An improved numerical model of a UV-PCO reactor for air purification applications
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An improved numerical model of a UV-PCO reactor for air purification applications
1. Department of Mechanical Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada 2. School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China 3. Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2W2, Canada
Abstract
Keywords
Ultraviolet photocatalytic oxidation (UV-PCO) is a promising gaseous volatile organic compounds (VOCs) elimination method, of which the PCO kinetics are closely related to the radiation and airflow (contaminants) fields. Mathematical models have been developed in extensive studies to demonstrate the PCO kinetic reactions. Computational fluid dynamics (CFD) simulation was also carried out to display the irradiance and flow fields in the reactor. However, it still lacks an in-depth understanding of the light and mass transfer within the porous film coating where the microscopic structures dominate. To close this gap, this paper concentrates on the development of mathematical models for describing the light propagation, mass transfer, and reaction kinetics within the porous film coating. Incorporated with a CFD model for solving the mass, momentum and energy conservation, the sophisticated PCO process in the reactor can be accurately reproduced. The developed models have been validated by the experimental data, and are comparable with other models in the literature. The developed numerical models provide the implications of mass transfer for film coating UV-PCO reactor design.
computational fluid dynamics (CFD),
Research Article
Hao Luo1, Guangxin Zhang2, Zaher Hashisho3, Lexuan Zhong1 ()
ultraviolet photocatalytic oxidation (UV-PCO), mass transfer, kinetic model, porous film
Article History Received: 30 January 2020 Revised: 25 April 2020 Accepted: 06 May 2020 © Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
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Introduction
E-mail: [email protected]
Building Systems and Components
Volatile organic compounds (VOCs) are one type of the most common indoor chemical contaminants with high vapor pressures. As a promising indoor gaseous VOC elimination method, photocatalytic oxidation (PCO) technology has gained increasing attention in the past decades. A UV-PCO reactor uses titanium dioxide (TiO2) as a semiconductor as it generates electrons and positive holes upon the absorption of UV light. The subsequently formed hydroxyl radicals, as well as positive holes and superoxide radicals, act as oxidizing agents for the mineralization of organic molecules (Zhong and Haghighat 2011). Extensive experimental studies have been conducted on the UV-PCO reaction mechanisms: the direct attack by semiconductor holes, oxidation by hydroxyl radicals and reaction with superoxide radicals were reported as the three major degradation pathways (Bielski et al. 1985; Ishibashi et al. 2000; Murakami et al. 2007; Nosaka and
Nosaka 2017; Muñoz-Batista et al. 2019). And the
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