ABSTRACT
Knowledge regarding the static pressure drop in granular layers is of fundamental importance in the development of efficient drying and aeration projects of agricultural products. Thus, the objective of this study was to evaluate the effects of impurity contents on the static pressure drop in different bed depth of castor bean grains, as well as modify the mathematical models per the obtained experimental data and select the model that best represents this phenomenon. First, impurities in castor bean grains of the Guarani variety were eliminated and 6% of the moisture content (dry basis) was retained. The coarse impurity contents were obtained with 2%, 4%, and 6% of mass addition. The pressure drop in different bed depth of clean and impure castor bean grains were determined using an experimental determination equipment of pressure drop in bed depth with an airflow rate ranging 0.2 - 1.0 m3 s−1 m−2. The pressure drop linearly increases with an increase in the depth of the grain layer, and the increase in the airflow rate leads to an increased pressure drop in the castor bean grains layer. The impurity contents increase causes a reduction in pressure drop. The models that best represent castor beans grains pressure drop experimental data, without and with impurities, are Hukill & Ives (1955)Hukill WV, Ives NC (1955) Radial airflow resistance of grains. Agricultural Engineering 35:332-335. and Nimkar & Chattopadhyay (2002)Nimkar PM, Chattopadhyay PK (2002) Airflow resistance of greem gram. Biosystems Engineering 82:407-414., respectively.
KEYWORDS
bulk density; load loss; porosity; Ricinus communis L.; moisture content
