Numerical Investigation Of Flow Field Near The Exhaust Opening Indoor

Airflow field and effective region for pollution discharge were predicted around a circular flanged exhaust opening, three different turbulent models were employed to simulate airflow field near the exhaust opening indoor. Numerical results show that air velocity decreases gradually in radial direction and axis direction away from origin, and changes most dramatically at corner of the opening. The projection of velocity contour is similar to a semi-ellipse, but when the air velocity decreases, it gradually changes the hemisphere with larger outer radius. When the velocity is 2 m/s, the long axis of the semi-ellipse is 0.70 times the diameter of the exhaust port and the short axis is 0.45 times the diameter of the exhaust port. When the velocity is 0.3m/s, the diameter of the outlet is 1.60 times of that of the long axis and 1.55 times of that of the short axis. The effective area of pollutant emission is similar to the equivalent surface with velocity of 0.3m/s, and its shape is semi-elliptic.