Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3193
2016-07-26T06:34:16ZNumerical analysis of the turbulent fluid flow through valves. Geometrical aspects influence at different positions
http://hdl.handle.net/2117/85986
Numerical analysis of the turbulent fluid flow through valves. Geometrical aspects influence at different positions
Rigola Serrano, Joaquim; Aljure Osorio, David E.; Lehmkuhl Barba, Oriol; Pérez Segarra, Carlos David; Oliva Llena, Asensio
The aim of this paper is to carry out a group of numerical experiments over the fluid flow through a valve reed, using the CFD&HT code TermoFluids, an unstructured and parallel object-oriented CFD code for accurate and reliable solving of industrial flows. Turbulent flow and its solution is a very complex problem due to there is a non-lineal interaction between viscous and inertial effects further complicated by their rotational nature, together with the three-dimensionality inherent in these types of flow and the non-steady state solutions. In this work, different meshes, geometrical conditions and LES turbulence models (WALE, VMS, QR and SIGMA) are tested and results compared. On the other hand, the fluid flow boundary conditions are obtained by means of the numerical simulation model of hermetic reciprocating compressors tool, NEST-compressor code. The numerical results presented are based on a specific geometry, where the valve gap opening percentage is 11% of hole diameter and Reynolds numbers given by the one-dimensional model is 4.22 × 105, with density meshes of approximately 8 million CVs. Geometrical aspects related with the orifice's shape and its influence on fluid flow behaviour and pressure drop are analysed in detail, furthermore, flow results for different valve openings are also studied.
Published under licence in IOP Conference Series: Materials Science and Engineering by IOP Publishing Ltd.
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
2016-04-20T13:46:11ZRigola Serrano, JoaquimAljure Osorio, David E.Lehmkuhl Barba, OriolPérez Segarra, Carlos DavidOliva Llena, AsensioThe aim of this paper is to carry out a group of numerical experiments over the fluid flow through a valve reed, using the CFD&HT code TermoFluids, an unstructured and parallel object-oriented CFD code for accurate and reliable solving of industrial flows. Turbulent flow and its solution is a very complex problem due to there is a non-lineal interaction between viscous and inertial effects further complicated by their rotational nature, together with the three-dimensionality inherent in these types of flow and the non-steady state solutions. In this work, different meshes, geometrical conditions and LES turbulence models (WALE, VMS, QR and SIGMA) are tested and results compared. On the other hand, the fluid flow boundary conditions are obtained by means of the numerical simulation model of hermetic reciprocating compressors tool, NEST-compressor code. The numerical results presented are based on a specific geometry, where the valve gap opening percentage is 11% of hole diameter and Reynolds numbers given by the one-dimensional model is 4.22 × 105, with density meshes of approximately 8 million CVs. Geometrical aspects related with the orifice's shape and its influence on fluid flow behaviour and pressure drop are analysed in detail, furthermore, flow results for different valve openings are also studied.Hygrothermal analysis of characteristic public building rooms before energy efficient retrofitting solutions
http://hdl.handle.net/2117/84013
Hygrothermal analysis of characteristic public building rooms before energy efficient retrofitting solutions
Souaihi, Oussama; Capdevila, Roser; Lopez, Joan; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim
In the present paper, a modular, object-oriented and parallel methodology for the multiphysics simulation of buildings is presented. The whole building is modeled as a collection of basic elements (e.g., walls, rooms, outdoor, people, ventilation, solar radiation distributor, etc.). These elements can be modeled with different physical models and scales. A combined heat and moisture transfer model for the building envelopes and rooms have been implemented and validated with different benchmark cases. The simulation tool has been used within the framework of EU project for the simulation of hygrothermal behavior of various existing characteristic rooms inside three different public buildings (hospital, university and school) located in distinct locations of Europe (Spain, England and Sweden). Simulations allow the analysis of energy performance of different characteristic rooms of these demosites before the retrofitting solution of these buildings.
2016-03-08T18:41:53ZSouaihi, OussamaCapdevila, RoserLopez, JoanLehmkuhl Barba, OriolRigola Serrano, JoaquimIn the present paper, a modular, object-oriented and parallel methodology for the multiphysics simulation of buildings is presented. The whole building is modeled as a collection of basic elements (e.g., walls, rooms, outdoor, people, ventilation, solar radiation distributor, etc.). These elements can be modeled with different physical models and scales. A combined heat and moisture transfer model for the building envelopes and rooms have been implemented and validated with different benchmark cases. The simulation tool has been used within the framework of EU project for the simulation of hygrothermal behavior of various existing characteristic rooms inside three different public buildings (hospital, university and school) located in distinct locations of Europe (Spain, England and Sweden). Simulations allow the analysis of energy performance of different characteristic rooms of these demosites before the retrofitting solution of these buildings.Comparative study of subfilter scalar dissipation rate and mixture fraction variance models
http://hdl.handle.net/2117/82232
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
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, which vary from algebraic relations
between resolved magnitudes, to the full transport of the subfilter magnitudes. In this
paper a comparative between different published models is made in the context of a amelet based combustion model. A turbulent hydrogen/methane flame is used as test case.; 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, which vary from algebraic relations
between resolved magnitudes, to the full transport of the subfilter magnitudes. In this
paper a comparative between different published models is made in the context of a amelet based combustion model. A turbulent hydrogen/methane flame is used as test case.
