EXPERIMENTAL STUDY OF AIR PULSE AND MECHANICAL IMPACT TO PREVENT SILO BLOCKAGE

A laboratory silo is developed to study the obstruction a11d discharge rate in detail. Effects of the silo geometrical parameters and physical properties of the stored materialsare investigated. These properties include the hopper angle, hopper outlet size, materials type, materials mesh size and moisture. Results show that the materials moisture has undeniable effect on the obstruction occurrence. Auxiliary mechanisms including an air pulse system and a mechanical impact mechanism are employed to facilitate the material flow and solve the jamming problem. For instance, it was proved that the air pulse is a11 acceptable equipment to overcome the silo jatnming however. by increasing the moisture its ability is reduced. As another conclusion, it was seen that by increasing the average grain size, the anti-jamming performance of the air pulse was reduced. Moreover, it was seen that impact mechanism is a good candidate as anti—jamming aid. It prevented the jamming of silos containing a wide range of granules from micron to centimeter. Actually, both flow aid methods reduced the critical dimensionless outlet size ratio however, for the test conditions in the current study, the impact mechanism acted more successfully. Results of the current research can be useful in both theoretical and practical viewpoints.

Keywords:

Silo: Blockage , Jamming , Air pulse , Impact , Cohesive powder