Simulation of Temperature and Moisture Changes During Storage of Rough Rice in Cylindrical Bins Owing to Weather Variability

Temperature and moisture content are the two most crucial factors limiting the distribution and abundance of arthropods and fungi that contaminate stored grain. A two-dimensional mathematical model, based on the finite-difference method of calculating heat transfer, has been developed to simulate the temperatures in cylindrical storage bins containing rough rice with respect to ambient temperature fluctuations throughout a storage period. The model has been programmed in BASIC, compatible with microcomputers, thus requiring less time for computer simulation of temperatures. Simulated temperatures are incorporated with the equilibrium moisture content (EMC) models of Zuritz-Singh, Henderson, and Chung-Pfost, respectively, to simulate the moisture distribution at different locations of the storage bins. The simulated results have been compared with experimental results and good agreement has been observed both for temperature and moisture content of grain with the exception of the Chung-Pfost EMC model. In most of the cases, EMC predicted by the Chung-Pfost model was lower than the observed EMC values. The heat transfer and EMC models can be used to predict the distribution of temperature and moisture within the bin, for given ambient conditions as a function of time.