| dc.description.abstract | The heat transfer coefficient between side wall and granular material in indirect heated rotating drum under different rotational speed and wall roughness was experimentally investigated in this study. The drum made by aluminum with inner diameter of 100 mm, thickness of 10 mm. Test particles are 2 mm glass beads. Smooth side wall and 1 mm, 2 mm, 2.5 mm, 3 mm, 5 mm glass beads be glued on side wall to provide six roughness factor: 0, 0.5, 1, 1.25, 1.5, 2.5. The drum be operated under rolling regime for rotational speed 3, 6, 9, 12 rpm. Drum be heated by electric heater apply constant heat flux from initial temperature 25 to final temperature is 60 . Obtain the temperature field by IR camera to calculate heat transfer coefficient. Analysis granular motion behavior by PIV to calculated velocity field. The area ratio is used to express the mixing ability of the particles. According to the results we find higher roughness factor will cause higher the heat transfer coefficient because thermal contact resistance decrease. Higher rotational speed will enhance granular convection and heat transfer coefficient. The heat transfer coefficient and area ratio of smooth wall and rough wall are expressed as two linear functions. The initial spacing is caused by the contact resistance. | en_US |