NUMERICAL INVESTIGATIONS OF HEATED AND UNHEATED LATERAL JETS DISCHARGING INTO A CONFINED SWIRLING CROSSFLOW

ABSTRACT

Heated and unhealed jets discharging normally into a confined swirling crossflow are investigated numerically. Emphases are placed on the effects of temperature difference on the trajectory and mixing characteristics of the lateral jet in the swirling crossflow and the detailed impingement process of the opposed jets in the crossflow. Parameter variations studied include jet temperature, jet-to-crassflow velocity ratio, jet number, and swirl strength. Numerical errors are also discussed. The results show that the pressure force caused by the presence of the opposing jets will hinder the penetration and increase the velocity as the jets impinge. After impingement, the jet bifurcation phenomenon occurs, and the mixing path and the turbulence are greatly changed. Swirl prevents the jet from penetration due to the swirl-induced radial pressure gradient and the hydrodynamic instability. The spiraling jet flow in the swirling crossflow enhances turbulence near the tube center, and the swirl-generated turbulence can enhance the jet mixing. The jet-decaying process is almost independent of the temperature difference between the heated jet and the crossflow. The jet-spreading process is dependent on the inlet mass flux ratio and the mixing conditions.