Mechanical Characteristics of the Rubbed Maize Straw During Screw Conveying

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.

Design and Experiment of Substrate Grass Seed Blanket Extrusion Device

“…The above two teams the response surface method mainly for the selection of important influencing parameters. Meanwhile, the response surface method can used for more detailed optimization of parameters, such as Chunguang Wang's team in the study of kneading corn straw screw conveying device to optimize the screw pitch, screw shaft speed, and feeding volume of three parameters, and finally obtain the optimal combination of parameters, so that the overall performance of the device can be improved [41]. In the same way, Wanzhang Wang's team also used the response surface method to optimize the vibration parameters in the lifting device of the tiger fruit harvester to obtain the optimal parameters of vibration frequency, vibration amplitude, lifting speed and lifting angle, and the results of the study provide theoretical references for the design optimization and simulation analysis of the tiger fruit harvester [42].…”

Research History of Forest Gap as Small-Scale Disturbances in Forest Ecosystems

“…The gap partitioning hypothesis suggests that resource heterogeneity allows ecological niche redistribution for stable forests [188], with regenerating tree species regenerating and spreading along the gap environment gradient according to varying resource demands [189]. In some relatively barren habitats, where the plasticity intensity and light range width of the tree species are most important [190], individual trees have genetically determined growth strategies; fast-growing genotypes are more common in light-rich environments [191], and vegetation in forest gaps has a greater competitive advantage with higher light and water availability [192]. However, community assemblages are controlled by local ecology (limited ecological niches).…”

A Theoretical Analysis and Experimental Study of a Coupled Screw-Pneumatic Conveyor for Chopped Cornstalks

“…Among them, the screw conveyor is widely used in the processing of cornstalk because it is compact and airtight, its assembly is flexible, and its feed is adjustable. However, its transportation performance is unstable due to the characteristics of cornstalk, such as light density, high viscosity and poor fluidity (Wulantuya et al, 2019a). To date, the study of screw conveyors for fibrous agricultural materials has mainly focused on equipment for harvesting and processing (Kaplan et al, 2012;Jiang et al, 2013;Feng et al, 2015;Nachenius et al, 2015a andNachenius et al, 2015b;Chamberlin et al, 2018).…”

“…To date, the study of screw conveyors for fibrous agricultural materials has mainly focused on equipment for harvesting and processing (Kaplan et al, 2012;Jiang et al, 2013;Feng et al, 2015;Nachenius et al, 2015a andNachenius et al, 2015b;Chamberlin et al, 2018). Our team previously investigated the screw conveying process of chopped cornstalk and found that the biomass material underwent overall screw-type motion under the joint effects of below-normal thrust and tangential friction of the screw blades and axial and circumferential friction of the screw shaft and interior casing (Wulantuya et al, 2015(Wulantuya et al, , 2016(Wulantuya et al, and 2019a. The chopped cornstalk was constantly squeezed Engenharia Agrícola, Jaboticabal, v.43, n.3, e20220068, 2023 during transportation.…”

“…Based on the analysis of screw conveyor characteristics and the principle of screw flow transportation, this study combined the two elements of screw flow and pneumatic coupling and produced an airflow where the screw angle of the blades produced a coupled screw-pneumatic effect in the screw groove (Wulantuya et al, 2019b(Wulantuya et al, , 2020(Wulantuya et al, and 2021. Therefore, a theoretical analysis of the coupled screwpneumatic conveying process with respect to the non-plug flow theory of solid transfer and fluid dynamics was conducted, and a transport model considering the compressibility and mechanical properties of the material was established accordingly.…”