PH—Postharvest Technology: Airflow induced by Falling Cottonseed Particles

Bulk materials falling freely in a chute draw air with them. Experiments were carried out to study the parameters that influence the induced airflow. The bulk material consisted of fuzzy and delinted cottonseeds and hulls. The experimental equipment included a loading, open hopper and an unloading enclosure connected to a chute. An orifice flowmeter was provided in the enclosure wall. The air drawn into the enclosure left it through the flowmeter orifice. The parameters varied during the experiments were the kind and the flow rate of falling particles, and the length, cross-section and slope of the chute. The measured data showed that the airflow rate grows with increasing chute length, cross-section or slope. The airflow rate also increased with the fuzziness of the cottonseed and decreased as the particles' terminal velocity increased. Dimensional analysis was used to formulate an approximate form of the law governing the process. It was found that the terminal velocity of the falling particles characterizes well their aerodynamic properties. Graphs plotted in accordance with the law developed in this work compared favourably with most measured data.