Modeling and Validating a Continuous Flow Ultraviolet Light Emitting Diode Water Purification Reactor

David A. Kohlhepp


The Department of Defense has a need for a small, man-portable, point of use water purification device that is not currently available commercially in a configuration that meets all the use requirements. A device that utilizes ultraviolet (UV) light-emitting diodes (LEDs) to continuously treat water flowing from a dirty reservoir to a clean reservoir with low weight and power penalties would meet those requirements. This research pursued the development of such a device through the use of computer modeling, specifically in the area of computational fluid dynamics (CFD) and transport of diluted species. It sought to validate the use of the model for design optimization by duplicating concentration tracer tests accomplished in a laboratory with a prototype UV LED reactor at four different flow rates. By measuring the tracer concentration over time at the reactor effluent, the model results were compared to the experimental data qualitatively by the residence time density functions and quantitatively by hydraulic residence times, density curve characteristics, and the dispersion coefficient. The research found that the model has difficulty accurately reproducing the experimental results at lower flow rates, but finds success at the higher rates, rendering the model a useful tool for prototype design and development.