Articles de revista
http://hdl.handle.net/2117/3191
Thu, 08 Dec 2016 04:11:11 GMT
20161208T04:11:11Z

Parallel load balancing strategy for VolumeofFluid methods on 3D unstructured meshes
http://hdl.handle.net/2117/97703
Parallel load balancing strategy for VolumeofFluid methods on 3D unstructured meshes
Jofre Cruanyes, Lluís; Borrell Pol, Ricard; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio
l VolumeofFluid (VOF) is one of the methods of choice to reproduce the interface motion in the simulation of multifluid flows. One of its main strengths is its accuracy in capturing sharp interface geometries, although requiring for it a number of geometric calculations. Under these circumstances, achieving parallel performance on current supercomputers is a must. The main obstacle for the parallelization is that the computing costs are concentrated only in the discrete elements that lie on the interface between fluids. Consequently, if the interface is not homogeneously distributed throughout the domain, standard domain decomposition (DD) strategies lead to imbalanced workload distributions. In this paper, we present a new parallelization strategy for general unstructured VOF solvers, based on a dynamic load balancing process complementary to the underlying DD. Its parallel efficiency has been analyzed and compared to the DD one using up to 1024 CPUcores on an Intel SandyBridge based supercomputer. The results obtained on the solution of several artificially generated test cases show a speedup of up to similar to 12x with respect to the standard DD, depending on the interface size, the initial distribution and the number of parallel processes engaged. Moreover, the new parallelization strategy presented is of general purpose, therefore, it could be used to parallelize any VOF solver without requiring changes on the coupled flow solver. Finally, note that although designed for the VOF method, our approach could be easily adapted to other interfacecapturing methods, such as the LevelSet, which may present similar workload imbalances. (C) 2014 Elsevier Inc. Allrights reserved.
© 2016. This version is made available under the CCBYNCND 4.0 license http://creativecommons.org/licenses/byncnd/4.0/
Fri, 02 Dec 2016 13:23:56 GMT
http://hdl.handle.net/2117/97703
20161202T13:23:56Z
Jofre Cruanyes, Lluís
Borrell Pol, Ricard
Lehmkuhl Barba, Oriol
Oliva Llena, Asensio
l VolumeofFluid (VOF) is one of the methods of choice to reproduce the interface motion in the simulation of multifluid flows. One of its main strengths is its accuracy in capturing sharp interface geometries, although requiring for it a number of geometric calculations. Under these circumstances, achieving parallel performance on current supercomputers is a must. The main obstacle for the parallelization is that the computing costs are concentrated only in the discrete elements that lie on the interface between fluids. Consequently, if the interface is not homogeneously distributed throughout the domain, standard domain decomposition (DD) strategies lead to imbalanced workload distributions. In this paper, we present a new parallelization strategy for general unstructured VOF solvers, based on a dynamic load balancing process complementary to the underlying DD. Its parallel efficiency has been analyzed and compared to the DD one using up to 1024 CPUcores on an Intel SandyBridge based supercomputer. The results obtained on the solution of several artificially generated test cases show a speedup of up to similar to 12x with respect to the standard DD, depending on the interface size, the initial distribution and the number of parallel processes engaged. Moreover, the new parallelization strategy presented is of general purpose, therefore, it could be used to parallelize any VOF solver without requiring changes on the coupled flow solver. Finally, note that although designed for the VOF method, our approach could be easily adapted to other interfacecapturing methods, such as the LevelSet, which may present similar workload imbalances. (C) 2014 Elsevier Inc. Allrights reserved.

