Ali Salehi - M.Sc. student School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran;
Alireza Jalali - Assistant professor, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran;

The disinfection process generally involves two types:physical and chemical processes. In the past, chlorinegas was the most commonly used disinfection method(chemical method). Using chlorine as a disinfectant willresult in the production of byproducts in water, and thepresence of these substances in water poses a health riskto humans. Nowadays, physical methods have gainedincreasing popularity because of the destructive effectsof chemical methods. Ultraviolet (UV) radiation is oneof the most effective physical methods for theinactivation of microorganisms. Traditionally, UVreactors equipped with an ultraviolet lamp source havebeen used to produce ultraviolet rays. Water poisoningis always a concern with ultraviolet lamps because theycontain mercury and are fragile. Due to thedisadvantages of ultraviolet lamps and the progress ofsemiconductor technology, ultraviolet light emittingdiodes (LEDs) are being studied more and more. In thisresearch, a radiation model is developed to simulate theintensity of UV radiation within UV-LED waterpurification reactors. In particular, the radiation patternof an UV-LED in a U-shaped photoreactor will beinvestigated. This model considers the LED as a pointlight source. The radiation pattern of the LED isdetermined by using the radiation intensity diagram,fitting a curve to it, and using the discrete ordinatemethod. Finally, the obtained information will beverified and using the data available in the literature.

Disinfection, ultraviolet light emittingdiodes (UV-LEDs), photoreactor, radiation intensity