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在火电机组直接空冷凝汽器中采用空冷技术,可以有效降低富煤缺水地区火力发电对水资源的消耗。通过数值模拟的方法,对锯齿形短翅片应用于火电机组直接空冷凝汽器扁平管空气侧强化传热的可行性进行探讨。研究发现,,采用所提出的扁平管交错蛇形短翅片结构,与传统的连续蛇形翅片相比,在各种迎面风速条件下均能起到强化空气侧传热的效果。随着短翅片交错排数的增加,翅片变短,强化传热的效果更为明显。在n 5时,强化传热综合性能评价准则数(performance evaluation criteria,PEC)可达到1.05~1.09;但随着迎面风速的增加,流动阻力的增加变得更为显著,强化传热的效果受到抑制。利用实际数据对模型的有效性进行验证,并对计算域网格数进行校验,结果表明所得结论具有一定的可靠性。
The use of air-cooled technology in the direct air-cooled condenser of thermal power units can effectively reduce the thermal power consumption of water resources in areas rich in coal and water. By means of numerical simulation, the feasibility of using zigzag short fins for heat transfer enhancement on the air side of flat tubes of direct air cooled condenser of thermal power units is discussed. It has been found that the proposed serpentine short finned structure with alternating flat tubes can enhance the heat transfer at the air side compared with the conventional continuous serpentine fin at various oncoming wind speeds. With the short fin staggered row number increases, the fin becomes shorter, the effect of enhanced heat transfer is more obvious. At n 5, the performance evaluation criteria (PEC) of enhanced heat transfer can reach 1.05 ~ 1.09. However, with the increase of oncoming wind speed, the increase of flow resistance becomes more significant, and the effect of enhanced heat transfer is affected inhibition. The validity of the model is verified by the actual data, and the number of grids in the computational domain is verified. The results show that the conclusions obtained are of certain reliability.