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Ara es mostren els items 294-313 de 344

    • Recent developments in the design of a new air-cooled, hot-water-driven H2O-LiBr absorption chiller 

      Castro González, Jesús; Oliva Llena, Asensio; Pérez Segarra, Carlos David; Oliet Casasayas, Carles (ASHRAE, 2008)
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      This paper explains the up-to-date stage of development of an air-cooled H2O-LiBr absorption chiller. The methodology of development is based on the systematic application of advanced numerical and experimental techniques, ...

    • Regularization modeling of wall-bounded turbulent flows 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Verstappen, R.W.C.P.; Oliva Llena, Asensio (2010)
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      Since direct numerical simulations cannot be computed at high Reynolds numbers, a dynamically less complex formulation is sought. In the quest for such a formulation, we consider regularizations of the convective term ...

    • Reliable overnight industrial LES: challenges and limitations. Application to CSP technologies 

      Alsalti Baldellou, Àdel; Colomer Rey, Guillem; Hopman, Johannes Arend; Álvarez Farré, Xavier; Gorobets, Andrei; Trias Miquel, Francesc Xavier; Pérez Segarra, Carlos David; Oliva Llena, Asensio (European Research Community on Flow, Turbulence, and Conbustion (ERCOFTAC), 2023)
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      Preserving the operators’ symmetries at the discrete level is crucial to enable reliable DNS and LES simulations of turbulent flows. Moreover, real-world applications demand robust and stable numerical methods suitable for ...

    • Robust and reliable DNS and LES on unstructured grids 

      Trias Miquel, Francesc Xavier; Hopman, Johannes Arend; Santos Serrano, Daniel; Gorobets, Andrei; Oliva Llena, Asensio (European Research Community on Flow, Turbulence, and Conbustion (ERCOFTAC), 2023)
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      Preserving the operators symmetries at discrete level is the key aspect to enable reliable DNS and LES simulations of turbulent flows. On the other hand, realworld applications demand robust and stable numerical methods ...

    • Sensitivity Study To An Absorption System Performance Considering Heat And Mass Transfer Enhancements 

      Zheng, Jian; Castro González, Jesús; Papakokkinos, Giorgos; Oliva Llena, Asensio (Purdue University, 2022)
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      This work describes the absorption system performance with working pairs LiBr-H2O and Carrol-H2O (Carrol contains LiBr and EG -Ethylene glycol- with a mass ratio at 4.5:1) considering the thermal characteristics enhancement. ...

    • Simulation of the two-fluid model on incompressible flow with Fractional Step method for both resolved and unresolved scale interfaces 

      Hou, Xiaofei; Rigola Serrano, Joaquim; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (2015-04)
      Article
      Accés obert
      In the present paper, the Fractional Step method usually used in single fluid flow is here extended and applied for the two-fluid model resolution using the finite volume discretization. The use of a projection method ...

    • Simulaton of absorption of H2O in falling film of LiBr aqueous in vertical tubes in wavy regime 

      García-Rivera, Eduardo; Castro González, Jesús; Farnós Baulenas, Joan; Oliva Llena, Asensio (2011)
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      A mathematical model of falling film absorption of H2O by LiBr aqueous solutions which considers wavy regimes has been implemented. The model is semi-empirical, based on Navier Stokes equations together with energy and ...

    • Spectrally-consistent regularization modeling at very high Rayleigh numbers 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Verstappen, R.W.C.P.; Oliva Llena, Asensio (Begell House, 2012)
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      The incompressible Navier-Stokes equations constitute an excellent mathematical modelization of turbulence. Unfortunately, attempts at performing direct simulations are limited to relatively low-Rayleigh numbers because ...

    • Spectrally-consistent regularization modeling of turbulent natural convection flows 

      Trias Miquel, Francesc Xavier; Verstappen, R.W.C.P.; Gorobets, Andrei; Oliva Llena, Asensio (Université de Poitiers, 2012)
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      The incompressible Navier-Stokes equations constitute an excellent mathematical modelization of turbulence. Unfortunately, attempts at performing direct simulations are limited to relatively low-Reynolds numbers because ...

    • Spectrally-consistent regularization modeling of wind farm boundary layers 

      Trias Miquel, Francesc Xavier; Folch, David; Gorobets, Andrei; Oliva Llena, Asensio (2012)
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      The incompressible Navier-Stokes equations constitute an excellent mathematical modelization of turbulence. Unfortunately, attempts at performing direct simulations are limited to relatively low-Reynolds numbers because ...

