Науково-теоретичні основи процесу різання харчових продуктів водополімерним струменем та розробка обладнання для його реалізації: автореф. дис. на здобуття наук. ступеня д-ра техн. наук: 05.18.12 - процеси та обладнання харчових, мікробіологічних та фармацевтичних виробництв

Abstract

Робота присвячена розробці науково-теоретичних основ процесу різання харчових продуктів водополімерним струменем та обладнання для універсального водополімерного різання в режимі 3D за умов енергоресурсозбеження і забезпечення вимог щодо екологічності виробництва. Отримані нові дані про вплив різних за конструкцією гідрорізальних струменеформуючих голівок на особливості гідродинамічної поведінки водних розчинів поліетеленоксиду під час їх протікання крізь голівки та встановлені закономірності впливу динамічних структур, що утворюються, на ефективність різання харчових продуктів водополімерним струменем. Комплексне вивчення особливостей різання харчових продуктів водополімерним струменем дозволило розробити математичну модель процесу водополімерного різання харчових продуктів. З’ясовано молекулярно-надмолекулярний механізм різання харчових продуктів водополімерним струменем. Розроблено концептуальне рішення конструкції машини для універсального різання харчових продуктів водополімерним струменем в режимі 3D з можливістю отримання різної конфігурації поверхні розрізів харчової сировини за умов енергоресурсозбеження. Дослідницько-промислова апробація МОВПС-100 підтвердила, що процес різання харчових продуктів водополімерним струменем є екологічно безпечним, на 60% менш енергоємним і на 25% більш ресурсозберігаючим порівняно з різанням струменем води.

Pogrebnyak A.V. Scientific and Theoretical Bases of the Process of Hydro-jet Water-polymer Cutting of Food Products and Development of Equipment for its Implementation. – Manuscript. Dissertation for the Doctor’s Degree of Technical Sciences by Specialty 05.18.12 – Processes and Equipment of Food, Microbiological and Pharmaceutical Industries. – Kharkiv State University of Food Technology and Trade of the Ministry of Education and Science of Ukraine, Kharkiv, 2018. The work is dedicated to the development of scientific and theoretical bases of the process of hydro-jet water-polymer cutting of food products and equipment for its implementation. The peculiarities of the flow of an aqueous solution of polyethylene oxide (PEO) through the nozzle of the jet forming head and the structure of the hydrodynamic field in the inlet region of the nozzle are established. The problem of the dynamics of PEO molecules in the inlet region of the nozzle of the hydro-cutting jet head is solved, and the nature of the dynamic structure formation during the course of the PEO solution flow through the hydro-cutting jet-forming head is clarified. The results of studies of the influence of geometric and dynamic parameters of a water-polymer jet on the indices of the process of hydro-cutting food products are described (frozen chicken fillet, hoki fish, pork and beef at different temperatures). The problem of the structure of the water-polymer jet from the moment of its formation in the air to the degeneration into a drop stream under different flow conditions, concentrations and molecular weights of polymer additives is solved, as well as the degree of force action of the water-polymer spray on the obstacle along the flow axis. It is established that the rational parameters of the hydro-cutting jet forming head are determined by the nozzle diameter and the length of the initial section of the water-polymer jet, which is a function of the concentration and molecular weight of the polymer and which characterizes the quality of the formation of the water-polymer jet. The calculated dependences of the length of the initial section of a high-speed water-polymer jet on the relaxation time of aqueous solutions of PEO and the quality of nozzle etching, the feed channel and their parameters, and the calculated dependence of the diameter of water-polymer jets along their length, allowing determination of the diameter of the water-polymer jet at various distances from the nozzle cut quality of its formation. To substantiate and choose the criterion of resistance to hydro-jet water-polymer processing of various frozen food products, the effect of various indices of the physical and mechanical properties of the frozen flick of the broiler hoki fish, pork and beef at different temperatures on the cutting process was studied. Using a generalized analysis of experimental data, methods of the theory of similarity and dimensions, and methods of probability theory and mathematical statistics, a calculated dependence was obtained in dimensionless form to determine the depth of cut in food products, taking into account their strength in uniaxial compression, the optimum distance between the nozzle cut and the surface of food product, nozzle diameter, as well as the hydraulic and regime parameters of the water-polymer jet, the velocity of the jet and the quality of its formation. An important feature of this equation is that it takes into account the quality of the formation of a water-polymer jet, which is a function of the molecular weight of the polymer and its concentration in solution. The peculiarities of the influence of the main parameters of hydro-cutting by a water-polymer jet of food products on the rate of increment and the quality of the lateral surface of the section are revealed. The generalization of the experimental results obtained made it possible to establish a mechanism for hydro-jet water-polymer cutting of food products, consisting of the destructive action of the dynamic pressure of the water-polymer jet “reinforced” by strongly deployed macromolecular chains and dynamic supermolecular structures formed by the effect of the stretching flow in the inlet region of the nozzle of the jet head. Scientifically substantiated principles of design and calculation of devices for hydro-jet water-polymer cutting of food products have been developed. Criteria are obtained that determine the conditions for the expedient use of polymer additives in water during hydro-jet cutting of food products. The influence of the effects of elastic deformations on the value of the anomalously high cutting capacity of a water-polymer jet for nozzles of a jet-forming head with different entrance angles is investigated. The calculation of the flow regimes of the water-polymer solution through the elements of the hydro-cutting jet-forming head is based on the use of the established criterion characterizing the onset of the onset of dynamic structure formation in water-polymer solutions during their flow through the nozzle of the hydro-cutting jet head. Consideration of the problem of the flow of a Newtonian liquid (water) in the input region of the nozzle of the jet-forming head and the numerical analysis of the flow of an elastically viscous liquid (polymer solution) through a nozzle made it possible to justify the method of calculating the longitudinal velocity gradient in the input region of the jet-forming element elements. The formulated scientifically grounded principles of design calculations of equipment for hydro-jet water-polymer cutting of food products and practical recommendations for improving the process of water-polymer cutting of food products allowed developing a design and technical documentation on the machine MPWPJ-100 for processing water-polymer jet of food products. The practical importance of the work was confirmed by 4 patents of Ukraine, the 2 acts of implementing the results of work, the license agreement, as well as the results of the research and industrial approbation of the experienced sample MPWPJ-100, which confirmed the expediency and cost-effectiveness of using the process of water-polymer cutting of food products.