基于局部热湿平衡原理和多孔介质传热传质理论,建立了储粮通风过程中粮堆内部流动及热湿耦合传递的数学模型。采用计算流体动力学的方法,对横向谷冷通风时粮堆空气内部流动、热量传递和水分迁移过程进行了数值分析。研究发现,横向通风约72h,粮仓进风口冷空气平均温度为17.5℃、相对湿度为85%,仓内粮堆一次降温从32.2℃降低到23.6℃,降温幅度为8.6℃。水分从12.2%降到12.0%,降水幅度为0.2%。相对于地上笼垂直通风而言,横向通风时粮堆内部速度分布均匀、温度梯度较小,且具有降温速度快,冷却效率高的特点。
A mathematical model of internal flow and heat and humidity coulped transport of grain bulk during the aeration of stored grains based on the principle of local heat and humidity balance and theory of heat and mass transfer in porous media is established. Based on the method of computational fluid dynamics, numerical analysis has done for internal air motion, heat transfer and water migration process of grain bulk during the horizontal grain aeration with cooling air. It' s found by study that in case of horizontal aeration for about 72 h, average temperature of cold air at the air intake of grain elevator, with relative humidity being 85%, temperature of grain bulk inside decreases from 32.2 ~C to 23.6 ~C, with temperature drop range being 8.6 ~C. Moisture decreases from 12.2% to 12.0% with dropping extent being 0.2%. Compared to ground cage vertical aeration, horizontal aeration is characterized by homogeneous distribu- tion of internal speed of grain bulk, less temperature gradient, quick cooling rate and high cooling efficiency.