Convective Drying Analysis of a Single Wheat Kernel Based on an Irreversible Thermodynamics Model

Abstract

The application of irreversible thermodynamics offers a formal treatment for drying analysis that allows the evaluation of intra-particle or intra-medium temperature and moisture profiles, and enthalpy, liquid, and vapor fluxes. However, researchers have claimed that its implementation is complex. This work presents a simple methodology for modeling, solving, and validating the drying equations, as applied to wheat kernels, and for obtaining the inherent and usually unavailable transport coefficients. To clarify and simplify the ensuing physical analysis, a spherical shape and isotropy were assumed. Additionally, solutions obtained with both Dirichlet and convective boundary conditions were analyzed and compared against experimental data. The thermal and hydro-stresses depend heavily on internal vapor and liquid fluxes and on the respective drying evaporation fronts, all of which were evaluated and compared.

Effect of Thermophysical Properties on Coupled Heat and Mass Transfer in Porous Material during Forced Convective Drying

“…By inverse problem method [19,20], the thermophysical parameters were estimated and the heat and mass transfer coefficients were = 2.54 × 10 −7 m 2 s −1 , = 6.95 × 10 −8 m 2 s −1 , = 0.0124 K −1 , and = 0.0185 K. Figure 4 shows the comparison of the simulated and experimental values of temperature and average moisture content within the potato sample during forced convective drying. Figure 4(a) illustrates that the local temperature of every layer of the sample will become higher as drying time goes by.…”

Drying Kinetics and Mathematical Modeling of Casuarina Equisetifolia Wood Chips at Various Temperatures

“…Semi-theoretical models are only valid within a given temperature, relative humidity, airflow velocity and moisture content range for which they are developed [24,25]. Empirical models describe the drying curve for the conditions of the experiments but they neglect fundamentals of the drying process and their parameters have no physical meaning [26,27]. These two model types deem only the external resistance to moisture movement [28,29].…”