UV-LED radiation modeling and its applications in UV dose determination for water treatment

Abstract

Abstract With the growing application of the ultraviolet light emitting diodes (UV-LED) for water treatment purposes, the significance of modeling their output for designing UV reactors becomes crucial. In this study, the radiation distributions of two UV-LEDs with different radiation profiles are modeled. These UV-LEDs represent the two most common radiation profiles of UV-LEDs – balloon shape and heart shape. Irradiance and fluence rate distribution were predicted and experimentally validated by measuring irradiance through an accurate radiometry setup and determining fluence rate by iodide-iodate actinometry. The consistency of the results among the actinometry, radiometry, and the model proves the reliability of the model. The model helps demonstrate the extend to which the irradiance distribution and average fluence rate are affected as a function of distance and how they are affected by the UV-LED’s radiation profile. For UV-LEDs with any radiation profiles, higher average fluence rate occurs at closer distances to the UV-LED; however, to study the microbiological inactivation kinetics, uniformity of the radiation distribution on the surface of the petri dish has to be taken into account. Using the validated model, common radiation modeling presumptions such as the point source assumption and symmetry assumption for radiation profile of UV-LEDs are evaluated.