TY - GEN
T1 - PARAMETRIC STUDY ON LAMINAR-TURBULENT TRANSITION IN SQUARE ROD BUNDLES
AU - Aldeia Machado, Luiz C.
AU - Dutra, Carolina S.B.
AU - Bistany, Sean P.
AU - Merzari, Elia
N1 - Publisher Copyright:
© 2023 by JSME.
PY - 2023
Y1 - 2023
N2 - During the lifetime of a nuclear reactor, the coolant inside the pressure vessel can experience different flow regimes. Laminar and turbulent flow regimes are widely studied and have several models that can be applied. However, the mechanism of laminar-turbulent transition is less well understood. Understanding such transition is crucial since it can be essential during transients such as reactor startup or accidents. It can also play an important role in advanced reactors that operate at low flow conditions. In this work, we perform a parametric numerical study to identify how the Reynolds Number (Re), Pitch-to-diameter ratio (P/D), and domain length (L) affect the laminar-turbulent transition region. We focus on squared array rod bundles. The simulations are carried out using the spectral-element code NekRS and a Direct Numerical Simulation (DNS) approach [1, 2]. We imposed a no-slip condition on the walls. The P/D ranged from 1.05 to 1.20, while the Re varied from 250 to 3500. We analyze the temporal and spatial behavior of the instabilities as a function of P/D and (Re) in detail, including the Power Spectral Density (PSD) method [3].
AB - During the lifetime of a nuclear reactor, the coolant inside the pressure vessel can experience different flow regimes. Laminar and turbulent flow regimes are widely studied and have several models that can be applied. However, the mechanism of laminar-turbulent transition is less well understood. Understanding such transition is crucial since it can be essential during transients such as reactor startup or accidents. It can also play an important role in advanced reactors that operate at low flow conditions. In this work, we perform a parametric numerical study to identify how the Reynolds Number (Re), Pitch-to-diameter ratio (P/D), and domain length (L) affect the laminar-turbulent transition region. We focus on squared array rod bundles. The simulations are carried out using the spectral-element code NekRS and a Direct Numerical Simulation (DNS) approach [1, 2]. We imposed a no-slip condition on the walls. The P/D ranged from 1.05 to 1.20, while the Re varied from 250 to 3500. We analyze the temporal and spatial behavior of the instabilities as a function of P/D and (Re) in detail, including the Power Spectral Density (PSD) method [3].
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M3 - Conference contribution
AN - SCOPUS:85178187656
SN - 9784888982566
T3 - International Conference on Nuclear Engineering, Proceedings, ICONE
BT - Proceedings of the 30th International Conference on Nuclear Engineering "Nuclear, Thermal, and Renewables
PB - American Society of Mechanical Engineers (ASME)
T2 - 30th International Conference on Nuclear Engineering, ICONE 2023
Y2 - 21 May 2023 through 26 May 2023
ER -