储粮横向通风多尺度热湿耦合传递研究

温湿度是影响粮食安全储存的重要因素，为保证储粮安全，采用机械通风，使粮堆和粮粒的温度和水分含量可以得到有效控制。该文基于多孔介质的传热传质理论，建立了仓储稻谷通风过程中粮堆内部流动和热湿耦合传递的数学模型以及粮粒的热量传递和水分输运模型。采用计算流体力学的方法，从粮堆尺度和粮粒尺度，分析了机械通风过程中仓储粮堆和粮粒内部的温度、水分分布规律。研究发现，通风过程阶段，粮堆内部温度降温显著，粮堆整体平均水分呈降低趋势，且粮堆内部温湿度受外界环境温湿度的影响很大；研究还发现粮粒水分扩散速度远小于温度扩散速度。研究结果可以为储粮横向通风保水降温的工作以及粮堆局部霉变、发热和害虫的发育的预防提供参考。

Multi-Scale Coupled Heat and Moisture Transfer in Grain Storage with Horizontal Ventilation

Temperature and humidity are important factors that affect the safe storage of grain. In order to ensure the safety of grain storage, mechanical ventilation is used to effectively control the temperature and moisture content of grain bulk and grain. In this paper, a mathematical model of internal flow and coupled heat and moisture transfer in the grain bulk and heat and moisture transfer model of grain during the aeration of stored rice based on the theory of heat and mass transfer in porous media were established. Based on the method of computation fluid dynamics (CFD), from which the two scales of grain bulk and grain, the temperature and moisture distribution inside the storage grain bulk and grains during mechanical ventilation were analyzed. The results show that the temperature inside the grain bulk decreases significantly during the ventilation process, and that the average moisture content of the whole grain bulk decreases, and that the temperature and humidity inside the grain bulk are greatly affected by the temperature and humidity of the external environment; It is also found that the grain moisture diffusion rate is far less than the temperature diffusion speed. The results can provide reference for the horizontal ventilation of grain storage over the work of water retention and cooling and the prevention of local mildew, fever and pests'' development in grain bulk.