Papers by Author: Yong Wei Wang

Abstract: Turbulence mixing in T-junctions filled with porous metal materials is numerical investigated using Large-eddy simulation turbulence model. Three cases of porous metal materials, made of three sintered metal spheres with different thermal conductivities (387.6 W/m۟۬•K for copper, 202.4 W/m۟۬•K for aluminum and 16.3 W/m۟۬•K for steel), are predicted. Compared the results of three cases, a higher thermal conductivity can also contribute more greatly to heat transfer enhancement. In T-junctions filled with porous metal materials, thermal conductivity is weakened considerably by the turbulence mixing of hot and cold fluid. The temperature fluctuation are no obvious different.

Abstract: In the present work the temperature fluctuations in a mixing tee were simulated on FLUENT platform using the large-eddy simulation (LES) turbulent flow model with three kinds of sub-grid scale (SGS) models such as Smagorinsky-Lilly (SL) model, Wall-adapted Local Eddy-viscosity (WALE) model, and Kinetic-energy transport (KET) model. The normalized mean and root mean square temperatures were predicted and analyzed with consideration of buoyancy. The numerical results showed that buoyancy greatly influences the mixing flow and the thermal striping phenomena were quite obvious. These three SGS models have somewhat similar accuracies for prediction of the temperature fluctuation and thermal stripping in a tee of mixing hot and cold fluids.

Abstract: The velocity fields of turbulent flow in Tee junctions have been calculated using large-eddy simulations model for three cases of various inlet velocities with periodic porous media. The ratio of the inlet velocity of the main tube to that of the branch tube were respectively 0.5, 1 and 2 in three cases. In the porous medium region of the Tee junction, the velocity at the center is obvious larger than that at the top or the bottom and the pressure drop heightens rapidly. Comparison of the three cases, the pressure drop, mean velocity, normalized velocity fluctuation and the velocity oscillation versus time are increase as the inlet velocity of the main tube increase.