论文部分内容阅读
为考察八分裂导线阻力系数的屏蔽效应，设计制作了3种典型导线刚体模型和真型导线，采用水平横向布置的形式，进行了风洞实验。研究了风速、紊流度、迎风角度、导线直径等因素对八分裂导线阻力系数的影响。试验结果表明：均匀流场中，输电导线阻力系数随风速的增加有明显的降低，存在一个极小值，之后随风速增加而缓慢升高至稳定值；紊流场中的导线阻力均小于均匀流场数值，紊流场的阻力系数试验曲线的临界点较均匀流场更为靠前。3种型号的八分裂导线阻力系数在39.8 m/s 风速时较规范值均有大幅降低，导线直径越大，屏蔽效应越明显，阻力系数降低幅度越大。与现行规范结果相比，八分裂900/40导线在迎风角度变化过程中最大降低百分比为28.2%。在计算大截面八分裂导线风荷载时，现行规范风荷载偏于保守，可以考虑八分裂导线的屏蔽效应。“,” In order to investigate the shielding effects on drag coefficient of 8-bundled conductors, wind tunnel test on three typical rigid conductor model sections and real conductors placed horizontally with a supporting system were put forward. The factors that affect the drag coefficient, such as wind velocity, turbulence intensity, wind attack angle, and conductor diameter were studied. The results show that the drag coefficient drops obviously to a minimum value as the wind velocity increases to a relatively lower value. As the wind velocity increases to relatively higher, drag coefficient increases to a constant regardless of wind velocity. The drag coefficient in the turbulent flow is smaller than that in uniform flow and the critical wind velocity at the bottom of the curve in turbulent flow is also smaller that in uniform flow. Compared with the recommended value by the current design code, the drag coefficients for the three types of 8-bundled conductors decrease significantly under the wind velocity of 39.8m/s. The larger the diameter, the more obvious the shielding effects. The maximum reduction of drag coefficient for 8-bundled 900/40 conductor is 28.2% lower than that of the design code, which shows that the drag coefficient in the current code for large cross-sectional 8-bundled conductor is conservative. Shielding effect should be considered in calculation of wind load for large cross-sectional 8-bundled conductors.