Direct numerical simulation of multiphase flows with unstable interfaces
http://hdl.handle.net/2117/93051
Direct numerical simulation of multiphase flows with unstable interfaces
Schillaci, Eugenio; Lehmkuhl, Oriol; Antepara Zambrano, Óscar; Oliva Llena, Asensio
This paper presents a numerical model that intends to simulate efficiently the surface instability that arise in multiphase flows, typically liquidgas, both for laminar or turbulent regimes. The model is developed on the inhouse computing platform TermoFluids , and operates the finitevolume, direct numerical simulation (DNS) of multiphase flows by means of a conservative levelset method for the interfacecapturing. The mesh size is optimized by means of an adaptive mesh refinement (AMR) strategy, that allows the dynamic reconcentration of the mesh in the vicinity of the interfaces between fluids, in order to correctly represent the diverse structures (as ligaments and droplets) that may rise from unstable phenomena. In addition, special attention is given to the discretization of the various terms of the momentum equations, to ensure stability of the flow and correct representation of turbulent vortices. As shown, the method is capable of truthfully simulate the interface phenomena as the KelvinHelmholtz instability and the PlateauRayleigh instability, both in the case of 2D and 3D configurations. Therefore it is suitable for the simulation of complex phenomena such as simulation of airblast atomization, with several important application in the field of automotive and aerospace engines. A prove is given by our preliminary study of the 3D coaxial liquidgas jet.
Published under licence in Journal of Physics: Conference Series 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.
Mon, 07 Nov 2016 15:57:06 GMT
http://hdl.handle.net/2117/93051
20161107T15:57:06Z
Schillaci, Eugenio
Lehmkuhl, Oriol
Antepara Zambrano, Óscar
Oliva Llena, Asensio
This paper presents a numerical model that intends to simulate efficiently the surface instability that arise in multiphase flows, typically liquidgas, both for laminar or turbulent regimes. The model is developed on the inhouse computing platform TermoFluids , and operates the finitevolume, direct numerical simulation (DNS) of multiphase flows by means of a conservative levelset method for the interfacecapturing. The mesh size is optimized by means of an adaptive mesh refinement (AMR) strategy, that allows the dynamic reconcentration of the mesh in the vicinity of the interfaces between fluids, in order to correctly represent the diverse structures (as ligaments and droplets) that may rise from unstable phenomena. In addition, special attention is given to the discretization of the various terms of the momentum equations, to ensure stability of the flow and correct representation of turbulent vortices. As shown, the method is capable of truthfully simulate the interface phenomena as the KelvinHelmholtz instability and the PlateauRayleigh instability, both in the case of 2D and 3D configurations. Therefore it is suitable for the simulation of complex phenomena such as simulation of airblast atomization, with several important application in the field of automotive and aerospace engines. A prove is given by our preliminary study of the 3D coaxial liquidgas jet.

Numerical dynamic analysis of reciprocating compressor mechanism. Parametric studies for optimization purposes
http://hdl.handle.net/2117/93043
Numerical dynamic analysis of reciprocating compressor mechanism. Parametric studies for optimization purposes
Pont Vilchez, Arnau; López Mas, Joan; Rigola Serrano, Joaquim; Pérez Segarra, Carlos David
A complete numerical dynamic analysis of reciprocating compressor mechanism is presented, coupling the instantaneous pressure in the compression chamber, the electric motor torque and the hydrodynamic reactions, which arise from the piston and crankshaft secondary movements. Additionally, nonconstant crankshaft angular velocity and the piston and crankshaft misalignment torques have also been considered. Two sensitivity analyses have been carried out to prove that neither the inertial forces in the directions of the secondary movements, nor the oscillations of the angular velocity produce significant differences in the compressor behaviour. Finally, a set of parametric studies has been developed to evaluate the influence of geometrical parameters in the stability of the secondary movements, the friction power losses and the compressor consumption
© 2016. This version is made available under the CCBYNCND 4.0 license http://creativecommons.org/licenses/byncnd/4.0/
Mon, 07 Nov 2016 14:55:23 GMT
http://hdl.handle.net/2117/93043
20161107T14:55:23Z
Pont Vilchez, Arnau
López Mas, Joan
Rigola Serrano, Joaquim
Pérez Segarra, Carlos David
A complete numerical dynamic analysis of reciprocating compressor mechanism is presented, coupling the instantaneous pressure in the compression chamber, the electric motor torque and the hydrodynamic reactions, which arise from the piston and crankshaft secondary movements. Additionally, nonconstant crankshaft angular velocity and the piston and crankshaft misalignment torques have also been considered. Two sensitivity analyses have been carried out to prove that neither the inertial forces in the directions of the secondary movements, nor the oscillations of the angular velocity produce significant differences in the compressor behaviour. Finally, a set of parametric studies has been developed to evaluate the influence of geometrical parameters in the stability of the secondary movements, the friction power losses and the compressor consumption

A levelset aided singlephase model for the numerical simulation of freesurface flow on unstructured meshes
http://hdl.handle.net/2117/91452
A levelset aided singlephase model for the numerical simulation of freesurface flow on unstructured meshes
Schillaci, Eugenio; Jofre Cruanyes, Lluís; Balcázar Arciniega, Néstor; Lehmkuhl, Oriol; Oliva Llena, Asensio
A new singlephase scheme for the numerical simulation of freesurface problems on 3D unstructured meshes is presented. The flow field is obtained from the discrete solution of the incompressible NavierStokes equations, whereas a conservative levelset method is employed to capture fluid interfaces on an Eulerian approach. The scheme is based on a novel treatment of the interface for the deactivation of the light phase, allowing an optimization of the classic twophase model for the cases in which the influence of the lighter phase is negligible. The deactivation is performed by directly imposing the appropriate pressure at the surface boundary, and, unlike similar approaches, without the need to treat nearinterface velocities. The method is validated against various analytical and experimental references, demonstrating its potential on both hexahedral and unstructured meshes. Moreover, it shows higher numerical stability in comparison to twophase solvers, as well as significant advantages in terms of computational performance.
