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In the present work, the flow field is analysed for Mach number, pressure and temperature in 2D computational domains for a planar nozzle of symmetrical geometry as used in the experimental tests for cold (air) flow. The study has been considered for three mean angles of the divergent section: α = 9°, α = 11.01° and α = 13°, and for four pressure ratios: NPR = 2.412, NPR = 3.413, NPR = 5.423 and NPR = 8.78. For the numerical simulation of the turbulence in the presence of shock waves, the RANS model, the Sutherland equation and the Spalart-Allmaras turbulence model were used in the ANSYS-Fluent R16.2 code. The results obtained show fluctuations at the intersections of the internal shocks in the divergent, and the fluctuation decreases as the angle of the divergent increases. For NPR = 3.413, NPR = 5.423 and NPR = 8.78, the Mach number at the nozzle exit is the same, where for α = 11.01° Mach 2.00 was obtained, and based on this reference, for α = 13° there is an increase in velocity of 4.15% and for α = 9° a decrease in velocity of 3.78%. The lowest pressure and temperature drop occurs at the nozzle outlet for α = 13°.

El patrón de flujo en toberas supersónicas lo definen los perfiles aerodinámicos de la geometría de las paredes internas, entre otros parámetros, donde la garganta es una sección crítica. En el presente trabajo, el objetivo es analizar el comportamiento del flujo en la sección recta de la garganta de una tobera cónica experimental de un motor de cohete sonda de combustible sólido. El flujo sobreexpandido se simuló con el código ANSYS-Fluent en un dominio computacional 2D, empleando el modelo RANS y el modelo de turbulencia de Menter, y la ecuación de Sutherland para la viscosidad en función de la temperatura. Se llevaron a cabo cinco casos de estudio para la longitud de garganta en el rango de 1-10 mm. Se obtuvo fluctuaciones de número de Mach, presión y temperatura, ondas de choque oblicuas en la sección de la garganta para la longitud de 10 mm; para longitudes menores disminuyó la intensidad de la magnitud del choque. Se concluye que para la longitud de garganta de 1 mm el flujo es transónico sin la presencia de choques oblicuos. En la sección divergente, las ondas de choque varían en su intensidad y cambian de posición.

The flow pattern in supersonic nozzles is defined by the aerodynamic profiles of the geometry of the internal walls, among other parameters, the throat being a critical section. In the present work, the objective is to analyze the behavior of the flow in the straight section of the throat of an experimental conical nozzle of a solid fuel probe rocket engine. The over-expanded flow was simulated with the ANSYS-Fluent code in a 2D computational domain, using the RANS model and the Menter turbulence model, and the Sutherland equation for viscosity as a function of the temperature. Five case studies were performed for the throat length in the range of 1-10 mm. Fluctuations of Mach number, pressure and temperature, oblique shock waves in the throat section were obtained for the length of 10 mm; for shorter lengths the intensity of the shock magnitude decreased. It is concluded that, for the throat length of 1 mm, the flow is transonic without the presence of oblique shocks. In the diverging section, shock waves vary in intensity and change position., El patrón de flujo en toberas supersónicas lo definen los perfiles aerodinámicos de la geometría de las paredes internas, entre otros parámetros, donde la garganta es una sección crítica. En el presente trabajo, el objetivo es analizar el comportamiento del flujo en la sección recta de la garganta de una tobera cónica experimental de un motor de cohete sonda de combustible sólido. El flujo sobreexpandido se simuló con el código ANSYS-Fluent en un dominio computacional 2D, empleando el modelo RANS y el modelo de turbulencia de Menter, y la ecuación de Sutherland para la viscosidad en función de la temperatura. Se llevaron a cabo cinco casos de estudio para la longitud de garganta en el rango de 1-10 mm. Se obtuvo fluctuaciones de número de Mach, presión y temperatura, ondas de choque oblicuas en la sección de la garganta para la longitud de 10 mm; para longitudes menores disminuyó la intensidad de la magnitud del choque. Se concluye que para la longitud de garganta de 1 mm el flujo es transónico sin la presencia de choques oblicuos. En la sección divergente, las ondas de choque varían en su intensidad y cambian de posición.

Estudios numéricos del campo de flujo para toberas convergentes-divergentes con longitud de garganta, han reportado fluctuaciones del flujo con ondas de choque oblicuo en la sección de la garganta, para la condición de flujo sobre-expandido. Sin embargo, para otras condiciones del flujo, para un mismo tipo de tobera, el conocimiento es limitado. En el presente trabajo, el objetivo es determinar el comportamiento del flujo en la longitud de garganta y en la divergente, para una tobera cónica experimental clasificada como Helios-X, para la condición de flujo sub-expandido. Se realizaron simulaciones numéricas 2D del campo de flujo con el código ANSYS-Fluent versión 12.1, aplicando el modelo RANS. Se emplearon las ecuaciones gobernantes para el flujo compresible, conservación de la masa, cantidad de movimiento, energía y de estado; así como, para la turbulencia el modelo SST k − ω de Menter y para la viscosidad en función de la temperatura la ecuación de Sutherland. En la sección de la garganta, adyacente a la pared, el flujo presentó fluctuaciones, en la simetría axial el flujo presentó una aceleración escalonada; en la sección divergente, el flujo se desaceleró en cierta región, sin embargo, el flujo salió de la tobera a velocidad supersónica ligeramente mayor de Mach 3. Se concluye que en la sección de la longitud de garganta se presenta un patrón de flujo, así como, en la sección divergente.//Numerical studies of the flow field for convergentdivergent nozzles with throat length, have reported fluctuations of the flow with oblique shock waves in the throat section, for the over-expanded flow condition. However, for other flow conditions, for the same type of nozzle, knowledge is limited. In the present work, the objective is to determine the behavior of the flow in the throat length and in the divergent, for an experimental conical nozzle classified as Helios-X, for the under-expanded flow condition. 2D numerical simulations of the flow field were performed with the ANSYS-Fluent version 12.1 code, applying the RANS model. The governing equations for compressible flow, conservation of mass, momentum, energy, and state were used; as well as, for turbulence, the Menter model SST k − ω and for the viscosity as a function of temperature the Sutherland equation. In the section of the throat, adjacent to the wall, the flow presented fluctuations, in the axial symmetry the flow presented a stepped acceleration; in the divergent section, the flow slowed in a certain region, however, the flow exited the nozzle at a supersonic speed slightly greater than Mach 3. It is concluded that in the throat length section there is a flow pattern, as well as, in the divergent section.

