ISSN Online: 2377-424X
ISBN Print: 978-1-56700-421-2
International Heat Transfer Conference 15
Multi-scale Second Moment Modelling of Turbulence and Heat Transfer in Porous Media
Résumé
To predict turbulence and heat transfer in porous media, double (volume and Reynolds) averaged transport
equations are considered. In the momentum equation, there appear unknown terms which are namely the dispersive
covariance and the volume averaged Reynolds stress that is split into the macro-scale Reynolds stress
and the micro-scale Reynolds stress. Although an algebraic model is applied to the dispersive covariance, to
obtain the Reynolds stress, a second moment closure is applied to the volume averaged Reynolds stress, coupled
with a two-equation k − ε eddy viscosity model for the micro-scale Reynolds stress. For solving scalar fields, a two-energy equation model, which solves the energy of solid and fluid phases, is developed to consider non equilibrium energy fields between the energy of solid and fluid phases. In the double averaged scalar
transport equations, two kinds of scalar fluxes (the dispersion heat flux and the volume averaged turbulent heat
flux which is split into the macro-scale and the micro-scale turbulent fluxes) and the energy exchange terms
(wall heat transfer and tortuosity) between fluid and solid phases come out. In this study, algebraic models of
the volume averaged turbulent heat flux and wall heat transfer terms are discussed. The proposed models of
turbulence and heat transfer are evaluated in fully developed square rod array flows. The results suggest that
the present models are promising.