多回路高压输电塔典型横担结构风力系数风洞试验研究

Experimental study of wind force coefficients on typical crossarms of a multi-circuit high-voltage transmission tower

应用高频测力天平技术,对多回路高压输电塔典型横担模型进行了不同紊流度下的风洞试验,研究了其风力特性。结果表明风场对横担结构的平均风力系数影响较小,静风力主要以顺风向风力为主,而顺、横风向和扭矩向脉动风力值都较大,不能忽略。横担阻力系数0°风向附近取值最大,随风向基本呈单调递减趋势。通过对比不同模型升力系数可以发现,升力系数取值与横担的长度有关,横担越长,横风向升力系数越大。不同规范中给出阻力系数与本文试验结果较为接近,但需要注意的是,相关格构式结构规范均未考虑横、扭风向风力对结构的影响。通过相关性分析可以看到,横担基底剪力与扭矩相关性很小,风场对相关性有一定的影响。

Typical crossarms of a multi-circuit high-voltage transmission tower have been tested in a wind tunnel using high-frequency-force-balance technique to investigate the characteristics of wind forces acting on them.The results indicate that along-wind wind force is the major load on the crossarms for the static wind effects,while magnitudes of the along-wind,across-wind and torsional fluctuating loads are in the same level and each of them cannot be ignored.The drag coefficients of crossarms reach maximums at the 0＆#176;wind direction and generally decrease with the incoming wind directions.By comparing the lift coefficients of testing models,it can be seen that the lift coefficients of crossarms have a great relationship with the length of side arms.With the increase of side arm＇s length,the lift coefficients will be larger. At same time,some exiting codes about drag coefficients are compared with testing results,it turns out that the testing results are very close to the code values,but all the codes do not consider the impact of across-wind force and the torsional moment acting on the crossarms.In addition,the correlation of along-wind,across-wind and torsional forces is small;wind field has some influence on the correlations.