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Information × Registration Number 0222U000336, 0121U111811 , R & D reports Title Investigation of the effect of Prandtl numbers variability on the the secondary vortex structure stability in the near-wall region popup.stage_title Head Baskova Oleksandra О., Кандидат технічних наук Registration Date 06-01-2022 Organization The Institute of Hydromechanics of the National Academy of Sciences of Ukraine popup.description2  The object of research is thermohydraulic processes in internal flows with variable Prandtl numbers. The purpose of research: to establish patterns of development of vortex structures, which are artificially generated in the boundary layer in the presence of centrifugal effects, taking into account the thermal processes in liquids. Research methods: numerical experiment. The urgency of the work: results of studies of the influence of non-isothermal on the formation of the vortex structure will develop a geometry of heat exchange surface development, which will be possible to intensify heat transfer with minimal hydraulic losses. At the first stage of work was: 1) geometric models of smooth pipe, pipe with corrugated and the channel with a pair of oval holes are constructed. A partition grid has been created for each model. A mathematical model is made taking into account the non-isothermal nature of the problem. The boundary and initial conditions for conducting a numerical experiment are determined. 2) the first test calculations were performed in a smooth pipe. A preliminary comparison of the vortex flow in two-dimensional and three-dimensional formulation, as well as for the isothermal and non-isothermal case. In the values of the Reynolds number and temperature pressure from the ranges of the corresponding parameters considered in this paper there are no perturbations in the isothermal flow. In the nonisothermal formulation of the problem, the parameters of vortex motion in two- and three-dimensional problems coincide. The only difference is that in three-dimensional problems the generation of vortex structures occurs higher downstream than in two-dimensional ones. 3) it is shown that the intensification of perturbations in the non-isothermal flow, in comparison with the isothermal flow at the same Reynolds number, is determined by the value of the negative viscosity gradient of the medium relative to the pipe surface. Product Description popup.authors Baskova Oleksandra О. Rudnytska Mariya O. popup.nrat_date 2022-03-09 Close