Single-phase mixing studies by means of a directly coupled CFD/system-code tool

Bertolotto, Davide; Manera, Annalisa; Frey, Simon; Prasser, H.-M.; Chawla, R.

doi:10.1016/j.anucene.2008.11.027

Cited by 40 publications

(17 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many applications of coupling system codes with CFD codes can be found in the literature, such the above-mentioned coupling between SAS4A/SASSYS-1 and STAR-CD [14]. In all applications, careful control of data exchange flow and the time-synchronization are essential for a numerically stable, and physically valid simulation.…”

Section: General Considerationsmentioning

confidence: 99%

Strategy for Multi-Scale Single-Phase Flow Coupling

Hu¹,

Thomas²,

Fanning³

2013

View full text Add to dashboard Cite

EXECUTIVE SUMMARYFor practical nuclear engineering applications, multi-scale analysis by adopting the combined use of different scale computational tools, such as system thermal-hydraulics and CFD codes is vital when three-dimensional effects play an important role in the evolution of a given transient or accident scenario. The feasibility of coupling low-fidelity systems codes with higher fidelity CFD tools was demonstrated previously under NEAMS by coupling SAS4A/SASSYS-1 with the commercial CFD code STAR-CD and STAR-CCM+. An "adhoc" coupling strategy was implemented. With the advances in numerical techniques and software engineering, such as the availability of PETSc and MOOSE, modernization of existing systems codes or the development of new system code becomes more compelling. MOOSE (Multi-physics Object Oriented Simulation Environment) is a parallel computational framework developed at INL for enabling the solution of complex, fully-implicit multiphysics systems. It has been utilized in many nuclear applications including the system analysis codes RELAP-7 and the SFR module under current NEAMS Reactor Product Line (RPL). This motivates the development of a coupled scheme for MOOSE-based system analysis code and the commercial CFD code STAR-CCM+. STAR-CCM+ is a generalpurpose commercial CFD code using finite volume formulation for the analysis of compressible and incompressible flows and heat transfer, and it is being included in the toolkit of the NEAMS RPL. This investigation is important for the integration between the MOOSE-based system codes and the high-fidelity advanced simulation capabilities developed under the NEAMS RPL.Careful control of data exchange flow and the time-synchronization is essential for a numerically stable, and physically valid coupled code simulation. The general issues of coupling of system code and CFD code have been addressed in this report, including data exchange method, driving mechanism, time synchronization scheme, and the selection of data for exchange. Then the coupling strategy between the MOOSE-based system analysis code for SFR and CFD code STAR-CCM+ was derived and implemented based on these considerations and the characteristics of each code. The developed strategy for the coupling of MOOSE-based system codes and STAR-CCM+ is applicable to other multi-scale or multiphysics code coupling applications. A simple test model was developed to examine the coupling strategy and its implementation in the system code and CFD code. The flow loop of the test model consists of one tank, one pump, and four pipes. In the coupled simulation, the tank, with cover gas, was modeled by STAR-CCM+, while the rest of the hydraulic loop was modeled by the system code. The coupling strategy was demonstrated by the three test cases: steady state, flow transient, and temperature transient. Stand-alone system code simulations have also been performed to examine the differences and consistency between the couple code and standalone system code simulations.In steady-state simulations, the press...

show abstract

Section: General Considerationsmentioning

confidence: 99%

Strategy for Multi-Scale Single-Phase Flow Coupling

Hu¹,

Thomas²,

Fanning³

2013

View full text Add to dashboard Cite

show abstract

“…The system code TRACE was first coupled to CFX at Paul the Scherrer Institute (PSI) using the PVM and both explicit and semi‐implicit temporal coupling approach . The work was verified using data from the double T‐junction experiment and the FLORIS experiment .…”

Section: A Review Of the Multiscale Thermal‐hydraulic Coupled Codesmentioning

confidence: 99%

The multiscale thermal‐hydraulic simulation for nuclear reactors: A classification of the coupling approaches and a review of the coupled codes