2016-01-28T16:02:36ZVentosa Molina, JordiLehmkuhl Barba, OriolPérez Segarra, Carlos DavidMuela Castro, JordiOliva Llena, AsensioAccurate 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, which vary from algebraic relations
between resolved magnitudes, to the full transport of the subfilter magnitudes. In this
paper a comparative between different published models is made in the context of a amelet based combustion model. A turbulent hydrogen/methane flame is used as test case.
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, which vary from algebraic relations
between resolved magnitudes, to the full transport of the subfilter magnitudes. In this
paper a comparative between different published models is made in the context of a amelet based combustion model. A turbulent hydrogen/methane flame is used as test case.On the wake transition in the flow past a circular cylinder at critical Reynolds numbers
http://hdl.handle.net/2117/80121
On the wake transition in the flow past a circular cylinder at critical Reynolds numbers
Rodríguez Pérez, Ivette María; Lehmkuhl Barba, Oriol; Chiva Segura, Jorge; Borrell Pol, Ricard; Oliva Llena, Asensio
2015-12-02T14:31:39ZRodríguez Pérez, Ivette MaríaLehmkuhl Barba, OriolChiva Segura, JorgeBorrell Pol, RicardOliva Llena, AsensioEnergy simulation of a single family dwelling with a modular object-oriented tool
http://hdl.handle.net/2117/79043
Energy simulation of a single family dwelling with a modular object-oriented tool
Capdevila Paramio, Roser; Chiva Segura, Jorge; López Mas, Joan; Rigola Serrano, Joaquim; Lehmkuhl Barba, Oriol
2015-11-11T14:12:29ZCapdevila Paramio, RoserChiva Segura, JorgeLópez Mas, JoanRigola Serrano, JoaquimLehmkuhl Barba, OriolImprovements on the numerical analysis of viscoplastic-type non-Newtonian fluid flows
http://hdl.handle.net/2117/27318
Improvements on the numerical analysis of viscoplastic-type non-Newtonian fluid flows
Carmona Muñoz, Ángel; Lehmkuhl Barba, Oriol; Pérez Segarra, Carlos David; Oliva Llena, Asensio
The aim of this work is to delve into the numerical analysis of viscoplastic-type non-Newtonian fluid flows with the objective of carrying out more advanced numerical simulations for them. Specifically, improvements in the spatial discretization schemes and the temporal integration methods are proposed to overcome the numerical problems introduced by the transpose diffusive term and associated with the velocity field discontinuity, the artificial viscous diffusion and the transpose viscous coupling.
2015-04-14T12:53:37ZCarmona Muñoz, ÁngelLehmkuhl Barba, OriolPérez Segarra, Carlos DavidOliva Llena, AsensioThe aim of this work is to delve into the numerical analysis of viscoplastic-type non-Newtonian fluid flows with the objective of carrying out more advanced numerical simulations for them. Specifically, improvements in the spatial discretization schemes and the temporal integration methods are proposed to overcome the numerical problems introduced by the transpose diffusive term and associated with the velocity field discontinuity, the artificial viscous diffusion and the transpose viscous coupling.Spectrally-consistent regularization of turbulent Rayleigh-Bénard convection
http://hdl.handle.net/2117/26901
Spectrally-consistent regularization of turbulent Rayleigh-Bénard convection
Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio
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 out at Ra = 10^8. A fourth-order energy-conserving discretizations have been used that ensure non-physical dissipative effects introduced usually in other numerical schemes. The two sensitive fine-scales kinetic and thermal dissipation rates have been studied statistically to reveal high correlation within the thermal boundary layers and equilibrium zones of the two dissipations at strong thermal and kinetic interactions. It has been found that the foregoing zones could mark the plumes since these last reflect significant correlation regions of the kinetic and thermal fields. Afterwards, a novel class of symmetry-preserving regularization models that restrain the convective production of small scales of motion in unconditionally stable manner, have been applied on the studied problem. The obtained results are compared directly with the DNS ones to show a reasonable correspondence with and without model at this kind of moderate turbulence.
