密闭储存粮堆内部自然对流和热量传递分析

Analysis of natural convection and heat transfer in grain bulk during sealed storage

基于多孔介质流动和传热传质理论,建立了仓储粮堆内部自然对流、热湿耦合传递的数学模型。采用近似分析原理和数值模拟方法研究了仓储粮堆内的传热和自然对流过程及其影响因素。结果表明对于颗粒较小的谷物如小麦,储存过程中的温度主要受热传导的影响,但是对于颗粒较大的谷物如玉米,自然对流的影响会更大。通过理论分析和数值模拟证明了粮仓中低速的水分迁移对储粮温度变化影响很小。在"瘦高"型的圆筒仓中,自然对流的影响作用较强,自然对流作用会使粮仓内温度混合更加均匀。

Based on the theory of heat and mass transfer in porous medium the mathematical model of nat- ural convection and coupled heat moisture transfer in grain bulk was established. The heat transfer and natural convection processes and their influence factors were studied by the method of approximate analy- sis and numerical simulation. The results showed that the temperature was mainly affected by the heat transfer in cereals of small kernel, such as wheat, while for cereals of larger kernel, such as corn, natu- ral convection was the main effect. The theoretical analysis and numerical simulation proved that the effect of low moisture migration in grain bin on the temperature change of grain was very small, which could be neglected. In silos, the effect of natural convection was significant, which enabled the tempera- ture in silo more uniformity.