Zhang

2020

Int J Energy Res

View full text Add to dashboard Cite

Summary Simulation is becoming increasingly important in the safety analysis of nuclear reactors nowadays. The physical phenomena in a nuclear power plant happen on three classified scales: system scale (phenomenon over the whole plant is concerned), component scale (phenomenon in specific component is concerned), and mesoscale (phenomenon in a small part of a component is concerned). Owing to the particular emphases, various codes are developed to simulate particular problems. System codes intend to predict the behavior of the whole power plant during normal or accidental phases (system scale). Subchannel codes are for core behavior predictions (component scale). CFD codes can simulate the thermal‐hydraulic in a fixed part of the plant (mesoscale). Those codes are coupled together to better predict the conditions in a nuclear reactor in last the two decades, which is the multiscale thermal‐hydraulic simulation approach for nuclear power systems. Diverse coupling approaches are developed and various coupling codes are implemented. This paper first proposes a classification of those approaches. It tells that a multiscale coupling is composed of five items: coupling architecture, operation mode, domain coupling, field mapping, and temporal coupling. Numbers of options are available for each item. For coupling architecture, it can be internal coupling, via‐IO coupling, server‐client, or serverless coupling. For operation mode, it can be either parallel or serial. For domain coupling, it can be either domain‐decomposition or domain‐overlapping coupling. For field mapping, it can be manual‐definition, processed by user‐developing toolkit, or handled by third‐party libraries. For temporal coupling, it can be explicit coupling, semi‐implicit coupling, or implicit coupling. An evaluation of the approaches is performed based on new‐proposed criterion. A general review of the multiscale thermal‐hydraulic coupled codes is made based on the classification. Especially, a review of the domain‐overlapping approach is present considering it is the most promising but challenging method for multiscale thermal‐hydraulic simulation.

show abstract

“…Moreover, the various modeling options were identified and some first Best Practice Guidelines has been proposed (Bestion, 2012). In particular, promising is the coupling of CFD codes to best estimate system codes, adopted for safety analysis and transient thermal hydraulic calculations, as RELAP5 or TRACE (Aumiller et al, 2002;Bertolotto et al, 2009). The coupling between the codes limits the application of the more computationally expensive CFD to those areas where three dimensional flow effects and mixing phenomena are important, avoiding at the same time the modeling of the entire geometry (Anderson et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

CFD study of an air–water flow inside helically coiled pipes

Colombo

Cammi

Guédon

et al. 2015

Progress in Nuclear Energy

View full text Add to dashboard Cite

a b s t r a c tCFD is used to study an airewater mixture flowing inside helically coiled pipes, being at the moment considered for the Steam Generators (SGs) of different nuclear reactor projects of Generation IIIþ and Generation IV. The two-phase mixture is described through the EulerianeEulerian model and the adiabatic flow is simulated through the ANSYS FLUENT code. A twofold objective is pursued. On the one hand, obtaining an accurate estimation of physical quantities such as the frictional pressure drop and the void fraction. In this regard, CFD simulations can provide accurate predictions without being limited to a particular range of system parameters, which often constricts the application of empirical correlations. On the other hand, a better understanding of the role of the centrifugal force field and its effect on the two-phase flow field and the phase distributions is pursued.The effect of the centrifugal force field introduced by the geometry is characterized. Water is pushed by the centrifugal force towards the outer pipe wall, whereas air accumulates in the inner region of the pipe. The maximum of the mixture velocity is therefore shifted towards the inner pipe wall, as the air flows much faster than the water, having a considerably lower density. The flow field, as for the singlephase flow, is characterized by flow recirculation and vortices. Quantitatively, the simulation results are validated against the experimental data of Akagawa et al. (1971) for the void fraction and the frictional pressure drop. The relatively simple model of momentum interfacial transfer allows obtaining a very good agreement for the average void fraction and a satisfactory estimation of the frictional pressure drop and, at the same time, limits the computational cost of the simulations. Effects of changes in the diameter of the dispersed phase are described, as its value strongly affects the degree of interaction between the phases. In addition, a more precise treatment of the near wall region other than wall function results in a better definition of the liquid film at the wall, although an overestimation of the frictional pressure drop is obtained.

show abstract

Single-phase mixing studies by means of a directly coupled CFD/system-code tool

Cited by 40 publications

References 2 publications

Strategy for Multi-Scale Single-Phase Flow Coupling

Strategy for Multi-Scale Single-Phase Flow Coupling

The multiscale thermal‐hydraulic simulation for nuclear reactors: A classification of the coupling approaches and a review of the coupled codes

CFD study of an air–water flow inside helically coiled pipes

Contact Info

Product

Resources

About