直接空冷风机进口空气流动特性

Inlet Flow Characteristics of Fans in Direct Dry Cooling Systems

直接空冷风机数十台集群运行,掌握其运行特性,对空冷系统的设计、运行具有指导意义。在空冷风机集群效应中,风机进口空气流动特性又是影响集群运行的关键因素之一。文中从数值模拟和模型实验2个角度探讨了空冷风机(群)进口流动特性。研究结果表明,单台风机运行时,由于进气角度过大。最外侧出现速度较小区。当有风机抢风时,这一情况改善,但最外侧的风机进气条件不好,这是产生风机群集群效应时最外侧风机流量偏小的原因之一。文中提出位置系数的概念,并用位置系数分析了6台风机同时运行时的进口空气流动特性,为进一步揭示风机群的运行规律提供参考。

Tens of axial flow fans are arranged in an array in the direct dry cooling system.It is benefit to the design and operation of air-cooled condensers to investigate the aerodynamic behavior of the array of axial flow fans,in which the inlet flow characteristics of axial flow fans are key issues.The numerical simulation and model experiments were presented to clarify the inlet flow characteristics of axial flow fans.The results show that the flow distortion induced inlet flow angle is so high that the exterior flow area of the axial flow fan has small velocity when the axial flow fan is independently running.It is improved when the axial flow fan is running together with other fans.The inlet flow distortions are deteriorated for the exterior fans in the array of axial flow fans,resulting in the low flow rates for the exterior fans.The location coefficient was proposed to evaluate the inlet flow characteristics of six axial flow fans,which is of importance to further clarify the cluster operation of axial flow fans in direct dry cooling system.