摘要
数值模拟了球突翅片管外空气的流动和换热,并基于耗散概念对球突翅片换热的不可逆性进行了分析。结果表明:与平直翅片相比,直接空冷器单排管换热器采用球突翅片可使换热显著强化。当球突个数相同时,错排布置方式优于顺排;在Re=600～1 500的范围内,球突错排时,平均换热系数比平直翅片增加30%～55%,阻力系数增加50%～85%,同功耗强化换热指数PEC为1.14～1.27。球突翅片的等效热阻显著减小,其传热的不可逆性减弱,这正是球突翅片具有良好强化换热性能的物理机制。
The air flow and heat transfer around a dimpled fin in an air-cooled condenser were numerically studied.The irreversibility of the convective heat transfer was analyzed based on the entransy concept.The results show that the heat transfer is significantly enhanced in a single row tube heat exchanger with dimpled fins in a direct air-cooled condenser compared with a plain fin candenser.The heat transfer performance of the staggered dimple pattern is better than the in-line pattern with the same number of dimples for Reynolds numbers between 600 and 1 500.The Nusselt numbers for the staggered pattern are enhanced 30%～55%,while the friction factors are increased by 50%～85% compared with the plain fins.The performance evaluation criterion（PEC） of the staggered dimple fin then reaches 1.14～1.27.The equivalent thermal resistance defined by the entransy dissipation in the dimple fins is much less than in the plain fin.Therefore,the heat transfer irreversibility in the dimple fins is reduced,which is the physical mechanism for their better heat transfer performance.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2010年第7期1104-1108,共5页
Journal of Tsinghua University(Science and Technology)
基金
国家重点基础研究发展规划资助项目(2007CB206901)
关键词
空冷器
球突翅片
(火积)耗散
等效热阻
air-cooled condenser
dimple fin
entransy dissipation
equivalent thermal resistance
