基于大涡模拟超大型冷却塔施工期风荷载时域特性分析  

Analysis on Time Domain Characteristics of Wind Loads during Construction Period of Super Large Cooling Towers Based on Large Eddy Simulation

作　　者：柯世堂[1] 徐璐[1] 朱鹏[1] KE Shitang;XU Lu;ZHU Peng(Department of Civil Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学土木工程系,江苏南京210016

出　　处：《湖南大学学报（自然科学版）》2018年第11期62-72,共11页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51208254);国家自然科学基金面上项目(51878351);中国博士后科学基金资助项目(2013M530255;1202006B);江苏省优秀青年基金项目(BK20160083);江苏高校"青蓝工程"资助项目;江苏高校优势学科建设工程基金资助项目~~

摘　　要：现有冷却塔风荷载研究成果均忽略了施工期的影响,以国内在建世界最高220 m超大型冷却塔为对象,基于大涡模拟(LES)方法获得了施工期冷却塔周围流场信息和三维气动力时程,并将成塔平均风压分布结果与规范及实测曲线进行对比验证了数值模拟的有效性.在此基础上,对比分析了冷却塔施工期平均风压分布规律和流场特性,并基于不同工况下冷却塔周围速度和涡量变化提炼出施工期流场特性与作用机理,揭示了施工期冷却塔脉动风压、极值风压、升/阻力系数及测点间相关性的分布规律,最终基于非线性最小二乘法原理给出了随高度变化的极值风压拟合公式.研究结果表明,端部效应的影响使冷却塔负压极值随施工高度增加由-3.91升至-1.75后降至-2.28,升力系数随施工高度增加逐渐减小,而阻力系数呈先减小后增大的趋势,脉动风荷载的相关性随高度变化先增强后变弱.主要结论可供此类大型冷却塔施工期设计风荷载取值参考.The impact on construction period is ignored in all existing research results on wind load of cooling towers.Taking the 220 m the world's highest super large cooling tower under construction as the example,the flow field information and three-dimensional aerodynamic forces during construction period are obtained based on large eddy simulation(LES)method.The validity of numerical simulation is verified through comparing the average wind pressure distribution of the entire tower with the standard curve and the measured curve.On this basis,the average wind pressure distribution and flow field characteristics under construction period are investigated.At the same time,the flow field characteristics and action mechanism are extracted from the velocity and vorticity changes of the cooling tower under different working conditions.The distribution regularities of the pulsating wind pressures and extreme wind pressures,lift/resistance coefficients and the correlations between points are revealed.Finally,the fitting formula of extreme wind pressures is given based on the nonlinear least square method.Studies show that the pressure extreme value on cooling tower firstly increases from-3.91 to-1.75,then decreases to-2.28 with the increase of construction height,the lift coefficient decreases with the increase of construction height,and the correlation of fluctuating wind loads firstly increases,and then decreases with height increase.Main conclusions can be used as reference to design wind loads on such large cooling towers during the construction.

关 键 词：超大型冷却塔 施工期 大涡模拟 时域特性 极值风压 相关性 

分 类 号：TU279.7[建筑科学—建筑设计及理论]