Application of CFD Simulation to Predicting Upper-Room UVGI Effectiveness

This paper outlines the potential for Computational Fluid Dynamics (CFD) simulation to be used to predict upper-room ultraviolet germicidal irradiation (UVGI) effectiveness to aid system design and the development of future guidance. A numerical study of two wall-mounted UVGI lamps in a mechanically-ventilated test chamber is used to assess the influence of modelling parameters on prediction of dose distribution and microorganism inactivation. Irradiance fields for both UVGI fixtures are obtained via radiometry and implemented in the model. A series of sensitivity studies consider the importance of UVGI field accuracy and computational grid and turbulence model selection. Results show that 2D irradiance fields are sufficient for calculating dose and inactivation whereas a 1D field is inadequate for modelling purposes. Further parametric studies consider the effects of ventilation parameters, UVGI lamp configuration and microorganism susceptibility. These demonstrate the feasibility of modelling the interaction of the airflow and UV field in a room to quantify the dose distribution. Microorganism inactivation can also be accomplished by employing passive scalars and species transport models, however further validation data is necessary before this can be used to make reliable quantitative predictions.