Calderón

Calderón es el repositorio institucional del CUD (Centro Universitario de la Defensa) en la ENM (Escuela Naval Militar). El CUD, siguiendo las iniciativas Open Access, pone a disposición de la Comunidad este repositorio donde se da acceso a la producción investigadora, principalmente en forma de Trabajos Fin de Grado, pero también Trabajos Fin de Máster, y otros artículos de investigación publicados por el personal docente e investigador del Centro.

Algunos de los documentos publicados en este repositorio tienen restringido el acceso. Para solicitar su consulta, o para plantear cualquier duda respecto a los contenidos de este respositorio, puede:
  • Enviar un correo electrónico a biblioteca@cud.uvigo.es.
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  • Miniatura
    Item type:Ítem,
    Thermal study of a passive cooling device operating through a bubble lifting CLTPT of NOVEC 7000 with a two-fluid condenser
    (International Journal of Heat and Mass Transfer (Elsevier Ltd), 2021-06-06) Gómez Rodríguez, Miguel A.; Bellas Rivera, Roberto; González-Gil, Arturo; Cacabelos Reyes, Antón; Larrañaga Janeiro, Ana
    In the framework of cooling technology applied to electronics, multiple setups and coolants have been used to achieve effective methods to remove high heat density fluxes. In this paper, an innovative device based on the combination of two fluids in a closed loop two-phase thermosiphon is proposed as an effective passive system to cool electronic components. The cooling device is an external flow boiling system that uses NOVEC 7000 as a circulating boiling fluid to transport heat from an evaporator capsule to a condenser. The bubble lifting effect in the closed-loop thermosiphon accelerates the fluid circulation and creates a natural jet impingement effect in the evaporator. In the condenser, the NOVEC bubbles ascend through a water pool, achieving a highly effective heat exchange between the fluids. The advantage of this two-fluid condenser system is highly efficient condensation since the vapour of NOVEC is condensed in a water pool, which produces a high heat transfer between the fluids and is not sensitive to the presence of non-condensable gases. In addition, the movement of the NOVEC bubbles produces high agitation in the water that enhances the heat transfer to the condenser walls. The system was tested under different working conditions with several power generation rates in the heat source and operating at atmospheric pressure and in a vacuum. The system was tested to assess the effect of water in the condenser, and heat transfer coefficients were calculated for the setup operating with and without water. In addition, a numerical model was developed to predict the different temperatures in the system and extrapolate the results for different operating conditions. Several tests were performed, and the results showed robust working of the system and good control of temperatures in the element to be cooled. The system was able to maintain a temperature lower than 70 °C in the aluminium block working with a heat flux of 220 kW/m2 without any extra energy consumption. The effect of water in the condenser was shown to be effective in improving heat transfer and coolant condensation. The heat transfer coefficients in the condenser can be improved by 22 to 133%. The model for temperature prediction showed reasonably good results for most of the experiments regarding both transient behaviour and stabilization temperatures.
  • Miniatura
    Item type:Ítem,
    Assessment of the Fire Dynamics Simulator for Modeling Fire Suppression in Engine Rooms of Ships with Low-Pressure Water Mist
    (Fire Technology (Springer), 2020-05-01) Bellas, Roberto; Gómez, Miguel A; González-Gil, Arturo; Porteiro, Jacobo; Míguez, José L.
