扇形覆冰导线气动力特性及驰振不稳定性研究

Aerodynamic force characteristics and galloping instability of a sector-shape iced conductor

采用刚性节段模型高频天平测力风洞试验测试了不同紊流度下的8种扇形覆冰导线气动力,依据DenH-artog驰振机理分析了扇形覆冰导线的横风向驰振不稳定性,讨论了覆冰厚度、覆冰角度、紊流度对平均气动力特性及横风向驰振不稳定性的影响。结果表明:覆冰厚度的增大增强了气动升力,不同覆冰角度模型平均气动力系数随风向角的变化规律差别较大,紊流度的增高有助于减小覆冰导线承受的平均气动力;8种扇形覆冰导线在不同风向角下均有发生横风向驰振的可能,覆冰角度对驰振不稳定风向角位置及范围有较大影响,紊流度的增加提高了可能的驰振临界风速,因此高紊流度对驰振有一定的抑制作用。

By applying a high frequency balance technique to rigid section models in wind tunnel, aerodynamic forces of eight sector-shape iced conductor models were investigated in different turbulent intensity flows. Galloping instability of sector- shape iced conductors were＇predicted with DenHartog galloping criterion. The effects of ice thickness, ice angle, turbulent intensity on＂ aerodynamic forces and galloping instability were also discussed. The results indicated that the aerodynamic lift force is reinforced with increase in ice thickness; aerodynamic force variations with wind direction are significantly affected by ice angle; aerodynamic forces decrease with increase in turbulent intensity; the cross wind galloping of eight models possibly occurs with different wind direction angle significantly affected by ice shape; the occurrence of galloping is prevented under higher turbulent intensity because of higher galloping critical wind speed.