Computational modeling of heterogenous pore structure and airflow distribution in grain aeration system

To understand the significance of heterogeneous pore structure characteristics and its overall effect on airflow distribution and pressure drop within stored bulk grains, porosity and tortuosity models developed based on grain compaction were incorporated into the computational fluid dynamics (CFD) model using ANYSS FLUENT. CFD Fluent simulations were developed for both constant (homogenous) and variable (hetemgenous) pore structure beds and validated. Generally, comparing experimentally measured data with the predicted values obtained from the simulations indicated that the simulated static pressure drop for compaction was about 31.9% higher than that for non-compaction at airflow velocity of 0.1 m s(-1). The relative standard error in pressure drop between the experimental data and simulated values for compaction was below 9.5% whereas the standard error between the experimental data and the simulated values without considering compaction was more than 51.8%. This indicated that the CFD model including the compaction effect were in close agreement with the reported experimental data when compare with the results from the CFD model without considering compaction effect. Thus, the developed variable pore structure (heterogenous) CFD model was applied in different scenario to predict airflow velocities and pressure drop distributions in aeration systems for various floor configurations, aspect ratios, and horizontal airflow designs.