对垂直窄缝(窄缝尺寸规格分1、1.5和2.5mm3种)环形管内氟-113单相受迫对流换热进行了研究，环缝的加热方式采用热水逆流双面加热。详细介绍了实验装置、过程和方法。实验结果表明，窄缝环形管内单相流动换热的Nu数与普通圆管内层流公式计算值相差较大，不能套用传统的单相流动换热模型来计算管内的对流换热系数。根据实验数据，将修正的Dittus-Boelter公式用于计算窄缝环形管内的Nu数，平均误差在18.6％以内。%A study was made for the single- phase forced convection heat transfer of the internal fluorine - 113 of the vertical narrow -gap circular pipes (the sizes of narrow gap were lmm, 1.5mm, and2.5mm), the heating method for the loop gaps was counter current two- side heating with hot water. The experi mental units, process, and methods were presented in detail. The experimental result showed that the Nu number of the single - phase flow heat transfer in the narrow- gap circular pipes was higher than that in the common circular pipes, the traditional sin gle- phase flow heat transfer model could not be used to calculate the convection heat transfer coefficients in pipes. The average error was less than 18.6% when the rectified Dittus - Boelter formula was used to calculate Nu number in the narrow - gap circular pipes based on the experimental data.
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