Prior studies reported in miniature two-phase mini/micro-channel heat sinks were mainly attentive to determining the heat transfer coefficient, pressure drop, and critical heat flux during flow boiling. The current study addresses heat transfer attributes and operating limits for large heat sinks with longer mini/micro-channels. Thermal design limits for two-phase saturated flow boiling with R-134a as the working fluid are investigated for various dimensions of the micro-channel's geometric parameters in the heat sink. It was observed that for low volumetric flow rates, the heat flux limit was associated with the dryout incipience limit, regardless of the channel hydraulic diameter. The design limit for higher volumetric flow rates was related to the critical flow limit. On the way to limit the temperature within the heat sink to the desired value, the wall temperature deviation limit becomes a more critical design factor in setting the heat flux limit than the critical flow and dryout incipience design limits. When the temperature uniformity corresponding to the large mini/micro-channel heat sink is required precisely, the heat flux limit becomes more and more constrained, and the permissible design limit decreases.

中文翻译：

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具有壁温偏差限制的大型迷你/微通道散热器中 R-134a 流动沸腾的热设计限制

先前报道的微型两相迷你/微通道散热器的研究主要集中于确定流动沸腾期间的传热系数、压降和临界热通量。当前的研究解决了具有较长迷你/微通道的大型散热器的传热属性和操作限制。针对散热器中微通道几何参数的各种尺寸，研究了以 R-134a 作为工作流体的两相饱和流动沸腾的热设计限制。据观察，对于低体积流量，热通量限制与干燥初期限制相关，无论通道水力直径如何。较高体积流量的设计限制与临界流量限制相关。在将散热器内的温度限制到所需值的过程中，壁温偏差限制成为设置热通量限制时比临界流量和干燥初期设计限制更关键的设计因素。当精确要求大型微型/微通道散热器对应的温度均匀性时，热通量限制变得越来越受限，允许的设计极限降低。