© 2016. This version is made available under the CCBYNCND 4.0 license http://creativecommons.org/licenses/byncnd/4.0/
Thu, 03 Nov 2016 17:52:28 GMT
http://hdl.handle.net/2117/91452
20161103T17:52:28Z
Schillaci, Eugenio
Jofre Cruanyes, Lluís
Balcázar Arciniega, Néstor
Lehmkuhl, Oriol
Oliva Llena, Asensio
A new singlephase scheme for the numerical simulation of freesurface problems on 3D unstructured meshes is presented. The flow field is obtained from the discrete solution of the incompressible NavierStokes equations, whereas a conservative levelset method is employed to capture fluid interfaces on an Eulerian approach. The scheme is based on a novel treatment of the interface for the deactivation of the light phase, allowing an optimization of the classic twophase model for the cases in which the influence of the lighter phase is negligible. The deactivation is performed by directly imposing the appropriate pressure at the surface boundary, and, unlike similar approaches, without the need to treat nearinterface velocities. The method is validated against various analytical and experimental references, demonstrating its potential on both hexahedral and unstructured meshes. Moreover, it shows higher numerical stability in comparison to twophase solvers, as well as significant advantages in terms of computational performance.

A methodology for determining optimum solar tower plant configurations and operating strategies to maximize profits based on hourly electricity market prices and tariffs
http://hdl.handle.net/2117/91438
A methodology for determining optimum solar tower plant configurations and operating strategies to maximize profits based on hourly electricity market prices and tariffs
Guedez, Rafael; Topel, Monica; Conde, Ines; Ferragut, Francisco; Callaba, Irene; Spelling, James; Hassar, Zhor; Pérez Segarra, Carlos David; Laumert, Bjorn
The present study analyzes the influence that market conditions have on determining optimum molten salt solar tower plants with storage that maximizes profits (in terms of plant configuration, sizing, and operation) for a location in South Africa. Three different scenarios based on incentive programs and local wholesale electricity prices are considered. A multiobjective optimization modeling approach was followed, showing the tradeoff curves between minimizing investment and maximizing profits when varying critical sizerelated parameters (such as nameplate capacity, solar multiple ISM), and storage capacity) together with powercycle design and operating specifications including dynamic startup curves and different storage dispatchabiliry strategies. Results are shown by means of a comparative analysis between optimal plants found for each scenario, highlighting the value that storage has wider the current twotier tariff scheme and the relevance of designing a suitable policy for technology development. Finally, a final analysis is performed with regard to the indicators used for economic evaluation of power plants, by comparing the differences between optimum designs found when using the levelized cost of electricity (LCoE) solely as performance indicator instead of cashflows and profitbased indicators, such as the internal rate of return (IRR).
