A new approach for the optimization of UV-reactor design by mean of CFD simulation

Ultraviolet (UV) sterilization is an emerging technology for beverages and waste water treatment. It can either be used as disinfection barrier, where the UV light is used to inactivate pathogenic microorganisms, or in combination with hydrogen peroxide as an advanced oxidation process. In this paper, a new simulative approach is presented for both fluid dynamics and optical optimization of UV reactors. The fluid dynamics analysis is carried out with a commercial CFD software (Tdyn Multyphisics), while the optical simulation is done by mean of an original tool, named "UVdose", which was developed in collaboration with the software developer SmartCAE. This software takes into account both physical-chemical parameters of water (i.e., turbidity) and optical effects, such as refraction; as output, it provides the statistical distribution of the dose absorbed by the fluid across the reactor. We consider two configurations of the reactor. The first one is a commercial UV reactor with 3 medium-pressure lamps, designed by the Italian company Puro s.r.l.; the second one is a modified configuration of the same reactor, with a different placement of the lamps. These configurations are compared from both the fluid dynamics and optical point of view, in order to identify the configuration which provides the best treatment to the fluid processed. For this latter configuration, we finally develop a framework which correlates the minimum UV dose required with some design parameters of the reactor, and is thus useful during the design stage of UV reactors. The method we used in this paper can be extended to the optimization of any type of UV reactors, including more operating parameters of the reactor (e.g., type and number of lamps, type and number of baffles, layout etc...)