CFD simulations to characterize near wall heat transfer in high Prandtl number packed bed conditions

• Published in: Nuclear engineering and design Vol. 396; p. 111868
• Main Authors: Jaymes Dionne, C., Gutowska, Izabela, Brian Jackson, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2022
• Subjects: Computational fluid dynamics; Convective heat transfer; High Prandtl number; Near-wall Nusselt number; Packed bed; Convective heat transfer; Packed bed; Computational fluid dynamics; Near-wall Nusselt number; High Prandtl number
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2022.111868

•Current Nuw correlations do not align with high-Prandtl number flow.•Packed bed length effect the result of thermal non-equilibrium of fluid and wall.•Low Re flow results in breakdown of heat transfer correlations.
Computational fluid dynamics conjugate heat transfer simulations were performed on a packed bed test facility using Dowtherm-A as the working fluid. Multiple test cases were simulated for a Reynolds number range of 188 – 1524 and a set heater power of 60 kW. Temperature profiles were extracted, and the near-wall heat transfer coefficient was calculated using heat transfer approximations. The heat transfer coefficient behavior matched qualitatively with the works of others but differed quantitatively due to the nature of the high-Prandtl number fluid. Updated correlations were developed for Dowtherm-A for use in the test facility simulated, with further usage for the development of molten salt-cooled pebble bed reactors.