Authors & Affiliations
Matyukhin N.M., Sorokin A.P., Denisova N.A.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Matyukhin N.M. – Senior Researcher.
Sorokin A.P. – Chief Researcher, Dr. Sci. (Tech.). Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7 (484) 399-84-47; e-mail:
Denisova N.A. – Lead Engineer.
Abstract
The results of the analysis of the experimental data obtained in air using the DISA hot-wire anemometer sensor on the velocity and temperature profiles at the normal to the vertical isothermal surface under laminar and mixed convection for the case of thermogravitation are presented. The data are of great practical importance in solving a wide range of applied engineering problems in the nuclear power industry, including the removal of decay heat from a fast neutron reactor by means of an emergency heat removal system. The temperature measurement accuracy was 0,1°С, and the accuracy of speed measurement is 2–8%. Regularities of change in dimensionless velocity U/U∞ are characterized by a number of features. So, in the range of variation of the parameter of mixed convection 1,88 ≤ ξ ≤ 16,021 (Richardson number), the speed changes from zero on the wall to the maximum value Umax/U∞ at some distance hmax normal to the surface. With distance from the surface, the speed decreases from the maximum value U/U∞ up to 1 at η>4, and for values of the Richardson number Rix<1,884 the regularity in the velocity distribution in the mixed convection regime goes over to the regularity in the purely forced convection regime. By introducing new scales of velocity and temperature, generalized dependences are obtained for dimensionless profiles of velocity and temperature, which agree with the measured distributions of velocity and temperature. The obtained generalizing dependences can be used both for checking the quality of modeling of thermal hydraulics in computational codes, and for the subsequent analysis of the physics of processes with a mixed convective flow of the coolant along the vertical heat exchange surface.
Keywords
hydrodynamics, heat transfer, experiment,
vertical surface, air, thermal anemometry, velocity profile, temperature
profile, natural convection, mixed convection, Richardson number
Article Text (PDF, in Russian)
UDC 532.517.4