Research of Energy Parameters in Plant Shredding Using Flail Working Bodies

Abstract

The aim of this study is the theoretical substantiation of the energy parameters of the process of shredding plant residues using a combined rotating working body that integrates the action of flail and cutting elements. Based on the Euler–Bernoulli beam equation and the Green’s function, the dynamics of the impulse interaction between the flail and the stem are determined, as well as the threshold energy conditions for plant destruction. Additionally, the task is to evaluate the influence of the structural parameters of the working bodies, kinematic modes, and aerodynamic resistance on the total power consumption of the drum drive.

In this work, a mathematical model of stem bending under the action of an impact impulse from a flail working body is developed, where the stem is considered as a cantilever beam and the load as a short-term delta impulse. The Euler–Bernoulli equation is solved using the Green’s function, which makes it possible to determine the spatiotemporal characteristics of deformations, maximum bending moments, and critical failure conditions. Based on the model, expressions for the flail impulse, impact energy, and energy absorbed by the stem are derived and an energy-based fracture criterion for the plant is formulated. The case of flail deflection on a hinge and the transition of shredding to the cutter blades is also analyzed, for which an estimation of cutting energy is provided. The influence of rotor aerodynamic resistance is considered, the area of elements creating resistance is determined and the corresponding force and power relationships are obtained. The throughput capacity of the device under a given stem density is established, and formulas for the average power consumed in mulching and in the operation of cutting elements are derived. A numerical experiment is conducted for real geometric and kinematic parameters of the drum, within which graphical dependencies of absorbed energy, components of drive power and the increase in energy consumption when switching to cutting mode are obtained.

The developed model made it possible to determine threshold values of energy and speed of flail elements at which effective stem destruction is ensured. It is shown that the aerodynamic resistance of the rotor constitutes a significant portion of energy consumption, while the power required for shredding plants with flail elements is not dominant in the overall energy balance. For a drum with a 0.6 m diameter, it is determined that the minimum circular speed of the flail should be at least 12 m/s, and the maximum total drive power is about 12.1 kW under the studied conditions. The proposed methodology can be used in the design of combined rotating working bodies, optimization of their kinematic modes, and prediction of energy consumption in the mulching process.