2015-03-20T13:50:56ZDabbagh, FirasTrias Miquel, Francesc XavierGorobets, AndreiOliva Llena, AsensioDirect 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 out at Ra = 10^8. A fourth-order energy-conserving discretizations have been used that ensure non-physical dissipative effects introduced usually in other numerical schemes. The two sensitive fine-scales kinetic and thermal dissipation rates have been studied statistically to reveal high correlation within the thermal boundary layers and equilibrium zones of the two dissipations at strong thermal and kinetic interactions. It has been found that the foregoing zones could mark the plumes since these last reflect significant correlation regions of the kinetic and thermal fields. Afterwards, a novel class of symmetry-preserving regularization models that restrain the convective production of small scales of motion in unconditionally stable manner, have been applied on the studied problem. The obtained results are compared directly with the DNS ones to show a reasonable correspondence with and without model at this kind of moderate turbulence.Unstructured 3D numerical modeling of the melting of a PCM contained in a spherical capsule
http://hdl.handle.net/2117/26897
Unstructured 3D numerical modeling of the melting of a PCM contained in a spherical capsule
Galione Klot, Pedro Andrés; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim; Pérez Segarra, Carlos David; Oliva Llena, Asensio
2015-03-20T13:34:04ZGalione Klot, Pedro AndrésLehmkuhl Barba, OriolRigola Serrano, JoaquimPérez Segarra, Carlos DavidOliva Llena, AsensioDirect numerical simulation of the flow over a spherical bubble in a turbulent pipe flow
http://hdl.handle.net/2117/26896
Direct numerical simulation of the flow over a spherical bubble in a turbulent pipe flow
Jofre Cruanyes, Lluís; Balcázar Arciniega, Néstor; Lehmkuhl Barba, Oriol; Borrell Pol, Ricard; Castro González, Jesús
This work aims at investigating, by means of a direct numerical simulation, the flow over a clean spherical bubble fixed on the axis of a turbulent pipe flow. The simulation is performed by means of a parallel unstructured symmetry-preserving formulation on a mesh of 5.4M cells. The main features of the turbulent flow are described by analyzing the time-averaged data collected over a significant period of time. The numerical results conclude that the bubble generates a wake, similarly to the case of a solid sphere, however, it differs in the fact that the fluid slips through the surface of the bubble instead of stopping, thus, no boundary layer is created. Moreover, due to viscosity, a transfer of momentum from the fluid surrounding the bubble to the fluid inside of it is produced. This transfer of momentum generates a turbulent toroidal vortex inside the bubble. In consequence, two short recirculation zones are found at the extremes of the bubble’s diameter, while in between, the axial velocity inverts its sign.
2015-03-20T13:21:20ZJofre Cruanyes, LluísBalcázar Arciniega, NéstorLehmkuhl Barba, OriolBorrell Pol, RicardCastro González, JesúsThis work aims at investigating, by means of a direct numerical simulation, the flow over a clean spherical bubble fixed on the axis of a turbulent pipe flow. The simulation is performed by means of a parallel unstructured symmetry-preserving formulation on a mesh of 5.4M cells. The main features of the turbulent flow are described by analyzing the time-averaged data collected over a significant period of time. The numerical results conclude that the bubble generates a wake, similarly to the case of a solid sphere, however, it differs in the fact that the fluid slips through the surface of the bubble instead of stopping, thus, no boundary layer is created. Moreover, due to viscosity, a transfer of momentum from the fluid surrounding the bubble to the fluid inside of it is produced. This transfer of momentum generates a turbulent toroidal vortex inside the bubble. In consequence, two short recirculation zones are found at the extremes of the bubble’s diameter, while in between, the axial velocity inverts its sign.Numerical modeling of simultaneous heat and moisture transfer under complex geometry for refrigeration purposes
http://hdl.handle.net/2117/26805
Numerical modeling of simultaneous heat and moisture transfer under complex geometry for refrigeration purposes
Hou, Xiaofei; Rigola Serrano, Joaquim; Lehmkuhl Barba, Oriol; Oliet Casasayas, Carles; Pérez Segarra, Carlos David
The aim of the paper is to gain a better insight into heat and moisture transfer in refrigerator and to do fundamental study for water evaporation and condensation in refrigeration application. The governing transport equations (continuity, momentum, energy and concentration equations) in 3D Cartesian coordinates are firstly introduced. As the mixed convection is simulated in the paper, buoyancy forces caused by both temperature and concentration gradient are considered and are also included in momentum equation. Numerical results are carried out by using Termofluids code. The pressure-velocity linkage is solved by means of an explicit finite volume fractional step procedure. In order to validate the code, a humid air flowing in a horizontal 3D rectangular duct case is carried out and compared with the published numerical and experimental results. The contour of temperature and vapor density of air at a cross section is provided and analyzed. Finally, the heat and mass transfer process during the moist air flow through complicated geometry is simulated and temperature and humidity distributions are obtained.
2015-03-18T13:40:45ZHou, XiaofeiRigola Serrano, JoaquimLehmkuhl Barba, OriolOliet Casasayas, CarlesPérez Segarra, Carlos DavidThe aim of the paper is to gain a better insight into heat and moisture transfer in refrigerator and to do fundamental study for water evaporation and condensation in refrigeration application. The governing transport equations (continuity, momentum, energy and concentration equations) in 3D Cartesian coordinates are firstly introduced. As the mixed convection is simulated in the paper, buoyancy forces caused by both temperature and concentration gradient are considered and are also included in momentum equation. Numerical results are carried out by using Termofluids code. The pressure-velocity linkage is solved by means of an explicit finite volume fractional step procedure. In order to validate the code, a humid air flowing in a horizontal 3D rectangular duct case is carried out and compared with the published numerical and experimental results. The contour of temperature and vapor density of air at a cross section is provided and analyzed. Finally, the heat and mass transfer process during the moist air flow through complicated geometry is simulated and temperature and humidity distributions are obtained.