EXPERIMENTAL INESTIGATION ANID COMPUTER MODELING OF HEAT AND MASS TRANSFER DURING CASSAVA MASH DRYING

Abstract

This work presents a mathematical model of gari drying in which diffusion of water, moisture evaporation, heat and mass transfer through tile porous solids were taken into consideration. Several tests were run using a Laboratory-size dryer for data acquisition with different initial moisture contents of the cassava mash and the drying time monitored. The effect of such factors as initial moisture content (Mo), mash initial weight (W1), fryer temperature (TP), mash thickness (L), and final moisture content (Mf) were related mathematically to the total time of gari frying (TT). A computer program was written in FORTRAN LANGUAGE to generate a drying model that was used to formulate appropriate equation for the drying process. Detailed theoretical study of the heat and mass transfer of cassava mash during drying were made and the results showed that drying of gari involved both the constant and falling rate drying phenomena. Microsoft Excel 7.0 Statistical package software was used to analyse the results of the model. All the measured parameters that is, mash initial moisture content, mash initial weight, trough temperature, mash thickness and the final moisture content have a strong correlation (R2 = 0.81) with the total time of frying (TT). The mash thickness (L) has the greatest effect on the time of frying. A multiple regression was done to develop the relationship between the total drying time (TT) as a dependent variable and initial moisture content (Mo), initial weight(WTo), fryer's temperature(TP), mash ti1ickness(L), and final moisture content(MF) as independent variables