![]() ![]() The radiative transfer equation in dimensionless monoliths was solved by the Monte-Carlo method to yield the radiation field in the reactor. In this article, the optimal design of monolith photocatalytic reactors irradiated by cylindrical UV lamps was investigated. The tools for optimal design of photocatalytic air purifiers are still being established. This reaction takes place inside a microreactor operated in a batch recycling system with polychromatic radiation.The values obtained portray the same behaviour as that of the energy densities calculated previously (Part I), thus becoming a valid, accurate method for the experimental measurement of the absolute values of the radiation field that are sought after (volumetric rate of energy absorption).The proposed approach is able to produce quasi-point values of the absolute values of the VREA at the microreactor as an excellent approximation to the absolute values of the LVREA (local measurements).The present work also points out the qualitative and quantitative discrepancies of the results predicted by the line models when compared with those of the extense source model with volumetric emission. The expressions representing the local volumetric rate of energy absorption (LVREA) were formulated and applied to the prediction of the rate of an actinometric reaction. This study of the radiation field generated in a cylindrical photoreactor irradiated from the bottom presents the theoretical foundations of a method for the experimental verification of three different radiation models. If shadowing is not included in fluence rate distribution models, the fluence rate will be over predicted in the shadow zone of a neighboring lamp, falsely skewing model inactivation predictions. With multiple lamp reactors, the impact of shadowing can significantly affect fluence rate distribution and thus the level of microbial inactivation. At fluence rates above 8 mW cm−2, the actinometry measured fluence rate was lower than the modeled rate, presumably from saturation of the actinometer solution at high fluence rates (close to the lamp). These effects, as well as the fluence rate at various points in the lamp matrix were effectively modeled using RAD-LSI and UVCalc3D fluence rate distribution models. ![]() Reflection from the lamp surface added 3–9% to the fluence rate, depending upon position in the reactor. Two fluence rate distribution models were tested to determine the ability to predict the fluence rate distribution measured by the actinometers. A matrix of four low-pressure UV lamps in air were investigated to evaluate the potential for shadowing and reflection to impact the fluence rate within and surrounding the lamp array. A method for measuring the fluence rate among a multiple lamp array was demonstrated using spherical actinometry. Use of mathematical modeling for determination of ultraviolet (UV) fluence in disinfection reactors requires accurate knowledge of the fluence rate distribution in a multiple lamp array.
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