Numerical study of heat transfer in gravity-driven dense particle flow around a hexagonal tube

In the present paper, the heat transfer of gravity-driven dense particle flow around a hexagonal tube is numerically studied. The velocity vector, time-averaged particle contacting number, particle contacting time and heat transfer coefficient of particle flow are carfully analyzed. Furthermore, the heat transfer performances of particle flow around a hexagonal tube, circular tube and elliptical tube are also compared. The results show that, the effect of top angle (Θ) on the particle flow around a hexagonal tube is noticeable. When Θ decreases from 120° to 60° (v_out = 2 mm/s), the averaged heat transfer coefficient of particle flow would increase by 29.7%. The heat transfer performances of particle flow around different shape tubes are quite different. When Θ equals 60° (v_out = 2 mm/s), as compared with circular tube, the averaged heat transfer coefficient of particle flow around an elliptical tube and a hexagonal tube increases by 17.2% and 20.5%, respectively.