Authors

Abstract

In order to reduce the power consumption of screw conveyor and to improve the productivity, this study investigated such mechanical characteristics of rubbed maize straw as coefficient of sliding friction, angle of repose, internal friction coefficient, cohesion, flow function value and compressible coefficient with respect to its moisture content and density. An experiment was designed and consists of a sliding friction characteristic test-bed, a direct shear apparatus, a self-made device with adjustable density and compression. The results showed that: the coefficient of sliding friction increases with the increase of moisture content and density; the angle of repose and internal friction coefficient each increases with increasing moisture content respectively; there is no significant effect between the moisture content and the cohesion of rubbed maize straw; the flow function value goes up with the increase of the moisture content; also the increase of the moisture content leads to the increased bulk density due to the reduced materials gap and the increased compression coefficient, which makes it hard to compress. The equation of pressure and density was found, and it is suitable for the analysis of compression characteristic of rubbed maize straw. The research results lay a theoretical foundation and a basis for the further study on mechanical properties of maize straw.

Abstract in Chinese

为了减少螺旋输送机的功耗并提高生产率，采用滑动摩擦特性试验台，直切仪、自行研制的密度调节装置和压缩装置试验研究了揉碎玉米秸秆的滑动摩擦系数、休止角、内摩擦系数、粘聚力、流动函数值和可压缩系数等力学特性与含水率、密度之间的关系。结果表明，滑动摩擦系数随着含水率和密度的增加而增大。休止角和内摩擦系数随含水量的增加而增大。含水率对揉碎玉米秸秆粘聚力的影响不显著。流动函数值随含水率的增加而增大。随着含水率的增加物料间的间隙减小，压缩系数增大，堆积密度增大，使物料难以压缩。压强和密度的关系式 适合揉碎玉米秸秆的压缩特性的分析。研究结果可为玉米秸秆力学性能的研究奠定了理论基础。