Vortex generators (VGs) have been widely applied in the microchannel heat sinks to improve the thermal-hydraulic performance in multicore processors. However, most studies focus on global heat transfer enhancement of microchannel, while the hotspot temperature is often neglected. In this paper, a numerical study of hotspot-targeted thermal management using VGs is performed in a rectangular microchannel with a heat flux of 400 W/cm and 50 W/cm respectively at the hotspot and background region. With the maximum thermal resistance, pumping power and the overall performance factor as the key metrics, the performances of VGs in four configurations (co-flow-up, co-flow-down, counter-flow-up and counter-flow-down) are compared with a smooth microchannel without VG. Deionized water with temperature-dependent thermo-physical properties is used as the coolant with the Re in the range of 66–330. The results indicate that the adoption of VGs can significantly improve the cooling effect over the hotspot with a lower pressure loss penalty comparing with the smooth microchannel. In addition, the VGs in a “co-flow” configuration lead to the fluid circulation effect and transport the coolant in the core region of the microchannel to the sidewalls. It is also noted that comparing with the smooth microchannel, more than 78.8% pumping power can be saved by using the “co-flow-down” configuration to achieve the same cooling effect to maintain the average temperature at 304.7 K over the hotspot. Geometric parameter analysis reveals that the increase in the height and attack angle of VGs results in more pressure loss, whereas the enhanced heat transfer is insignificant when the VG's height ratio exceeds 0.2 or the attack angle surpasses 45°. Taking full account of the heat transfer performance and pressure loss, VGs with a height ratio of 0.2 and attack angle of 45° are recommended for practical applications.

中文翻译：

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带涡流发生器的微通道散热器中的热点热管理


涡流发生器（VG）已广泛应用于微通道散热器中，以提高多核处理器的热工水力性能。然而，大多数研究关注微通道的整体强化传热，而热点温度往往被忽视。本文在热点区域和背景区域的热通量分别为 400 W/cm 和 50 W/cm 的矩形微通道中进行了使用 VG 的热点目标热管理数值研究。以最大热阻、泵浦功率和整体性能因数为关键指标，展示了四种配置（同流上流、同流下流、逆流上流和逆流下流）VG 的性能与没有 VG 的平滑微通道进行比较。使用具有与温度相关的热物理特性的去离子水作为冷却剂，其Re在66-330范围内。结果表明，与光滑微通道相比，采用 VG 可以显着改善热点区域的冷却效果，且压力损失损失更低。此外，“同流”配置的VG会产生流体循环效应，并将微通道核心区域的冷却剂输送到侧壁。还值得注意的是，与光滑微通道相比，使用“共流向下”配置可以节省超过 78.8% 的泵浦功率，以达到相同的冷却效果，将热点平均温度维持在 304.7 K。几何参数分析表明，VG高度和攻角的增加会导致更大的压力损失，而当VG高度比超过0.2或攻角超过45°时，强化传热不显着。 综合考虑传热性能和压力损失，实际应用中推荐高度比为0.2、攻角为45°的VG。