空調用熱交換器のフィンピッチ乱れに及ぼすフィン材特性の影響

Abstract

To cope with the disarrangement of aluminum fins (called “Avec”) which occasionally occurs during the expansion process of copper tubes in the heat exchanger of room air conditioners, the effects of the mechanical properties, the thickness and the surface treatments of the aluminum fin stock on avec were investigated. These results are summarized as follows. (1) For avec, the compressive load on the fins at the unexpanded part of the heat exchanger, due to shrinking of the copper tube by the expansion, has a great influence on avec. When the compressive load on the fins is within the range for the fin shape, avec occurs. (2) The friction coefficient of the fin's surface treatment significantly affects the compressive load on the fins. By using a surface treatment having a very low friction coefficient, the compressive load can be sufficiently reduced to prevent avec. (3) The effect of the mechanical properties on avec have not been determined. The fin thickness has a small influence on avec. By using thicker fins, the occurrence of avec could be slightly reduced.