ASABE Technical Library - Abstract

Abstract. The effects of grain mass configuration and foreign materials content on airflow distribution inside a rice bin were investigated by using three dimensional computation fluid dynamics (CFD) simulations and experiments. A finite volume method with porous media formulation was used to simulate air flow characteristics in peaked, inverted, and leveled grain mass configurations for long grain rough rice with initial MC of 25% wet basis, porosity of 0.55, and mean particle size distribution of 0.00294 m. The airflow rates studied varied between 0.02, and 0.06 ms^-1. The model was validated with airflow velocity of 0.02 ms^-1 measured from a bin in field with cone shaped grain mass configuration and capacity of 700 Mt. The result showed that long-grain rice has viscous and inertial resistance coefficients of 2.6E-07 and 9317, respectively. Non uniform airflow distribution dominated peaked and inverted grain mass configuration with peaked configuration having the highest restriction to airflow. Airflow at peak positions in the bed were significantly (p<0.05) lower compared to other parts. The average non uniformity coefficient (NUF) measured directly from the bin was 34% and those obtained from the model using constant and variable porosities were 38% and 96%, respectively.