Ara es mostren els items 60-79 de 343

    • Can we hit the ultimate regime of thermal turbulence using LES simulations at low Prandtl numbers? 

      Trias Miquel, Francesc Xavier; Gorobets, Andrey; Oliva Llena, Asensio (Begell House, 2023)
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      In this work, we aim to shed light on the following research question: can we hit the ultimate regime of thermal turbulence using large-eddy simulations (LES) at low Prandtl numbers? This is motivated by our recent findings ...
    • CFD simulation of the thermal behavior of a wind mill power generator nacelle 

      Colomer Rey, Guillem; Lehmkuhl Barba, Oriol; Borrell Pol, Ricard; Oliva Llena, Asensio (2009)
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      In this work we use the Large Eddy Simulation model to predict the thermal behavior of the air inside of a wind generator nacelle, where several elements with di erent thermal characteristics are found. Outside air enters ...
    • Characteristics of the near wake region behind a cylinder at critical and super-critical Reynolds numbers 

      Rodríguez Pérez, Ivette María; Lehmkuhl Barba, Oriol; Chiva Segura, Jorge; Borrell Pol, Ricard; Oliva Llena, Asensio (Begell House, 2015)
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      Large-eddy simulations (LES) of the flow past a circular cylinder are used to investigate the characteristics of the near wake region at Reynolds numbers Re = 2.5 × 105 - 8.5 × 105. This range encompasses both the critical ...
    • Coherent structures in a flow past a circular cylinder at critical and super-critical Reynolds numbers 

      Rodríguez Pérez, Ivette María; Lehmkuhl Barba, Oriol; Chiva Segura, Jorge; Borrell Pol, Ricard; Oliva Llena, Asensio (Springer, 2015)
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      It is well known that the wake topology in the flow past a circular cylinder remains almost unchanged up to Reynolds number ~105 Williamson (Annu Rev Fluid Mech 28(1), 477–539 (1996)) [1]. Then, at Re~2×105 major changes ...
    • Combined heat and moisture transfer in buildings systems 

      Damle, Rashmin; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim; Oliva Llena, Asensio (2012)
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      Temperature and humidity are the two main parameters indicating the comfort level of the building occupants. Although the effect of temperature is taken into account in thermal simulation of buildings, the moisture transfer ...
    • Comparative study of subfilter scalar dissipation rate and mixture fraction variance models 

      Ventosa Molina, Jordi; Lehmkuhl Barba, Oriol; Pérez Segarra, Carlos David; Muela Castro, Jordi; Oliva Llena, Asensio (2014)
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      Accurate characterisation of mixing at the subfilter level is a critical aspect in many LES combustion models, such as flamelet based and Conditional Moment Closure models. Several models can be found in the literature, ...
    • Comparison of the performance of falling film and bubble absorbers for air-cooled absorption systems 

      Castro González, Jesús; Oliet Casasayas, Carles; Rodríguez Pérez, Ivette María; Oliva Llena, Asensio (2009-07-01)
      Article
      Accés obert
      Small capacity, air-cooled NH3–H2O absorption systems are becoming more attractive in applications where the input energy can be obtained for free (e.g., solar energy, exhaust gases of engines, etc.), due to the increasing ...
    • Compressible 1D-3D simulation of a muffler with pseudosound prediction levels 

      López Mas, Joan; Ruano Pérez, Jesús; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim; Oliva Llena, Asensio (International Institute of Refrigeration, 2015)
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      Numerical software for the simulation of thermal and fluid-dynamic behavior of hermetic reciprocating compressors is a must for its understanding and improvement. Hence, these tools are widely used to improve ...
    • Computational investigation of the hexagonal honeycomb adsorption reactor for cooling applications: Honeycomb adsorption reactor for cooling 

      Papakokkinos, Giorgos; Castro González, Jesús; Oliet Casasayas, Carles; Oliva Llena, Asensio (2022-02-05)
      Article
      Accés obert
      Adsorption cooling is a sustainable technology, since it can utilize solar energy or waste heat, while employing substances without ozone depletion and global warming potential. The adsorption reactor design is determinant ...
    • Conservative discretization of multiphase flow with high density ratios 

