集沙仪结构设计及其性能实验研究

集沙仪作为专门用于收集风蚀颗粒的采样仪器对土壤风蚀研究具有重要意义。从通风屏的位置和面积,形成通风屏的筛网目数和进沙口位置等方面设计了16种集沙仪。通过在风洞内进行的等动力性实验和采集率实验最终筛选出面积为9 884mm2的通风屏位于集沙仪顶部,进沙口凸出集沙仪迎风面的集沙仪是16种集沙仪中采集性能最好的集沙仪。其修正后的进沙口风速与实验风速比为0.870;对0.10～0.25,0.075～0.10和<0.075mm粒径范围的土样,各风速的平均采集率分别为83.58%,81.16%和60.93%,适合采集跃移及部分悬移运动颗粒;该集沙仪结构简单,操作方便,可采集同一位置不同高度的风蚀尘,也可添加旋转装置用于野外观测,符合室内外风蚀研究需要。

Structural Design and Performance Experiment on a Sand Sample

As the special equipment for collecting soil particles in wind erosion,research on sand sampler is of significance.Sixteen sand samplers were designed with the difference in respect of position,area and mesh size of the screen,as well as position of opening for sand collecting.Through isokinetic tests and collecting tests in the wind tunnel,performance of the sand sampler with a 120-mesh screen on the top and a protruded opening was considered to be the best of all sixteen.Its revised ratio of wind velocity at the opening to predetermined wind velocity is 0.870.Average collecting efficiency of soil with the particle size ranges of 0.10~0.25,0.075~0.10 and <0.075 mm were 83.58%,81.16% and 60.93%,respectively.It was suitable for collecting the saltation particles and part of suspension particles.In addition,the sand sampler with simple structure and simplified operation can collect wind erosion dusts at the different heights.It also meets the demands of indoor and outdoor researches if equipped with rotary apparatus.