中文摘要：

本文实验研究了水在间隙为2．1、2．2、3．6mm的垂直矩形窄通道内流动沸腾压降，包括入口过冷的情况，得到了在不同操作条件下压降随热流密度的变化曲线，同时分析了曲线变化的原因。实验结果发现：在实验参数范围内，流动沸腾的压降随着质量流速、热流密度和入口干度增加而增大；随着窄缝间隙的增大而减小。窄通道内的压降计算与大通道有显著不同，本文针对窄通道的特点，修正了传统的压降计算模型，模型预测值与实验结果比较，误差在±15．4％之内。

英文摘要：

Pressure drop of flow boiling at vertical channel with gaps of 1.7, 2.2 and 3.6 mm was experimentally investigated. The variation of the two-phase frictional multiplier vs. heat flux at various operating conditions was gotten experimentally, possible mechanism of the two-phase frictional multiplier trends of narrow channel were analyzed. Experimental results revealed that the two-phase frictional multiplier increased at lower flow rate and heat flux, as well as higher vapor quality, and dropped at wider flow gap. The multiplier can not be estimated by commonly used method for ordinary gap, thus a modified model of pressure drop for narrow channel was proposed considering the size effects of channel. The error of the predicted two-phase frictional multiplier is within ±15.4% compared with experimental results.