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Постійне посилання колекціїhttps://dspace.nuft.edu.ua/handle/123456789/7522
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Документ Modelling of thermoradiative-convective drying process of products of plant origin(2023) Dubkovetskyy, Igor; Melnyk (Tkachuk), Nataliia; Burlaka, Tatiana; Tkachuk, YuliiaModeling of thermoradiative-convective drying of cultivated mushrooms was carried out when the moisture content decreased from 809 to 30% within 80 minutes, and for hawthorn, the moisture content decreased from 330 to 38% in 60 minutes. The drying time of apple snacks is 70 minutes and increases by 10 minutes compared to apples, which is due to the sugar content in the snacks and the osmotic properties of sugar to retain moisture. According to the developed mathematical model of the drying process, the diffusion capacity of moisture was calculated, which is the largest among the studied products for cultivated mushrooms and is 9.58 × 10−4 m2/s, due to the lowest density of 750 kg/m3 and the highest porosity of the mushroom, which leads to deeper penetration of infrared radiation with a thermal diffusion coefficient of 1,011•10-3 1/K. The moisture diffusion coefficient for hawthorn is 6,8•10-7 m2/s, with a density of 1173,4 kg/m3 and a thermal diffusion coefficient of 0,51•10-2 1/K, due to the fact that the hawthorn fruits are spherical and were placed in the dryer in a heap. Apples and apple snacks when placed in the dryer were cut into slices of 4...6 mm, for which the moisture diffusion coefficient for apples is 8,48•10-5 m2/s, with the density of apples 880 kg/m3 and the thermal diffusion coefficient 3,096•10-5 1/K. Apple snacks were made by blanching apple cores in sugar syrup before drying, which led to a decrease in the moisture diffusion coefficient to 8,28•10-6 m2/s, an increase in density to 965 kg/m3, and a thermal diffusion coefficient of 4,06•10-2 1/K compared to apple slices.Modeling the interaction of convective and thermoradiative energy supply in pulse mode allows to ensure the maximum technological effect.Документ Determining the mechanism for generating cavitation pressure fluctuations in throttle devices at high-head throttling of liquid(2024) Tarasenko, Taras; Badakh, Valerii; Makarenko, Mykola; Lukianov, Pavel; Dubkovetskyy, IgorThe object of this study is the process of generating cavitation pressure fluctuations behind the throttle device at high-head throttling of liquid. This paper addressed the problem of calculating the amplitude of cavitation pressure fluctuations at high-pressure liquid throttling. It was established that cavitation pressure fluctuations are a consequence of collisions of discrete masses of a transiting liquid jet in the region of pressure recovery. The range of cavitation pressure fluctuations reaches the pressure values at the inlet to the throttle device. The frequency band of cavitation pressure fluctuations is in the range from 1.5 to 20 kHz and higher. At high-head throttling of the liquid, caverns attached to the surface of the throttle channel, moving caverns and small bubbles in the transit flow are formed. Moving caverns compress the transit flow and divide it into separate fluid blocks. In the region of pressure restoration, the moving caverns are slammed shut and discrete fluid blocks collide. This causes high-frequency pressure fluctuations. Special feature of the results is the possibility of estimating the range of cavitation pressure fluctuations depending on the pressure drop on the throttle device. When the back pressure on the throttle device increases, the amplitude of cavitation pressure fluctuations decreases, and the frequency band shifts to the high-frequency region. The results make it possible to calculate the range of cavitation oscillations, to predict the development of cavitation erosion of materials depending on the parameters of throttling of the working fluid. The results of the work are used to design devices for cleaning products from contamination, for determining the volume content of water in aviation fuel, for intensification of technological processes in the chemical and food industries.Документ Application of radiation-convective drying method to remove water from gels(2021) Kambulova, Yuliia; Overchuk, Nataliya; Dubkovetskyy, Igor; Kokhan, Olena; Yurchak, Vera; Zviahintseva-Semenets, Yuliia; Onofriichuk, OksanaВ статті наведені результати досліджень по застосуванню інфрачервоного випромінювання в процесі сушіння фруктового мармеладу на основі різних цукрів: сахарози, глюкози, фруктози. Встановлено, що при додатковому застосуванні інфрачервоного випромінювання разом з традиційним конвекційним сушінням тривалість технологічної стадії сушіння може бути скорочений на 4-5 год.The article presents the results of research on the application of infrared radiation in the process of drying fruit marmalade based on various sugars: sucrose, glucose, fructose. It was established that with the additional use of infrared radiation together with traditional convection drying, the duration of the technological stage of drying can be reduced by 4-5 hours.