Thu, 03 Nov 2016 15:21:51 GMT
http://hdl.handle.net/2117/91438
20161103T15:21:51Z
Guedez, Rafael
Topel, Monica
Conde, Ines
Ferragut, Francisco
Callaba, Irene
Spelling, James
Hassar, Zhor
Pérez Segarra, Carlos David
Laumert, Bjorn
The present study analyzes the influence that market conditions have on determining optimum molten salt solar tower plants with storage that maximizes profits (in terms of plant configuration, sizing, and operation) for a location in South Africa. Three different scenarios based on incentive programs and local wholesale electricity prices are considered. A multiobjective optimization modeling approach was followed, showing the tradeoff curves between minimizing investment and maximizing profits when varying critical sizerelated parameters (such as nameplate capacity, solar multiple ISM), and storage capacity) together with powercycle design and operating specifications including dynamic startup curves and different storage dispatchabiliry strategies. Results are shown by means of a comparative analysis between optimal plants found for each scenario, highlighting the value that storage has wider the current twotier tariff scheme and the relevance of designing a suitable policy for technology development. Finally, a final analysis is performed with regard to the indicators used for economic evaluation of power plants, by comparing the differences between optimum designs found when using the levelized cost of electricity (LCoE) solely as performance indicator instead of cashflows and profitbased indicators, such as the internal rate of return (IRR).

Technoeconomic performance evaluation of solar tower plants with integrated multilayered PCM thermocline thermal energy storage: a comparative study to conventional twotank storage systems
http://hdl.handle.net/2117/90561
Technoeconomic performance evaluation of solar tower plants with integrated multilayered PCM thermocline thermal energy storage: a comparative study to conventional twotank storage systems
Guedéz, Rafael; Ferruzza, Davide; Arnaudo, Monica; Rodríguez Pérez, Ivette María; Pérez Segarra, Carlos David; Hassar, Zhor; Laumert, Björn
Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multilayered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multilayered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing technoeconomic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multilayered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the twotier South African tariff scheme.
Copyright 2016 AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
Wed, 05 Oct 2016 16:19:16 GMT
http://hdl.handle.net/2117/90561
20161005T16:19:16Z
Guedéz, Rafael
Ferruzza, Davide
Arnaudo, Monica
Rodríguez Pérez, Ivette María
Pérez Segarra, Carlos David
Hassar, Zhor
Laumert, Björn
Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multilayered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multilayered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing technoeconomic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multilayered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the twotier South African tariff scheme.

Particulate immersed boundary method for complex fluidparticle interaction problems with heat transfer
http://hdl.handle.net/2117/86702
Particulate immersed boundary method for complex fluidparticle interaction problems with heat transfer
Zhang, Hao; Yuan, Haizhuan; Trias Miquel, Francesc Xavier; Yu, Aibing; Tan, Yuanqiang; Oliva Llena, Asensio
In our recent work (Zhang et al., 2015), a Particulate Immersed Boundary Method (PIBM) for simulating fluidparticle multiphase flow was proposed and assessed in both two and threedimensional applications. In this study, the PIBM was extended to solve thermal interaction problems between spherical particles and fluid. The Lattice Boltzmann Method (LBM) was adopted to solve the fluid flow and temperature fields, the PIBM was responsible for the noslip velocity and temperature boundary conditions at the particle surface, and the kinematics and trajectory of the solid particles were evaluated by the Discrete Element Method (DEM). Four case studies were implemented to demonstrate the capability of the current coupling scheme. Firstly, numerical simulation of natural convection in a twodimensional square cavity with an isothermal concentric annulus was carried out for verification purpose. The current results were found to have good agreement with previous references. Then, sedimentation of twoand threedimensional isothermal particles in fluid was numerically studied, respectively. The instantaneous temperature distribution in the cavity was captured. The effect of the thermal buoyancy on particle behaviors was discussed. Finally, sedimentation of threedimensional thermosensitive particles in fluid was numerically investigated. Our results revealed that the LBMPIBMDEM is a promising scheme for the solution of complex fluidparticle interaction problems with heat transfer.
