In this study, a discrete pore-scale model is developed to predict the drying characteristics of an aggregate composed of primary particles with a multimodal size distribution. The solid phase is represented by a cubic particle packing and the complementary pore space is constructed by using the pore-scale finite volume approach. The vapor forming as a result of (slow) evaporation escapes through the top surface of a porous particle aggregate. A drying algorithm is implemented that takes into account the formation of liquid clusters and which is based on the combination of the classical invasion percolation algorithm, applied to each cluster, and the computation of the evaporation rate for each cluster. Both capillary liquid flow and vapor diffusion are obtained from a pore-scale finite volume model. Taking a regular mono-sized particle aggregate as a reference, the size and spatial distributions of the primary particles are systematically varied to represent the change in the corresponding void space structure. The simulation results indicate the impact of the spatially correlated pore-scale heterogeneity on the drying kinetics of these particle aggregates. This work is our first step towards simulating the complex thermo-mechanical behavior of particle aggregates during drying.
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