翅片管与空气-水蒸汽混合气间传热规律研究

CONVECTIVE HEAT TRANSFER BETWEEN THE FIN TUBE AND THE AIR-WATER VAPOUR MIXTURE

本文研究水蒸汽重量百分含量为10—35%的空气—水蒸汽混合气纵向流过翅片管时,翅片管与空气—水蒸汽混合气间的对流传热。研究表明,由于水蒸汽在翅片面上的冷凝,翅片管与空气—水蒸汽混合气间的对流传热系数高于翅片管与干气体间的对流传热系数,并且翅片间距越大,水蒸汽冷凝使对流传热系数增加的程度越大。从理论上对实验现象做出了较好的解释,并给出了有冷凝发生时,翅片管与空气—水蒸汽混合气间对流传热系数的关联式。

This paper studies the heat transfer characteristics offin tube when the air-water vapour mixture with the water vapourmass fraction of (10-35 )% flows longitudinally over the fin tubes.The experimental studies show that because of the condensation ofwater vapour from the air water-vapour mixture, the heat transfercoefficient between the fin tube and the air-water vapour mixtureis larger than the heat transfer coefficient between the fin tube andthe dry gas, the larger the fin pitch, the larger the heat transferenhancement due to water vapour condensation. In the paper, someexperimental phenomena are explained theoretically and the emperi-cal correlation for predicting the heat transfer coefficient betweenthe fin tube and the air-water vapour mixture are also given.