Moisture Dependent Physical and Engineering Properties of Sorghum Grains

An experimental study on engineering, frictional, and aerodynamic properties of sorghum grain was conducted which are essential to design different post-harvest gadgets such as threshers, winnowers, and storage bins. Since most of the post-harvest operations of sorghum are accomplished within moisture content range from around 10.0% to 25.0% (wb) in India, the study was conducted within the moisture content range from 8.7% to 21.8%(wb).It was observed that the linear dimensions such as length, width, and thickness increased with an increase in moisture content in the said range. With an increase in moisture content, the geometrical mean diameter, arithmetic mean diameter, square mean diameter, and equivalent mean diameter increased from 3.20 to 3.53 mm, 3.38 to 3.70mm, 5.74 to 6.30 mm and 4.11 to 4.51 mm, respectively. The coefficient friction for glass, mild steel surface, GI sheet, and plywood increased linearly from 0.25 to 0.31, 0.26 to 0.43, 0.27 to 0.42, and 0.30 to 0.45, respectively with an increase in moisture content. It was observed that glass has the lowest coefficient friction whereas plywood has the highest coefficient of friction as compared to other 3 surfaces. Angle of repose, terminal velocity, aspect ratio, sphericity, surface area, volume, and 1000 grain weight were increased from 39.840 to 43.190, 7.06 to 7.99 m-s, 0.705 to 0.735%, 32.27 to 39.25 mm2, 17.25 to 23.13 mm3 and 20.67 to 22.01 g, whereas bulk density, true density and porosity decreased from 755.75 to 723.50 kg m-3, 1671.50 to 1161.00 kg m-3 and 0.53 to 0.37% within the said moisture content range.