Simulation of Heat and Mass Transfer in a Grain Pile on the Basis of a 2D Irregular Pore Network

The so-called pore network model has great advantages in describing the process of heat and mass transfer in porous media. In order to construct a random two-dimensional (2D) irregular pore network model for an unconsolidated material, image processing technology was used to extract the required topological and geometric information from a 2D sample of soybean particles, and a dedicated algorithm was elaborated to merge some adjacent small pores. Based on the extracted information, a 2D pore network model including particle information was reconstructed and verified to reflect the pore structure of discrete particles. This method was used to reconstruct a random 2D irregular pore network model of wheat. Accordingly, a multi-scale heat and mass transfer model was implemented to simulate the drying of wheat. The simulation results were consistent with the experimental results, which indicates that the reconstructed irregular pore network model can effectively simulate the real pore structure inside unconsolidated porous media. The present approach may be regarded as the foundation for establishing in the future a three-dimensional pore network model and studying the heat and mass transfer process in a grain pile.