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The dynamic flow field in T‐jet mixers is characterized by means of 3D computational fluid dynamics simulations. The main goal of this work is to identify and discuss the chaotic flow regime in T‐jet reactors and the parameters that enable this flow regime, namely, the critical Reynolds number and design parameters of these mixers. The 3D chaotic flow regime that occurs in T‐jet mixers is described herein with unprecedented detail regarding the mixing scales, flow dynamics, and coherent structures. The mixing scales are proven to be set by the mixer dimensions. The chaotic flow regime in T‐jets is of practical interest due to its capability to promote very fast mixing, although descriptions in the literature are scarce. Fully resolved flow dynamics in T‐jet mixers are obtained from 3D computational fluid dynamics simulations, particularly those on chaotic flow regimes that are characterized by a vortex issuing from the jet impingement point. The design and operational conditions to promote the chaotic flow regime are analyzed, and mixing scales and dynamics are assessed. [ABSTRACT FROM AUTHOR]

The present work evaluates ozone driven processes (O 3 , O 3 /UVC, O 3 /TiO 2 /UVA) in the NETmix mili-photoreactor, as a cost-effective alternative for the removal of volatile organic compounds (VOCs) from air streams, using n-decane as a model pollutant. The network of channels and chambers of the mili-photoreactor was coated with a TiO 2 -P25 thin film, resulting in a catalyst coated surface per reactor volume of 990 m 2  m -3 . Ozone and n-decane streams were fed to alternate chambers of the mili-photoreactor, promoting a good contact between O 3 /n-decane/catalyst. Initially, direct reaction between n-decane and ozone (ozonation) was assessed for different O 3 /n-decane (O 3 /dec) feed molar ratios and total feed flow rates. Under the best conditions, ozonation process achieved total n-decane conversion (below the limit of detection), yielding a reaction rate (r dec ) of 6.8 μmol min -1 or 6.7 mmol m -3 reactor s -1 . However, the low reactivity of ozone with the degradation by-products resulted in a quite poor mineralization (~10%). For the O 3 /UVC system, an increase on relative humidity from 7 to 40% slight improved the n-decane oxidation rate, mainly associated with the generation of HO from the reaction of active oxygen radicals (O) and water molecules. A strong synergistic effect was observed when coupling TiO 2 /UVA photocatalysis with ozonation (O 3 /TiO 2 /UVA), enhancing substantially the mineralization of n-decane molecules up to 100% under O 3 /dec feed molar ratio of 15, photonic flux of 2.67 ± 0.03 J s -1 and a residence time of 2.0 s. Different reaction intermediates were detected for O 3 , TiO 2 /UVA and O 3 /TiO 2 /UVA oxidative systems, indicating the participation of different oxidant species (O 3 , HO, O, etc.)., (Copyright © 2019 Elsevier B.V. All rights reserved.)