ABSTRACT
The geometric features and operational parameters of rotary blades on rotary tillers significantly impact their performance characteristics. The sweepback angle is a geometric feature of the 'L'-shaped rotary blade that has remained unexplored in previous studies. This study aimed to analyze the effect of geometrical and operational parameters on the performance dynamics of the 'L'-shaped rotary blade. The investigation was conducted using the discrete element method (DEM) and further validated through experiments conducted in a soil bin. The simulation experiment was conducted by dividing the particle bed into horizontal particle zones. The effect of the geometrical (sweepback angle) and operational parameters (forward speed, rotational speed, and depth) on the power requirement, disturbance intensity, and mixing index was studied. The novel method was adopted to determine the mixing capability of rotary blades in terms of sub-domain mixing index (SMI) and overall mixing index (OMI). The results revealed that the power requirements for a sweepback angle of 18° were 26.39% and 16.50% lower than those for sweepback angles of 6° and 12°, respectively. The sweepback angle tends to have the least effect on the overall mixing index compared to operational parameters. The average particle velocity decreased by 22.19% and 29.60% with sweepback angles of 12° and 18°, respectively, compared to the sweepback angle of 6°. The relative error during the experiment varied between 1.29% and 13.51%. It was concluded that the sweepback angle was found to be a feasible option for reducing the power requirement with good mixing indices.
ABSTRACT
In many Indian regions, paddy wheat is the main crop rotation and facing the problem of straw incorporation for seed bed preparation in short period. The handling of straw in combine harvested paddy fields is a significant issue in the paddy wheat rotation. In order to solve this issue, efforts were carried out to cut paddy straw into small pieces by the newly proposed counter-rotating blades, followed by the simultaneous incorporation of a rotary tiller into the soil. Therefore, a tractor operated chopping cum tilling mixing machine was developed. In the study, three different blades (straw management system (SMS) Serrated, cutter bar and SMS plain) were tested in the terms of torque and required to chop the straw. SMS serrated blade was best suitable for the chopping mechanism as it required minimum cutting torque for the straw bunches. The developed chopping cum tilling mixing machine was tested at three different levels of forward speed (1.77, 2.3, and 3 km h-1), moisture content at three levels (35 ± 3.4, 24 ± 2.2 and 17 ± 2.6%) with fix rotary tiller rotational speed of 810 rev min-1. Optimum operating condition of the machine was obtained at a forward speed of 1.9 km h-1 and a moisture of 24%. At these optimized values, the mixing index (96%), mean weight diameter (7.9 mm), bulk density (1230 g cc-1) and fuel consumption (3 l h-1) were 96%, 7.9 mm, 1230 g cc-1 and 3.0 l h-1 respectively. The developed machine performs three operations i.e., chopping, tilling, and mixing in single pass for effective in-situ straw management.
Subject(s)
Triticum , Agriculture/methods , Equipment Design , Soil/chemistry , Crop Production/methodsABSTRACT
To simulate the bending behaviour of paddy straw at varied moisture contents after crop harvesting, we created a flexible paddy straw specimen model based on the Hertz-Mindlin with parallel contact bonding model using the discrete element model (DEM) approach. The research presented in this study aims to investigate a new approach called Definitive Screening Design (DSD) for parameterizing and screening the most significant parameters of the DEM model. This investigation will specifically focus on the three-point bending test as a means of parameterization, and the shear plate test will be used for validation purposes. In addition, the most influential DEM parameters were optimized using another Design of Experiments approach called Central Composite Design. The findings from the DSD indicated that parameters such as bonded disk scale, normal stiffness, and shear stiffness have the highest impact on the bending force, while the coefficient of static friction (Straw-Steel) has the least effect. The three bonding parameters were respectively calibrated with the loading rate (0.42, 0.5, and 0.58 mm s-1) and a good agreement between actual and simulated shear force at moisture content M1-35 ± 3.4%, M2-24 ± 2.2% and M3-17 ± 2.6%. Modelled stem helps simulate the straw with low error and increases the accuracy of the simulation. The validated model, with an average relative error of 5.43, 7.63, and 8.86 per cent, produced reasonable agreement between measured and simulated shear force value and loading rate.