倾斜式波纹翅片管传热及流动阻力性能比较试验

Comparative Experiment on Heat Transfer and Flow Resistance for New Type of Finned Tubes of Air - Cooled Heat Exchangers

对新开发的空气冷却器倾斜式波纹翅片管与传统的国产平直翅片管的传热性能及流动阻力性能进行了对比试验,给出了相应的传热系数曲线和流动阻力系数曲线,并分析了产生该试验结果的原因及理论依据。当空气流经该新型倾斜式波纹翅片管时,由于该翅片管能使气流产生强烈的扰流,破坏气流的边界层,导致掠过翅片管束的气流紊流程度加剧,从而提高了翅片管外空气膜传热系数。由试验结果可知,该新型倾斜式波纹翅片管与平直翅片管的j／f值相比,有较大的提高,表明新型倾斜式波纹翅片管的传热及流动性能优于国产平直翅片管,具有较高的工程应用价值,因此新型倾斜式波纹翅片管具有较好的推广应用前景。

The comparative experiment on heat transfer and flow resistance of new type of declinational wavy finned tubes and traditional home- grown flat finned tubes of air- cooled heat exchangers was carried out and curves on heat transfer coefficient and flow resistance coefficient were given. The reasons and theoretic reference of testing results were analyzed. When airflow fly through the declinational wavy finned tubes, the airflow was strongly disturbed and the boundary layer was broken down, so it led to the airflow turbulent fluid extent being inteasified, so that the heat transfer coefficient of finned - tubes was enhanced. From the results of the test, it can be learned that the j/f value of declinational wavy finned tubes is higher than that of flat finned tubes. It is pointed out that the characteristics of heat transfer are preferable, so the new type of declinational wavy finned tube has a good applied prospect.