新型平口式集沙仪对不同粒级颗粒的收集效率

Sampling Efficiency of A New Flat Opening Collector for Particles with Various Sizes

目前,国内缺少对集沙仪集沙效率问题的深入研究。采用风洞实验手段,就新型平口式集沙仪对不同粒级颗粒的收集效率进行了研究。结果表明:该集沙仪对1~0.85、0.85~0.5、0.5~0.25、0.5~0.1、0.25~0.1、0.1~0.05、<0.1、<0.05 mm粒级颗粒的平均收集效率分别为54.9%、59.6%、69.7%、52.6%、24.6%、21.0%、17.7%、13.2%,表现出对>0.25mm粒级颗粒收集效率较高、对<0.25mm粒级颗粒收集效率较低的特点。该集沙仪的集沙效率不是随着颗粒粒级增大而一直增大的,而是在0.5mm左右存在一个峰值。集沙仪的集沙效率没有表现出随风速变化的明显规律性,与各粒级颗粒风蚀强度之间也没有必然的联系。造成集沙仪对不同粒级颗粒收集效率差距较大的原因可能是不同粒级颗粒运动状态的差异和沙网孔径的大小。

There is a lack of knowledge on sampling efficiency of sand collector in China.The sampling efficiency of a new flat opening collector for particles with various sizes was calibrated by wind tunnel experiment in the paper.The results show that the average sampling efficiencies are 54.9%,59.6%,69.7%,52.6%,24.6%,21.0%,17.7%,13.2% for 0.8-1.0,0.5-0.8,0.25-0.5,0.1-0.5,0.1-0.25,0.05-0.1,〈0.1,〈0.05 mm sediment,respectively.Its sampling efficiency is high for〉0.25 mm sediment（〉50%）and low for〈0.25 mm sediment（〈25%）.Sampling efficiency of the collector cannot improve constantly with the particle sizes increasing,but has a peak at about 0.5 mm in diameter.There is not obviously changing regularity of sampling efficiency with wind speed increasing,and there is not essential connection between sampling efficiency and wind erosion intensity at all particle sizes.The large disparity in sampling efficiency for different sizes of particles is determined probably by the difference in transporting modes by wind due to different particle sizes and the aperture sizes of the filtering screen.