Sliusenko A. Scientific-practical principles of improving the ejection apparatus of food productions

The aim of the dissertation work is the scientific substantiation of improvement of ejector apparatuses for food production, development of the theory of liquid-gas ejectors, based on theoretical, experimental and CFD studies of improvement and development of promising designs of ejectors and highly efficient equipment for the food industry. In the first chapter of the dissertation work methods of intensification of technological processes are considered and the conclusion about expediency of application of ejectors (ejector apparatuses) in food industry is made. When working, they combine hydrodynamic phenomena, cavitation effects, intensive renewal of the phase contact surface, the possibility of ejecting a sufficient amount of passive flow without additional energy costs for carrying out technological processes. By the example of using ejection apparatuses in technological processes of sugar industry (sulphitation and saturation) it is established that the known constructions of jet sulphitators and saturators do not allow achieving high quality indicators of technological liquids purification. The explanation for this can be inaccuracies that were made in the design of ejectors, in which to a large extent pass heat and mass exchange processes. Therefore, the scientific and practical bases for improving the ejector apparatuses of food production, creating energy-efficient ejectors and equipment on their basis is an urgent task. The second chapter of the dissertation presents a mathematical model of the liquid-gas ejector with a conical-cylindrical (combined) mixing chamber, developed on the basis of the mass balance equation and the energy balance equation in the form of the Bernoulli equation, and a method of determining the ejection coefficient (Kej). The calculations of the ejection coefficient showed the adequacy of the developed mathematical model to the experimental data. The third chapter of the dissertation reflects the results of experimental studies of nozzles and liquid-gas ejection apparatuses, which were carried out on the laboratory setup of the Department of Technological Equipment and Computer Design Technologies of NUFT. The fourth chapter of the dissertation work is devoted to the study of the operation of nozzles and liquid-gas ejectors by means of CFD technologies in the environment of the academic version of the software package ANSYS 2020 R2. On the basis of comprehensive research, promising designs of liquid-gas ejectors and equipment for technological processes of food production, which presented in the fifth chapter of the dissertation, have been developed.