Estudios numéricos del campo de flujo para toberas convergentes-divergentes con longitud de garganta han reportado fluctuaciones del flujo con ondas de choque oblicuo en la sección de la garganta, para la condición de flujo sobreexpandido. Sin embargo, para otras condiciones del flujo, para un mismo tipo de tobera, el conocimiento es limitado. En el presente trabajo, el objetivo es determinar el comportamiento del flujo en la longitud de garganta y en la divergente, para una tobera cónica experimental clasificada como Helios-X, para la condición de flujo subexpandido. Se realizaron simulaciones numéricas 2D del campo de flujo con el código ANSYS-Fluent versión 12.1, aplicando el modelo RANS. Se emplearon las ecuaciones gobernantes para el flujo compresible, conservación de la masa, cantidad de movimiento, energía y de estado; así como, para la turbulencia el modelo SST de Menter y para la viscosidad en función de la temperatura la ecuación de Sutherland. En la sección de la garganta, adyacente a la pared, el flujo presentó fluctuaciones, en la simetría axial el flujo presentó una aceleración escalonada; en la sección divergente, el flujo se desaceleró en cierta región, sin embargo, el flujo salió de la tobera a velocidad supersónica ligeramente mayor de Mach 3. Se concluye que en la sección de la longitud de garganta se presenta un patrón de flujo, así como, en la sección divergente.

During the day of October 7-8, the congress has invited experts from the sector of Smart Cities to organize a sectoral debate. This debate will be composed of prestigious companies in the sector, Public Administration, as well as specialized consultants. The aim is to give a business point of view around Smart Cities. CYTED is the Ibero-American Program of Science and Technology for Development, created by the governments of Ibero-American countries to promote cooperation on issues of science, technology and innovation for the harmonious development of Ibero-America. CYTED achieves its objectives through different financing instruments that mobilize Ibero-American entrepreneurs, researchers and experts and allow them to be trained and generate joint research, development and innovation projects. Thus, the countries that make up the CYTED Program are able to keep up to date with the most recent advances and scientific-technological developments.

This article includes a compilation and analysis of relevant information on the state of the art of the implementation of the Droop Control technique in microgrids. To this end, a summary and compilation of the theoretical models of the Droop Control and a summary of implementations have been made and, in general, try to summarize the great variety of experiences developed in this topic. The chosen experiences have been selected according to the research motivations that are available in the future and that are explained throughout this article, since this will serve as a starting point and guide for future research in microgrids and similar novel topics such as Low Voltage Distribution in Direct Current (LV DC) and DC microgrids (DC MG). The LV DC distribution for this article is related to houses in direct current (DC Home).

A mathematical model is presented for the estimation of the contribution of biomass to the generation of electricity for a valley as a geographical scope of application. It is considered that a valley has several species that are cultivated during the year and that have by-products of the harvest that we have considered as biomass that can be used for the production of electricity that would benefit the valley’s inhabiting community. We have called this integration between population and crops SmartValley, which leads to the use of monitoring, control, management and planning among the different agricultural-energy actors. The cultivation and production of plants shows production variations during the year and throughout the years. For this, the mathematical model has as an essential part the data of usable biomass from which the electricity production estimate is made. A case study has been considered for the present study: a typical valley on the north coast of Peru, where rice crops are quite common, and; they have the potential to be used for electricity generation.

The interconnection between DC microgrids has been studied through the modeling and simulation of two DC microgrids and utility network with independent connection to each microgrid. Each microgrid has generation sources, storage source, electrical charges, two points of common coupling (one with the utility network and other with the neighboring microgrid) and a central controller. By performing the simulations and searching for new ways in which the interconnection can be made, the following contributions are reached: (a) although a nominal voltage is present on the DC microgrid bus, it becomes necessary to have three mini-voltage scales (one for the micro-sources, another for the storage sources and a third for AC/DC converter output that connects the utility supply and DC microgrid bus); (b) the power to avoid being heavily dependent on random variables requires temporary storage at the generation sources and that electrical loads define a very stable demand and clearance for certain period of time (of a few minutes), said period would be a new time scale of microgrid operation; (c) the cost associated with generation and storage sources must be optimized for the microgrids operation on the new unit of measurement and for which linear programming techniques have been used, and (d) it representing new coordination actions for tertiary control among central controllers of the microgrids. The new strategies of control, voltage and power will serve to propose and study new designs of: topologies of the electrical network, interconnection devices between microredes and other topics.