Of the influence of buoyancy on the turbulent flow in single-medium thermocline sensible heat storage
Abstract
Although numerical models of sensible thermal energy storage (STES) are already effective, efforts are still required to better understand and represent the combined effects of turbulence and buoyancy on STES efficiency. Axisymmetric URANS k-ω-SST simulation is conducted considering the temperature-dependent variations of fluid properties to study the turbulence structure. The influence of the approximation used to account for density variations is investigated: low Mach number, standard (linear) Oberbeck-Boussinesq and quadratic Oberbeck-Boussinesq approximations. The numerical model is compared to experimental data and shows good agreement. Numerical results show that the injected turbulence is significantly damped before entering the thermocline. Downstream of the thermocline, the flow remains laminar. Turbulent damping is mainly due to viscous effects and by both viscous and buoyant effects in the vicinity of the tail of the thermocline. A local negative peak of buoyant production delimits a region preceding the thermocline, this region separates a downstream domain with high turbulent mixing and a homogeneous temperature from a domain with quasi-laminar flow and a steep temperature gradient. The simulated thermocline is found to extend when the buoyant production term is neglected, owing to penetration of turbulent mixing into the thermocline. Conversely, when the buoyant production term is accounted for, temperature profiles exhibit sharper variations and an asymmetry between the tail (affected by turbulent mixing) and the head (where pure molecular diffusion dominates) of the thermocline. This phenomenon contributes to the asymmetry of the temperature profiles observed in the experiments
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BibTeX
@article{rudkiewicz2026influence,
title = {{Of the influence of buoyancy on the turbulent flow in single-medium thermocline sensible heat storage}},
author = {Martin Rudkiewicz and Arnaud Bruch and Jérôme Pouvreau and Remi Manceau and Sylvain Serra and Alexis Ferré},
journal = {Journal of Energy Storage},
year = {2026},
month = may,
doi = {10.1016/j.est.2026.122296},
url = {https://inria.hal.science/hal-05728172v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Of the influence of buoyancy on the turbulent flow in single-medium thermocline sensible heat storage
AU - Martin Rudkiewicz
AU - Arnaud Bruch
AU - Jérôme Pouvreau
AU - Remi Manceau
AU - Sylvain Serra
AU - Alexis Ferré
PY - 2026
DA - 2026/05/13
JO - Journal of Energy Storage
DO - 10.1016/j.est.2026.122296
UR - https://inria.hal.science/hal-05728172v1
AB - Although numerical models of sensible thermal energy storage (STES) are already effective, efforts are still required to better understand and represent the combined effects of turbulence and buoyancy on STES efficiency. Axisymmetric URANS k-ω-SST simulation is conducted considering the temperature-dependent variations of fluid properties to study the turbulence structure. The influence of the approximation used to account for density variations is investigated: low Mach number, standard (linear) Oberbeck-Boussinesq and quadratic Oberbeck-Boussinesq approximations. The numerical model is compared to experimental data and shows good agreement. Numerical results show that the injected turbulence is significantly damped before entering the thermocline. Downstream of the thermocline, the flow remains laminar. Turbulent damping is mainly due to viscous effects and by both viscous and buoyant effects in the vicinity of the tail of the thermocline. A local negative peak of buoyant production delimits a region preceding the thermocline, this region separates a downstream domain with high turbulent mixing and a homogeneous temperature from a domain with quasi-laminar flow and a steep temperature gradient. The simulated thermocline is found to extend when the buoyant production term is neglected, owing to penetration of turbulent mixing into the thermocline. Conversely, when the buoyant production term is accounted for, temperature profiles exhibit sharper variations and an asymmetry between the tail (affected by turbulent mixing) and the head (where pure molecular diffusion dominates) of the thermocline. This phenomenon contributes to the asymmetry of the temperature profiles observed in the experiments
SN - 2352-152X
SN - 2352-1538
ER -