Finite element analysis of particle and liquid flow through an ultravioletreactor

A computational fluid dynamics program was used to simulate liquid flow thr ough an ultraviolet (UV) reactor. Salt tracer tests were performed at diffe rent flow rates to validate results from the program. Temporal and spatial descriptions of particle trajectories from the flow model were used to quan tify flow pathways through the UV reactor. Particle trajectory information was then used in a separate numerical program to estimate temporal distribu tion of particles exiting the domain during discrete time steps for the flo w solution. From these data, the exit time for particles transported throug h the modeled flow domain were compared with experimental tracer results. A t low flow rates, the simulation results were within 95% confidence interva ls established from the experimental data. At higher flow rates, the simula tion results tended to predict a shorter exit time for particles than that observed experimentally with salt tracer studies. The results of this resea rch can be used to compare UV disinfection efficacy on low transmission liq uids without the need for extensive experiments or construction of prototyp es. (C) 1998 Elsevier Science B.V. All rights reserved.