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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL SIMULATION OF CONVECTION-RADIATION COUPLING ON THERMAL PLUMES IN CAVITIES

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.023273
pages 3565-3572

Аннотация

Natural convection flow generated from a hot line source is studied numerically in a confined cubic cavity, with the help of Direct Numerical Simulation (DNS). The objective is to study the characteristics of 3D plumes and to investigate in what way a radiative participating medium affects the plume properties, especially for the stability of the flow. A 2D representation in pure convective case is considered first, to validate the code and to compare the value of the critical Rayleigh number for the onset of a periodic flow with previously published values. Next, simulations are extended to 3D configuration for Rayleigh numbers around the transition to unsteadiness, which appears much earlier than in the 2D case. For steady state regime, the structure of the flow is mainly 2D in the cavity, except very near the front and rear walls. For oscillating regime, a torsion mode of the whole structure of the flow is observed. Simulations coupling convection and radiation with a grey gaseous medium are then performed for the same range of Rayleigh numbers. The gas radiation leads to a decrease of the global circulation and heat transfer at the walls. Moreover it delays the onset of unsteadiness.