M. Montiel Gonzalez, J. Hinojosa Palafox, C. Estrada Gasca.

Abstract

A comparison was made between six turbulence models and experimental temperature profiles for the turbulent natural convection in a tilted open cubic cavity. The experimental setup consists of a cubic cavity of 1 m by side with one vertical wall receiving a constant and uniform heat flux, whereas the remaining walls are thermally insulated. The thermal fluid is air and the aperture is facing the heated wall. The temperature profiles were obtained at different heights and depths and each one consists of 10 positions inside the cavity. A commercial computational fluid dynamic software was used for the simulation and different turbulence models of k-εt and k-ω families were evaluated against experimental data. The lowest absolute average percentage difference for the experimental and numerical temperature profiles was for the rk-εt model and the highest was for the sk-ω model.

Numerical study of the Boussinesq approach validity for natural convection and surface thermal radiation in an open cavity

Publicado en Revistas Arbitradas

Carlos Antonio Pineda Arellano, A. Jiménez González, Susana Silva Martínez, Iván Salgado-Tránsito, Cesar Pérez Franco

Abstract

Atrazine is a highly persistent and carcinogenic compound used as herbicide around the world. This compound has been banned in USA and some European countries but in Mexico it is still widely used in the agriculture. In order to achieve a high mineralization of atrazine, present as active compound in the Gesaprim commercial herbicide, detoxification studies in two-compound parabolic solar reactors by means of photo-Fenton process followed by TiO2 photocatalysis was carried out. The atrazine contents in the Gesaprim solutions tested were 35 mg L−1 (19.0 mg L−1 of TOC) and 20 mg L−1 (9.5 mg L−1 of TOC). [H2O2]0/COD0 ratios of 1, 3 and 5 (1.5 × 10−3, 4.5 × 10−3 and 7.5 × 10−3 mol L−1 H2O2, respectively) were evaluated in combination with 5 mg L−1 and 10 mg L−1 Fe2+ at pH 2.8 in the photo-Fenton oxidation; whereas, in the photocatalytic process, the influence of the pH (4.8, 7.0 and 11.0) and type of TiO2 (Degussa P25 and HB) were studied with TiO2 content of 200 mg L−1. The study showed that photo-Fenton process followed by TiO2 photocatalysis produce a 72% of mineralization (for an initial TOC of 19 mg L−1) and decrease above 90% of toxicity in compliance with NMX-AA-110-1995-SCFI1 Mexican Norm. In order to established a minimum amount of chemical reagents these photodegradation processes were carried out with special emphasis on the optimization of experimental parameters such as concentrations of photocatalyst and oxidant. Atrazine mineralization was influenced by the pH of the solution, the initial concentration of hydrogen peroxide and iron ions.

Enhanced mineralization of atrazine by means of photodegradationprocesses using solar energy at pilot plant scale

Publicado en Revistas Arbitradas

Videos HoSIER

Entrevista HoSIER Factor Ciencia Canal Once (14/12/2015)