Investigating flow pattern in Vortex Settling Basin based on the automatic Particle Tracking algorithm

The vortex settling basin, which includes a cylindrical chamber and a central orifice in its bottom, the inlet and outlet channel, is used with the purpose of separating particles from water flow, the present research is done by image processing technique. The study of particle movement in the field of vortex flow in a laboratory model of settling basin was done. The particle velocity distribution, particle detention time, and settling length were calculated using the particle tracking technique by an automatic code. Also, the abstraction ratio, particle flow path and water surface profile were measured, identified and drawn, and also to determine the tangential, radial and axial velocities flow inside basin by Nortek 21 MHz Micro-ADV three-dimensional magnetic speedometer. The results showed that similar to the velocity distribution obtained by the semi-automatic code, the velocity distribution of the automatic code in the vortex basin is in the form of a sinusoidal function and there is a good match between the water surface profile obtained from direct measurement and the profile obtained from image processing, so that the average relative error is 1.36%. The values of particle and flow velocity (ADV device data) are close to each other, which proves the hypothesis of equality of particle velocity and flow velocity.