特大型冷却塔单塔内表面风荷载三维效应及其设计取值

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.

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

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 analysis 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 meridional 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.