predicting solute transport parameters in saturated porous media using hybrid algorithm

This study aims to estimate the solute transport parameters in saturated porous media using a hybrid algorithm. in this study, the physical non-equilibrium (pne) model was used to describe the transport of solutes in porous media. a numerical solution for the pne model is obtained using the finite volume method (fvm) based on the ttri-diagonal matrix algorithm (tdma). the developed program, written in matlab, is capable to solve the advection-dispersion (ade) and the pne equations for the mobile -immobile (mim)model with linear sorption isotherm. the solute transport parameters, (immobile water content, mass transfer coefficient, and dispersion coefficient), are estimated using different algorithms such as the levenberg-marquardt algorithm (lm), genetic algorithm (ga), simulated annealing algorithm (sa). to overcome the limitations of deterministic optimization models which are rather unstable and divergent around a local minimum, a hybrid algorithm (ga+lm, sa+lm) permits to estimate of the solute transport parameters. numerical solutions are verified using the experiments conducted by semra (2003) which are about the transport of toluene through a column composed of impregnated chromosorb grains at ambient temperature (20 °c) for three flow rates (1, 2 and 5ml/min). the results show that the hybrid algorithm (ga+lm, sa+lm) is more accurate than others (ga, sa, and lm). comparing to the ade model, the pne with linear isotherm model gives a better description to the beakthrough curves (btcs) with higher values of determination coefficient (r^2) and lower values of root mean square error (rmse). also, the solute transport parameters tended to vary with the flow rate.