应用多孔消能墙改善直接空冷系统换热效率的数值模拟研究

Numerical Simulation of Direct Air-cooled System Considering Cross Wall of Porous Energy Dissipation Improvement

对某2×1 000 MW直接空冷机组进行了空冷系统散热数值模拟。在环境温度38℃下,针对其8 m/s、12 m/s、16 m/s三种环境风速,16种来流风向进行组合进行计算。考察有无十字多孔消能墙两种方案下电厂模型的运行能力。由计算结果可知,十字多孔消能墙能够有效地降低环境风对空气冷凝器不利影响,减少冷凝器底部风机的热回流,从而进一步提高空气冷凝器的换热效率,降低汽轮机的背压。

The numerical simulation was made with CFD for a 2 × 1 000 MW direct air-cooled unit. When the ambient temperature is 38 ℃, the external flow field of the air cooled power plant was caculated at three environ- mental wind speeds （8 m/s, 12 m/s, and 16 m/s） and in 16 directions of wind in order to study the operational capability of the power plant with the cross wall of porous energy dissipation. The results show that the cross wall of porous energy dissipation can effectively reduce the adverse effects of ambient wind on air-cooled condensers and re-duce the thermal reflows of the fans under air-cooled condensers. Furthermore, the heat exchange efficiency of air-cooled condensers is improved, and reduced the back pressure of steam turbines.