关键词: 纵翅片, 结构型式, 强化换热, 综合性能

Abstract: Recovery of low-temperature heat energy has become a hot spot as the world is facing increasing energy shortage. As the core components of medium to low-temperature waste heat recovery equipment,the longitudinal finned heat exchangers have the advantages of low fouling and scaling,but the relatively low heat exchanging efficiencies limit the applications of this type of heat exchangers. This paper investigated the methods of optimizing the structure of traditional flat longitudinal finned tubes and enhanced heat transfer effects of the fin and fluid outside the tube,and applied j/f,j/f^1/2和j/f^1/3 as comprehensive performance index to analyze heat transfer performances of four different types of longitudinal finned tubes. The results showed that the longitudinal louvered finned tubes was 90% better in heat changing efficiency than ordinary flatbed longitudinal finned tubes,but the pressure drop was the largest among the tested tubes,Under the same pressure drop and pumping power conditions,comprehensive performance of longitudinal louvered finned tubes was better than other types of exchangers. The numerical simulation results were similar to the experimental results with the average relative error of 15%.

Key words: longitudinal fin, structure type, enhance heat transfer, comprehensive performance