LES Simulation of Mixed Convection for Downward Mercury Flow in a Nonuniformly Heated Vertical Pipe Using Conjugate Problem Statement.

Autor: Artemov, V. I., Makarov, M. V., Yan'kov, G. G., Minko, K. B.
Zdroj: Thermal Engineering; Nov2022, Vol. 69 Issue 11, p875-885, 11p
Abstrakt: Studies of hydrodynamics and heat transfer for turbulent flow of liquid metals in channels having various spatial orientations in longitudinal and transverse magnetic fields under the conditions of uniformly and nonuniformly heated walls in a wide range of the Hartmann, Reynolds, and Grashof numbers are of significant interest in connection with the development of thermonuclear fusion technologies. In the overwhelming majority of accomplished experimental and numerical studies, the influence of channel wall thermophysical properties on the averaged and fluctuation flow characteristics was not analyzed. In recent studies, the authors have shown that the use of a conjugate problem statement, even with involvement of a simplified wall thermal model, makes it possible to obtain a significantly better agreement between the simulation results and reliable experimental data on rms fluctuations of liquid temperature in the near-wall region in comparison with the results of direct numerical simulation of turbulence in the conventional formulation that does not take into account the pipe's thermophysical properties. The article presents verification of the LES subsystem of in-house CFD code ANES in the formulation conjugate with the wall without any simplifications of a real pipe wall, and with involvement of experimental data on turbulent mercury downward flow in a nonuniformly heated pipe when there is no magnetic field. Problems with and without taking into account the wall properties at the Reynolds number equal to 104, Grashof number equal to 6 × 107, and Prandtl number equal to 0.025 are considered. In addition to this, simulations in a conjugate problem statement with involvement of a few popular turbulent viscosity models are carried out. The simulation results are compared with experimental data. The effect that the consideration of wall properties has on various flow characteristics is analyzed. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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