MODELING THE AIR FLOW RESISTANCE OF BULK SPONGE GOURD (LUFFA CYLINDRICA) SEEDS

Abstract

The knowledge of airflow resistant of agricultural materials is important to the design of drying and aeration systems and enhances proper fan selection for these systems. This study investigated the pressure drop across a bed of sponge gourd (Luffa cylindrica) seeds at moisture contents in the range of 9.98 to 16.5% (w.b), airflow rate of 0.11 to 0.32 m³s^-1m^-2, material bed depth (0.2 to 0.8 m) and bulk density (loose, medium, and high). Pressure drop data was fitted to three common airflow resistance models (Shedd’s, Hukill and Ives’s, and Ergun’s models). An empirical equation comprised bulk density, moisture content, and airflow rate was also developed to predict the pressure drop of sponge gourd seeds. Results obtained indicated that the airflow resistance of sponge gourd seeds increased with increase in airflow rate, bed depth but decreased with moisture content. Increased bulk density resulting from loose to densely filled resulted in an increase in resistance to airflow. Shedd model was selected to be the best for predicting pressure drop across bulk sponge gourd seeds for all the condition studied due to its high value for Coefficient of Determination (R²) of 0.996 and a low root mean square error value (0.0279) compared to other models. The empirical equation developed predicted well the pressure drop with R² and RMSE values of 0.950 and 0.264 respectively.