CFD prediction of cold airflow field for multiair channel pulverized coal burner in rotary kiln

This work presents a 3D numerical study with CFX - 4.3 software on airflow field of a four-air channel coal burner in alumina clinker rotary kiln. The main objective of this work is to investigate the effects of the geometric parameters and operation parameters of the burner on airflow field, which provides reference for simulation of temperature distribution, and for optimal design and operation of the multiair channel coal burner. A thermal measurement was conducted on one of the alumina clinker rotary kilns in China Aluminum Corp. Henan Division, then the boundary conditions for the calculation were determined by the measuring. The results show that the central backflow is mainly dependent on the shape of exit nozzles, the velocity of each airflow, while the external backflow and entrainment rate are mainly dependent on the velocity of external flow, the outlet nozzle mode of outer channel and the ratio of internal flow to external flow. Calculation also shows that the structure of whirl vane has an effect on central backflow and entrainment rate.