A pore-scale model for predicting resistance to airflow in bulk grain. (March 2017)

• Record Type: Journal Article
• Authors: Yue, Rong; Zhang, Qiang
• Is Part Of: Biosystems engineering. Volume 155(2017)
• Page Start: 142
• Page End: 151
• Publication Date: 2017-03
• Subjects: Grain -- Airflow resistance -- Pore structure -- Discrete element method; Bioengineering -- Periodicals; Agricultural engineering -- Periodicals; Biological systems -- Periodicals; Génie rural -- Périodiques; Systèmes biologiques -- Périodiques; 631
• DOI: 10.1016/j.biosystemseng.2016.12.007
• Languages: English
• ISSNs: 1537-5110

Abstract

Abstract : A pore-scale model was developed to predict airflow resistance through grain bulks. The model consisted of two components: simulation of pore structures and prediction of pressure drop through connected pores that formed airflow paths in the grain bulk. The discrete element method (DEM) was used to simulate the spatial arrangement (pore structure) of grain kernels in a grain bulk. The grain kernels were approximated as spherical particles in the DEM model. Based on the DEM simulations, a collection of tetrahedron units was constructed to represent local airflow paths (individual pores) and these local paths were then connected to form global airflow paths. A flow branching model was developed to predict pressure drop within each local flow path, and the total pressure drop through the grain bulk was then calculated as the sum of resistances of all local paths associated with the global path. An experiment was conducted to validate the proposed model. The results showed that the model predictions were in reasonable agreement with the experimental data. The predicted pressure drop was 12% higher than the experimental value at a low superficial air velocity of 0.013 m s −1 when the inertial effect was negligible, and 17% lower than the measured value at a high air velocity of 0.027 m s −1 when some inertial effect existed. Highlights: The discrete element method was used to simulate the pore structures of grain bulks, based on which airflow paths were predicted. The proposed pore-scale model considered the effect of some fundamental pore structure properties on airflow resistance. The model predictions were in good agreement with the experimental data.