摘要
针对大跨度平房仓粮堆温度分层大、降温不均等问题,基于多孔介质粮堆传热传质理论,结合计算流体力学的方法,进行传热、流体和水分传递的多物理场耦合,建立了一种适用于粮堆热湿传递的数学物理模型,对大跨度高大平房仓的降温保水实验进行了模拟,对实验数据和数值模拟结果进行了比较,探究了实仓通风和数值模拟通风过程的温度和水分变化.结果表明,模型可以预测粮堆内部的气流速度、温度和相对湿度的变化;粮堆初始平均温度相同时,进风温度由-17℃提升至-4℃,通风时间由37 h延长至108 h,出口速度由0.24 m/s提升至0.31 m/s时,通风时间由228 h缩短至176 h;改变进风温度或出口风速会对所需的通风时间产生影响,建立进风温度与表观风速、出口风速与表观风速的关系可得到经济的通风时间,并选择合理功率的风机,为实仓降温通风保水操作提供参考,保障粮食的安全储存.
In view of the problems of large temperature stratification and uneven cooling of grain piles in large warehouses,this paper is based on the theory of heat and mass transfer in porous media grain piles.This study incorporates methods from computational fluid dynamics coupled with the physics of heat transfer,fluid and moisture transport.A mathematical physical model for heat and moisture transfer in grain piles is established.The ventilation experiment of the one-story warehouse is simulated.The results from the experimental data and the results from the numerical simulations are compared.The temperature and moisture changes during actual ventilation and numerical simulation ventilation were explored.The results show that the model can predict the changes of airflow velocity,temperature and relative humidity inside the grain pile;when the initial average temperature of the grain pile is the same.When the inlet air temperature is increased from-17℃to-4℃,the ventilation time isextended from 37 h to 108 h.When the speed is increased from 0.24 m/s to 0.31 m/s,the ventilation time is shortened from 228 h to 176 h.Changing the inlet air temperature or outlet wind speed will affect the required ventilation time.Economical ventilation time can be obtained by establishing the relationship between inlet air temperature and apparent wind speed,and outlet air speed and apparent wind speed.The fan with reasonable power can be selected based on this.Provide a reference for the ventilation operation of grain piles.
作者
袁越锦
戴航
石天玉
李倩倩
YUAN Yue-jin;DAI Hang;SHI Tian-yu;LI Qian-qian(College of Mechanical and Electrical Engineering,Shaanxi University of Science&Technology,Xi′an 710021,China;Academy of National Food and Strategic Reserves Administration,Beijing 100037,China)
出处
《陕西科技大学学报》
北大核心
2022年第6期133-139,共7页
Journal of Shaanxi University of Science & Technology
基金
国家自然科学基金项目(51876109)
陕西省国际科技合作计划重点项目(2020KWZ-015)
陕西高校青年创新团队计划项目(2019)。
关键词
平房仓
热湿传递
数值模拟
large warehouses
heat and moisture transfer
numerical simulation
