Experimental and numerical investigations on heat transfer of a water-cooled lance for blowing oxidizing gas in an electrical arc furnace

•Numerical and experimental investigations of the electrical arc furnace are conducted.•A 3D model accurately predicts the experimental data taken from thermograph pictures.•New cooling system for blower is designed, constructed and tested inside the furnace.•Maximum temperature of external surface in new system is 170°C lower than old system.•Equipment lifetime improves from 1500 to 1775 melts to 2500 during one-year operation.