风雨共同作用超大型冷却塔气动力和受力性能

为定量评价雨荷载对超大型冷却塔气动力和风效应的影响,以国内某在建世界最高的220m超大型双曲线间接空冷塔为例,基于计算流体动力学(computational fluid dynamics,简称CFD)方法对冷却塔周围风场进行数值模拟,验证模拟结果的有效性后添加离散相模型(discrete phase model,简称DPM)进行雨强为50mm/h的暴雨模拟,系统分析了风雨共同作用下冷却塔表面流体绕流特性、风雨荷载特征值及平均压力系数的变化。在此基础上,采用有限元方法分析了风荷载和风雨荷载共同作用下超大型冷却塔风致稳定性和受力性能。研究表明:冷却塔表面所受总雨荷载占总风荷载的6.71%,部分区域内雨压系数可达0.07以上,与风压系数的比值最高可以达到26.98%;相比于风荷载,风雨荷载共同作用降低了冷却塔整体屈曲稳定和局部稳定性能,增大了塔筒、支柱和环基结构内力响应,屈曲位移最大增量达10%,0°子午向轴力最大增量达17.4%。该结论可为此类大型冷却塔结构抗风/雨荷载设计提供参考依据。

Aerodynamic Forces and Mechanical Properties Studies for Super Large Cooling Towers Under Simultaneous Action of Wind and Rain

In order to quantitatively evaluate the influence for rain load on aerodynamic force and wind effects of super large cooling towers, a 220m high (the highest in the world) indirect air hyperbolic cooling tower which is being built in domestic is taken as an example. Firstly, the wind field around the cooling tower is simulated based on computational fluid dynamics (CFD) method, and the strong rainstorm of 50 mm/h is also simulated by adding the discrete phase model (DPM) after the effectiveness is verified. Flow characteristics, characteristic value of wind and rain loads, change of mean pressure coefficient were systematically analyzed. On this basis, the stable performance and mechanical property of super large cooling tower are analyzed contrastively under simultaneous action of wind and rain with finite element method. Studies show that the total rain load of cooling tower surface is up to 6.71% of total wind load. Rain pressure coefficient can reach more than 0.07 in a particular area, and the ratio is even up to 26.98% compared with the wind pressure coefficient. Compared to the wind load, buckling stability and local stability of cooling tower are reduced and the inner force of drum, pillars and base of cooling tower are increased under simultaneous action of wind and rain. The maximum buckling displacement of cooling tower increased about 10%, and axial force of windward side increased about 17.4%. Main Conclusions can provide references for wind/rain loads design of such large cooling towers.