Evaluating Airflow Uniformity in Covered Outdoor Piles through CFD Simulations

Authors: PETINGCO, MARVIN - Kansas State University; ELSAYED, SHERIF - Ge Vernova; CASADA, MARK - Retired ARS Employee; WEI, MINGJUN - Kansas State University; MAIER, DIRK - Iowa State University; SABBIR, YOUNUS BHUIYAN - Iowa State University

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Covered outdoor grain piles have become a common addition to grain elevator facilities to provide additional temporary storage. The covered piles use a suction aeration system to counter wind forces and hold the tarpaulin down. These aeration systems could also provide cooling benefits to help maintain grain quality, but there are no studies of their effectiveness in uniformly cooling the grain to a safe storage temperature. We evaluated the airflow uniformity in rectangular piles commonly used in Kansas using computational fluid dynamics (CFD) models of the airflow through the grain from suction of multiple fans. Regions with poor air flow were identified for a variety of duct and fan designs and grain pile designs to identify the combination with the most uniform airflow and the smallest region of poor air velocity. These results identified areas airflow distribution is poor within these grain piles, which can be used by designers and manufacturers to improve the design of covered outdoor piles to reduce losses and maintain better quality stored grain.

Technical Abstract: Adequate and uniform airflow within covered outdoor piles is critical for preserving grain quality during storage. Poor airflow uniformity can lead to uneven moisture distribution, temperature gradients, and localized hotspots within the grain mass, creating an environment conducive to the growth of molds, fungi, and insect infestations. Consequently, such compromised storage conditions can lead to significant economic losses for farmers and impact the availability and affordability of grain-based products in the market. However, despite considerable literature addressing airflow uniformity in permanent storage structures, aeration system designs for covered outdoor piles have not generally included in-depth analyses affecting airflow distribution. This study aimed to investigate the airflow uniformity in covered outdoor piles using Computational Fluid Dynamics (CFD) simulations. A rectangular grain pile, commonly used in Kansas, was modeled using ANSYS Fluent. Various configurations of covered outdoor piles were evaluated regarding airflow velocity and uniformity. The velocity magnitude, vector plots, and contour plots of velocity were used to visualize the air velocity in the different regions of the grain pile. The uniformity index was used to determine the degree of uniformity. Results showed which configuration has better uniformity and identified the hazardous airflow dead zones in the grain mass. By determining the airflow distribution within the grain mass, we can identify potential areas for improvement in the design of covered outdoor piles.