Experiments of evaporation are carried out in a two-dimensional micromodel under quasi-isothermal conditions. Three basic cases are investigated : in the absence of gravity forces, in a stabilizing gravity field and in a destabilizing gravity field. The drying rates are measured and compared to the results of numerical pore network simulations. While an excellent agreement between the simulations and the experiments were found in a previous study in terms of phase distributions, the agreement is only qualitative as far as drying rates are concerned. The poor quantitative agreement between the simulations and the experiments is explained by the existence of roughness and corner flows within the micromodel during drying. These liquid him flows are not taken into account in the simulations.