Research on the design load of the flights of a rotary kiln based on thermal granular flow coupling

The rotary kilns are widely used in chemical, food and metallurgical industries, and the design load of the internal flights has a significant effect on the drying efficiency of the rotary kilns. The motion of granular flow and heat absorption process inside the rotary kilns were simulated by establishing a coupled CFD and DEM model. The average heat absorption rate of granules was proposed to simulate the “L” type and three segments flights, and the results showed that the average heat absorption rate of granules was in accordance with the conclusions of previous scholars. We used the average heat absorption method of granules to optimize the structural parameters of the “J” type flights design load, the best parameter was obtained, and then compared with the “L” type and three segments of the flights, we found that the drying efficiency of “J” type flights is the best, followed by three segments and “L” type is found to be the worst. At the same time, the active region was divided to explore the relationship between the area occupied by the granules in different regions and the average heat absorption rate of granules, and it was found that under the same shape of the flights, the larger the area occupied by the granules in region 2, the larger the corresponding average heat absorption rate of granules.