Abstract:Pulverized coal combustion, flow, and heat transfer in Φ4.5 m×90 m alumina rotary kiln were simulated with FLUENT soft. Temperature and velocity distribution were obtained under different ratios between internal and external air volume. The results show that with ratio set to 0.6 and 0.8, temperature distribution shows better conformance. The effective length of flame can reach up to 8.6 m or above, and temperature can reach as high as 2 030 K, which accord with the requirements of clinker burning. The ratio can be adjusted within 0.6~0.8 in practice production. Axial velocity will drop with decrease of external air volume, and radial velocity will go down with the decrease of speed difference between internal and external air volume.