基于数值模拟技术的电站冷却塔性能优化

Performance optimization of cooling tower based on numerical simulation technology

针对环境风对间接空冷塔换热性能的不利影响,提出一种环状导流板与内部挡风墙的组合装置,以协同降低散热器进口压降,抑制塔内热风穿透和涡流的形成,改善环境风工况下间接空冷塔的性能。基于Fluent软件,建立环境风工况下间接空冷塔热力特性的数值计算模型,研究组合装置对间接空冷塔流场特性的影响,得到不同风速工况下空冷散热器的散热量。结果表明,环境风工况下,展宽平台和塔体之间的非流线型连接将造成塔内较大范围的负压区,且环境风速越高,塔内负压区的范围越大。组合装置可使几乎所有扇段的换热量得到提高,总散热量在4 m/s和12 m/s风速下分别提高0.9%和17.6%,其中以侧风面扇段的改善效果最为明显。塔内挡风墙的长平板应沿主导风向布置,以达到更高的性能提升。

A new approach to improve the performance of indirect dry cooling tower(IDCT)under windy conditions is proposed in this manuscript by installing the combination of annular air deflector and interior windbreakers,aiming to alleviate the unfavorable effect of ambient wind.The proposed combination configuration may reduce the pressure drop at the inlet of radiators,shrink the negative pressure region and prevent hot wind penetration and the vortexes inside the tower.The impacts of the proposed combination configuration on the IDCT performance are investigated by means of numerical simulation based on Fluent Software.The heat rejection of radiator is calculated corresponding to different wind speeds.The results show that the negative pressure region is mainly caused by the poor connections between the widening platform and the tower shell.In addition,the scope of negative pressure region is enlarged with the increase in the wind speed.The heat transfers of almost all sectors are improved by the combined devices,especially for the sectors in the lateral side.Under the wind speeds of 4 m/s and 12 m/s,the overall heat rejections are respectively improved by 0.9%and 17.6%as considering the proposed combined devices.It is recommended to place one of long plates of the windbreakers rather than short plates in the dominant wind direction,aiming to achieve better performance improvement.