H型翅片管束空气流动及换热特性

为了对不同排列方式的H型翅片管进行数值分析,建立不同布置方式下H型翅片管束流动及换热数值模型,获得两种典型布置下的流动及传热特性变化规律。结果表明,H型翅片特殊沟槽结构使背风侧形成纵向冲刷流场,存在明显的三维流动特征,使得其具有自清理、不易积灰的功能;错排翅片基管传热系数大于等间距排列的基管,并且随速度增大,换热效果差异越明显;管束行距对翅片管传热系数的影响明显大于列距的影响,管束行距增大,引起流道内空气平均速度下降,传热系数降低,流道损失减小。

Numerical study on the air motion of H-type finned tubes and heat transfer characteristics

In order to analyze H-type finned tubes in different arrangement modes numerically, flow and heat transfer numerical models of H-type finned tubes in different arrangement forms were established. The change rules of flow and heat transfer characteristics of two typical arrangements has been obtained. The result showed that the special groove structure of H-type finned tubes turned leeward side into vertical flushing flow field with obvious three-dimensional flow characteristics which had the functions of automatic cleaning and nearly gathering no dust. The heat transfer coefficient of staggered finned parent tubes was higher than that of the parent tubes arranged in equal interval. Additionally, the difference of heat transfer effect was increasingly obvious with the increase of speed. The influence of array pitch of tubes on the heat transfer coefficient of finned tubes was remarkably greater than that of row pitch. The increase of the array pitch of tubes lowered the average speed of air in flow channel, heat transfer coefficient and the loss of flow channel.