Optimum UV Disinfection between Concentric Cylinders

To optimize UV disinfection of microbes between concentric cylinders, inactivation in the plug flow reactor geometries of laminar Poiseuille flow, turbulent flow, and laminar Taylor−Couette flow is investigated experimentally and numerically. It is found that there is an optimum ratio of radiation penetration depth to gap width λ/ d for each of the three flow patterns. The optimum λ/ d for laminar Poiseuille flow, turbulent flow, and laminar Taylor−Couette flow are 1.5, 1, and 0.5, respectively. It is also concluded that laminar Poiseuille flow provides inferior (small) inactivation levels while laminar Taylor−Couette flow provides superior (large) inactivation levels. The relative inactivation levels are as follows: laminar Poiseuille flow < turbulent flow < laminar Taylor−Couette flow.