The present study aims to numerically determine the geometric proportions that maximize the performance of a Savonius rotor with a split Bach blade profile. For this, the response surface methodology was used through a full factorial experimental design, comprised of four factors corresponding to the width (C) and length (L) of the overlap, and the eccentricity (E) and radius (R) of the blade, which define the geometry of the rotor. The models built from the different treatments of the experimental designs were analyzed using computational simulations in order to obtain the power coefficient ($C_P$), considered as the response variable. The same parameters and models of computational fluid dynamics were used to analyze each geometry through the ANSYS Fluent software. The analysis of the obtained results showed that there is a great interaction among the evaluated factors, which demonstrates the importance of analyzing them together. The results obtained with the full factorial experiment design were compared with those obtained from a face-centered central composite design, evidencing a difference of only 0.30% in the estimate of the regression model. A $C_P$ of 0.2661 was obtained from the optimized geometry, which represents a 36.50% increase in its performance with respect to the conventional semicircular profile. The optimal dimensions obtained are 4.69, 21.45, 5.52 and 25.15 in percentage values of the rotor diameter, for parameters C, L, E and R parameters, respectively. Experimental data available in the literature were used to contrast the numerical results and a good fit was revealed.

In the present study, the implementation of multi-blade profiles in a Savonius rotor was evaluated in order to increase the pressure in the blade’s intrados and, thus, decrease motion resistance. The geometric proportions of the secondary element were determined, which maximized the rotor’s performance. For this, the response surface methodology was used through a full factorial experimental design and a face-centered central composite design, consisting of three factors, each with three levels. The response variable that was sought to be maximized was the power coefficient ($C_P$), which was obtained through the numerical simulation of the geometric configurations resulting from the different treatments. All geometries were studied under the same parameters and computational fluid dynamics models through the ANSYS Fluent software. The results obtained through both experimental designs showed a difference of only 1.06% in the performance estimates using the regression model and 3.41% when simulating the optimal proportions geometries. The optimized geometry was characterized by a $C_P$ of 0.2948, which constitutes an increase of 10.8% in its performance compared to the profile without secondary elements and of 51.2% compared to the conventional semicircular profile. The numerical results were contrasted with experimental data obtained using a wind tunnel, revealing a good degree of fit.

Con la construcción de este banco de pruebas se logra realizar la caracterización de sistemas solares fotovoltaicos autónomos y además medir el rendimiento de los paneles solares fotovoltaicos. Este banco de ensayos le permite a los estudiantes y usuarios conocer los componentes de un sistema fotovoltaico aislado para vivienda y validar el funcionamiento de cada uno de estos; componente de protección, las conexiones, el componente de transformación DC-AC, entre otros. El banco fue diseñado para realizar diferentes prácticas de laboratorio, tales como: identificar y evaluar la curva de operación de los paneles según la radiación recibida, medir voltaje y corriente de salida del sistema según sus conexiones en serie y paralelo, realizar conexiones para corriente directa o corriente alterna, entre otras. La práctica más compleja y relevante es la medición del rendimiento de los paneles solares, ya que se deben incluir unas resistencias a diferente capacidad medida para ir creando la curva de corriente vs voltaje (I vs V); se diseñó un circuito electrónico donde el panel es conectado a una carga resistiva variable y se registra el valor de corriente y voltaje. Para la medición de voltaje el multímetro se conecta en paralelo en el circuito y para la medición de amperaje se conecta en serie. Algunos de los resultados más importantes de las prácticas fueron; el poder identificar la variación significativa de la eficiencia de los paneles solares a medida que cambia la posición del sol, Identificar cómo la temperatura afecta el rendimiento del panel y determinar las condiciones excepcionales en las que un panel genera la energía especificada por el fabricante.

