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针对火电空冷凝汽器采用的扁平管蛇形翅片长度较大,空气在翅片间流动对强化传热的效果受到边界层发展抑制的缺陷,根据锯齿翅片通过破坏边界层发展强化传热的思想,提出一种扁平管交错蛇形短翅片结构。实验结果表明,扁平管交错蛇形短翅片的传热性能优于原有结构,在不同雷诺数Re范围,努塞尔数Nu增加了1.4%～16%;同时空气侧流动阻力也明显增加,摩擦系数f增加了18%～45%。由综合评价指标PEC也可以得到,扁平管交错蛇形翅片有效地强化了空气侧的换热。
In view of the fact that the length of the serpentine fin of the flat tube used in the air-cooled condenser of the thermal power plant is large, the effect of air flowing between the fins on the enhancement of heat transfer is restrained by the development of the boundary layer. According to the development of serrated fins by destroying the boundary layer, The idea of a flat tube staggered serpentine short fin structure. The experimental results show that the heat transfer performance of the serpentine short fins with flat tubes is better than that of the original structure. Nusselt number Nu increases 1.4% ~ 16% at different Reynolds number Re, and the air flow resistance also increases obviously , The friction coefficient f increased by 18% ~ 45%. It can also be obtained from the comprehensive evaluation index PEC that the serpentine fins of the flat tubes are interlaced to effectively enhance the heat exchange on the air side.