    • Spectrally-Consistent Regularization of Navier–Stokes Equations 

      Trias Miquel, Francesc Xavier; Folch Flórez, David; Gorobets, Andrei; Oliva Llena, Asensio (2019-05)
      Article
      Accés obert
      The incompressible Navier–Stokes equations form an excellent mathematical model for turbulent flows. However, direct simulations at high Reynolds numbers are not feasible because the convective term produces far too many ...

    • Spectrally-consistent regularization of turbulent Rayleigh-Bénard convection 

      Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (International Association for Computational Mechanics (IACM), 2014)
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      Direct numerical simulation (DNS) of turbulent Rayleigh-Bénard convection in an air filled (Pr = 0,7) rectangular cell of squared cross-section with periodic boundary conditions in the span-wise direction, has been carried ...

    • Strategies for increasing the arithmetic intensity on ensemble averaged parallel-in-time simulations 

      Plana Riu, Josep; Trias Miquel, Francesc Xavier; Alsalti Baldellou, Àdel; Oliva Llena, Asensio (Parallel Computational Fluid Dynamics (ParCFD), 2023)
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      Extracting flow statistics from flow simulations requires generally long in- tegration intervals in which a good deal of the time is spent time-averaging the results. In order to avoid this, ensemble averaging can be applied ...

    • Strategies to increase the arithmetic intensity of the linear solvers 

      Alsalti Baldellou, Àdel; Álvarez Farré, Xavier; Gorobets, Andrei; Oliva Llena, Asensio; Trias Miquel, Francesc Xavier (Parallel Computational Fluid Dynamics (ParCFD), 2022)
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      The present work presents a strategy to increase the arithmetic intensity of the solvers. Namely, we profit spatial reflection symmetries to block diagonalise Poisson's equation and split the resulting blocks into a common ...

    • Study of stochastic models for subgrid dispersion in Lagrangian-Eulerian formulation 

      Muela Castro, Jordi; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (Springer, 2018)
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      Dispersed multiphase turbulent flows are present in many industrial and commercial applications like internal combustion engines, turbofans, dispersion of contaminants, steam turbines, etc. Therefore, there is a clear ...

    • Study of the autoignition of a hydrogen jet in a turbulent co-flow of heated air using LES modelling 

      Muela Castro, Jordi; Ventosa, Jordi; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (2013)
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      The autoignition process of a hydrogen jet into a preheated turbulent air stream is numerically studied. A Progress-variable model with the turbulence-chemistry interaction s modelled using a Presumed Conditional Moment ...

    • Study of the influence of surfactants and surface treatments on the minimum wetting rate of falling films of aqueous LiBr and Carrol solutions 

      Zheng, Jian; Castro González, Jesús; García Rivera, Eduardo; Oliet Casasayas, Carles; Oliva Llena, Asensio (Elsevier, 2022-09)
      Article
      Accés restringit per política de l'editorial
      The wettability is one of the critical properties of the falling film type absorber, limiting the wetting area in the absorber, hence the total mass transfer performance. To achieve low values of wetting rate in the ...

    • Study on temperature distribution of vertical liquid falling film heat transfer with Al2O3 nanofluid 

      Zheng, Jian; Castro González, Jesús; Liu, Yue; Oliva Llena, Asensio; Pérez Segarra, Carlos David (Elsevier, 2024-02-15)
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      Accés obert
      This study presents a laminar smooth 2-D theoretical model of the falling liquid film using an in-house code and validated with experimental results. The numerical model considers thermophysical property enhancements with ...

    • Subgrid-Scale Model Based on the Invariants of the Gradient Model Tensor 

      Folch Flórez, David; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (2021)
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      The incompressible Navier-Stokes equations stand as the best mathematical model for turbulent flows. However, direct numerical simulations at high Reynolds numbers are not yet feasible because the convective term produces ...

    • Surface tension and contact angle measurement of LiBr and Carrol solution 

      Zheng, Jian; Castro González, Jesús; Oliet Casasayas, Carles; Oliva Llena, Asensio (Technishe Universität Berlin, 2021)
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      The surface tension and contact angle play a relevant role in the heat and mass transfer for the absorption system working pairs. However, LiBr aqueous solution surface tension/contact angle studies are limited and for ...