PH—Postharvest Technology: Airflow Resistance of Green Gram

Pressure drops were measured in clean green gram beds at moisture content in a range of 8·36–16·65% d.b. for superficial air velocities which ranged between 0·0104 and 1·0875 m3 s−1 m−2 at bed depths of 0·2 to 0·6 m with bulk density ranging from 760 to 855 kg m−3. The airflow resistance of green gram increased with the increase in airflow rate, bulk density, bed depth and decreased moisture content. Results indicated that 1% increase in moisture content decreased the pressure drop by 2·43% whereas, 1% increase in bulk density increased the pressure drop by 6·6%. Modified Sheddʹs equation, Hukill and Ives equation and modified Ergun equation all with two parameters were examined. Airflow resistance was accurately described by modified Sheddʹs equation and an empirical equation, composed of airflow rate, moisture content and bulk density.