    Water mist-based fire-extinguishing systems are gaining acceptance for the protection of ship machinery spaces. The use of simulation tools presents a great potential for taking a performance-based design (PBD) approach to these fire scenarios. The Fire Dynamics Simulator (FDS) is the most frequently used and validated fire modeling software; however, studies of low-pressure water mist fire suppression modeling in ship engine rooms are rare. This paper contributes to the current literature by using the FDS to model a series of fire suppression scenarios defined by the International Maritime Organization (IMO) Circulars, including spray and pool fires with heptane and diesel oil, as well as exposed and obstructed fires. The simulation results are compared to data from full-scale tests conducted at recognized fire testing laboratories. Furthermore, an analysis of both the experimental and model uncertainties is carried out to assess the simulations performance. In general, a good agreement in compartment temperature evolution and fire extinguishing time is found for the modeled fire scenarios. The results support the application of FDS in a PBD approach for the design of water mist fire extinguishing systems for machinery spaces in ships. In this way, designers and engineers could model different machinery volumes and nozzles spacings that differ from those prescribed for a one story square engine room of the IMO, and, thus, predict the evolution of temperatures and extinguishing times for get the authorities approval
  • Miniatura
    Item type:Ítem,
    A framework for integrating human factors in the early stages of ship design: Application to the mess halls of a surface combatant
    (Society of Naval Architects and Marine Engineers, 2020-02-01) González-Cela, Gerardo; Bellas, Roberto; Carreño, Rafael; Martínez, Javier; Touza, Ramón; González-Gil, Arturo; Gómez, Miguel; González, Diego
    The new F-110 frigates project is currently in the conceptual design and definition phase. General arrangement has to be defined; there are many demands and proposals of changes. One of them is the design of the most crowded areas, the mess halls. The aim of this article is to provide the Spanish Navy Staff with a decision tool that helps in determining the optimal distribution of the future F-110 mess halls. For this purpose, a new "analytical decision maker" model was designed providing advanced statistical methods and computer pedestrian simulations within multicriteria decision-making framework that allows optimizing conceptual designs. To reduce subjectivity, crew movement simulations and statistical methods were added to the multicriteria decision model, thus creating a less-subjective decision tool. A sensitivity analysis was conducted to check the robustness of results. An integrative decision and design approach are necessary for broad acceptance of human factors adoption within naval architecture design.
  • Miniatura
    Item type:Ítem,
    Physico-chemical properties of C60(OH)22–24 water solutions: Density, viscosity, refraction index, isobaric heat capacity and antioxidant activity
    (Elsevier, 2019-03-15) N.E. Podolsky; M.A. Marcos; D. Cabaleiro; K.N. Semenov; L. Lugo; A.V. Petrov; N.A. Charykov; V.V. Sharoyko; T.D. Vlasov; I.V. Murin
    This paper investigates the physico-chemical properties of several polyhydroxylated fullerene (fullerenol, C60(OH)22–24) water solutions. The values of densities (ρ), refraction indexes (nD), isobaric heat capacities (Cp) and viscosities (η) were experimentally determined in the temperature range 278.15–323.15 K and at fullerenol concentrations up to 40 g·dm−3. For the highest fullerenol concentration (40 g·dm−3), density, viscosity and isobaric heat capacity modifications reach 4.5%, 56%, and 3%, respectively. Either temperature, T, and concentration, x, dependences of these physical properties were described by polynomial fittings or well-known expressions as the Vogel-Fulcher-Tamman equation, while T-x behaviors were described with the use of a second order polynomial function of both temperature and concentration (the standard deviations do not exceed 0.04). The dynamic and structural characteristics of (fullerene-water) and (fullerenol-water) binary systems were determined by using DFT and MD methods. Finally, the study was completed with the characterization of antioxidant activity of the fullerenol.
  • Miniatura
    Item type:Ítem,
    Optimization of Energy Allocation Strategies in Spanish Collective Self-Consumption Photovoltaic Systems
    (Sustainability, 2023-06-06) Ana Ogando-Martínez; Xela García-Santiago; Saúl Díaz García; Fernando Echevarría Camarero; Gonzalo Blázquez Gil; Pablo Carrasco Ortega
    Collective self-consumption (CSC) systems offer a great opportunity to increase the viability of photovoltaic installations by reducing costs and increasing profitability for consumers. In addition, CSC systems increase self-sufficiency (SS) and self-consumption (SC). These systems require a proper energy allocation strategy (EAS) to define the energy distribution within the CSC. However, most EASs do not analyze the individual impact of the rules and mechanisms adopted. Therefore, six different EASs are proposed and evaluated in terms of both collective and individual cost, SC, and SS. The results show that the EASs based on minimizing collective costs are the most beneficial for the community, although they imply an unfair distribution of energy among users. On the other hand, the other EASs proposed stand out for reaching an equilibrium in terms of cost, SS, and SC, although the collective profitability is lower. The best results are achieved considering dynamic coefficients, which are preferred over static ones.