格构式塔架风力特性试验研究

Experimental study of wind force on latticed tower

应用高频测力天平技术,对格构式输电塔塔身模型进行了不同紊流度下的风洞试验,研究其风力特性。结果表明风场对塔架结构的平均风力系数影响较小,塔架结构平均风力以顺风向风力为主,顺风向的脉动风力大于横风向,扭转脉动力可以忽略不计。同时还对比了不同国家规范中关于格构式塔架平均阻力系数的规定。谱分析表明,塔架结构顺风向主要表现为来流紊流激励;横风向力谱较为复杂,可能存在复杂的激励机制;塔架扭转功率谱是一明显的宽频谱,较顺、横风向功率谱值小很多,且随紊流度谱值变化不大。相干性分析表明,塔架结构横风向基底剪力与基底扭矩的相干性较强,紊流度对其影响不大。

A model of latticed tower(LT) was tested in TJ-1 wind tunnel in Tongji University using high-frequency-force-balance technique to investigate the characteristics of wind forces acting on the tower.The results indicate that the mean force coefficients have no practical variability with turbulence.Along-wind wind force is the major load on the LT for the static wind effects,and along-wind fluctuating forces are larger than across-wind fluctuating forces,but the fluctuating torsional force can be ignored.Some exiting codes and standards about mean drag coefficients were compared.Based on the analysis of power spectrum densities(PSDs) of the forces,some conclusions are drawn that incoming wind turbulence has great contribution to along-wind forces,and PSD of across-wind forces is more complicated,multiple excitations may exist.In addition,the torsional PSD is a broadband frequency spectrum,and its value is smaller than PSD values of along-wind and across-wind force.With the increase of turbulence,the torsional PSD value does not change remarkably.Furthermore,the coherence between across-wind forces and torsional moment is strong,and turbulence intensity has little influence on coherence.