支风道高度对浅圆仓径向通风的影响

Influence of Height of the Branch Air Duct on Radial Ventilation of Squat Silo

机械通风是粮食仓储过程中调控粮堆温湿度、保证储粮品质的有效方法。浅圆仓通常采用地槽通风,但存在通风均匀性差、阻力大、能耗高等问题。目前,浅圆仓径向通风技术研究逐步深入,其通风管网的合理布置是浅圆仓径向通风技术标准化应用和确保其通风效率的关键。本文通过数值模拟的方法,研究了支风道高度对浅圆仓径向通风流场、降温速率、降温均匀性及水分损耗的影响。结果表明,浅圆仓直径为25 m,装粮线20 m时,支风道高度为12.5 m时粮堆降温速率最大,可达到0.051℃/h,粮堆温度变异系数整体达到15.61%;浅圆仓径向通风系统支风道高度h与粮堆平均降温速率Y的满足Y=0.0203+0.00386 h-1.22×10^(-4) h^(2)方程,R^(2)值为0.97;支风道高度的增加对粮堆整体水分影响较小,但是对粮堆表面水分影响较大。

Mechanical ventilation is an effective method to control the temperature and humidity of grain piles and ensure the quality of grain storage during grain storage.Squat silo usually adopts ground trough ventilation,but there are problems of poor ventilation uniformity,large resistance and high energy consumption.At present,the research on the radial ventilation technology of the squat silo is gradually deepening,and the reasonable arrangement of the ventilation pipe network is the key to the standardized application of the radial ventilation technology of squat silo and to ensure its ventilation efficiency.In this paper,the effect of the height of the branch air duct on the radial ventilation flow field,cooling rate,cooling uniformity and moisture loss had been studied by means of numerical simulation.The results indicated that when the diameter of the squat silo was 25 m and the grain loading line was 20 m,the height h of the branch air duct of the squat silo and the average cooling rate of the grain pile Y satisfied the equation y=0.0203+0.00386 h-1.22×10^(-4) h^(2),R^(2) value was 0.97.When the height of the branch air duct was 12.5 m,the cooling rate of the grain pile was the largest,reaching 0.051℃/h,and the overall temperature variation coefficient of the grain pile reached 15.61%.The increase in the height of the branch air duct had little effect on the overall moisture of the grain pile but had a greater impact on the surface moisture of the grain pile.