Modeling and numerical simulation of residence time of cut tobacco in cylinder dryer

For deeply studying the drying process inside a cylinder dryer and promoting cigarette quality, a model for the residence time of cut tobacco in a cylinder dryer was established by analyzing the movement process of cut tobacco inside a cylinder. The variations of theoretical model along with the changes of technical parameters were analyzed via numerical simulation. The results showed that: the residence time of cut tobacco decreased with the increase of rotational speed, radius and inclination angle of cylinder, slightly reduced with the increase of air velocity inside cylinder, and positively proportioned to cylinder length. Technical parameters in the order of their influences on cut tobacco's residence time were inclination angle > radius > rotational speed > cylinder length > air velocity. Experiments were carried out to validate the relationship between cylinder rotational speed and cut tobacco residence time, the results well agreed with the results of numerical simulation. The model can predict the residence time of cut tobacco in a cylinder dryer accurately and is helpful to process control of cut tobacco drying and the improvement of processing quality.