Abstract Local single-phase flow heat transfer downstream a single pin fin in a microchannel was experimentally and numerically studied. Three distinct flow regimes, depending on the Reynolds number, were characterized, namely: laminar flow with steady wake, laminar flow with unsteady wake, and turbulent flow. Local temperature measurements with high spatial resolution were obtained by incorporating an array of micro resistance temperature detectors (RTDs) (∼55 µm × 55 µm) on the internal microchannel surface. Local surface temperatures were related to the flow structures under different flow regimes. An enhanced local heat transfer coefficient at the trailing edge of the wake region downstream the pillar was observed. It is believed to be a result of vortex shedding and large-scale flow mixing triggered by flow instability at high Reynolds number. The numerical model enabled a full conduction/convection conjugate analysis of the entire system including heat conduction within the solid substrates and heat losses to the surrounding environment. Local heat transfer coefficient downstream the pin fin at each Reynolds number was obtained.

中文翻译：

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针翅微通道局部传热的实验与数值研究

摘要 通过实验和数值研究了微通道中单个针翅下游的局部单相流传热。根据雷诺数的不同，表征了三种不同的流动状态，即：具有稳定尾流的层流、具有不稳定尾流的层流和湍流。通过在内部微通道表面上加入一系列微电阻温度检测器 (RTD)（~55 µm × 55 µm），可以获得具有高空间分辨率的局部温度测量。局部表面温度与不同流态下的流动结构有关。在柱子下游的尾流区域的后缘观察到增强的局部传热系数。据信，这是由高雷诺数下的流动不稳定性引发的涡旋脱落和大规模流动混合的结果。该数值模型能够对整个系统进行完整的传导/对流共轭分析，包括固体基板内的热传导和对周围环境的热损失。获得了在每个雷诺数下针翅下游的局部传热系数。