为克服目前输电线覆冰数学模型存在各种上缺陷的问题,利用输电线雾凇覆冰的数值模拟方法系统探讨了输电线覆冰过程中过冷却水滴撞击输电线表面的碰撞特性,分析总结了各碰撞特性参数之间的相互依赖关系并导出了简单有效的碰撞特性估算公式,分析结果表明,水滴与筒状物的总碰撞率可由Finstad经验公式描述,局部碰撞率沿冰面为抛物线分布。在碰撞特性估算公式基础上分别给出不同状态下输电线雾凇覆冰的工程估算方法,估算结果表明,圆筒状雾凇覆冰估算工程模型结果与实验结果比较相符,表明估算方法正确有效;固定导线雾凇覆冰工程估算方法结果与数据模拟结果相较,覆冰质量估算的误差较小,但覆冰外形有一定的差别,需要进一步改进外形估算方法。
The collision parameters of super-cooled water droplet impingement on transmission lines are investigated from a 2-D icing model simulation of the rime accretion process on transmission lines. Two important collision parameters of the icing model, i. e. , the collision efficiency and local collision efficiency, are evaluated on the basis of time-dependent airflow computations and water droplet trajectory calculations. Results show that the collision efficiency agrees well with the Finstad's formula and the local collision efficiency is in parabola distribution along the ice surface. Based on the study of the interrelationship among collision parameters, an estimating formula is established for the local collision eefficiency. Furthermore, engineering estimation method is presented for circular shape ice accretion and fixed transmission lines ice accretion, respectively. The estimated results agree well with the former and differ slightly from the latter.