Design and Development of a Pneumatic Based Abrasive Polisher for Pearl Millet (Pennisetum glaucum. L.)

A pneumatic polisher based on Storch 1 cyclone for polishing pearl millet was designed with different diameters. The study involved simulating the designs with varying diameters (0.15 and 0.20 m) and air inlet velocities (20, 25, and 30 m s^-1) to analyze total pressure and wall shear stress on polisher’s walls. A polisher with a diameter of 0.20 m was chosen for additional simulation to investigate the velocity and static pressure distribution within the polisher. Results of the simulation showed that the inlet air velocity has a substantial impact on both, the distribution of air velocity and the effectiveness of grain polishing. A polisher with a diameter of 0.20 m was developed, comprising an inner wall coated with a 254-micron abrasive surface. The independent variables used for evaluating performance of the developed pneumatic polisher were air inlet velocities (15, 20, and 25 m s^-1) and number of passes ranging from 10 to 80. The responses consisted of the degree of polishing (DoP), head yield (HY), and broken percentage (BP). Study demonstrated a positive correlation between the number of passes and the DoP while indicating a negative correlation between the number of passes and HY. The developed pneumatic-based polisher is applicable for polishing pearl millet with maximum and minimum DoP of 15.74% and 2%, respectively.