Grain movement between the cylinders of a semi-automatic rotary dryer during heating

The drying efficiency depends on many factors, in particular, on the movement of grain in the space between the outer cylinder and the inner cylinder during its heating and drying. During these periods, the grain layer in the space between the outer cylinder and the inner cylinder was divided into three sublayers: A, B, C. In sublayer A and sublayer B, not only convective heating of the grain will be carried out, but also heat transfer by the grain during its heating. In sublayer B, only convective heating of the grain is carried out, almost no heat transfer is carried out by the grain. Therefore, the presence of sublayer B is undesirable, or its thickness should be minimal. The only possible way to reduce the thickness of the sublayer B is to increase the width of the blades on the inner cylinder. On the other hand, an increase in the width of the blades on the inner cylinder will lead to an increase in the ratio of air flow velocities along the perimeter of the inner cylinder. Finally, the optimal width of the blades on the inner cylinder can be determined only after calculating the entire grain drying process.