Justification of the design parameters of the forming nozzle of the fodder expander

Abstract

Purpose. On the basis of numerical modeling, justify the shape and design parameters of the forming nozzle of the expander and determine the quality indicators of the technological process of fodder expansion. Methods. Numerical modeling was carried out in the STAR-CCM+ CAE system. The following continuum models are adopted for modeling: meshless discrete element model (DEM), Lagrangian multiphase, DEM boundary forces, non-stationary implicit solver, solution interpolation model, gravity. The components of the feed mixture are presented in the form of solid spherical DEM particles with a constant density. The interaction of particles between themselves and the wall was subject to Hertz-Mindlin models with rolling resistance and linear coupling. Results. As a result of numerical modeling, the dynamics and distribution of the components of the feed mixture in the cavity between the cylinder of the forming nozzle and the cone were determined by the pressure force Fp and the force of contact interaction of the components of the feed with each other , depending on the radius of the narrowing of the cylinder of the forming nozzle Rr, the radius of the concave cone Rc and the distance between the cone and the cylinder δc. The regression equations of the density ρout of the plasticized mass of feed components at the exit from the forming nozzle and the maximum pressure Pmax, which must be applied to push the plasticized mass of feed components through the forming nozzle along their movement from the specified research factors, are established. Conclusions. As a result of numerical modeling, the dynamics and distribution of the components of the feed mixture in the cavity between the cylinder of the forming nozzle and the cone were determined according to the pressure force Fp and the force of contact interaction of the feed components with each other depending on the radius of the narrowing of the cylinder of the forming nozzle Rr, the radius of the concave cone Rс and the distance between the cone and the cylinder δс. The regression equation of the density ρout of the plasticized mass of feed components at the exit from the molding nozzle and the maximum pressure Pmax, which must be applied to push the plasticized mass of feed components through the molding nozzle along their movement, is established, from the specified research factors. As a result of solving the task of multi-criteria optimization of the research criteria, namely reducing the pressure Pmax and increasing the density ρout, on the basis of finding the optimum of the multiplicative objective function, rational design parameters of the molding nozzle were established: Rr = 14.2 mm, Rс = 89.9 mm, δс = 5.7 mm. Keywords: expander, forming nozzle, numerical simulation, parameter, design, density, pressure.