Application of CFD Modeling to Support UV Disinfection Reactor Design

摘要

Computational Fluid Dynamics (CFD) has emerged as a powerful tool to aid design of UV reactors by providing the UV dose delivered by the proposed reactor design and allowing engineers to evaluate alternative designs in much less time and at a reasonable cost. This paper describes the CFD modeling process and lessons learned from a UV manufacturer’s standpoint. Degremont Technologies has historically outsourced CFD modeling needs, an approach that appeared to be both time and cost consuming, especially as UV development has advanced over the years with the higher demands placed on reactor functionality and versatility. Accordingly, in 2005 Degremont’s North American Research and evelopment Center acquired the full capability to perform CFD modeling in house, a decision which has provided greater flexibility in UV reactor design reiteration. The CFD software, Fluent, allows coupling of the fluence rate modeling and the particle trajectories of target pathogens within a single software package. Issues encountered and lessons learned during implementation of the new tool are discussed within this paper. UV reactor meshing strategies, calibration of the model and selection of the modeling parameters are all discussed from a practical viewpoint. Additionally, modeling results from a series of closed – vessel in line reactors with the lamps arranged parallel to the flow are presented. Proper use of the modeling tool supported the optimization of key components impacting reactor performance, such as lamp positioning, flow defector baffle design and the wiper plate arrangement. In general, acquisition of the in-house CFD modeling capability has clear benefits towards improving the efficiency of new UV reactor development initiatives.