The Effect of Inner Walls Reflection on Microorganisms Inactivation in Water Ultraviolet Reactor using computational fluid dynamics

The inner walls reflection of ultraviolet radiation is one of the effective components on the ultraviolet reactor efficiency. In this study, the effect of inner walls reflection of the reactor on the performance of the multi-lamp ultraviolet reactor has been evaluated using of UV dose distribution and log inactivation values of MS2 and Bacillus subtilis microorganisms. The simulation of the flow field is performed using the SSTk-ω model and discrete ordinate model (DOM) for radiation is considered. The wall reflectivity are in the range of zero (no reflection) to 100 (ideal reflection) percent. In this range of reflections, for the reactor walls with aluminum cover, reflectivity of 80.5% and 26.1% for the steel wall and UV transmittance (UVT) of 87.7 and 78.5% was calculated. For UV transmittance (UVT) of 78.5%, the received dose and log inactivation change with increasing reflectivity was very low but for UVT of 87.7%, there is a tangible increase in these values. The results variation procedure for two different flow rate was similar in UVT of 78.5%. The performance of the reactor was investigated in two different lamp powers and UVT of 78.5%, which in higher power, the reflectivity effect has become more apparent.