Direct numerical simulation of turbulent forced and mixed convection of LBE in a bundle of heated rods with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si41.svg"><mml:mrow><mml:mi>P</mml:mi><mml:mo>/</mml:mo><mml:mi>D</mml:mi><mml:mo linebreak="goodbreak" linebreakstyle="after">=</mml:mo><mml:mn>1.4</mml:mn></mml:mrow></mml:math>

Angeli, Diego; Fregni, Andrea; Stalio, Enrico

doi:10.1016/j.nucengdes.2019.110320

Cited by 20 publications

(8 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The complete derivation of the governing equation in fully-developed conditions and the determination of source terms in the momentum and energy equations for the present case is omitted here for brevity, and can be found in ref. [51].…”

Section: Numerical Methodologymentioning

confidence: 99%

Direct Numerical Simulation of natural, mixed and forced convection in liquid metals: selected results

Fregni

Angeli

Cimarelli

et al. 2022

Nuclear Engineering and Design

View full text Add to dashboard Cite

Selected results of three Direct Numerical Simulations are presented, on relevant test cases for the thermal hydraulics of liquid-metal-cooled nuclear reactors, encompassing a wide spectrum of turbulent convection regimes. The first test case is a Rayleigh-Bénard cell at a Grashof number Gr = 5×10 7 , representative of the conditions in the unstably stratified layer of coolant in a reactor pool in both standard operating conditions and emergency situations, e.g. shutdown of the cooling system. The second case is the mixed convection in a cold-hot-cold triple jet configuration, representative of liquid streams exiting from the core into the pool, and relevant for the modeling of thermal striping and thermal fatigue phenomena on the vessel containment walls. The third case is the fully-developed flow in a vertical bare rod bundle with triangular arrangement and a pitch-to-diameter ratio P/D = 1.4, in both forced and mixed convection conditions. These regimes respectively represent normal operation or decay heat removal conditions in reactor cores. The availability of these numerical databases will allow for an in-depth analysis of the turbulent flow and heat transfer in liquid metals under different convection regimes, and is also relevant for the development, calibration and validation of turbulent heat transfer models.

show abstract

Section: Numerical Methodologymentioning

confidence: 99%

Direct Numerical Simulation of natural, mixed and forced convection in liquid metals: selected results

Fregni

Angeli

Cimarelli

et al. 2022

Nuclear Engineering and Design

View full text Add to dashboard Cite

show abstract

“…The forced convective heat transfer for this flow configuration was simulated at Prandtl numbers of 0.1 and 0.005, which is typical of sodium. Moreover, we include the dataset by Angeli et al [40] which considers the convective heat transfer around cylindrical rods arranged in bundles. This kind of non-isothermal flow is of relevant interest in the nuclear reactor community, as it reproduces the cooling of reactor core fuel assemblies.…”

Section: Description Of the Databasementioning

confidence: 99%

Section: A Priori Validationmentioning

confidence: 99%

“…The data-driven model was then used to predict the turbulent heat flux over the DNS data of the rode bundle flow [40], which was not used for the model training. The turbulent heat flux predictions in the x, y and z directions are depicted in Figures 9,10 [40] the highest peaks are located close to the bundle walls. The current model also well predicts the distribution of the streamwise turbulent heat flux (Figure 11), which is identically zero for the Kays correlation due to the standard gradient assumption.…”

Section: A Priori Validationmentioning

confidence: 99%

“…Figure5: Contours of the components of the dispersion tensor D by the ANN using the DNS input data provided by Angeli et al[40] …”

mentioning

confidence: 99%

See 2 more Smart Citations

Physics-constrained machine learning for thermal turbulence modelling at low Prandtl numbers

Fiore¹,

Koloszar²,

Mendez³

et al. 2022

Preprint

View full text Add to dashboard Cite

Liquid metals play a central role in new generation liquid metal cooled nuclear reactors, for which numerical investigations require the use of appropriate thermal turbulence models for low Prandtl number fluids. Given the limitations of traditional modelling approaches and the increasing availability of high-fidelity data for this class of fluids, we propose a Machine Learning strategy for the modelling of the turbulent heat flux. A comprehensive algebraic mathematical structure is derived and physical constraints are imposed to ensure attractive properties promoting applicability, robustness and stability. The closure coefficients of the model are predicted by an Artificial Neural Network (ANN) which is trained with DNS data at different Prandtl numbers. The validity of the approach was verified through a priori and a posteriori validation for two and three-dimensional liquid metal flows. The model provides a complete vectorial representation of the turbulent heat flux and the predictions fit the DNS data in a wide range of Prandtl numbers (Pr=0.01-0.71). The comparison with other existing thermal models shows that the methodology is very promising.

show abstract

Liquid metal cooled fast reactor thermal hydraulic research development: A review

Agbevanu

Arthur

Debrah

2023

Heliyon

View full text Add to dashboard Cite

Direct numerical simulation of turbulent forced and mixed convection of LBE in a bundle of heated rods with P/D=1.4

Cited by 20 publications

References 25 publications

Direct Numerical Simulation of natural, mixed and forced convection in liquid metals: selected results

Direct Numerical Simulation of natural, mixed and forced convection in liquid metals: selected results

Physics-constrained machine learning for thermal turbulence modelling at low Prandtl numbers

Liquid metal cooled fast reactor thermal hydraulic research development: A review

Contact Info

Product

Resources

About