直接空冷扁平翅片管束散热性能的实验研究

Experimental Study on Heat Transfer Property of Direct Air-Cooling Flat Finned Tube Bundle

扁平翅片管束是电站直接空冷系统的基本散热元件,研究其结构特点和流动换热特性,对于电站空冷系统的优化设计与高效运行具有重要意义。以直接空冷系统典型的连续蛇形翅片扁平管束为研究对象,通过实验研究不同的翅片间距对翅片间冷却空气的流动换热特性的影响,以及垂直进风和倾斜进风工况下,翅片散热性能的变化。结果表明,在相同的风速下,随着翅片间距的减小,翅片的换热系数增大,而阻力系数的变化相对复杂。实验条件下,翅片间距为56.8 mm时整体性能较优。翅片间距一定时,随着风速的增大,换热系数逐渐增大,阻力系数逐渐减小。但随着风速的增加,两者变化趋势渐缓。研究结果为扁平管连续翅片结构的进一步优化提供了基础数据。

Flat finned tube bundle is the basic radiating element of direct air-cooling system in thermal plant, so the study on its structure feature, flow and heat transfer property has important significance to the optimization design and efficient operation of air-cooling system in power plant. Taking the typical continuous serpentine fin flat tubes of direct air- cooling system as examples, this paper studied the impact of different fin spacings on the flow and heat transfer property of the cooling air and the changes of fin＇s heat transfer performance under vertical and tilt flow conditions. The result shows that the heat transfer coefficient of fin grows up with the decrease of its spacing at the constant wind speed, while its resistance coefficient varies complexly. Under the experimental conditions, the flat tube with fin spacing of 56.8 mm has the best property. When the fin spacing is constant, with the growth of wind speed, the heat transfer coefficient increases and the resistance coefficient decreases gradually. However, the trends become gentle at high wind speed. The research results can provide basic datas for the further optimization of the structure of continuous flat tube fin.