大型冷却塔风荷载干扰系数的取值方法  

Discussion on different methodologies for calculating interference factor of large cooling towers

作　　者：周旋[1] 牛华伟[1] 陈政清[1] 王振宇[2] 

机构地区：[1]湖南大学风工程试验研究中心,湖南长沙410082 [2]华东电力设计院,上海200063

出　　处：《中南大学学报（自然科学版）》2014年第10期3637-3644,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学青年基金资助项目(50908085);国家自然科学基金重大资助项目(91215302)~~

摘　　要：以国内某电厂超大型冷却塔为研究对象,采用刚性模型测压试验方法获得塔体表面风压时程,通过计算获得各风向角下按不同取值依据得到的干扰系数,探讨合适的取值方法以指导设计。基于风洞试验风压测试数据和有限元时程响应分析得到的位移和应力数据,分别计算群塔状态的干扰系数,比较分析不同干扰系数的特点,进一步基于风压分布积分表达式推导力系数与风压系数之间的关系,并比较研究双塔布置状态下不同干扰系数取值方法之间的差异。研究结果表明:与响应干扰系数相比最大正压干扰系数偏小而最小负压干扰系数偏大,阻力系数干扰系数无法完全衡量壳体响应干扰效应,而通过有限元计算得到的位移或应力干扰系数离散性较小且直接反映风荷载作用效应,推荐设计中以之为依据进行取值。With two super large cooling towers of a domestic power plant to be built, a rigid model was made to obtain wind pressure time history on the tower surface. Different interference factors of several azimuths were calculated by different methods. In order to find an appropriate method to calculate interference factor, the characteristics of different interference factors were compared. Based on wind pressure test data and FEM analysis results of stress and displacement,different interference factors were calculated and compared respectively. Furthermore, based on the wind pressure distribution integral expression, the relationship between the force coefficient and wind pressure coefficient was deduced,and double towers interference was also experimented to compare different interference factors using different calculation methods. The results show that the interference factor calculated by maximum positive pressure coefficient is smaller than that calculated by response, while the interference factor calculated by minimum negative pressure coefficient is larger than that calculated by response. And the interference factor calculated by drag coefficient cannot show shell response interference effect completely. However, using the stress or displacement obtained by FEM analysis to calculate interference factors has smaller discreteness and reflects the interference effect of tower response directly, which is recommended as design basis.

关 键 词：冷却塔 风洞试验 刚性模型 干扰系数 双塔干扰 

分 类 号：TU317.1[建筑科学—结构工程] TU311.3