWPD-Mix）情况都考虑在内。使用具有三维共轭层流模型的商业计算流体动力学代码，可以在计算域内离散和求解控制方程。然后用文献中的实验和理论对数值模型进行验证，并在平均努塞尔数（Nu观察到_avg）和表观摩擦系数（f _app）。几何参数的影响，即突出/凹坑的直径（D _fr  = 200-230μm）和节距（S _fr  = 400-1200μm），工作参数，即雷诺数（Re = 100–1000）和热通量（q _w  = 50–100 W / cm ²）对传热和流体流动特性进行了检查，以提供对能量管理的更好的物理理解。结果表明，在MCHS的不同壁上添加凸起/凹痕可显着改善热传递，并适当降低压降。通过更好的混合和更低的泵浦功率增加来传输与平直的MCHS相同的热负荷，从而改善了在不同壁上添加凸起/凹痕的流体流动方式。建议根据热增强因子（ƞ）和熵产生率（\（{\ dot {\ mathrm {S}}} _ {\ mathrm { gen}} \））。在建议的墙面配置中，与BWP相比，AWP通过使最大的1/3的改进提高了AWP的热性能。与直线型MCHS相比，与AWP对准的MCHS在Re = 1000和q _w  = 100 W / cm ^2的相同操作条件下，以f _app的最高_平均应用能力实现了Nu _avg的115％的最大提高，而对于配置配置而言，则为f _app。此外，这项研究的结果有望为将来的此类用于节能和管理的MCHS设备的实验提供一些重要的指导。