Ni-P化学镀层表面实现滴状冷凝传热

摘要

In order to achieve the surface preparation techniques that promoted the formation of dropwise condensation heat transfer,Ni-P coating on carbon steel by electroless plating,and its condensation heat transfer performance were studied.The results showed that complete dropwise condensation was achieved on the surface of Ni-P electroless coating,the heat flux and heat transfer coefficient was 3 to 5 times higher than the values calculated by Nusselt film theory.Meantime,it was found that the amorphous of coating was the main reason for promoting the formation of dropwise condensation heat transfer.The co-existence state of dropwise and filmwise was obtained when the coating was crystallized by heat treatment.%为了探索能实现滴状冷凝传热的表面制备技术,采用化学镀技术在碳钢表面制备非晶态Ni-P化学镀层,对其冷凝传热性能进行了实验研究。结果表明,Ni-P化学镀层表面常压水蒸气下实现了完全的滴状冷凝传热,表面热通量和传热系数均比膜状冷凝Nusselt理论计算结果提高了3～5倍。同时发现,镀层的非晶态是实现滴状冷凝传热形态的主要原因,经过热处理晶化后,表面形成的是滴膜共存的冷凝传热形态,冷凝传热强化效果显著降低。