Numerical Simulation of Sediment Distribution in Vortex Settling Basin

One of the main challenges associated with the development of irrigation systems and other water distribution systems is the sediment removal from the inlet channel. Vortex settling basin (VSB) is one of the types of sediment extractors with small size and high efficiency which removes the sediments using the vortices of the flow. Studies on the proper design of VSBs are generally based on experimental and physical models which are highly costly and time-consuming. In this study, SSIIM model was evaluated for the simulation of flow field and sediment distribution in a VSB and the results were compared with experimental measurements. After ensuring the relative agreement of the model results with experimental measurements, the effect of different design parameters such as inlet sediment size, bottom outlet discharge ratio, and bed level difference between inlet and outlet channels were investigated. The results showed that among the design parameters, trap efficiency of the VSB is more sensitive to the sediment size. By increasing the bottom discharge ratio, the efficiency increases, but this increase in the efficiency barely exceed 4 % for bottom discharge ratios higher than 10 %. In addition, increasing the bed elevation difference between the inlet and outlet channels can increase the efficiency up to 18 % for fine-grained sediments, while this increase is less than 10 % for coarse-grained sediments.