Numerical approach to improve UVC radiation for air disinfection and investigation of the scalability

Abstract

This study simulates the inactivation of SARS-CoV-2 viruses by UVC radiation. A reference case is simulated with computational fluid dynamics, which is designed the same way as the experimental decentral air purifier test device to use valid boundary data. The UVC radiation sources are small LEDs. They are implemented on the inside faces of two penetrable baffles in the airway. The distance between the two baffles and the slots in the baffles will be altered. The number of open slots determines the flow structure in the light chamber. IF all slots are open the flow is straight through the chamber. In two other cases the flow is forming a vortex. The simulations have three goals: First, validate the CFD-model with experimental data. Second, maximizing the radiation on each simulated aerosol and reducing the pressure difference of the device. Third, is to show the scalability to larger HVAC devices. In this study a maximum UVC dose is reached with partly closed slots and short distance between the baffles. Generally, more slots reduce the pressure loss. Extending the light chamber increase the radiation dosage for straight flows, in the case of vortex flow the dosage decreases. The problem is scalable, the solution is only partly scalable.