Radiative effects on turbulent buoyancy-driven airflow in open square cavities

Journal ar
International Journal of Thermal Sciences
  • Volumen: 100
  • Fecha: 01 February 2016
  • Páginas: 267-283
  • ISSN: 12900729
  • Source Type: Journal
  • DOI: 10.1016/j.ijthermalsci.2015.10.002
  • Document Type: Article
  • Publisher: Elsevier Masson SAS 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442
© 2015 Elsevier Masson SAS. The effects of the radiative effects and the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low-Reynolds kg ¿ turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide range of the Rayleigh number varying from 103 to 1016. The results obtained taking into account the variable thermophysical properties of air are compared to those calculated assuming constant properties and the Boussinesq approximation. In addition, the influence of considering surface radiative effects on the differences reached for the Nusselt number and the mass flow rate obtained with several intensities of heating is studied; specifically, the effects of thermal radiation on the appearance of the burnout phenomenon is analyzed. The changes produced in the flow patterns into the cavity when the radiative heat transfer and the effects of variation of properties are relevant, are also shown.

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