Numerical Investigation of Angled Baffle on The Flow Pattern in a Rectangular Primary Sedimentation Tank

It is essential to have a uniform and calm flow field for a settling tank with high performance. In general, however, the circulation zones always appear in the sedimentation tanks. The presence of these regions may have different effects. The non-uniformity of the velocity field, the short-circuiting at the surface and the motion of the jet at the bed of the tank that occurs because of the circulation in the sedimentation layer, are affected by the geometry of the tank. There are some ways to decrease the size of these dead zones, which would increase the performance. One is to use a suitable baffle configuration. In this study, the presence of baffle with different position and angle has been investigated by computational modeling. The results indicate that the best position and angle of the baffle is obtained when the volume of the recirculation region is minimized and the flow field trend to be uniform in the settling zone to dissipate the kinetic energy in the tank.