The measurement and estimation of pressure drop through porous beds are important in the design and development of grain drying and aeration systems. Three inlet interconnected channels were designed and developed as inlet duct floors of an experimental grain silo. The channels were formed into shapes resembling the characters E, F and H. The pressure drop and air distribution were evaluated at different airflow rates for use as a small scale on-farm grain silo. It was observed that the pressure drop increased with the airflow rate and the height of the rough rice in the storage bin. Duct configuration of F and H represents the maximum and minimum values for pressure drop, respectively. The pressure at different heights inside the bed was uniform for all three air inlet duct configurations. Hukill & Ives and Ergun equations were used to fit with experimental data. The modified constant coefficients of both equations were determined for each of the three configurations. The Ergun equation fitted best the experimental data for the entire airflows range. Using the modified Ergun equation, a numerical simulation of the flow inside the rough rice bed was performed in the COMSOL Multiphysics software v6.1 and the velocity distribution inside the bed was presented. The simulated results revealed that the bin with H inlet duct configuration has better performance in continuous aeration process compared to E and F configurations, whereas an F duct configuration has better air penetration ability at the bottom and near the centre of the bin.