The Effect of Ventilation Hole Number on Flow Behavior and Heat Transfer of Rotary Drum Dryer

Abstract

The effect of ventilation holes on flow behavior and heat transfer of rotary drum dryer were studied by using Computational Fluid Dynamics (CFD). In the experimental apparatus, the drum was heated by direct burning with flame from LPG at the bottom surface of the drum. In steady state condition, the temperature distribution on the surface of the drum was detected by using infrared camera. The average temperature on the cap surface was 80oC, the drum surface was 130oC, and the temperature inside rotary drum was 120oC. In order to maintain the air temperature inside the drum at 120oC, the number of ventilation holes was varied by using CFD. In the 3‐D numerical model of the drum including ambient air was simulated in transient. The ventilation holes were drilled on the drum caps, and the number of the hole on each cap was varied at 6, 8, 12, and 18 holes. The results showed that the air temperature inside the drum at the condition of ൒12 holes was the highest with the shortest time. The longest time of 1,400 seconds and 1,600 seconds were observed to be uniform temperature and uniform velocity flow in this research.