Experimental measurements of flow mixing in cold leg of a pressurized water reactor

Orea, Daniel; Vaghetto, Rodolfo; Nguyen, Thien; Hassan, Yassin A.

doi:10.1016/j.anucene.2019.107137

Cited by 22 publications

(9 citation statements)

References 17 publications

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“…( The latter assumptions of linear viscosity and density changes are experimentally well recovered (Orea et al 2020). The governing equations in the gravity field for a newtonian fluid satisfying the Stokes' hypothesis write, under conservative formulation 1 (Chassaing et al 2002):…”

Section: Governing Equationsmentioning

confidence: 92%

“…It may be again argued that a finer mesh would be required to get closer to the measured values, because these two quantities have a low magnitude and show the largest RMSE between M 3 and M 4 , as shown in Tables 3 and 4, suggesting that the mesh convergence is not fully reached. By the way, note that the maximum PIV measurement errors assessed in Orea et al (2020) are 0.00276 m/s for U mean and 0.0000261 m/s for V mean . Hence, the calculated values of V mean go distinctly beyond the uncertainty bars in places, contrary to U mean .…”

Section: Validation In the Cold Legmentioning

confidence: 97%

“…After a long time, the concentration field would reach a stationary stable stratified state with a fluid remaining at rest, but the experiment focuses on the transient state, which is observed over several tens of seconds. The measurement techniques are described in detail in Orea et al (2020). The measurements are made by Particle Image Velocimetry (PIV) in two zones included in the plane z = 0, one in the cold leg and one in the downcomer.…”

Section: Experimental Facilitymentioning

confidence: 99%

“…The CLM benchmark has been designed to perform Verification, Validation and Uncertainty Quantification (VVUQ) of CFD codes. The validation is made against experimental measurements provided by the Texas A&M University (Orea et al 2020). The facility mimics the critical scenario of a PTS in a reactor vessel and the accurate prediction of the transient flow using CFD has been found to be a challenging issue.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Wall-Resolved Large Eddy Simulations of the Transient Turbulent Fluid Mixing in a Closed System Replicating a Pressurized Thermal Shock

Angeli

2021

Flow Turbulence Combust

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The isothermal mixing of a heavy and a light liquid of different physical properties is numerically investigated by means of Large Eddy Simulations. The validation is based on experimental data held in a system reproducing various components of a pressurized water nuclear reactor, during a scenario of cold water injection at a low Atwood number of 0.05. The flow has two distinct stages: first a buoyancy-driven phase is characterized by a fluid front development in the cold leg and gives rise to Kelvin-Helmholtz whorls under the action of density changes. Then, the heavy liquid discharges into the downcomer filled with light liquid, which causes a turbulent mixing. These phenomena are analyzed through a single-phase approach where the density of the working fluid is either variable or modeled by the Boussinesq approximation. The influence of grid refinement is deeply examined, which shows that the mesh convergence is well achieved for the main flow quantities, unlike the low-magnitude spanwise components. Overall, the numerical solutions are found to reproduce the experimental measurements with a fair accuracy for both physical models used. These latter exhibit similar trends, due to the small density difference under consideration. The predictions in the downcomer appear to be more challenging owing to a strongest turbulence than in the cold leg, some flow features being not properly captured. However, the experimental data in the downcomer are found to be incomplete and somewhat dubious for a strict validation of the numerical simulations. Lastly, the flow distribution in the dowcomer is investigated, providing further insight on the mixing process.

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Section: Governing Equationsmentioning

confidence: 92%

Section: Validation In the Cold Legmentioning

confidence: 97%

Section: Experimental Facilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wall-Resolved Large Eddy Simulations of the Transient Turbulent Fluid Mixing in a Closed System Replicating a Pressurized Thermal Shock

Angeli

2021

Flow Turbulence Combust

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“…17 Xu et al researched the unsteady pressure pulsation characteristics in an RCP with a steamgenerator simulator, and the influence of rotational speed on pressure pulsation was investigated. 18 The noncontact measurement techniques such as Laser Doppler Velocimetry 19 and Particle Image Velocimetry 20,21 are indispensable approaches to acquiring the unsteady flow information within a special pump. Zhang et al obtained the velocity and vorticity distributions in the diffuser and spherical casing of an RCP model by using the PIV method, and the complexity of the flows in the RCP was revealed.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the unsteady pressure pulsation and vibration of a nuclear pump test loop

Zhou

Dong

et al. 2022

Energy Science & Engineering

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The nuclear reactor coolant pump (RCP) is the key equipment of the Pressurized Water Reactor, of which the coolant circulation inherently brings flow fluctuation and, therefore, flow-induced vibration exists, which is detrimental to the safe and stable operation of nuclear power plants.Experiments were carried out on a nuclear pump test loop to investigate the characteristics of pressure pulsation and vibration under various rotational speeds and operational temperatures. Signals of pressure pulsation and vibration synchronously measured from the sensors located among the test loop and the bottom of the motor were analyzed by the Root Mean Square and the Fast Fourier Transform methods. Pronounced pressure pulsation peaks corresponding to the blade passage frequency and its higher harmonics are captured, and pressure pulsation amplitude variations are closely associated with the sensor positions and operating conditions. Vibration magnitude along the outlet direction of the nuclear RCP is the largest and increases with the increasing rotational speed but not the operating temperature. Finally, a coherent analysis was conducted between the vibration at the bottom of the motor and the unsteady pressure pulsation in the test loop. This study can provide meaningful scientific guidance in practical engineering applications.

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Numerical prediction of a single phase Pressurized Thermal Shock scenario for crack assessment in an Reactor Pressure Vessel wall

Uitslag-Doolaard

Stefanini

Shams

et al. 2020

Annals of Nuclear Energy

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Experimental measurements of flow mixing in cold leg of a pressurized water reactor

Cited by 22 publications

References 17 publications

Wall-Resolved Large Eddy Simulations of the Transient Turbulent Fluid Mixing in a Closed System Replicating a Pressurized Thermal Shock

Wall-Resolved Large Eddy Simulations of the Transient Turbulent Fluid Mixing in a Closed System Replicating a Pressurized Thermal Shock

Experimental investigation on the unsteady pressure pulsation and vibration of a nuclear pump test loop

Numerical prediction of a single phase Pressurized Thermal Shock scenario for crack assessment in an Reactor Pressure Vessel wall

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