Airflow resistance and pressure drop behavior in different conditions of bulk‐stored onion and its dynamic modeling

Abstract

The knowledge of airflow resistance and distribution pattern in a highly porous-bed commodity like an onion is an important consideration in designing an appropriate ventilation system and for proper selection of fans. The resistance to airflow through bulk onions was determined at the airflow rates range of 0.04–1.0 m3/s.m2, bed depth of 0–100 cm, and scaled and descaled condition of onion at vertical and horizontal position of the onion stock. Three models (Shedd, Hukill and Ives, and Ergun) were investigated to describe pressure drop data of onion bulbs. The pressure drop through bulk onion was increased with an increase in airflow rate and bed depth. Also, pressure drop was 43.5 and 33.3% higher in scaled condition over the descaled condition of bulbs at the vertical and horizontal position of the column, respectively. Shedd model was found to more reliable among three models to describe airflow resistance in bulk of onion bulbs.