Didyk A. Justification of the design and technological parameters of a vibrating machine for drying walnuts

Didyk A.M. Justification of the design and technological parameters of a vibrating machine for drying walnuts. – Qualification scientific work on the rights of the manuscript. Thesis for the degree of Doctor of Philosophy (PhD) in the specialty 133 – Industrial Engineering. – Vinnytsia National Agrarian University, Vinnytsia, 2025. The urgent scientific task of increasing productivity and reducing energy costs while maintaining the standard quality of the finished product during the drying of walnuts has been solved by developing and substantiating the design and technological parameters of a vibrating machine. The relevance of the research is highlighted, its purpose is defined, and the main tasks for achieving the set goals are formulated. The scientific novelty of the work and its practical significance are characterized, and the author's personal contribution to the research is noted. Information on the testing of the obtained results and their publication is provided, and the structure and scope of the dissertation are presented. The achievement of the goal of this work is reduced to solving the following scientific and applied tasks: based on the analysis of existing means for drying walnuts, as well as the results of theoretical and experimental studies, to develop a schematic diagram of a vibrating machine for drying walnuts; to develop a mathematical model of nut heating during the drying process depending on the initial conditions and technological parameters of the process; to develop a methodology and conduct research to determine the physical, mechanical, and thermophysical characteristics of walnuts, as well as changes in the intensity of negative internal heat sources during the drying process; develop and manufacture an industrial prototype of a vibrating machine for drying nuts; experimentally confirm the feasibility of using vibration as a means of intensifying the walnut drying process; develop a methodology and conduct experimental studies to establish rational parameters for the operation of the vibrating machine; verify the adequacy of the obtained mathematical model; conduct production testing of a pilot industrial model of a vibrating machine for drying walnuts and evaluate its economic efficiency. Energy consumption was minimized while maintaining the quality of walnuts during their convective drying in a vibrating machine. This was achieved by substantiating the design scheme and its technological parameters. A mathematical model of walnut heating was developed, which ensured the determination of its core temperature depending on the initial state of the material, operating parameters, and drying exposure. The model was obtained based on the analytical solution of the equation of unsteady heat conduction for the geometric figure “ball in a sphere” taking into account negative internal heat sources, the intensity of which varied according to an exponential law. The influence of temperature, drying agent velocity, and vibration acceleration of the working chamber on the energy efficiency of the drying process and the patterns of change in the total and current intensity of internal heat sources in the material was established. It was determined that the heat capacity, thermal conductivity, and temperature conductivity of walnuts changed in accordance with the patterns characteristic of colloidal capillary-porous plant materials. The research results can be used in the design and modernization of dryers with vibration action on the drying chamber, which reduces energy consumption, increases productivity, and improves the energy efficiency of the drying process.