Abstract: A three-dimensional model， which fully coupled the combustion， flue gas flow， flue gas and billet heat transfer in an eight-staged walking beam reheating furnace in a steel plant was established. The billet motion was simulated by the dynamic mesh method. The heat transfer between flue gas and billet in furnace， temperature uniformity and temperature distribution of billet under different cushion structures(i.e.， a column of cushion block， thousand island cushion block and dislocation beam)were analyzed. The results show that the proposed numerical model for reheating furnace can accurately simulate the combustion， turbulence and heat transfer processes. The structure of cushion block has a decisive influence on the temperature distribution of the billet. Thousand island cushion block and dislocation beam can reduce the temperature difference of skid marks by 40% and 50%， respectively. The numerical model can successfully solve the problems of billet movement and the coupled heat transfer between flue gas and billet for the complex structures like walking beam， billet， pad block and water pipe column in walking beam reheating furnace.

Key words: walking beam reheating furnace, combustion in furnace, coupled heat transfer, skid marks, numerical model