Contexto: Las turbinas eólicas de eje vertical, y en particular las turbinas de arrastre tipo Savonius, aventajan a los otros tipos de turbinas en aplicaciones que comprenden vientos erráticos y de baja velocidad. Si bien su eficiencia está entre las más bajas, esto puede verse compensado con sus bajos costos, lo que las convierte en una alternativa sostenible y atractiva para este tipo de aplicaciones. En esta investigación se busca seleccionar la geometría de mayor rendimiento para el álabe de una turbina eólica tipo Savonius. Método: Para ello, se analizan numéricamente diversas configuraciones geométricas empleadas en este tipo de turbinas, las cuales fueron consultadas en la literatura. Todos los modelos de perfil son estudiados bajo los mismos parámetros y modelos de dinámica de fluidos computacional a través del software ANSYS Fluent. Resultados: A través de las simulaciones computacionales se estiman las condiciones de optimo rendimiento de cada una de las geometrías. Dichas condiciones permiten comparar, bajo los mismos términos, el desempeño de los perfiles e identificar los de mayor rendimiento. Se determina que el perfil semicircular convencional y el conocido como Bach modificado presentan coeficientes de potencia de 0,287 y 0,395 respectivamente, lo que representa un aumento en su rendimiento del 37,8 %. Conclusiones: Este resultado superior motiva a un análisis detallado del perfil Bach modificado que permita encontrar las proporciones geométricas óptimas para su desempeño aerodinámico. Context: Vertical-axis wind turbines, and Savonius-type turbines in particular, outstrip other types of turbines in applications that include erratic and low-speed winds. Although their efficiency is among the lowest, this can be compensated by their low cost, turning them into a sustainable alternative which is also appealing for this type of applications. This research seeks to select the highest-performance geometry for the blade of a Savonius-type wind turbine. Method: To this effect, various geometric configurations used in this type of turbines, which were consulted in the literature, are numerically analyzed. All the profile models are studied under the same computational fluid dynamics parameters and models through the ANSYS Fluent software. Results: Through computational simulations, the optimal performance conditions of each of the geometries are estimated. These conditions allow comparing the performance of the profiles under the same terms, as well as identifying the ones with the highest performance. It is determined that the conventional semicircular profile and the one known as the modified Bach have power coefficients of 0,287 and 0,395, respectively, which represents a performance increase of 37,8%. Conclusions: These superior results motivate a detailed analysis of the modified Bach profile which allows finding the optimal geometric proportions for its aerodynamic performance.

Numerical solutions of 2-D laminar flow over a backward-facing step using the lattice Boltzmann equation method (LBEM) are presented in this article. Unlike conventional numerical schemes based on macroscopic continuum equation (mass conservation and Navier-Stokes) discretisation, the LBEM is based on microscopic models and mesoscopic kinetic equations. The simulations were validated for a wide range of Reynolds numbers (100 ≤ Re ≤ 1,000), comparing them to previous studies. Several flow features, such as primary and secondary vortex location at the bottom and top of the wall, respectively, were investigated regarding Reynolds number. Two typical classes of boundary condition were implemented in the LBEM model: the Drichlet condition at the inlet flow (parabolic speed profile) and the Newman condition at the outlet flow (zero gradient speed). The results showed that the LBEM gave accurate results over a wide range of Reynolds number; these were compared with other numerical methods and experimental data.

Ante el reto que representa para las empresas de la ciudad de Cúcuta (Colombia) implementar un Sistema de Gestión de Calidad (SGC) que les permita ofrecer servicios de calidad, garantizando su sostenibilidad y rentabilidad, el presente trabajo tiene por objeto evaluar el impacto que ha tenido la certificación ISO 9001 para las empresas de la región. Para efectos metodológicos se emplea un instrumento validado el cual se aplica sobre 71 empresas. Los resultados cuantitativos, analizados mediante estadística descriptiva, revelan que 23 de los 24 criterios evaluados se cumplen en más del 95% de las empresas analizadas, siendo la mejora continua el factor de mayor impacto; mientras que el 13% de estas revelan que no se han generado proyectos de innovación y desarrollo tras la implementación de un SGC.