【摘要】 综述了水平低翅片管外凝结传热的基本模型,阐述了二氧化碳制冷剂的物性特点,讨论了表面张力与凝液滞留角及二氧化碳管外凝结换热系数的关系,分析了翅片密度、环形翅片管尺寸对翅片效率、滞留角、凝结换热系数以及传热增强比的影响,优化了外翅片管的齿高与齿距,并求得相应的强化传热增强比。结果表明,对于根径为20mm的低翅片管,最佳翅片密度为每米435个翅片,最佳齿高为5.1mm,最佳齿距2.3mm。更多还原

【Abstract】 Condensation heat transfer models of refrigerant outside horizontal low-finned tubes were surveyed.Thermodynamic properties of carbon dioxide were present.Surface tension effects on condensate retention angle and condensation heat transfer coefficient of carbon dioxide were studied.Effects of fin density and size upon fin efficiency,retention angle,condensation heat transfer coefficient,and heat transfer enhancement ratio were analyzed.Optimum fin size and heat transfer enhancement ratio were obtained.The generated results for a finned tube with a root diameter of 20 mm is that optimum fin density is 435 fins per meter,optimum fin height is 5.1 mm,and optimum fin pitch is 2.3 mm.更多还原