Simulation Study on Heat and Moisture Transfer in Cross-Flow Drying Aeration of Bulk Corn in a Cone-Bottom Silo Using Natural and Low-Temperature Air

Abstract

Using variable temperature and relative humidity of natural air based on local climatic conditions for natural drying aeration of grain is an energy-saving and efficient method. The study of heat and moisture transfer within grain piles during natural air and low-temperature air drying aeration of bulk corn in low-humidity areas, which can provide theoretical support for selecting efficient and low-consumption grain drying processes and practical applications. In this study, the mathematical model of the coupled heat and moisture transfer dynamics in the dry silo was verified using experimental datum of grain storage drying aeration experiment, and the relative error was less than 5% between the simulated and the experimental datum. Based on this validated model, the temperature and moisture content variations of in-silo bulk corn drying were simulated by computational fluid dynamics (CFD) numerical simulation techniques. The simulations included continuous drying aeration with daily average, hourly average temperature and relative humidity of the local natural air, and low-temperature air drying aeration with heated up to 3°C over the ambient temperature, as well as intermittent drying aeration. Drying effectiveness and economic efficiency were also analyzed and evaluated. The costs for continuous drying aeration with hourly average of natural air and low-temperature, intermittent drying aeration with hourly average of natural air are 0.032, 0.042, and 0.016 CNY/kg, respectively. Compared to traditional high-temperature hot air drying, the costs of these methods were reduced by 0.048, 0.038, and 0.064 CNY/kg, respectively.