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Information × Registration Number 0220U101381, 0118U002192 , R & D reports Title Thermohydraulic instability of coolant flows and development of thermophysical mechanisms to overcome its destructive impact on the elements of power equipment popup.stage_title Head Davydenko Borys V., Доктор технічних наук Registration Date 10-02-2020 Organization Institute of Engineering Thermophysics of NAS of Ukraine popup.description2 By analyzing the results of numerical simulation, the features of the ascending air flow in the vertical cylindrical channel, which is formed due to free convection at the local supply of heat into the stream, were determined. Under these conditions, it is found that the flow is unstable and is characterized by oscillatory changes in pressure time and average velocity. One example of this instability is vibration combustion. Based on the results of numerical simulations, the amplitudes and frequencies of oscillations of these quantities at different time periods are determined. The regularities of the influence of the heat source power source and the channel height on the amplitude and frequency of channel pressure fluctuations are established. Suggestions for reducing the amplitude of pressure oscillations are formulated in order to prevent the destructive effects of instability in the flow on the elements of power equipment. Among them - dispersion of heat source, reduction of local hydraulic resistance of equipment elements, change of geometrical characteristics of the channel. The results of the study of heat exchange, hydrodynamics and instability in microfluids of pure liquid and nanofluid are presented. The results of the study of conditions of flow instability in curvilinear microchannels and the appearance of backflows depending on the magnitude of the radial gap, temperature gradient, Brownian and thermophoretic diffusion, Prandtl and Schmidt numbers are considered. The results of modeling a fully developed turbulent flow in a rotating microchannel are presented. The influence of angular velocity on the stability of the flow is shown. The results of the study of thermocapillary instability in a thin evaporating liquid film with allowance for evaporation in the transition region of mechanical interaction between liquid and vapor phases are presented. Product Description popup.authors Avramenko Andriy O. Bieliaieva Tetiana H. Basok Borys I. Goncharuk Svitlana M. Gotsulenko Volodymyr V Davydenko Borys V. Dmitrenko Nataliya P. Kovetska Marharyta M. Kovetska Yulia Yu. Kravchuk Oleksandr V. Lysenko Oksana M. Nedbailo Oleksandr M. Novikov Volodymyr G. Novitska Maryna P. Oliynuk Lyudmila V. Sorokina Tatyana V. Tyrinov Andrii I. Tkachenko Myroslav V. Khibina Marina A. popup.nrat_date 2020-04-02 Close