Numerical prediction of CHF based on CFD methodology under atmospheric pressure and low flow rate

Zhang, Yapei; Zhang, Rui; Tian, Wenxi; Su, G.H.; Qiu, Suizheng

doi:10.1016/j.applthermaleng.2018.12.100

Cited by 26 publications

(8 citation statements)

References 14 publications

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“…Xi'an Jiaotong University has developed a FLUENT-based method for calculating CHF. The details of the mathematical model (such as the boiling model) and the corresponding CHF simulation method have been given in the references (Zhang et al, 2019). By secondary development on the basis of FLUENT15.0 software, the C languagebased User-Defined Function (UDF) can be used to calculate the flow heat transfer characteristics and void fraction distribution in the external flow channel of the pressure vessel under atmospheric pressure.…”

Section: Fluent-based Chf Calculation Methods 221 Methods Of Chf Calc...mentioning

confidence: 99%

Study on the influences of RPV deformation on CHF under IVR conditions

Wen

Gao²,

Zhang³

et al. 2023

Front. Energy Res.

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After the reactor core melt, the thermal impact of high temperature molten mixture to the lower head of reactor pressure vessel (RPV) will cause the shape change of cooling channel constituted by reactor pressure vessel outer surface and other supporting structures. This phenomenon may lead to local heat transfer deterioration and then cause the failure of in-vessel retention (IVR). Therefore, it is necessary to study the reactor pressure vessel deformation under in-vessel retention conditions. This paper proposes a numerical method for the CHF of the outer wall of reactor pressure vessel using ANSYS and FLUENT. The geometry of coolant channel is modeled by ANSYS with the coupling of temperature and mechanical field analysis in ANSYS, and the critical heat flux (CHF) of reactor pressure vessel outer surface is further predicted by FLUENT. With the comparing between test data and calculation, the calculation methods are verified. The results show that the CHF will be decreased by the deformation of PRV caused by the core melt.

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Section: Fluent-based Chf Calculation Methods 221 Methods Of Chf Calc...mentioning

confidence: 99%

Study on the influences of RPV deformation on CHF under IVR conditions

Wen

Gao²,

Zhang³

et al. 2023

Front. Energy Res.

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“…By applying Equations (7) and (8) to Equations (2)-(5), the Reynolds time-averaged N-S equations can be obtained. After the above operation on momentum Equation 3, six additional stresses called the Reynolds stresses are generated.…”

Section: Rans Turbulence Modelsmentioning

confidence: 99%

“…There are a few studies [5][6][7] focused on numerical simulations of the PRT-related components and structures in a nuclear reactor. Seung Min Baek et al [8] established a nonequilibrium three-region model to accurately predict the pressure of the PRT under some special circumstances, and conducted a number of numerical tests for the actual accident and nuclear power plant.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Turbulent Flow from a Steam Dumping Pressurizer Relief Tank

Zhang

Guo

et al. 2020

Energies

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Due to the complex geometry and turbulent flow characteristics, it is hard to simulate the process of steam dumping of the pressurizer relief tank (PRT). In this study, we develop a compressible fluid solver PRTFOAM to numerically study the turbulent flow dynamics from a PRT. The PRTFOAM is implemented based on the OpenFOAM and designed to be capable of integrating various turbulence models. Two representative Reynolds-averaged Navier–Stokes (RANS) models and a Smagorinsky–Lilly SGS model based on Large Eddy Simulation (LES) are coupled and tested with PRTFOAM. The case of a flow past a circular cylinder (Re = 3900) is tested and analyzed comprehensively as a benchmark case. Then, the turbulent steam dumping process in the full geometry of a PRT is analyzed and compared with ANSYS CFX and literature reports. In addition, we tested the WALE model based on the PRT steam dumping process. The results show that SST k-ω model and Smagorinsky–Lilly SGS model-based LES approach are more appropriate than the LRR model for PRT simulations. Moreover, it shows that the simulation results of Smagorinsky–Lilly SGS model and WALE model are basically consistent under the condition of PRT steam dumping process. Under this condition, the drawbacks of Smagorinsky–Lilly SGS model are not obvious. Furthermore, the comparison with CFX showed that our open source solver could be used to obtain better results in complex engineering cases. The design and testing results would provide guidance for further analysis of thermal-hydraulics in reactors based on open source codes.

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“…In this work, the CHF is estimated with the correlations proposed by [6,7] for the curved geometry of the RPV (Figure 1a) ( ) = 490 − 30.2 − 8.8 −1 2 + 1.35 −2 3 − 6.65 −5 4 (1)…”

Section: Introductionmentioning

confidence: 99%

“…The data points presented in Figure 1b can be fitted to a linear function of ∆ /18 slope. Thus, based on [2,7], a CHF correlation function of the angle and sub-cooling can be obtained multiplying Eq. (1) by a factor of 1 + (∆ /18):…”

Section: Introductionmentioning

confidence: 99%

CFD Analysis to Demonstrate in Vessel Retention Inducing a Bypass Flow

Strömgren¹,

Moigne²,

Sheng³

et al. 2021

14th WCCM-ECCOMAS Congress

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The goal of this work is to design a nozzle system around the Reactor Pressure Vessel (RPV) of a VVER-1000 nuclear reactor which would ensure successful melt retention during a severe accident. Simulations were performed with a multiphase model in ANSYS Fluent 19.1 to determine this. The results suggest that an efficient cooling can be achieved by inducing a flow rising parallel to the RPV walls in the flooded reactor cavity. In order to do this, it is proposed to use one central nozzle below the RPV and a ring of 32 nozzles 0.5 m above the RPV bottom. Assuming a 2 bar pressure, injection of 750 m 3 /h water at 80 o C through the nozzles led to little steam production and a heat flux below the critical value.

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Numerical prediction of CHF based on CFD methodology under atmospheric pressure and low flow rate

Cited by 26 publications

References 14 publications

Study on the influences of RPV deformation on CHF under IVR conditions

Study on the influences of RPV deformation on CHF under IVR conditions

Numerical Study of the Turbulent Flow from a Steam Dumping Pressurizer Relief Tank

CFD Analysis to Demonstrate in Vessel Retention Inducing a Bypass Flow

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