Mathematical Model for Solar Drying of Grains
A. O. Fagunwa *
Federal Institute of Industrial Research, Oshodi, Lagos, Nigeria.
O. A. Aregbesola
Department of Agricultural Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.
M. O. Faborode
Department of Agricultural Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Mathematical modeling of drying process is a complex procedure that should be carefully done. Moreso, model for solar drying, which is a unique method of drying due to constant fluctuation in the climatic conditions, requires complete integration of the complex phenomena that are involved for accurate prediction of moisture content and drying rate. A mathematical model was developed from heat and mass balance equation considering the physical and thermal properties of the grain, meteorological factors and convective heat transfer during solar drying of grains. The data obtained from the model was compared with experimental results obtained using a solar dryer to dry five selected grains – cowpea, soyabean, groundnut, maize and sorghum at airflow rates of 0.22 m/s, 0.76 m/s and 0.94 m/s. The results from statistical analysis and regression analyses used to compare the results showed that the model is adequate in predicting the moisture content and drying rate of the selected grains as well as other agricultural products with closer physical and thermal properties.
Keywords: Modeling, solar drying, moisture content, drying rate and grains.