In this paper, an experimental study on the effect of the low aspect ratio of microchannel on the critical heat flux (CHF) during saturated flow boiling of water is presented. Multiple parallel silicon microchannels with different aspect ratios, hydraulic diameter, and number of channels in the range of 0.2–0.5, 154.0–184.8 μm, and 3–9 respectively are fabricated, and the experiments are performed in the range of mass fluxes 24.1–806.5 kg m⁻² s⁻¹. It is found that the CHF is caused by the wall dryout near the microchannel exit. The effect of microchannel aspect ratio with the same hydraulic diameter on the CHF is found to be insignificant. Twenty-five CHF data points are obtained for microchannel flow boiling of water and are compared with the CHF predictive methods reported in the literature. A new CHF correlation is proposed, which predicts the measured CHF with the mean absolute deviation of 12.1%, which is substantially better than available CHF predictive methods. The findings from this study provide guidelines for designing multiple parallel microchannel heat sinks in two-phase flow for the thermal management of electronic equipment, spacecraft, satellites, energy conversion devices, and biomedical engineering.

本文提出了在水饱和流沸腾过程中，低通道长宽比对临界热通量（CHF）影响的实验研究。制作了多个平行硅微通道，其纵横比，水力直径和通道数分别在0.2-0.5、154.0-184.8μm和3-9之间，并且在质量通量24.1- 806.5千克米^-2  s ^-1。发现CHF是由微通道出口附近的壁变干引起的。发现具有相同水力直径的微通道纵横比对CHF的影响微不足道。对于水的微通道流动沸腾，获得了25个CHF数据点，并与文献中报道的CHF预测方法进行了比较。提出了一种新的CHF相关性，它可以以12.1％的平均绝对偏差来预测测得的CHF，这比可用的CHF预测方法要好得多。这项研究的发现为设计用于电子设备，航天器，卫星，能量转换设备和生物医学工程的热管理的两相流中的多个并行微通道散热器提供了指导。