Abstract Numerical study has been carried out to examine the heat transfer and fluid flow characteristics of open microchannel heat sinks consist of square pin fins. Variation of fin height evolves an open configuration of microchannel having open space available between fin top surface and top wall of the heat sink. Comparative analysis has been done amongst seven different heat sinks of varying fin height in the range of 0.5–2.0 mm with an increment of 0.25 mm. Fin height of 2.0 mm constitutes completely closed microchannel heat sink i.e. conventional configuration which has been considered to compare the performance with open heat sinks. Single phase liquid water flows through the microchannel where Reynolds number (Re) varies from 100 to 800. Uniform heat flux in the range of 75–150 kW/m2 is supplied to heat the microchannel. Comparative results of overall thermal performance have been presented to recognize the best configuration of the heat sink in the present ranges of operating conditions. Predicted results confirm that increasing the fin height in heat sink; augments the heat transfer rate however, it persists only up to 1.5 mm of fin height. Beyond this height of the fin, i.e. for 1.75 mm and 2.0 mm, heat dissipation capacity of the heat sink drops. Moreover, heat sinks of shorter fins (0.5–1.00 mm) depict considerably low thermal performance nevertheless; pressure drop is also lower in such configuration and increases with fin height. Superiority of the heat sink having fin height of 1.5 mm is also revealed through thermal performance factor and it is attributed to net convective surface area and availability of the open space that facilitates favourable flow behaviour for better heat transfer.

中文翻译：

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具有可变针鳍高度的开放式微通道散热器的热性能

摘要 对由方形针状翅片构成的开放式微通道散热器的传热和流体流动特性进行了数值研究。翅片高度的变化形成了微通道的开放构造，在翅片顶面和散热器顶壁之间具有可用的开放空间。已经在 0.5-2.0 毫米范围内以 0.25 毫米的增量在不同翅片高度的七种不同散热器之间进行了比较分析。2.0 毫米的鳍片高度构成了完全封闭的微通道散热器，即传统配置，已被考虑与开放式散热器进行性能比较。单相液态水流过微通道，其中雷诺数 (Re) 从 100 到 800 不等。提供 75-150 kW/m2 范围内的均匀热通量来加热微通道。提供了整体热性能的比较结果，以识别当前工作条件范围内散热器的最佳配置。预测结果证实，增加散热器的鳍片高度；提高了传热率，然而，它只持续到 1.5 毫米的翅片高度。超过鳍片的这个高度，即 1.75 毫米和 2.0 毫米，散热器的散热能力下降。此外，较短翅片（0.5-1.00 毫米）的散热器的热性能相当低。在这种配置中，压降也较低，并随着翅片高度的增加而增加。散热片高度为 1 的优势。