窄缝环形管内流动与传热实验研究Ⅰ.单相强制流动换热

对垂直窄缝 (窄缝尺寸规格分 1、1 5和 2 5mm 3种 )环形管内氟 1 1 3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 1 8 6%以内。

An experimental investigation on the flow and heat transfer of the narrow-gap tube vapor generators. I. Single-phase forced flow heat exchange.

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 1mm, 1.5mm, and 2.5mm ), the heating method for the loop gaps was counter current two-side heating with hot water. The experimental 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 single-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.