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

摘要： 在能源日益匮乏的今天,对低温热能的回收也逐渐成为热点.纵翅片换热器作为中低温烟气余热回收设备的核心部件,其中的平板式纵翅片管能有效解决翅片积灰、结垢问题,但却存在换热能力不理想而使得使用受到限制.本工作对传统平板纵翅片管进行结构改进,强化管外翅片与管外流体的换热效果,并分别采用j/f、j/f^1/2和j/f^1/3作为综合性能评价指标,分析研究4种不同结构型式纵翅片管的综合换热性能.结果表明:百叶窗式纵翅片管的换热性能要比普通平板式纵翅片管高90%以上,然而压降也是最大.通过评价指标可以看到在相同压降和相同泵功条件下,百叶窗式翅片管的综合性能要优于其他.通过实验研究,得到的测试结果与模拟结果相符,相对误差的平均值约为15%.研究成果为纵翅片结构优化提供了理论基础.

关键词: 纵翅片, 结构型式, 强化换热, 综合性能