Numerical analysis of density wave instability and heat transfer deterioration in a supercritical water reactor

Upadhyay, Raghvendra; Kumar, Shankar; Dutta, Goutam

doi:10.1007/s12206-018-0208-7

Cited by 15 publications

(10 citation statements)

References 17 publications

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“…The N spc is proportional to the difference in inlet specific enthalpy in comparison with the specific enthalpy at the PCP, whereas the N tpc is proportional to the power to mass flow ratio of the reactor. The MSB obtained in an earlier work [35] for the PV SCWR based on a singlechannel analysis considering the similar analysis of DWOs caused purely because of TH feedbacks is also superimposed in Fig. 6 for the comparison of the three MSBs obtained for three different case studies.…”

Section: Comparison Of Msbsmentioning

confidence: 96%

“…The TH model, used for the analysis of the PV SCWR based on a single channel [14,35], is extended at present to account for the radial or azimuthal non-uniformity in reactor power distribution among the different FAs by the incorporation of parallel channels in the TH model. To account for the effect of radial or azimuthal power variation inside the reactor core, a power asymmetry factor is introduced in such a way that the average reactor power remains the same.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…6 where in Fig 6a, b, the MSBs are plotted in a dimensional and non-dimensional planes, respectively. The non-dimensional plane [35] is composed of sub-pseudo-critical number N spc and trans-pseudocritical number N tpc . The N spc is proportional to the difference in inlet specific enthalpy in comparison with the specific enthalpy at the PCP, whereas the N tpc is proportional to the power to mass flow ratio of the reactor.…”

Section: Comparison Of Msbsmentioning

confidence: 99%

“…Ignoring the impact of neutronic coupling and including 2-3 channels in the numerical model, parallel-channel analysis of DWOs predicted the possibility of in-phase and out-of-phase modes of instabilities in the operating regime of a typical pressure tube (PT) SCWR [12] and quantified the effect of spatial reactor power variation in its respective MSBs. As per as the concept of the pressure vessel (PV) SCWR design and the related TH stability issues are concerned, the numerical investigations [33][34][35], which were based on a single-channel analysis, reported the possibility of DWOs in its relevant operating regime. Based on the linear perturbation approaches, the systematic studies on parallel-channel instabilities on the PV SCWR [1][2][3] considering three-region reactor core predicted the possibility of core-wide (in-phase) and out-of-phase modes of DWOs.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of parallel-channel density wave instabilities in a supercritical water reactor

Upadhyay

Raghuvanshi

Dutta

2020

J Braz. Soc. Mech. Sci. Eng.

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Supercritical water reactor (SCWR), a possible generation IV nuclear reactor, is expected to be more efficient and economical than the existing reactors. However, the possibility of thermal-hydraulic (TH) instabilities poses a challenge to its development. A generic pressure vessel (PV) SCWR concept, similar to the US SCWR design, is investigated at present for density wave oscillations (DWOs). An existing TH model, which was used earlier for the single-channel analysis, is extended here for the analysis of parallel channels. The TH model accounts for the regional heterogeneity in power distribution. The TH model is validated with the existing numerical results to access its capability to simulate the parallel-channel density wave instabilities (DWIs) in a supercritical water (SCW) system. Then, the TH model is used to capture the core-wide as well as regional modes of parallel-channel DWIs in the PV SCWR. The marginal stability thresholds are obtained for both the modes of DWOs and are compared. Subsequently, the aforementioned stability thresholds are compared with those obtained from the single-channel model as well, with the purpose to quantify the difference in stability thresholds obtained from the single-and parallel-channel analysis.

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Section: Comparison Of Msbsmentioning

confidence: 96%

Section: Mathematical Formulationmentioning

confidence: 99%

Section: Comparison Of Msbsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical analysis of parallel-channel density wave instabilities in a supercritical water reactor

Upadhyay

Raghuvanshi

Dutta

2020

J Braz. Soc. Mech. Sci. Eng.

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“…The present investigation is carried out using similar 1-D steady state conservation equations [4,[7][8][9][10][11][12] but with different methodology so as to find whether the criterion [6] given by Chatoorgoon [6] satisfies or not and thus we can determine the possibility of Ledinegg instability for the case study under consideration.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Computational Analysis of Static Flow Instabilities in Supercritical Natural Circulation Loop

Kumar

Kumar²,

Panwar

2020

Lecture Notes in Mechanical Engineering

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The present paper is to study and explore the possibility of static instability, Ledinegg flow excursion, in a rectangular supercritical natural circulation loop (RSCNCL). Due to drastic change of thermo-physical properties of fluid near the pseudo-critical point, various static and dynamic instabilities might occur in the loop. The instability may be either Ledinegg excursion or density wave oscillations (DWOs). Many previous researchers have analyzed dynamic instability, DWO, in SCNCL, whereas the Ledinegg excursive instability is not studied in depth. In the present research work, a mathematical model will be implemented to predict the Ledinegg instability in SCNCL. The numerical investigation is successful to find whether there would be any Ledinegg instability in the case of SCNCL or not. KeywordsLedinegg excursive instability • Supercritical water reactor • Rectangular natural circulation loop Nomenclature A Cross sectional area (m 2 ) D Hydraulic diameter (m) f Friction factor G Mass flux density (kg/m 2 ) H Loop height (m) h Specific enthalpy K Loss coefficient L Length of the section (m)

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Tube inlet orifice design of a once-through steam generator for flow stabilization

et al. 2019

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Numerical analysis of density wave instability and heat transfer deterioration in a supercritical water reactor

Cited by 15 publications

References 17 publications

Numerical analysis of parallel-channel density wave instabilities in a supercritical water reactor

Numerical analysis of parallel-channel density wave instabilities in a supercritical water reactor

Computational Analysis of Static Flow Instabilities in Supercritical Natural Circulation Loop

Tube inlet orifice design of a once-through steam generator for flow stabilization

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