Convective heat transfer coefficient is a key parameter in an ice thermal balance

and its accurate calculation plays an important role in improving the calculation accuracy of the heat balance equation. In the past

the iced conductor was usually treated as a smooth cylinder in the simulation of iced conductor. However

the freezing of supercooled droplets will lead to the difference of icing shape and the increase of roughness height of icing surface

which will greatly affect the calculation accuracy of heat transfer characteristics of icing conductor surface. Consequently

we established a finite element model of ice-coated transmission line with rough surface height for the working condition of hard fog and ice-coated surface. Moreover

we analyzed the influences of rough surface height of ice-coated conductor on its heat transfer characteristics by means of a fluid dynamics numerical simulation method. The results show that the surface roughness height of icing wire will change the fluid flow in the boundary layer

aggravate the fluid disturbance and enhance the heat transfer effect. When Reynolds number is 40 000

compared with the previous smooth icing model

rough icing model average heat transfer coefficients will increase to 1.333

1.452 and 1.667 times. In the same circumstances

crescent icing turbulent structure is slightly lower than the overall level of circular icing structure

and the average is less than the circular structure on icing flow heat transfer coefficient.