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摘 要： 对当量直径0.5mm，有效加热长度45.0mm的微圆通道进行了临界热流密度(CHF)的实验研究。实验发现微通道中的临界热流密度现象不同于常规通道。微通道中临界热流密度的产生的原因是由于微通道的蒸汽阻塞。在达到临界热流密度之前，微通道的流动和传热主要是周期性的过冷流动沸腾，从微通道逸出的汽泡和进入微通道的液体反复交替冲刷微通道。一旦达到临界热流密度，微通道中的流动和传热主要是一个蒸汽周期性逸出的过程。一直持续到过热蒸汽的出现，直到最后整个微通道被过热蒸汽阻塞。 关键词： 微通道 临界热流密度 蒸汽阻塞 The Phenomenon Of Chf In Micro-Tube Zhou Jijun Shi Wei Wan Jinqing Department of Thermal and Power Engineering .ShangHai Ocean University, 201306 Abstract: New CHF data are provided with water as working fluids, channel inside diameter of 0.5mm and effective heating length of 45mm. CHF is increased with increasing the mass flux and inlet liquid subcooling. Just before CHF is activated, the flow and heat transfer is governed by the periodic subcooled flow boiling process with periodic bubble emission and inlet liquid refilling after each bubble emission passed. Once CHF is activated, The flow and heat transfer inside the micro-tube is controlled by the vapor periodic emission but without liquid refilling. The outlet temperature and pressure drop signals are always out of phase with phase angle of 180degs. Such process is continued until the superheated vapor appears and the channel is fully blocked by the vapor inside the channel. Keywords: micro-tube, critical heat flux, periodic emission