Abstract A large amount of hot air in dry cooling tower of natural draft dry cooling system can be recovered for many applications, such as the boiler air supply and feed water preheating in power plants. However, the hot air extraction will definitely affect the aerodynamic characteristics of dry cooling tower and heat transfer performance of air-cooled heat exchanger. In this work, the impacts of hot air recovery on the thermo-flow performances of natural draft dry cooling system under crosswind conditions are investigated. The variable fields are presented and the outlet water temperature of air-cooled heat exchanger is calculated with the wind speed, the mass flow rate of recovered hot air and the height of hot air extractions considered. Finally, the turbine backpressure and power consumption of induced fans are compared to evaluate the overall cooling effect of dry cooling system with hot air extractions. The results show that hot air extraction is favorable for the cooling performance of natural draft dry cooling system, and the higher mass flow rate of recovered hot air leads to a stronger cooling capability. The hot air extractions are proposed to set near the tower inlet with the turbine backpressure most reduced by 9.28%, which can contribute to the design and operation of natural draft dry cooling system in need of energy conservation.

中文翻译：

---

热空气抽取以改善自然通风干冷系统的空气动力学和传热性能

摘要 自然通风干式冷却系统干式冷却塔中的大量热空气可回收用于电厂锅炉送风、给水预热等多种用途。但是，抽热风肯定会影响干式冷却塔的气动特性和风冷换热器的传热性能。在这项工作中，研究了侧风条件下热空气回收对自然通风干冷系统热流性能的影响。给出了变量场，并考虑了风速、回收热空气的质量流量和热空气抽取高度，计算了风冷换热器的出口水温。最后，比较引风机的涡轮背压和功耗，以评估干式冷却系统与热空气抽取的整体冷却效果。结果表明，抽热空气有利于自然通风干冷系统的冷却性能，回收热空气质量流量越大，冷却能力越强。拟将热抽风设置在塔入口附近，涡轮背压最大降低9.28%，有助于需要节能的自然通风干冷系统的设计和运行。回收的热风质量流量越大，冷却能力越强。拟将热抽风设置在塔入口附近，涡轮背压最大降低9.28%，有助于需要节能的自然通风干冷系统的设计和运行。回收的热风质量流量越大，冷却能力越强。拟将热抽风设置在塔入口附近，涡轮背压最大降低9.28%，有助于需要节能的自然通风干冷系统的设计和运行。