基于COMSOL静态储粮玉米粮堆温度场研究

Study on temperature field of corn grain pile in static storage based on COMSOL

以初始温度为26℃,边长为1 m并设有冷、热壁面的方形玉米粮堆仓为研究对象,利用数值模拟软件COMSOL,对仓内粮堆温度场进行数值模拟分析,并基于验证的模型研究粮堆内外存在温差时,其内部温度随时间的变化规律。结果表明:靠近冷、热壁面的粮堆温度变化较快;仓内粮堆温度在冷热壁面间形成梯度,出现分层现象;不同初始粮温条件下,壁面与粮堆温差影响仓内粮堆温度分布,储藏96 h后,初始粮温为22℃的粮堆温度变化幅度最大,为24.9℃;粮堆与壁面温差较大的条件下,热量传递较快,仓内粮堆温度逐渐趋于稳定;初始粮温一致,不同种类粮食条件下,在储藏192 h后,大豆、小麦、玉米、稻谷和油菜籽仓内粮堆最终温升分别为2.21、2.18、2.17、2.64和2.40℃;密度和孔隙率差异共同影响仓内粮堆温度的分布,孔隙率较大的玉米粮堆,温度更加均匀。

Taking the square com granary with initial temperature of 26℃,side length of 1 m and cold and hot wall as the research object,the numerical simulation software COMSOL was used to simulate and analyze the temperature field of the granary.Based on the verified model,the variation law of the internal temperature with time was studied when there was a temperature difference between the inside and outside of the granary.The results showed that the grain pile temperature near the cold and hot wall changed rap-idly.The grain pile temperature in the warehouse formed a gradient between the cold and hot walls,and there was a stratification phenomenon.Under different initial grain temperature conditions,the tempera­ture difference between the wall and the grain pile affected the temperature distribution of the grain pile in the warehouse.After 96 h of storage,the temperature of the grain pile with an initial grain temperature of 22℃had the largest change of 24.9°C.When the temperature difference between the grain pile and the wall was large,the heat transfer was faster,and the grain pile temperature in the warehouse gradually stabilized.Under the same initial grain temperature and different types of grain conditions,after 192 h of storage,the final temperature rise of grain heap in soybean,wheat,com,rice and rapeseed warehouses was 2.21,2.18,2.17,2.64 and 2.40℃,respectively.The difference of density and porosity affected the temperature distribution of grain pile in the warehouse.The temperature of com grain pile with larger porosity was more uniform.