Research Center in Engineering and Applied science

Cuernavaca, Mexico

Research Center in Engineering and Applied science

Cuernavaca, Mexico
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Vazquez L.,Research Center in Engineering and Applied science | Alvarez-Gallegos A.,Research Center in Engineering and Applied science | Sierra F.Z.,Research Center in Engineering and Applied science | Ponce de Leon C.,Tech Lab Group | Walsh F.C.,Tech Lab Group
Electrochimica Acta | Year: 2010

A commercial CFD code, Fluent, has been used to analyse the design of a filter-press reactor operating with characteristic linear flow velocities between 0.024 and 0.192 m s-1. Electrolyte flow through the reactor channel was numerically calculated using a finite volume approach to solve the Navier-Stokes equations. The length of the channel was divided into 7 sections corresponding to distances of 0, 0.01, 0.04, 0.08, 0.12, 0.14 and 0.15 m from the electrode edge nearest to the inlet. The depth of the channel was divided into three planes parallel to the channel bottom. For each channel section, a velocity profile was obtained at each depth together with the average velocity in each plane. The flow predictions show that the flow development, as the electrolyte passes through the cell, is strongly affected by the manifold causing strong vortex structures at the entrance and exit of the channel. Although the flow disturbances are a function of the flow rate, they gradually disappear downstream along the channel length. Simulated velocity profiles are considered for the typical current density range used in the FM01-LC reactor. © 2009 Elsevier Ltd.


Vazquez L.,Research Center in Engineering and Applied science | Alvarez-Gallegos A.,Research Center in Engineering and Applied science | Sierra F.Z.,Research Center in Engineering and Applied science | Leon C.P.d.,Tech Lab Group | Walsh F.C.,Tech Lab Group
Electrochimica Acta | Year: 2010

A commercial computational fluid dynamics code (Fluent) has been used to analyze the performance of a unit cell laboratory; the filter-press reactor (FM01-LC) operating with characteristic linear flow velocities between 0.024 m s-1 and 0.110 m s-1. The electrolyte flow through the reactor channel was numerically simulated using a finite volume approach to the solution of the Navier-Stokes equations. The flow patterns in the reactor were obtained and the mean linear electrolyte velocity was evaluated and substituted into a general mass transport correlation to calculate the mass transport coefficients. In the region of 150 < Re < 550, mass transport coefficients were obtained with a relative error between 5% and 29% respect to the experimental km values. The differences between theoretical and experimental values are discussed. © 2009 Elsevier Ltd.


Vazquez L.,Research Center in Engineering and Applied science | Alvarez-Gallegos A.,Research Center in Engineering and Applied science | Alvarez-Gallegos A.,Autonomous University of the State of Morelos | Sierra F.Z.,Research Center in Engineering and Applied science | And 2 more authors.
Journal of Applied Electrochemistry | Year: 2013

The internal manifold geometry strongly influences the flow distribution inside an electrochemical reactor. The mass transport coefficient is a function of the flow pattern and is a key parameter in successful electrochemical reactor design and scale-up. In this work, a commercial computational flow dynamics (CFD) package was used to describe the flow pattern in the FM01-LC reactor at controlled volumetric flow rates (corresponding to mean linear flow velocities past the electrode surface between 0.024 and 0.11 m s-1). Numerical Re numbers were obtained for each local flow velocity at different positions in the reactor channel. From a known mass transport correlation (based on dimensionless groups, i.e. Sh, Re, Sc), numerical km values were obtained (in the range 200 < Re < 1,000) at different positions in the reactor channel. Computed km numbers are compared against experimental values. This computational approach could be useful in reactor design or selection since it facilitates a fast, preliminary reactor flow and mass transport characterisation without experimental electrochemical measurements. © Springer Science+Business Media Dordrecht 2013.


Moreno-Bernal P.,Research Center in Engineering and Applied science | Cruz-Chavez M.A.,Research Center in Engineering and Applied science | Lopez O.,University Miguel Hernández | Malumbres M.P.,University Miguel Hernández | And 4 more authors.
Proceedings - 2013 International Conference on Mechatronics, Electronics and Automotive Engineering, ICMEAE 2013 | Year: 2013

Wavelet transforms have proved to be very powerful tools for image compression. Previous studies have verified that there is a strong correlation between the sign of a wavelet coefficient and the signs of their neighbors. This correlation opens the possibility of using a sign predictor in order to improve the image compression process. In this paper a new sign coding approximation method for the wavelet coefficients in a 2D image codec based on an iterated local search algorithm (ILS) is presented. The efficiency of the proposed algorithm versus simulated annealing algorithm (SA) and genetic algorithm (GA) using standard images and benchmarks of Kodak is compared. The proposed sign prediction algorithm is as efficient as other methods and it provides a significant reduction of wavelet coefficients sign information in the final bit-stream. © 2013 IEEE.

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