Fri, 06 May 2016 12:54:06 GMT
http://hdl.handle.net/2117/86702
20160506T12:54:06Z
Zhang, Hao
Yuan, Haizhuan
Trias Miquel, Francesc Xavier
Yu, Aibing
Tan, Yuanqiang
Oliva Llena, Asensio
In our recent work (Zhang et al., 2015), a Particulate Immersed Boundary Method (PIBM) for simulating fluidparticle multiphase flow was proposed and assessed in both two and threedimensional applications. In this study, the PIBM was extended to solve thermal interaction problems between spherical particles and fluid. The Lattice Boltzmann Method (LBM) was adopted to solve the fluid flow and temperature fields, the PIBM was responsible for the noslip velocity and temperature boundary conditions at the particle surface, and the kinematics and trajectory of the solid particles were evaluated by the Discrete Element Method (DEM). Four case studies were implemented to demonstrate the capability of the current coupling scheme. Firstly, numerical simulation of natural convection in a twodimensional square cavity with an isothermal concentric annulus was carried out for verification purpose. The current results were found to have good agreement with previous references. Then, sedimentation of twoand threedimensional isothermal particles in fluid was numerically studied, respectively. The instantaneous temperature distribution in the cavity was captured. The effect of the thermal buoyancy on particle behaviors was discussed. Finally, sedimentation of threedimensional thermosensitive particles in fluid was numerically investigated. Our results revealed that the LBMPIBMDEM is a promising scheme for the solution of complex fluidparticle interaction problems with heat transfer.

Turbulent flow around a square cylinder at Reynolds number 22,000: A DNS study
http://hdl.handle.net/2117/86080
Turbulent flow around a square cylinder at Reynolds number 22,000: A DNS study
Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio
The turbulent flow around a square cylinder at Reynolds number 22,000 (based on the cylinder diameter and the inflow velocity) is studied by means of direct numerical simulation. An overview of the numerical methods and the methodology used to verify the simulation is presented with special emphasis to determine the proper domain size and timeintegration period. Then, the timeaveraged flow results and turbulent statistics are discussed together with available experimental data showing a fairly good agreement. Finally, frequency analysis of velocity samples is used to analyze both the KelvinHelmholtz vortical structures produced by the flow separation at the leading edge of the cylinder and the Von Karman vortex shedding in the wake region. The former are observed more downstream compared with the experiments suggesting that transition to turbulence may occur later. However, comparison of the turbulent statistics in the near wall region indicates that transition is being well captured.
Thu, 21 Apr 2016 16:00:15 GMT
http://hdl.handle.net/2117/86080
20160421T16:00:15Z
Trias Miquel, Francesc Xavier
Gorobets, Andrei
Oliva Llena, Asensio
The turbulent flow around a square cylinder at Reynolds number 22,000 (based on the cylinder diameter and the inflow velocity) is studied by means of direct numerical simulation. An overview of the numerical methods and the methodology used to verify the simulation is presented with special emphasis to determine the proper domain size and timeintegration period. Then, the timeaveraged flow results and turbulent statistics are discussed together with available experimental data showing a fairly good agreement. Finally, frequency analysis of velocity samples is used to analyze both the KelvinHelmholtz vortical structures produced by the flow separation at the leading edge of the cylinder and the Von Karman vortex shedding in the wake region. The former are observed more downstream compared with the experiments suggesting that transition to turbulence may occur later. However, comparison of the turbulent statistics in the near wall region indicates that transition is being well captured.

Direct numerical simulation of a fully developed turbulent square duct flow up to Retau=1200
http://hdl.handle.net/2117/86076
Direct numerical simulation of a fully developed turbulent square duct flow up to Retau=1200
Zhang, Hao; Trias Miquel, Francesc Xavier; Gorobets, Andrey; Tan, Yuanqiang; Oliva Llena, Asensio
Various fundamental studies based on a turbulent duct flow have gained popularity including heat transfer, magnetohydrodynamics as well as particleladen transportation. An accurate prediction on the turbulent flow field is critical for these researches. However, the database of the mean flow and turbulence statistics is fairly insufficient due to the enormous cost of numerical simulation at high Reynolds number. This paper aims at providing available information by conducting several Direct Numerical Simulations (DNS) on turbulent duct flows at Retau = 300, 600, 900 and 1200. A quantitative comparison between current and previous DNS results was performed where a good agreement was achieved at Retau = 300. However, further comparisons of the present results with the previous DNS results at Retau = 600 obtained with much coarser meshes revealed some discrepancies which can be explained by the insufficient mesh resolution. At last, the mean flow and turbulent statistics at higher Retau was presented and the effect of Retau on the mean flow and flow dynamics was discussed.
