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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 Розрахунок коефіцієнта тепловіддачі для випадку випаровування з поверхні гравітаційно стікаючої плівки(1998) Форсюк, Андрій Васильович; Василенко, Сергій Михайлович; Прядко, Микола ОлексійовичВ результаті аналізу дослідних даних запропоновано емпіричну залежність для визначення локальних коефіцієнтів тепловіддачі при випаровуванні з поверхні та залежність для визначення величини зведеної еквівалентної шорсткості поверхні розподілу фаз. Це дало можливість розробити методику розрахунку коефіцієнта тепловіддачі від поверхні труби до плівки, що випаровується, яка наведена у статті. Calculation of the heat transfer coefficient for the case of evaporation from the surface gravel analysis of research data suggested an empirical relationship for determining the local heat transfer coefficients during evaporation from the surface and to determine the dependence of the consolidated equivalent interfacial roughness. This made it possible to develop a methodology for calculating the coefficient of heat transfer from the surface of the vaporizing tube to film here in state.