Browsing by Author "Osodo, Booker"

Now showing 1 - 2 of 2
  • Publication
    Publication
    Investigating the Effect of Selected Parameters on Moisture Removal Rate of an Experimental Forced Convection Solar Grain Dryer
    (Scientific & Academic Publishing, 2018) Osodo, Booker; Nyaanga, Daudi
    Although forced convection solar grain dryers achieve greater drying rates than natural convection dryers, optimum air velocity, grain layer thickness and drying air temperatures are necessary for improved performance. Number of trays used also affects performance. This study investigated the moisture removal rate (ratio of mass of moisture removed to mass of wet grain per hour) of a solar grain under different drying conditions. The effect of air velocity, layer thickness, number of trays and temperature on moisture removal rate (MRR) was investigated. MRR increased with increase in both drying air velocity and temperature at constant layer thickness. For 0.02 m thickness, MRR increased from 0.048 to 0.061 kg moisture / (kg wet grain. hour). However this increase was only significant at lower temperatures (below 45°C). Changing from 40 to 45°C caused a significant increase, but increasing temperature above 45°C did not. Also, MRR decreased with increase in layer thickness at constant air velocity. At 0.408 m/s air velocity, as layer thickness increased from 0.02 to 0.08 m, MRR decreased from 0.061 to 0.022 kg moisture / (kg wet grain. hour). Finally, when drying a given layer thickness, use of two trays did not significantly improve MRR.
  • Publication
    Publication
    Selection and Verification of a Drying Model for Maize (Zea mays L.) in Forced Convection Solar Grain Dryer
    (science and education publishing, 2017) Osodo, Booker; Nyaanga, Daudi; Muguthu, Joseph
    Various researchers have fitted experimental drying curves for various products to existing drying models. In this study, an experimental forced convection solar grain dryer was used to select the best fitting drying model for shelled maize. 0.04 m thick grain layer of shelled maize was dried an air velocity of 0.408 m/s and a 40°C drying air temperature. Using Root Mean Square Error (RMSE), Coefficient of Determination (R2) and Chi Square (𝜒𝜒2) the selected drying model was the one by Midilli et al. (2002), with R2, 𝜒𝜒2 and RMSE values of 0.9487, 0.4278 and 0.1723 respectively. The model coefficients were determined for drying air temperatures of 40, 45, 50 and 55°C. It was found that the predicted and experimental data agreed satisfactorily with R2 and RMSE values of 0.9225-0.9786 and 0.0325-0.0750 respectively. A computer simulation model was developed to predict moisture ratio at a given drying time.