环境风作用下小规模直接空冷系统流动传热性能分析

Analysis of Flow and Heat Transfer Performances of Small-scale Direct Dry Cooling System under Ambient Wind

环境风对直接空冷系统的流动换热性能具有重要影响。适用于光热等小型电站的小规模空冷系统的不利环境风作用规律不同于大型直接空冷系统尚待进一步研究。采用数值模拟方法,建立了某50 MW光热电站的直接空冷系统数学物理模型,研究了不同环境气象条件下该小规模直接空冷系统流动换热性能变化规律,获得了不同工况下空气侧流场及温度场分布规律,并对空冷岛各空冷凝汽器单元轴流风机冷却空气流量和入口空气温度进行了统计,绘制了机组背压随环境气象条件的变化曲线。结果表明,不同环境气象条件下,环境风的不利影响主要发生在迎风侧的空冷凝汽器单元,并且建筑物的扰流作用对直接空冷系统流动换热性能具有不利影响。研究结果可为小型直接空冷系统的优化运行提供参考。

Ambient Air plays an important role in the flow and heat transfer performances of direct dry cooling system.The action law of adverse wind of small-scale dry cooling system such as concentrating solar power plant is different from that of large-scale direct dry cooling system and needs further research.In this paper,we developed the mathematical and physical models of direct dry cooling system in a 50 MW solar-thermal power plant based on numerical modeling method to study the flow and heat transfer characteristics under different environmental and meteorological conditions.Obtaining distribution law of air side flow field and temperature field under different operating conditions,we collected the statistics of the cooling air flow rate and the inlet air temperature of the axial flow fan of each air-cooled condenser unit and drew the curve of the variation of unit back pressure with the environmental conditions.The results show that the adverse effects of the ambient wind mainly occur in the air-cooled condenser unit on the windward side under different meteorological conditions,and the building disturbance has a negative impact on the flow and heat transfer performances of direct dry cooling system.This paper may contribute to the optimal operation study of the small-scale direct dry cooling system.