Study on Periodic Pulsation Characteristics of Corn Grain in a Grain Cylinder during the Unloading Stage

Abstract

The fluctuation effect of corn grain often occurs during the unloading stage. To accurately explore the periodic pulsation characteristics of corn grain during the unloading stage, a discrete model of corn grain was established, and the effectiveness of the discrete element method in simulating the corn grain unloading stage was verified by a 3D laser scanner and the “spherical particle filling method”. The grain cylinder was divided into six areas, and the periodic pulsation characteristics at different heights were explored through simulation tests. The results showed that the faster the average speed of corn grain changes in unit time, the more significant the periodic pulsation characteristics were as the height of grain unloading increased. The corn grain pulsateon in the grain cylinder exhibited gradual upward transmission and gradual amplification in the process of transmission. The average velocity decreased with increasing height. The direct cause of pulsation was the variation in the average stress between grain layers. Simulation analysis of grain unloading for different half cone angles of the grain cylinder was carried out. The change in corn grain average velocity over time in the area below 20 mm of the upper free surface was extracted. The results showed that the speed of the top corn grain increased with increasing the half cone angle, and the periodic pulsation phenomenon became more obvious with increasing the half cone angle at half cone angles of 30–65°. A half cone angle of 65–70° marked the critical state of corn grain flow changing from funnel flow to overall flow in the grain cylinder. This study provides a method for studying the periodic pulsation characteristics of different crops during the grain unloading stage and provides a technical reference for the safe design of grain unloading equipment.

Porous Hot Air Tea De-Enzyming and Carding Machine Under Gas–solid Coupling Conditions: Numerical Simulations and Performance Testing

“…Therefore, the average velocity of airflow ua increases, which modifies the movement velocity of a given tea particle. The force analysis expounded above thus provides theoretical support for the subsequent simulation and experimental design (Tang et al, 2021).…”

“…According to Equations (12)(13)(14)(15)(16), the acceleration of tea particles moving in the pot is influenced by the average velocity of airflow (ua), the initial velocity (uv) of tea particles, and the angle θ between the gravity of tea itself and the direction of the gravitational component of tea particles. Due to the action of airflow forces F1 and F2, the tea particles' acceleration when moving along the inner wall of the pot groove increases significantly, which causes them to bounce around when moving along the pot groove .…”

Analysis and performance test on dynamic seed corn threshing and conveying process with variable diameter and spacing

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Study on the Technologies of Loss Reduction in Wheat Mechanization Harvesting: A Review

“…Due to low manufacturing levels and a lack of advanced technology g for domestic combine harvesters, the total loss rate of grain in field harvesting op may be as high as 10% [76,77]. Grain loss during combine harvester operation causes economic losses to farmers but also damages the soil environment and af growth of the next crop [78]. In accordance with the problems of a low cleaning rate and high loss rate from the cleaning system, scholars at home and abroad have carried out a lot of research on cleaning loss.…”

“…Due to low manufacturing levels and a lack of advanced technology guidance for domestic combine harvesters, the total loss rate of grain in field harvesting operations may be as high as 10% [76,77]. Grain loss during combine harvester operation not only causes economic losses to farmers but also damages the soil environment and affects the growth of the next crop [78].…”