Estimation Engineering Method of Rime Accretion Process on Transmission Lines

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.