大豆结露过程中湿热传递规律研究

Study on the Law of Heat and Humidity Transfer in Soybean Condensation Process

为研究粮堆结露过程中水分迁移特点及温湿度场变化规律,将含水量12%的东北大豆放入温差15℃(冷热源分别为15、30℃)的模拟仓中储藏24 d,分析大豆粮堆不同部位水分变化、粮堆温湿度场分布及结露部位温湿度变化,揭示了大豆粮堆结露过程中温湿度变化规律、水分迁移特点。结果表明,大豆粮堆在模拟仓冷热壁温度作用下产生了温差,由此形成的微气流带动水分子迁移,聚集于低温部位,致使大豆在近冷壁面上层结露;结露部位的粮食温度下降,最后趋于稳定,平衡温度在20.6℃左右,相对湿度先降低后升高,存在一个相对湿度最小值点;储藏过程中近热壁面大豆粮食水分下降,近冷壁面上层粮食水分升高,高湿区域不断扩大,粮堆由结露逐步发展为发霉。

In order to study the characteristics of moisture migration and the changing law of temperature and humidity field in the process of dew condensation in grain piles,soybeans from Northeast China with a moisture content of 12%were stored in a simulated warehouse with a temperature difference of 15℃(cold and heat sources of 15,30℃)for 24 days.The moisture changes in different parts of the soybean grain pile,the temperature and humidity field distribution of the grain pile,and the temperature and humidity changes at condensation parts were analyzed in this study,the law of water migration and the change of temperature and humidity during the condensation process of the soybean grain pile were revealed.The results showed that the soybean grain pile had a temperature difference under the action of the temperature of the cold and hot walls of the simulated warehouse,and the resulting micro-air flow led to the migration of water and gathered in low-temperature parts,causing soybean condensation in the upper layer near the cold wall;The temperature of the grain at the condensation parts decreased,and finally stabilized,the equilibrium temperature was about 20.6℃,the relative humidity first decreased and then increased,and there was a minimum point of relative humidity;During soybean storage,the moisture of the grain near the hot wall decreased,and the moisture of the upper layer near the cold wall increased,the high-humidity area continued to expand.The grain piles were gradually developed from condensation to moldy.