强制对流冷凝传热强化

研究了强制对流条件下，非共沸混合工质Ｒ１１／Ｒ１１３在三排水平直列光滑管及花瓣形翅片管束外的冷凝传热。实验结果表明：花瓣形翅片管由于具有特殊的三维翅片结构，既能激发流动的蒸气产生强烈地湍流，减小其气膜热阻，又能充分发挥冷凝液表面张力的作用，减少其液膜热阻，从而显著地强化了非共沸混合工质在管束外的冷凝传热。在相同热流率下，其管束平均冷凝传热系数是光滑管管束的３～５倍。

Forced Convective Condensation Heat Transfer Enhancement

The　condensation　heat　transfer　of　nonazeotropic　mixtures　R11/R113　on　3 row　horizontal　smooth　tubes　and　petal shaped　fin　tubes　was　studied　under　forced　convective　condition.Experimental　results　showed　that,because　of　its　special　three　dimensional　structure,petal shaped　fin　could　not　only　induce　strong　turbulence　for　flowing　vapor　and　make　the　heat　resistance　of　vapor　film　become　smaller,but　also　bring　the　condensation　surface　tension　into　full　play,and　make　the　heat　resistance　of　condensation　film　become　smaller,thus　obviously　enhancing　the　condensation　heat　transfer　of　nonazeotropic　mixtures　on　bundle.At　the　same　heat　flux,the　average　condensation　heat　transfer　coefficient　on　petal shaped　fin　tube　bundle　is　3～5　times　as　large　as　that　of　smooth　tube　bundle.