Numerical Study of Buoyancy-Opposed Wall Jet Flow

摘要

This paper describes a numerical study of the flow and thermal fields for an opposed wall jet. The hot water is injected from a plane jet down one wall of a vertical passage of a rectangular cross section into cooled water which moves slowly upward. The flow is assumed to be two-dimensional, steady, incompressible, and turbulent. The finite volume scheme is used to solve the continuity equation, momentum equations, energy equation, and k-ε model equations. The flow characteristics were studied by varying the Richardson number (0.0 ≤ Ri ≥ 0.052) and the ratio of background velocity to jet velocity (0.05 ≤ R ≤ 0.15). The results showed that the buoyancy limited the downward penetration of the jet and its lateral spread when the Richardson number increased. The shear layer formed at the interface between the two flow streams, and it became more concentrated at higher values of the Richardson number. In this region, the intensity of the turbulence became stronger and the turbulent shear stress had a minimum value. When the velocity ratio increased, the penetration of jet decreases, its lateral spreading becomes less. Also the temperature difference decreases with the velocity ratio increase. The numerical results give a good agreement with the experiment data of [1].