Thu, 21 Apr 2016 14:52:02 GMT
http://hdl.handle.net/2117/86076
20160421T14:52:02Z
Zhang, Hao
Trias Miquel, Francesc Xavier
Gorobets, Andrey
Tan, Yuanqiang
Oliva Llena, Asensio
Various fundamental studies based on a turbulent duct flow have gained popularity including heat transfer, magnetohydrodynamics as well as particleladen transportation. An accurate prediction on the turbulent flow field is critical for these researches. However, the database of the mean flow and turbulence statistics is fairly insufficient due to the enormous cost of numerical simulation at high Reynolds number. This paper aims at providing available information by conducting several Direct Numerical Simulations (DNS) on turbulent duct flows at Retau = 300, 600, 900 and 1200. A quantitative comparison between current and previous DNS results was performed where a good agreement was achieved at Retau = 300. However, further comparisons of the present results with the previous DNS results at Retau = 600 obtained with much coarser meshes revealed some discrepancies which can be explained by the insufficient mesh resolution. At last, the mean flow and turbulent statistics at higher Retau was presented and the effect of Retau on the mean flow and flow dynamics was discussed.

PIBM: Particulate immersed boundary method for fluidparticle interaction problems
http://hdl.handle.net/2117/85915
PIBM: Particulate immersed boundary method for fluidparticle interaction problems
Zhang, Hao; Trias Miquel, Francesc Xavier; Oliva Llena, Asensio; Yang, Dongmin; Tan, Yuanqiang; Shu, Shi; Sheng, Yong
It is well known that the number of particles should be scaled up to enable industrial scale simulation. The calculations are more computationally intensive when the motion of the surrounding fluid is considered. Besides the advances in computer hardware and numerical algorithms, the coupling scheme also plays an important role on the computational efficiency. In this study, a particulate immersed boundary method (PIBM) for simulating the fluidparticle multiphase flow was presented and assessed in both two and threedimensional applications. The idea behind PIBM derives from the conventional momentum exchangebased Immersed Boundary Method (IBM) by treating each Lagrangian point as a solid particle. This treatment enables Lattice Boltzmann Method (LBM) to be coupled with fine particles residing within a particular grid cell. Compared with the conventional IBM, dozens of times speedup in twodimensional simulation and hundreds of times in threedimensional simulation can be expected under the same particle and mesh number. Numerical simulations of particle sedimentation in Newtonian flows were canducted based on a combined LBMPIBMDiscrete Element Method (DEM) scheme, showing that the PIBM can capture the feature of particulate flows in fluid and is indeed a promising scheme for the solution of the fluidparticle interaction problems.
Tue, 19 Apr 2016 14:57:07 GMT
http://hdl.handle.net/2117/85915
20160419T14:57:07Z
Zhang, Hao
Trias Miquel, Francesc Xavier
Oliva Llena, Asensio
Yang, Dongmin
Tan, Yuanqiang
Shu, Shi
Sheng, Yong
It is well known that the number of particles should be scaled up to enable industrial scale simulation. The calculations are more computationally intensive when the motion of the surrounding fluid is considered. Besides the advances in computer hardware and numerical algorithms, the coupling scheme also plays an important role on the computational efficiency. In this study, a particulate immersed boundary method (PIBM) for simulating the fluidparticle multiphase flow was presented and assessed in both two and threedimensional applications. The idea behind PIBM derives from the conventional momentum exchangebased Immersed Boundary Method (IBM) by treating each Lagrangian point as a solid particle. This treatment enables Lattice Boltzmann Method (LBM) to be coupled with fine particles residing within a particular grid cell. Compared with the conventional IBM, dozens of times speedup in twodimensional simulation and hundreds of times in threedimensional simulation can be expected under the same particle and mesh number. Numerical simulations of particle sedimentation in Newtonian flows were canducted based on a combined LBMPIBMDiscrete Element Method (DEM) scheme, showing that the PIBM can capture the feature of particulate flows in fluid and is indeed a promising scheme for the solution of the fluidparticle interaction problems.