Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Effects of Molecular Gas Radiation on Rayleigh-Benard Convection in a 3D Cubical Cavity

Get access (open in a dialog) DOI: 10.1615/IHTC15.rad.009563
pages 7165-7179

Abstrakt

We investigate in this paper the coupling between natural convection and radiative transfer in a 3D cubical cavity heated at constant temperature from the bottom wall and cooled from the top wall. The four vertical walls are assumed to be adiabatic and the Rayleigh number is in the range 105 ? 107. The working fluid is air at room temperature with small amounts of water vapor and carbon dioxide, making the study relevant to heat transfer in building applications. Numerical simulations are carried out using a pseudo-spectral Chebyshev method for the DNS flow field equations under Boussinesq approximation, and a direct ray tracing method for radiative transfer. H2O and CO2 infrared absorption spectra are modeled using the global Absorption Distribution Function (ADF) model. The results are discussed in terms of the effects of radiation on the structure of the mean flows, on temperature fields and Nusselt numbers, and on the turbulent kinetic energy and temperature fluctuation variance when the obtained solutions are weakly turbulent. Radiation is shown to completely modify the structure of the mean flow and to increase both the mean and turbulent kinetic energies. Relatively small effects of radiation are however observed on the mean conductive Nusselt number, though its spatial distribution is greatly modified.