Numerical Simulation of Ice Accretion and Galloping Analysis of Auxiliary Conductors in Electrified Railway Overhead Contact Systems

Ice accretion and wind-induced galloping of auxiliary conductors threaten the operational reliability of electrified railway overhead contact systems. This study develops an integrated numerical framework for simulating ice-shape evolution and galloping responses of a 20.6-mm-diameter auxiliary conductor. Airflow and supercooled droplet trajectories are calculated using the SST k–ω model and the Lagrangian discrete-phase method, respectively. The Makkonen icing theory and Messinger heat-balance model are coupled to predict droplet collection, freezing, and ice growth. The effects of wind speed, droplet median volume diameter, liquid water content, and ambient temperature on ice morphology are investigated. A two-dimensional, two-degree-of-freedom fluid–structure interaction model is further established using an overset mesh and user-defined functions and validated through low-speed wind-tunnel tests. Results show that ice initially forms at the windward leading edge and extends toward both sides. Wind speed increases ice thickness and coverage, droplet size mainly enlarges the icing region, liquid water content promotes ice growth, and lower temperature concentrates ice on the windward surface. Unlike the decaying response of the bare conductor, the crescent-iced conductor exhibits sustained periodic galloping with amplitudes increasing markedly with wind speed. The proposed framework supports icing-risk assessment and anti-galloping design.