Investigating the effect of flow entrance and existence of baffle on sedimentation efficiency using Discrete Phase Model (DPM)

Document Type : Original Research Paper


1 Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

2 Mechanical Engineering department, Tarbiat Modares University, Tehran, Iran


Presence of salts in water has been one of the biggest problems of industrial equipment such as evaporators, boilers, and pipes. These salts gradually form scales on evaporators and boilers tubes and reduce their efficiency. Pretreatment processes are conducted to remove these salts; with sedimentation tanks being one of the essential equipment used in these processes. This study numerically simulates multiphase flows in the sedimentation tanks using Discrete Phase Model (DPM). Various important parameters, such as sedimentation tank entrance and existence of baffle in the case of non-homogenous injected particles are studied. The results indicated that the bottom entrance tank provides maximum sedimentation efficiency of 70.3%. In addition, baffle influence is dependent on entrance location; and in the case of the top entrance, baffle presence improves efficiency by 5.2%. Sedimentation tank efficiency is also demonstrated for different particle sizes, indicating a 100% efficiency rate of the sedimentation for particle sizes at 50 microns or higher.