By means of combining experiment with numerical computation, the heat exchange process with natural convection over horizontal circular pipe in large space was investigated It was found by the experiment that the heat exchange coefficient would increase with the temperature rising on the outersur-face of the pipe. Experimental correlation of natural convection heat exchange was fitted by using experimental data. The natural convection heat transfer of horizontal circular pipe was numerically analyzed on the platform of Fluent The result showed that the intensity of the natural convection heat exchange would be decided by the temperature difference between pipe wall and ambient air; the bigger the temperature difference was the faster the natural convection flow is and the bigger the maximum flowing velocity would be. The continual rising airflow would be formed around the pipe, which was drived by the uplift due to the temperature differences.%通过实验与数值计算相结合的方法,对大空间水平圆管的自然对流换热过程进行研究.实验得出圆管自然对流换热系数随管壁温度的升高而增大,并拟合了实验条件下的自然对流换热实验关联武.以Fluent为平台,对水平圆管在大空间内的自然对流换热进行数值分析.结果表明,自然对流换热强弱取决于圆管壁面与周围流体温差的大小,温差越大,自然对流流动发展越快,最大流速越大,圆管周围空气在温差产生的浮升力驱动下形成不断上升的气流.
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