Ultraviolet (UV) water disinfection systems employing excimer lamp technology represent a suitable choice
in situations where lamp mercury content is restricted, or otherwise undesirable. Excimer lamps
exist that generate germicidal UV radiation with appropriate electrical efficiency, and at relevant
wavelengths in terms of germicidal effectiveness and water transmittance.
In conjunction with NASA's interests in conducting long-duration human space missions, where
severe restrictions on mercury are evident, a UV system was designed based on XeBr* excimer
lamp technology. XeBr* excimer lamps emit nearly monochromatic radiation at a characteristic
wavelength of 282 nm. Baseline experiments conducted with a XeBr* excimer lamp
demonstrated its germicidal UV output to be highly effective for inactivation of Bacillus subtilis
spores.
A numerical prototype of this new reactor system was developed using a Lagrangian modeling
scheme. The modeling approach involved simulation of fluid mechanics and particle trajectories
using commercially available computational fluid dynamics software (FLUENT). Accurate
simulations of the radiation intensity field within the reactor required the development of a new
intensity field model. The final design of the reactor was produced by an iterative procedure
using these modeling tools, thereby allowing for optimization of reactor characteristics.
Simulations of the behavior of the numerical prototype indicated high efficiency, in terms of
microbial inactivation and power consumption. Includes 9 references, figures.