Numerical study of the effect of air outlet opening on natural ventilation in a workshop

The natural ventilation in an industrial workshop with heat sources was numerically simulated by computational fluid dynamics (CFD) method. The numerical calculation was carried out to simulate the flow and temperature feld in the workshop by realizable k-ε turbulent model combined with a Discrete Ordinate (DO) radiation model which took into account the radiation between the heat source and the wall. The effect of different height of air outlet opening on ventilation was analyzed. Results showed that the ventilation rate increased a little as the height of air outlet opening increased. When the height of air outlet opening was higher than the height of air inlet opening, the ventilation rate did not increase further. The average air temperature at operation zone decreased, but slightly as the air outlet height increased, while the difference between air inlet and outlet temperature almost kept constant. The heat distribution factor decreased as the height of air outlet opening increased. Therefore, a reasonable higher height of air outlet opening was helpful to improve the natural ventilation performance, but its effect was very small.