Study on the Evolution of Temperature in Wheat Pile Within an Underground Granary Under the Influence of Localized Heat Sources

Abstract

Abstract. Localized heat sources within wheat piles in underground storage can induce condensation and mold formation, thereby severely compromising grain storage safety. Investigating the influence of localized heating on the internal temperature evolution is crucial for ensuring safe grain preservation. This study developed a coupled heat and mass transfer numerical model that conceptualizes the wheat pile as a solid skeleton with interstitial air domains to analyze the temperature evolution in underground storage. Through 16 cases with varying quantities and surface temperatures of plane heat sources in condensation-prone areas, the impacts on temperature distribution were examined, and the effectiveness of natural ventilation in mitigating thermal inhomogeneity was evaluated. The results revealed that during static storage in winter, a localized heating zone gradually forms in the upper-middle grain layers with distinct temperature variations across different layers. Secondary heat sources tend to develop above the primary heating zone. The natural ventilation shows a certain effectiveness in reducing the temperature of the wheat pile, but the overall cooling effect remains limited. Incorporating heat source temperatures and thermal convection effects into the design of the ventilation and thermal management system enables more efficient temperature regulation. This research provides theoretical support for optimizing thermal control strategies in underground grain storage.