Comparative study of turbulence model predictions of upward supercritical fluid flow in vertical rod bundle subchannels

Bergmann, Cale; Ormiston, S.J.; Chatoorgoon, Vijay

doi:10.1016/j.nucengdes.2017.06.044

Cited by 7 publications

(1 citation statement)

References 44 publications

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“…The abrupt changes that water undergoes in its physical properties near the critical point contribute to the deterioration of heat transfer, due to the decrease in turbulent thermal conductivity and eddy viscosity, leading to lower turbulent heat flux and therefore higher surface temperatures [39]. This deterioration may be the result of a significant density variation near the critical point that deforms the velocity profile, flagging the turbulence [5], or even due to the thickening of the viscous underlayer depending on the fluid flow rate [40].…”

Section: Heat Transfer Deterioration In Scwg Experimentsmentioning

confidence: 99%

Heat Transfer Limitations in Supercritical Water Gasification

et al. 2021

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Supercritical water gasification (SCWG) is a promising technology for the valorization of wet biomass with a high-water content, which has attracted increasing interest. Many experimental studies have been carried out using conventional heating equipment at lab scale, where researchers try to obtain insight into the process. However, heat transfer from the energy source to the fluid stream entering the reactor may be ineffective, so slow heating occurs that produces a series of undesirable reactions, especially char formation and tar formation. This paper reviews the limitations due to different factors affecting heat transfer, such as low Reynolds numbers or laminar flow regimes, unknown real fluid temperature as this is usually measured on the tubing surface, the strong change in physical properties of water from subcritical to supercritical that boosts a deterioration in heat transfer, and the insufficient mixing, among others. In addition, some troubleshooting and new perspectives in the design of efficient and effective devices are described and proposed to enhance heat transfer, which is an essential aspect in the experimental studies of SCWG to move it forward to a larger scale.

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Section: Heat Transfer Deterioration In Scwg Experimentsmentioning

confidence: 99%