Assessment of a new model for the linear and nonlinear stability analysis of natural circulation loops with supercritical fluids

Debrah, Seth Kofi; Ambrosini, Walter; Chen, Yuzhou

doi:10.1016/j.anucene.2013.03.033

Cited by 27 publications

(3 citation statements)

References 19 publications

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“…Debrah et al [10] and Sharma et al [11] used a 1-D non-linear program to examine the effect of thermal wall storage on the flow stability boundary using a natural circulation loop. They reported that the flow stability of the system increases largely when modeled with the thermal wall storage.…”

Section: Relevant Workmentioning

confidence: 99%

Experiments on supercritical flow instability in two vertical parallel channels

Singh¹,

Chatoorgoon²

2020

International Conference on Fluid Flow and Thermal Science

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Very limited experimental data on supercritical flow instability is present in the literature. To enrich this limited database and to further the understanding of supercritical flow instability, an experimental study was conducted using two vertical parallel channels with supercritical CO2. A total of 7 experimental cases were performed with a system pressure range of 8.25-9.1MPa and inlet temperatures 0.5-10.05 °C. The channel inlet temperature and system pressure were held constant and the input power was increased gradually until mass flow oscillations commenced. The distribution of mass flow rate in the channels with input power increase was examined. Initially, at low input power, the flow rate in the channels was almost equal, with an increase in input power, it got distributed in channels and become asymmetric, and with the further input power increase, it started oscillating 180 °out-of-phase. The results for seven experimental cases are presented and these would be useful for code validation purposes.

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Section: Relevant Workmentioning

confidence: 99%

Experiments on supercritical flow instability in two vertical parallel channels

Singh¹,

Chatoorgoon²

2020

International Conference on Fluid Flow and Thermal Science

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“…Debrah et al [37] mentioned that numerical models equipped with heat transfer and friction correlations could not satisfactorily predict supercritical instabilities, and there is the need to examine different contributing Several types of studies have been made to understand and address flow instability at supercritical pressures by considering four structure types of the studied fluids. These types of investigations include studies involving single-channel stabilities, parallel-channel stabilities, reactor core flow instabilities and natural circulation or closed-loop system stabilities [41].…”

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confidence: 99%

Flow Instability in Parallel Channels with Water at Supercritical Pressure: A Review

Shitsi¹,

Debrah²,

Agbodemegbe³

et al. 2018

WJET

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Research into flow instability at both subcritical and supercritical pressures has attracted attention in recent years because of its potential of occurrence in industrial heat transfer systems. Flow instability has the potential to affect the safety of design and operation of heat transfer equipment. Flow instability is therefore undesirable and should be avoided in the design and operation of industrial equipment. Rahman et al. reviewed studies on supercritical water heat transfer with the aim of providing references for SCWR researchers. It was found out that most of the CFD studies and experimental studies were performed with single tube geometry due to the complexity of parallel channel geometry. Because studies performed with parallel channel geometry could provide detailed information to the design of the SCWR core, they called for more studies in parallel channel geometry at supercritical pressures in the future. In order to help understand how flow instability investigations are carried out and also highlight the need to understand flow instability phenomenon and equip the designers and operators of industrial heat transfer equipment with the needed knowledge on flow instability, this study carried out a review of flow instability in parallel channels with water at supercritical pressures.

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“…For all the experimental work, either with CO 2 or H 2 O, flow instability occurred only in a very narrow range when the loop was operated near the pseudo-critical temperature. Debrah et al (2013) analytically extended the non-dimensional parameters used for heated channels ) to a simplified supercritical natural circulation loop. The involvement of heat structures in modeling was found to be capable of stabilizing the natural circulation loops.…”

Section: Instability Studies Of Circulation Loop 23mentioning

confidence: 99%

Numerical Instability Study of Supercritical Water Flowing Upward in Two Heated Parallel Channels

Chatoorgoon

Ormiston

2017

Proceedings of the 20th Pacific Basin Nuclear Conference

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A three dimensional numerical investigation of supercritical water flowing upward in two heated parallel channels was developed using a RANS model in the Computational Fluid Dynamics (CFD) code ANSYS CFX. The standard k- turbulence model with scalable wall functions was adopted throughout this numerical study.The effects of spatial and temporal grid sizes on flow instability were studied first. Then oscillatory instabilities of nine experimental cases were predicted using the CFX code.For comparison purposes, Chatoorgoon"s 1-D non-linear SPORTS code was also used to determine the instability boundary. These new numerical results were compared with the experimental data and previous numerical results by other investigators.Additionally, the effects of changing the outlet plenum volume, the turbulent Prandtl number, the turbulence inlet conditions, the outlet K factor, the maximum iterations per time step in the transient analysis and the order of the transient scheme on the instability thresholds were examined.ii ACKNOWLEDGEMENTS

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Assessment of a new model for the linear and nonlinear stability analysis of natural circulation loops with supercritical fluids

Cited by 27 publications

References 19 publications

Experiments on supercritical flow instability in two vertical parallel channels

Experiments on supercritical flow instability in two vertical parallel channels

Flow Instability in Parallel Channels with Water at Supercritical Pressure: A Review

Numerical Instability Study of Supercritical Water Flowing Upward in Two Heated Parallel Channels

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