Analysis of Gas Entrainment Phenomenon From Free Liquid Surface for a Sodium-Cooled Fast Reactor Design: Validation of Velocity Profile and Strouhal Number in a Flow Field

2021 ◽  
Author(s):  
Mao Uchida ◽  
Moe Hirakawa ◽  
Aaru Sano ◽  
Keisuke Inoue ◽  
Takaaki Sakai ◽  
...  
Keyword(s):  
Flow Field ◽  
Velocity Profile ◽  
Strouhal Number ◽  
Fast Reactor ◽  
Liquid Surface ◽  
Reactor Design ◽  
Free Liquid Surface ◽  
Design Validation ◽  
Gas Entrainment

Analysis of Gas Entrainment Phenomenon From Free Liquid Surface for a Sodium-Cooled Fast Reactor Design: Validation of Velocity Profile and Strouhal Number in a Flow Field

2020 ◽  
Author(s):  
Mao Uchida ◽  
Moe Hirakawa ◽  
Aaru Sano ◽  
Keisuke Inoue ◽  
Takaaki Sakai ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Flow Velocity ◽  
Liquid Surface ◽  
Velocity Profiles ◽  
Reactor Vessel ◽  
Flow Channel ◽  
Wake Flow ◽  
Gas Entrainment ◽  
Piv Method

Abstract Gas entrainment (GE) from cover gas, which is an inert gas to cover sodium coolant in a reactor vessel, is one of key issue for Sodium-cooled fast reactors (SFRs) design to prevent unexpected effects to core reactivity. In this research series, evaluation method has been investigated for surface dimple depth growth of unstable drifting vortex dimples on the liquid surface in the reactor vessel. By using a computational fluid dynamics (CFD) code, analyses have been conducted to estimate the drifting vortex on water experiments in a circulating water tunnel. The unstable drifting flow vortexes on the water surface were generated as wake vortexes behind a plate obstacle. Downward flow velocity was induced by bottom slit flow pass along the flow channel. In the previous study, the onset conditions of the gas entrainment were evaluated based on existing non-dimensional numbers method by using the STREAM-VIEWER code. However, the CFD predication accuracy of the detail flow field itself was not clear especially for vortex frequency in the wake flow and detail velocity profiles in the flow channel. In this study, to clarify the accuracy of CFD analysis, Strouhal numbers of vortex frequency and detail flow velocity profiles were compared with experimental data which were measured by Particle Image Velocimetry (PIV) method. As the results, the Strouhal numbers of the vortex frequency behind the plate obstacle reasonably agreed with experimental data. Prediction accuracy for the velocity profiles in the flow channel were also confirmed by comparisons with measured data by the PIV method.

An Investigation of the Transverse Velocity Profile in the Case of Internal Viscous Aerodynamic Problems

1984 ◽  
Author(s):  
P. Kotidis ◽  
P. Chaviaropoulos ◽  
K. D. Papailiou
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Velocity Profile ◽  
Shear Layer ◽  
Transverse Velocity ◽  
Transverse Plane ◽  
Zone Model ◽  
Viscous Shear ◽  
Rotational Part ◽  
Confined Flows

The development of transverse velocity profile is directly related to the development of secondary vorticity. In the internal aerodynamics case with potential external flow, although vorticity remains confined inside the viscous shear layer, secondary vorticity induced velocities exist outside of it. If the secondary vorticity field is known, the induced secondary velocity field is well approximated following Hawthorne’s classical analysis. In the present work, the above analysis is used to separate the velocity field in the transverse plane into a potential and a rotational part. In the case of confined flows, the rotational part is confined inside the viscous shear layer, while the potential part occupies the whole flow field. This last part is the consequence of the “displacement” effects of the shear layer in the transverse plane. Therefore, the present work allows a re-examination of the flow two-zone model (separation of the flow field in a viscous and an inviscid part) in confined flows. On the other hand, the limitations of Hawthorne’s theory are examined, while a parallel analysis is presented for the case where the secondary vorticity distribution varies not only along the blade height, but also circumferentially.

scholarly journals Unsteady deformations of a free liquid surface caused by radiation pressure

2011 ◽  
Vol 682 ◽  
pp. 460-490 ◽  
Author(s):  
B. ISSENMANN ◽  
R. WUNENBURGER ◽  
H. CHRAIBI ◽  
M. GANDIL ◽  
J.-P. DELVILLE
Keyword(s):  
Analytical Model ◽  
Radiation Pressure ◽  
Liquid Surface ◽  
Acoustic Pulse ◽  
Free Liquid Surface ◽  
Time Dependent ◽  
Surface Dynamics ◽  
Fluid Interface ◽  
Numerical Predictions ◽  
Strongly Damped

We present an analytical model of the time-dependent, small-amplitude deformation of a free liquid surface caused by a spatially localized, axisymmetric, pulsed or continuous, acoustic or electromagnetic radiation pressure exerted on the surface. By exactly solving the unsteady Stokes equation, we predict the surface dynamics in all dynamic regimes, namely inertial, intermediate and strongly damped regimes. We demonstrate the validity of this model in all dynamic regimes by comparing its prediction to experiments consisting of optically measuring the time-dependent curvature of the tip of a hump created at a liquid surface by the radiation pressure of an acoustic pulse. Finally, we present a numerical scheme simulating the behaviour of a fluid–fluid interface subjected to a time-dependent radiation pressure and show its accuracy by comparing the numerical predictions with the analytical model in the intermediate and strongly damped regimes.

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