Natural convection in cavities containing internal sources

Numerical predictions are reported for buoyan- cy-induced circulations in a 2D closed cavity with internal heat sources. Two cases are considered: (A) two vertical plates with uniform heat generation, forming a short vertical channel within the enclosure; and, (B) a rectangular heating block with un iform wall temperature, placed central in the enclosure. Air, with a Prandt l number 0.71, is considered as the working fluid. The vertical enclosure w alls are isothermal, while the horizontal enclosure walls are adiabatic. Re sults are presented for two values of the Grashof number, one below the sta bility limit for laminar flow, and one well above it. In those latter cases , the long- term behaviour of the numerical solution is time-dependent, i.e . no steady-state can be reached. Heat transfer results are compared with p redictions from standard correlations for isolated surfaces.