Numerical Simulation and Experimental Study of Coagulating Sedimentation after Addition Chemicals in the Radiant Sedimentation Tank

Based on the principle of flocculation kinetics, and integrated the structure of radiant sedimentation tank (RST) and the elementary theory of particles sedimentation, hydraulic agitation is taken to realize the coagulating sedimentation after addition chemicals. Meanwhile, CFD software Fluent is used to research with numerical method the operation characteristics of conventional RST. On this basis, the physics model of a novel RST which can realize coagulating sedimentation is built with feasibility study using numerical simulation to determine the installation area of newly added reaction-cover, swirl-baffle and the position of dosing system. At the same time, the laboratory dynamic test model is established according to similarity principle and the optimized structure scheme of the coagulating sedimentation after addition chemicals is confirmed. In this scheme, the relation curve of dosage and turbidity of original water from the Yellow River with different sediment concentration are achieved, and included the corresponding optimal coagulant dose. The investigation provides an effective theoretical basis for practical engineering application.