Features of modeling the process of drying leaf-stem materials by active ventilation
Authors: Kotov B. ,   Podilskyi State University, Kuzmenko V. , Kalinichenko R. ,   Institute  of  Mechanics  and  Automatics  of Agroindustrial Production of the National Academy of Agrarian Sciences of Ukraine,   NUEBIP “Nizhyn Agrotechnical Institute”
Published: July 2024

Purpose. Refinement of the mathematical description of the process of drying fodder herbs by active ventilation due to taking into account the physical and mechanical properties of the drying object and identifying the parameters of the mathematical model based on experimental data Мethods. The theory of heat and mass transfer in drying processes is used, namely, the solution of the equation of mass conductivity of a solid body with the equation of external mass transfer of the surface of the body with the air flow in the presence of surface evaporation. Along with this, the equation of the material balance of the drying leaf-stem material and air flow was used. The physical and mechanical characteristics of the material as a drying object are taken into account. Based on the obtained analytical dependencies, the parameters of the mathematical model were identified by comparing them with experimental data. Results. Based on the analysis of the solutions of the differential equation of mass conductivity for the two components of the grass mass and the data of direct experiments of drying individual parts of plants and grass in a roll, the kinetic regularities of the drying process of the two-component material were determined. Mass conductivity coefficients and Bio criteria were determined by comparing theoretically and experimentally obtained data. Based on them, the drying coefficients of individual parts of plants in a dense layer with its forced ventilation were calculated. A mathematical model of the process of drying heterogeneous plant materials has been developed. Conclusions 1. Analytical dependences were obtained for determining the parameters of the grass drying process, which take into account mass transfer, physical and mechanical (different structure) properties, self-heating of raw materials, drying coefficients of two-component material, based on which a mathematical model of non-stationary processes of drying leaf-stem materials by active ventilation was formed. 2. On the basis of analytical analysis and experimental data, the regularities of drying wilted plants (fodder grass) during drying of individual plants were determined. The difference between analytical dependences and approximate experimental data for whole plants and their parts from the time of drying of the final moisture content will be 4.4 % (average value), and when drying in a dense layer – 9.4 %). 3. The obtained mathematical model containing the heterogeneity (multicomponent) of the drying objects, the equations of drying kinetics of each fraction, which are interconnected through the parameters of the medium, allows us to analyze continuous and pulse-continuous modes of drying forage grasses. Keywords: herbs for feed procurement, drying, hay, active ventilation, leaf, stem, roll, mass conduct-bearing, mass transfer.