An overview of the AHFM-NRG formulations for the accurate prediction of turbulent flow and heat transfer in low-Prandtl number flows

Shams, A.; Santis, Andrea De; Roelofs, F.

doi:10.1016/j.nucengdes.2019.110342

Cited by 26 publications

(10 citation statements)

References 23 publications

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“…One of the most relevant open issue in the simulation of heat transfer to liquid metals is the selection of a suitable method for the turbulent heat flux modelling (Shams et al 2019). In fact, the molecular Prandtl number of liquid metals is usually lower than unity (in the order of 0.01) and therefore they may not be suitable for the assumptions considered by the Reynolds analogy.…”

Section: Computational Domain and Turbulence Modelsmentioning

confidence: 99%

“…In fact, the molecular Prandtl number of liquid metals is usually lower than unity (in the order of 0.01) and therefore they may not be suitable for the assumptions considered by the Reynolds analogy. Shams et al (2019) suggested that algebraic heat flux models shall be used for a better representation of the turbulent heat fluxes; however, in literature, the most widely adopted technique still relies on the definition of a not unitary turbulent Prandtl number. This assumption proved to be sufficiently reliable yet allowing the use of simplified simulation techniques.…”

Section: Computational Domain and Turbulence Modelsmentioning

confidence: 99%

“…In literature several examples of CFD simulations of the thermal-hydraulics phenomena occurring in rod bundles of HLMRs are available (Groetzbach, 2003, Cheng and Tak, 2005, Chandra et al, 2009, Chandra and Roelofs, 2011, Shams et al, 2014, Shams et al, 2019, discussing both the capabilities and the drawbacks of the CFD approach. Particular attention was paid to the analysis of the turbulent heat flux phenomenon, pointing out the need for different definitions of the turbulent Prandtl number and suggesting the need for advanced correlations (see e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Particular attention was paid to the analysis of the turbulent heat flux phenomenon, pointing out the need for different definitions of the turbulent Prandtl number and suggesting the need for advanced correlations (see e.g. Shams et al, 2019). This work is dedicated to the phenomena occurring inside the Fuel Pin Simulator (FPS) component of the CIRCE-HERO facility (Pesetti et al, 2018a).…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the temperature distribution in the pin bundle of the CIRCE facility

Buzzi

Pucciarelli

Galleni

et al. 2020

Annals of Nuclear Energy

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In this paper, a CFD analysis of the Fuel Pin Simulator (FPS) of the CIRCE-HERO facility built at the ENEA research centre in Brasimone was performed. STAR-CCM+ code was used with the purpose of reproducing steady-state and transient experimental conditions adopting LBE as working fluid. RANS and URANS simulations were performed comparing the calculated temperature trends with the experimental data. In particular, the FPS average outlet temperature was monitored for the transient case and an exhaustive study of the heat transfer between the FPS and the pool during the transient was carried out. The impact of the involved heat transfer phenomena on the FPS energy balance was studied from a quantitative point of view and the relevant difference in terms of thermal inertia between pool and FPS component was pointed out.

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Section: Computational Domain and Turbulence Modelsmentioning

confidence: 99%

Section: Computational Domain and Turbulence Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of the temperature distribution in the pin bundle of the CIRCE facility

Buzzi

Pucciarelli

Galleni

et al. 2020

Annals of Nuclear Energy

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“…Unlike the SGDH method, the differential or algebraic heat flux model (D/AHFM) establishes differential or algebraic transport equations to consider the dissimilarity between velocity and the temperature field to improve the heat transfer accuracy of liquid metals. Assessment and calibration results of D/AHFM models for low Pr fluids completed in some simple geometries show that the heat transport of second-moment closure is very sensitive to the model coefficients and functions (Lai and So, 1990;Shikazono and Kasagi, 1996;Choi and Kim, 2007;Shams et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Development and Assessment of an Isotropic Four-Equation Model for Heat Transfer of Low Prandtl Number Fluids

Wang

et al. 2022

Front. Energy Res.

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In the simple gradient diffusion hypothesis, the turbulent Prandtl number (Prt) with a constant of 0.85 is difficult to accurately predict for liquid metals having low Prandtl numbers (Pr), while a four-equation model can improve this solution by introducing the turbulence time-scale into the calculation of turbulent thermal diffusivity. However, the four-equation model’s transport form and numerical stability are so complex that suitable commercial code is lacking. Therefore, an isotropic four-equation model with simple Dirichlet wall boundary conditions is built in the present work. Based on the open-source computational fluid dynamics program OpenFOAM, the fully developed velocity, temperature, Reynolds stress, and heat flux of low Pr fluids (Pr = 0.01–0.05) in the parallel plane are obtained by numerical simulation. The results show that the time-average statistics predicted using the present four-equation model are in good agreement with the direct numerical simulation data. Then, the isotropic four-equation model is used to analyze the flow and heat of liquid metal (Pr = 0.01) in a quadrilateral infinite rod bundle. The numerical results are compared with the various and available experimental relationships. The Nusselt numbers calculated using the isotropic four-equation model are betweenness the available correlations, while the turbulent Prandtl number model using a constant of 0.85 over predicts heat transfer. More detailed local heat transfer phenomena and distribution of low Pr fluids are obtained using the present isotropic four-equation model.

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Momentum and Energy Transport

Stieglitz,

Platzer

2024

Solar Thermal Energy Systems

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An overview of the AHFM-NRG formulations for the accurate prediction of turbulent flow and heat transfer in low-Prandtl number flows

Cited by 26 publications

References 23 publications

Analysis of the temperature distribution in the pin bundle of the CIRCE facility

Analysis of the temperature distribution in the pin bundle of the CIRCE facility

Development and Assessment of an Isotropic Four-Equation Model for Heat Transfer of Low Prandtl Number Fluids

Momentum and Energy Transport

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