Numerical Method-Based Grain Temperature Distribution of Semi-Underground Double-Storey Squat Silos During Static Storage

Abstract

Grain temperature (GT) is a crucial factor in determining the safety of grain storage. To elucidate the evolution rule of grain storage temperature distribution (TD) in semi-underground double-storey squat silos (SUDSSS), a numerical model of the TD of stored grain was constructed. A numerical model of the TD of the grain bulk (GBUL) in the squat silo and the underground silo was developed, and the model was validated through field experiments. Then, a numerical model of the TD of the GBUL in SUDSSS was established. The TD of storage grain in SUDSSS was analyzed by numerical simulation, and the 1-year temperature variation rule of stored grain in the static storage in SUDSSS was obtained. The study shows that (1) the GT within 2 m of the silo wall in the aboveground layer of the SUDSSS, was found to vary significantly with a range of 10.62°C–27.37°C based on the variation of the outside temperature. The GT in the underground layer remains at a quasi-low temperature throughout the year, with an average temperature of no more than 17°C. (2) The original GTs are set at varying levels in a SUDSSS. The temperature differential between the average GT and the original GT after 1 year of storage is 2.21°C, 1.79°C, 1.51°C, 1.13°C, and 0.34°C, respectively, in the aboveground layer. If the original temperature is relatively low, the greater the temperature change after 1 year of storage, which is still well below 20°C, long-term storage requires a lower original GT. (3) The temperature change of paddy in the SUDSSS was the most pronounced during the storage period. The temperature differential between the paddy stored in the aboveground layer for 8 months and the initial is 2.15°C, and the differential is 0.77°C when stored in the underground layer for 12 months. The temperature change of wheat and maize during storage was minimal, whereas the temperature of paddy exhibited significant fluctuations. (4) The maximum temperature differential of 15 and 3 m in condition one is 2.08°C and 2.28°C, respectively. An increase in grain height results in a reduction in temperature change during storage. Comprehensive different grain loading conditions, the GT in the peripheral area of the aboveground layer and the mean temperature of the underground layer discernible change with the varying grain loading heights. Furthermore, the temperature fluctuations of the aboveground and underground layers are largely independent of one another.