【作者】 邹云峰；

【导师】 陈政清；

【作者基本信息】 湖南大学 ， 土木工程， 2013， 博士

【摘要】 随着我国电力事业的发展，我国冷却塔高度即将突破200m，远远超过我国现行冷却塔设计规范165m的高度限值，也将创造新的世界纪录。为保证此类超大型冷却塔的安全性与经济性，同时也为我国规范的修订提供依据，本文采用风洞试验、CFD数值模拟和有限元响应分析等手段对200m高超大型冷却塔的风荷载、响应特性和风致干扰进行研究。本文主要研究内容和成果有：(1)通过CFD数值模拟对刚性模型内表面测压风洞试验存在的不足进行了分析，表明风洞试验得到的结果仍然可靠。风洞试验结果表明，冷却塔内表面风压受塔内雷诺数、风向角影响较小，而受十字挡风挡板和填料层透风率影响较大；总的来说，内压沿环向、高度基本不变。(2)分析了粗糙条各参数对风压分布的影响，发现粗糙度系数k/s是描述粗糙度大小的重要参数，风压分布与之密切相关；给出了根据k/s估算风压的计算公式和粗糙度雷诺数ReR与最小风压系数Cpmin之间的函数关系式，据此可较精确的预测待模拟目标曲线所需的粗糙度和试验风速大小。(3)对单塔外、内表面风压的三维绕流特性和设计取值简化进行了研究，发现冷却塔外表面风荷载三维效应显著，内压也并非严格的沿环向、高度均匀分布；证明了冷却塔变形以壳体的局部变形为主，响应大小与外表面风压分布特征密切相关，而与阻力系数大小并无绝对关系；外、内表面风压设计取值分别简化为“代表性曲线”和常数-0.50可保证结构的安全性。(4)通过理论推导和有限元方法证明了气动弹性连续壳体模型能同时满足冷却塔壳体、人字柱的各项刚度相似要求，并能实现质量、刚度的连续分布；发明了一套精度较高的冷却塔气动弹性连续壳体模型制作工艺，并利用高精度激光位移计对它的风振响应进行了深入分析，结果表明良态气候下冷却塔的风致响应不大，动力放大效应不明显。(5)基于刚性模型同步测压风洞试验对双塔干扰效应进行了研究，发现风致干扰对风压分布形态影响较大，并以串列时的下游塔最为严重；不同荷载参数得到的干扰因子差别较大，即使是同一荷载参数，由不同特征值得到的干扰因子也有差异；模型表面粗糙度对风荷载干扰因子影响较小。(6)利用气弹模型对双塔风致干扰效应进行了研究，发现动力响应特性受干扰影响较小，而风振系数略有增大；由反映荷载大小的力系数得到的干扰因子并不能真实反映干扰效应对响应的影响，冷却塔的风致干扰效应大小应以风致响应来考察；风致响应干扰因子受表面粗糙度影响较小。更多还原

【Abstract】 With the development of Chinese electrical utility, the height of the coolingtower is going to surpass the level of200m, with breaking through the world record,which is far exceed the limit height of165m in our current cooling tower designspecifications. In order to ensure the security and economy of such large coolingtower, as well as to provide reference for our specification revision, the wind load,response characteristics and wind-induced interference for200m high super largecooling tower are studied by wind tunnel tests, CFD simulations and finite elementanalysis of response in the present work. The main contents and conclusions aresummarized as follows:(1) The shortcomings of the rigidity model manometric experiment for innersurface pressure were analyzed by CFD simulations. The results show that the windtunnel test is still reliable. The wind tunnel test results indicate that the wind pressureof inner surface is less affected by Reynolds number and wind direction, while theventilation ratios of stuffing layers and cross baffle significant ly impact the internalwind pressure. In general, the internal pressure along hoop and meridional arebasically the same.(2) The influence of various parameters for rough strips on pressure distributionwere analyzed. It was found that roughness coefficient k/s is an important parameterto describe the roughness size, which closely affect the pressure distribution.Meanwhile, the estimation method of pressure according to k/s and the relationshipbetween roughness Reynolds numberRe Rand minimum pressure coefficient Cpminare obtained, according to which the test wind speed and roughness could beaccurately predicted for the simulation of target curve.(3) Wind loads characteristic and their design value of both outer and innersurface were investigated. It is shown that the wind loads on outer surface of thecooling tower behaved the remarkable three-dimensional effect, and the internalpressure is also not strictly uniformly distributed along the hoop and meridional. It isproved that local deformation of cooling tower play a major role in the total response,and the wind-induced response is closely associated with the distributioncharacteristics of wind pressure, while there is no clear description on relationshipbetween wind-induced response and the value of drag coefficient. It was also found that the design value of outer and inner surface could be simplified by representativecurve and constant-0.50respectively, which are proved to be sufficient safe for thestructure.(4) Similarity relations for full aero-elastic model of cooling tower were derivedand verified by finite element method, which show that full aeroelastic model cansatisfy the similar relationship of both cooling tower shell and column, and canachieve a successive distribution for mass and stiffness. A full aero-elastic model wasdesigned and processed with sufficient accuracy, and it’s wind-induced response wasmeasured by high-precision laser displacement meter and the data was carefullyanalyzed. The results show that the wind-induced response and dynamic amplificationof cooling tower is not obvious in normal climate.(5) Wind tunnel tests were carried out to study wind-induced interference effecton two200m high adjacent super large cooling towers based on rigidity modelsynchronization manometry wind tunnel tests. The results show that wind-inducedinterference affected the distribution of wind pressure significantly, particularly forthe downstream tower in the tandem configuration. Meanwhile, it is found thatinterference factors calculated by different load parameters are different, even for thesame load parameter, different eigenvalues could result in different values. Inaddition, test result show that surface roughness has less effects on the wind loadinterference factor.(6) Wind tunnel tests were carried out to study wind-induced interference effecton two200m high adjacent super large cooling towers based on full aero-elasticmodel. The test results indicate that interference effect has less effect on dynamicresponse characteristics, while gust loading factor increases slightly. Also,interference factor result from wind loads does not represent the effect of interferenceon the response, wind-induced interference effects of cooling tower should beexamined by wind-induced response. In addition, interference factor calculated bywind-induced response are less affected by surface roughness.更多还原