输电线路气动力系数研究

Research on the Aerodynamic Coefficient of Transmission Lines

对于型式复杂杆塔的塔头和横担等部位,一般推荐高频测力天平试验等方法确定其气动力系数。对于常规构件和杆塔,气动力系数与构件尺寸、形状、环向角(风向与角钢对称轴的夹角)、风向角(风向与线条方向的夹角)、雷诺数、杆塔密实度(杆塔投影面积与轮廓面积之比)等参数相关。有关资料表明,国内规范存在角钢塔气动力系数取值偏小、气动力系数随填充系数的变化规律不同。为此,对A、B、C、D、E、F、G七个地区荷载规范及线路设计规范中输电线路构件及杆塔气动力系数的规定进行了系统性的梳理比较,归纳出气动力系数的统一表达式。结合已有试验结果和工程经验对表达式中各参数进行了分析和拟合,总结出适用于输电线路构件及杆塔的气动力系数建议值,为输电线路抗风设计提供参考。

For complex tower types such as tower heads and cross arms,it is generally recommended to use methods such as high-frequency force balance tests to determine their aerodynamic coefficients.For conventional components and towers,the aerodynamic coefficient is related to the component size,shape,circumferential angle(the angle between the wind direction and the symmetry axis of the angle steel),wind direction angle(the angle between the wind direction and the line direction),Reynolds number,tower compactness(the ratio of the tower projection area to the outline area)and other parameters.According to relevant data,there are differences in the values of aerodynamic coefficients for angle steel towers in domestic regulations,as well as the variation patterns of aerodynamic coefficients with filling coefficients.Therefore,the provisions of the aerodynamic coefficient of transmission line components and tower in the load codes and line design codes of A,B,C,D,E,F and G are systematically sorted out and compared,and the unified expression of the aerodynamic coefficient is summarized.Based on existing experimental results and engineering experience,various parameters in the expression are analyzed and fitted,and recommended aerodynamic coefficients for transmission line components and towers are summarized,providing reference for wind resistance design of transmission lines.