特大型冷却塔单塔内表面风荷载三维效应及其设计取值

Three-dimensional Effect and Design Values of Inter Surface Wind Loading for Single Super-large Cooling Tower

通过刚性模型测压风洞试验获得某核电站220m高特大型冷却塔的内表面风荷载,分析冷却塔内表面风荷载的三维效应,采用有限元计算方法对内压设计取值简化进行探讨,并对结果产生的原因进行分析.结果表明,冷却塔内表面风压并非完全沿环向、高度均匀分布,这种不均匀性以风筒施工期间的空塔尤为严重;尽管内压的大小及分布特征会对响应产生一定的影响,但由于冷却塔的风致响应中以外压占主导地位,内压对响应的贡献较小,将具有'三维效应'的内压简化为沿高度、环向不变的常数进行设计可满足安全性要求,大小可取为-0.50.研究结果可为200m级特大型冷却塔设计内压取值和相关规范修订提供参考与依据.

Wind tunnel tests were carried out to measure the wind pressure on the internal surface of a 220 m-high super large cooling tower,and then analysis on the three-dimensional effect of internal pressure was conducted,and finally,simplified methods for obtaining the design value were investigated.The anal-ysis results indicate that the wind loads on the internal surface of the cooling tower behave with remarkable three-dimensional effect,and they are not strictly uniformly distributed along both the hoop and the merid-ional direction.This nonuniformity is particularly serious when the tower is in the construction period. The size and the distribution of the internal pressure have some influence on the wind-induced response, but because the outer pressure plays a dominant role in the wind-induced response of cooling tower,the contribution of the internal pressure to the response is small.So the design value of internal pressure can be simplified as constant -0.50,which is proved to be very safe for the structure.The results can provide reference for both the design of 200 m high super-large cooling tower and our specification revision.