Computational fluid dynamics and experimental study of turbulent natural convection coupled with surface thermal radiation in a cubic open cavity

Abstract

Turbulent heat transfer in open cavities is relevant in several thermal engineering applications. However, the influence of thermal radiation has not been thoroughly studied yet. In this work, experimental and numerical results were obtained to analyze turbulent natural convection coupled with surface thermal radiation in a cubic open cavity. Two emissivities were considered (0.98 and 0.03). Experimental temperature profiles were obtained at six different depths and heights consisting of 14 thermocouples each. Five turbulence models were evaluated against experimental data. The radiative heat transfer model was solved with the discrete ordinate method. The validated model was used to analyze temperature fields and flow patterns in different open cavities configurations, which are presented and discussed. The effect of thermal radiation on experimental heat transfer coefficients was quantified. It was found that experimental heat transfer coefficients increase between 8.5% and 12.52% when the emissivity of the walls changes from 0.03 to 0.98. The temperature distribution in the vertical adiabatic walls changes significantly when emissivity increases from ε=0.03 to ε=0.98 and thus have a relevant influence on the flow patterns in the open cavity.