中文摘要：

对水平环缝内冷水自然对流换热性能进行了实验研究。水平环缝宽度为6～18mm，外壁温度维持0℃，换热温差为2～24℃。结果表明，在实验范围内，内壁面的平均表面传热系数随环缝宽度的增大而增加；当温差小于4℃或大于8℃时，平均表面传热系数随温差的增大而增大，在4～8℃范围内，随温差的增大而减小。采用逐步线性回归方法，得到了内壁传热关联式。

英文摘要：

This paper conducts the experimental study on the natural convection characteristics of cold water near the maximum density in horizontal annulus with the fixed inner radius ri = 14 mm and different width l =6-18 mm. The temperature at outer wall is maintained at 0 ℃, and the temperature differences between the inner and outer walls range from 2 to 24℃. The results show that the heat transfer coefficient at inner wall increases with the increase of the annulus width. When the temperature difference is bellow 4 ℃ or above 8 ℃, the heat transfer coefficient increases with the increase of the temperature difference. When the temperature difference is between 4℃ and 8 ℃, it decreases with the increase of the temperature difference. The formula of heat transfer at inner walls is obtained by using the method of linear regression.