Heat and moisture transfer patterns in localized high-temperature and high-humidity regions within rice grain stacks

Abstract

This study addresses the challenge of developing effective strategies to prevent and control the deterioration of stored grain quality caused by biological activities and heating. The unclear mechanisms of water migration and humidity distribution within rice grain piles subjected to localized high temperatures complicate this effort. Using COMSOL simulation and model granaries, the study examines temperature fields, humidity fields, and water migration in high temperature and humidity areas. Results show that within 24–48 h of high-humidity rice exposure to high temperatures, the surrounding grain's temperature rises rapidly, with relative humidity increasing significantly within 48–72 h. The temperature peaks at around 96 h. The influence of high-humidity grain on its surroundings is minimal within the first 36 h, but as temperature increases, the relative humidity of the surrounding grain pile rises faster. The micro-airflow caused by temperature differences drives moist air to migrate to cooler areas, leading to a rise in moisture content in these regions. Therefore, interventions like ventilation and grain turnover should be implemented within 24 h of detecting high-temperature grain, with continuous monitoring of moisture content in adjacent low-temperature areas to prevent further deterioration.