      Jofre Cruanyes, Lluís; Lehmkuhl Barba, Oriol; Balcázar Arciniega, Néstor; Castro González, Jesús; Rigola Serrano, Joaquim; Oliva Llena, Asensio (WIT Press, 2014)
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      The computation of multiphase flows presenting high density ratios, where the fluids involved are considered immiscible, are of great importance for fundamental physics and industrial applications; such as the study of ...
    • Control strategy approach based on the operational results of a small capacity direct air -cooled LiBr -Water absorption chiller 

      Farnós Baulenas, Joan; Castro González, Jesús; Papakokkinos, Giorgos; Oliva Llena, Asensio (International Solar Energy Society, 2017)
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      The scope of this paper is to give a short overview of the state of the art regarding control strategies, identify the role of different operating conditions, and provide useful suggestions for the design and operation of ...
    • Cost-vs-accuracy analysis of self-adaptive time-integration methods 

      Plana Riu, Josep; Trias Miquel, Francesc Xavier; Pérez Segarra, Carlos David; Oliva Llena, Asensio (Begell House, 2023)
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      The integration in time of the semi-discrete Navier-Stokes equations has been historically bounded by the classic CFL condition, and later on, an innovative method has been defined by ensuring the eigenvalues of the method ...
    • Coupled radiation and natural convection: Different approaches of the slw model for a non-gray gas mixture 

      Colomer Rey, Guillem; Consul Serracanta, Ricard; Oliva Llena, Asensio (2007-09)
      Article
      Accés obert
      The coupling between non-gray radiation heat transfer and convection–conduction heat transfer is studied. The spectral line weighted sum of gray gases model (SLW) is used to account for non-gray radiation properties. The ...
    • Coupling CFD models of airflow with building simulation with an object-oriented and parallel infrastructure 

      Damle, Rashmin; Lehmkuhl Barba, Oriol; Rodríguez Pérez, Ivette María; Oliva Llena, Asensio (2012)
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      Integrating CFD & HT models with the general building program raises the computational time of building simulations as these simulations are usually performed over a period of one year. Within this context, our aim is ...
    • Data-driven prediction of flow parameters in a ventilated cavity using high-fidelity CFD simulations 

      Morozova, Nina; Trias Miquel, Francesc Xavier; Capdevila Paramio, Roser; Oliva Llena, Asensio (International Building Performance Simulation Association (IBPSA), 2021)
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      In this study, we develop a machine-learning-based data-driven model, which predicts comfort-related flow parameters in a ventilated room. The model is based on the results of high-fidelity computational fluid dynamics ...
    • Detailed analysis of fin-and-tube evaporators 

      Oliet Casasayas, Carles; Pérez Segarra, Carlos David; Oliva Llena, Asensio (2009-09-17)
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      This paper is devoted to the presentation of a new model for fin-and-tube evaporators, focusing on the solid core simulation and its integration with a quasi-homogeneous two-phase flow model for the in-tube refrigerant ...
    • Detailed numerical model for the receiver of a solar power tower plant 

      Chiva Segura, Jorge; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (2012)
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      In this paper, a numerical model for the simulation of the receiver of a solar power tower plant is presented. This global model is composed of 4 specific sub-models (heat conduction, two-phase, thermal radiation and natural ...
    • Detailed numerical model for the resolution of molten salt storage tanks for CSP plants 

      Pérez Segarra, Carlos David; Rodríguez Pérez, Ivette María; Oliva Llena, Asensio; Torras Ortíz, Santiago; Lehmkuhl Barba, Oriol (2012)
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      Considering the state-of-the-art in TES technologies, two-tank indirect system using molten salt is the most widespread within CSP plants. However, current techniques for design and optimization, as well as, for assessing ...
    • Detailed numerical study of turbulent flows in air curtains 

      Jaramillo Ibarra, Julian Ernesto; Pérez Segarra, Carlos David; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (2010)
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      Air curtains are generally a set of vertical or horizontal plane jets used as ambient separator. In order to prevent entrainment, a good air curtain should provide a jet with low turbulence level, enough momentum to ...
    • Detailed prediction of fluid-solid coupled phenomena of turbulent flow through reed valves 

      González Acedo, Ignacio; Naseri, Alireza; Rigola Serrano, Joaquim; Pérez Segarra, Carlos David; Oliva Llena, Asensio (Institute of Physics (IOP), 2019)
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      The operation of self-actuated valves in suction and discharge processes plays a crucial role in the thermal efficiency and structural reliability of hermetic reciprocating compressors. The present work provides a thorough ...