Numerical investigation of the effect of lamp position and reflectivity on disinfection performance of in duct UVC systems

In this study, disinfection performance of UV lamps that are positioned after a 45° contracting component in a square cross sectioned ventilation duct are investigated numerically. Axial positions of UV lamps (Z01-Z1), distance between lamps (H1-H7) and duct reflectance (0% and 25%) are considered as the main parameters and the each and combined effect of these parameters on disinfection performance are investigated. In the numerical analysis, air flow distribution is solved with Standard 𝑘 − 𝜀 turbulence model. Trajectory of each particle followed in the obtained flow domain are specified with using discrete phase modeling (DPM). Irradiation field formed by in-duct lamps are specified by using discrete ordinates method. Also, UV dose exposure of each particle tracked is calculated. In this respect, assessments are conducted in terms of air velocity fields, UV radiation fields, UV dose distributions, average UV dose values and RDE (Relative dose effectiveness) values, respectively. Although identical number and power of lamps are employed in each case, it is determined that air velocity and UV irradiation fields, UV dose distributions and RDE values shows varying characters up to lamp positions and duct wall reflectivity.