عنوان مقاله [English]
Disinfection is a process designed to disable pathogens, thereby preventing the transmission of waterborne diseases. An important aspect of chemical disinfection is the design of chlorine contact basins. Chlorine contact systems with sufficient time (contact time) disinfect the water for chemical reactions to inactivate pathogens. Design of chlorine contact basin or chlorine contact tanks is to maximize the phenomenon of Residence time through the flow of spiral of baffles through the basin or contact tank. Historically, chlorine contact tanks have been investigated by empirical relationships, physical model studies, or tracer studies after the construction of a contact tank. Construction of laboratory samples and tracer studies are time consuming and costly. In recent years, computational fluid dynamics models have been used to investigate the flow and processes of solute transport in contact tanks, which is the best way to design contact tanks before construction. In this study, a 3D simulation of the CT-1 contact tank is performed using Multiphysics 5.3a software. Also, several 3D simulations in the CT-1 contact tank, in which the effect of the baffle orientation in a longitudinal direction with three different channel widths was performed, it was concluded that the narrow channel with a ratio of Winlet /Wch=0.68 (channel to inlet width ratio) and Lbo / Wch ratio (baffle opening length to Channel width ratio) equal to 1 has the highest baffle factor and the least amount of Morill index and therefore optimal hydraulic.