Abstract Based on previous works, a performance evaluation plot (PEP) is presented to theoretically evaluate the techniques used in the determination of various thermophysical properties of fluids in energy saving. From it, PEP is divided into “three lines and four zones”. Zone-1 indicates enhanced heat transfer without energy-saving, and enhanced heat transfer are in Zone-2, Zone-3 and Zone-4 with energy-saving for a fixed pumping power, pressure drop and flow rate, respectively. Then, microchannel heat sinks (MCHS) with cavities and different ribs arrangements were designed and simulated by using water-Al2O3 nanofluids. Based on the estimation indicators of comprehensive thermal performance (PEP and the thermal enhancement factor η), all working points located in the Zone-3 and 4 indicate that the increase in the heat transfer ratio is higher than that in the friction factor. The maximum enhancement of η is 2.2517 and it is measured in an odd-symmetric ribs structure (Channel D) with Reynold number equal to 582. The reasons are that the arrangement of odd-symmetric ribs continuously interrupts the development of the flow and thermal boundary layers. Moreover, cavities facilitate the full mixing of cold and hot fluids and reduce pressure drop.

中文翻译：

---

使用纳米流体改善微通道散热器能量管理的性能评估图 (PEP)

摘要 在前人工作的基础上，提出了性能评估图（PEP），以从理论上评估用于确定节能流体各种热物理特性的技术。由此将PEP划分为“三线四区”。1区为强化传热不节能，强化传热在2区、3区和4区，分别为固定泵功率、压降和流量节能。然后，使用水-Al2O3 纳米流体设计并模拟了具有腔体和不同肋条排列的微通道散热器（MCHS）。基于综合热性能的估算指标（PEP和热增强系数η），位于区域 3 和区域 4 的所有工作点都表明传热比的增加高于摩擦系数的增加。η 的最大增强为 2.2517，它是在雷诺数等于 582 的奇对称肋结构（通道 D）中测量的。原因是奇对称肋的排列不断中断流动和热边界的发展层。此外，空腔有助于冷热流体的充分混合并减少压降。