【摘要】 该实验在底部设有进气口的模拟仓内装满玉米后,埋入3列5排N2传感器,充N2流速为5 L/min,时间约40 min,室内温度25℃,关闭N2后连续测定氮气浓度至250 min,以研究氮气扩散规律。结果表明:充气阶段,第1列各点在19 min内氮气浓度全部达到饱和值(100%),1#点仅仅用时4 min,上升速度最快;关闭氮气后,1#点氮气浓度下降速度也最快。由距离―浓度模型可知,在充气阶段第1列点,距离进气口越近,浓度越高;而第2列、第3列各点的氮气浓度正好与之相反。在关闭气源后第1列点,距离进气口越近,浓度值越低。由时间―浓度模型可知,第1列的点距离进气口越近,浓度值变化越快;第2、3列的点,距离进气口越近,浓度值变化越慢。越靠近进气口的横排,点与点之间的浓度差别越大;距离进气口较远的点,不同横排上的浓度越接近。分析纵横方向上与进气口等距离的点,得出N2向纵向扩散的速度极显著高于横向。更多还原

【Abstract】 Filling the corns in the stimulate barn with a inlet in the bottom,the N2 detectors were embedded in the barn with 3 row and 5 line. The nitrogen flow rate was 5L/min,charging time was about 40min,room temperature was 25 ℃,we measure the nitrogen concentration for 250 min after N2 flow closed. The result showed:in the Inflatable phases,the nitrogen concentration of the first row reaches a saturation value( 100%) in the 19min,the time of 1# point was less than 4 min,which was the fastest one of all. After nitrogen was closed,1# points declined the fastest,too. The distance– apparent density model showed,when points in the first row were in the phase of gas filled,the closer the distance from the inlet was,the higher the concentration value became; After the nitrogen closed, the first row of the other 2 both showed:the closer the distance from the inlet was,the lower the concentration value became. The time–apparent density models showed,the first row,the closer the distance from the inlet was,the faster the concentration changed; the second and third rows,the closer the distance from the inlet was,the slower the concentration changed,the closer the distance from the inlet was,the greater the concentration difference between points will be; the farther the distance from the inlet was,the smaller the concentration difference between points will be. The data of points in all directions with the same distance to the inlet were analyzed and found,the concentration of longitudinal points changed more significantly than the lateral points.更多还原