竖直窄环隙通道内的强迫对流换热

本文在常压下,以水为工质,对三种尺寸的竖直窄环隙流道进行了单相强迫对流换热实验研究。结果表明,窄隙流道内的换热在低雷诺数区表现出与普通流道不同的多变特性,而在高雷诺数区与普通流道相近。温差对换热的影响具有两重性。窄隙流道使紊流换热区域扩大,当流道间隙足够小时,换热没有明显的过渡区和层流区,均表现为紊流换热的特征。本文提供的经验公式可以在较宽的参数范围内关联实验数据。

FORCED CONVECTION HEAT TRANSFER IN VERTICAL NARROW ANNULI

Experiments were carried out to investigate the single-phase forced convection heat transfer with water in three vertical narrow annuli which were heated from inside by primary water. The results show that the performance of heat transfer in lower Re number region is poly tropic, and that in higher Re region is similar to conventional channel. Temperature difference has a dual-action on heat transfer. Turbulent heat transfer region is extended in narrow channels. When the width of channel is narrow enough, no obvious laminar and transition heat transfer was observed, and almost always shows turbulent convection heat transfer characteristics. The empirical correlations presented in the paper fitted the experimental data with satisfactory agreement in wide range of Re number.