微小管道内相变微胶囊悬浮液换热特性

通过实验研究了去离子水和10%浓度相变微胶囊悬浮液在1 mm、2 mm管道内换热特性，结果表明：在Reynolds数Re=400～1000，1 mm管道内去离子水和10%浓度相变微胶囊悬浮液局部Nusselt数Nu_x均比2 mm 管道的小，分析其原因，这主要是由于1 mm管道壁厚管径比大导致的轴向导热比2 mm管道强引起的；1 mm管道内去离子水中加入相变微胶囊颗粒能够增强与管壁之间对流换热，且随着Re的增加，Nu_x增大，而2 mm管道内去离子水中加入相变微胶囊颗粒，构成10%浓度相变微胶囊悬浮液，表现出比水更差的换热特性，并且随着Re的增加Nu_x降低。

Heat transfer characteristics of micro-encapsulated phase change material suspension in mini-tubes

The heat transfer characteristics of 10% micro-encapsulated phase change material suspension(MEPCMS) and distilled water in the mini-tube of radius 1 mm and 2 mm were investigated. It appears that:for Reynolds number ranging from 400 to 1000, the local Nusselt number of MEPCMS and water in 1 mm tube is smaller than it in 2 mm tube. From the analysis of reason it is mainly because the thickness of 1 mm tube is larger than 2 mm tube resulting in stronger axial thermal conductivity. The distilled water joined in MEPCM in 1 mm tube can enhance the heat transfer between the fluid and tube wall and the local Nusselt number increase with Reynolds number increasing. While the 10% micro-encapsulated phase change material suspension in 2 mm shows weaker heat transfer characteristics than distilled water and the local Nusselt number decrease with Reynolds number increasing.