Mixing process in opposing fow junction with diferent angles and junction radii

Opposing fow junctions are considered as important elements in thermal and hydraulic equipment. This study numerically investigates the efects of angles and junction radii on coherent fow structures at opposing fow junctions with subcritical conditions. Hence, the three-dimensional unsteady Reynolds-averaged Navier–Stokes equations are solved with the k–ε turbulence model on a non-staggered grid using the indirect addressing treatment. After the verifcation of the numerical model, several numerical simulations are conducted for angles 35°, 40°, 45°, 50°, 60°, 70°, 80°, and 90° with diferent upstream Froude numbers and junction radii. The streamwise-oriented vortical cells only elongate into the branch channel of the opposing fow junction with angle 90°. By decreasing the angle between the main channel and confuent tributary, these cells decay in the main channel width, and one of the separation zones is gradually eliminated, as that does not form in the opposing fow junctions with angle 40°. The enhancement of junction radii decreases the dimensions of the separation and stagnation zones. Numerical simulation results of a curved-edge opposing fow junction with angle 80° indicate that any of the streamwise-oriented vortical cells in the main channel and separations zones in the branch channel are not formed. In such a condition, three vortical cells formed along the branch without decay, two cells are located near the side wall, and another cell is near the free surface.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021)