Radiation effect on mixed convection cooling in a ventilated horizontal cavity with multiple ports

Summary In the present paper, numerical computations have been carried out to investigate the interaction between thermal radiation and laminar mixed convection in a multiple vented rectangular enclosure uniformly heated with a constant heat flux. Air, a radiatively transparent medium, is considered to be the cooling fluid which enters the enclosure by injection. The effects of the governing parameters, which are the Reynolds number, 300 ≤ Re ≤ 5000, the emissivity of the walls, 0 ≤ e ≤0.85, and the dimensionless position of the outflow opening, 0.2 ≤ L e ≤ 1.8, on flow and thermal fields and the resulting heat transfer are examined. Variations, versus the main controlling parameters, of the maximum and average temperatures, the ratio, Q E /Q L , of the heat quantities leaving the cavity through the exit, Q E , and through the vertical cold left side, Q L , are also explored. The results indicate that highest thermal performance is achieved by increasing the emissivity of the walls, the velocity of the external flow and when the outlet port is located on the middle (L e  = 1) of the top wall of the cavity.