Evaluation of reflection and refraction in simulations of ultraviolet disinfection using the discrete ordinates radiation model

摘要

Simulations of UV disinfection systems require accurate models of UV radiation withinnthe reactor. Processes such as reflection and refraction at surfaces within the reactor can impactnthe intensity of the simulated radiation field, which in turn impacts the simulated dose andnperformance of the UV reactor. This paper describes a detailed discrete ordinates radiation modelnand comparisons to a test that recorded the UV radiation distribution around a low pressure UVnlamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection andnrefraction at the quartz sleeve were investigated, along with the impact of wall reflection fromnthe interior surfaces of the chamber. Results showed that the inclusion of wall reflectionnimproved matches between predicted and measured values of incident radiation throughoutnthe chamber. The difference between simulations with and without reflection ranged from severalnpercent near the lamp to nearly 40% further away from the lamp. Neglecting reflection andnrefraction at the quartz sleeve increased the simulated radiation near the lamp and reducednthe simulated radiation further away from the lamp. However, the distribution and trends in thensimulated radiation field both with and without the effects of reflection and refraction at thenquartz sleeve were consistent with the measured data distributions.