Air leakage into tokamaks vacuum vessel during plasma burning or maintenance operations may lead to the fast pressurization of the vacuum vessel. A fraction of the dust inventory present in the vacuum vessel can be mobilized threatening the safety of staff and workers on site, the local population and the environment. A numerical analysis of the physical phenomena involved in such accidents is necessary in order to predict the thermal-fluid dynamics into the vacuum vessel after air ingress and consequent dust mobilization. Accuracy of the numerical results is also required in order to provide a sufficient margin in the design of the safety systems. The numerical simulation of Loss of Vacuum Accident (LOVA) scenarios is a challenging task for today numerical methods and models because it involves large volumes, multiphase flows ranging from highly supersonic to nearly incompressible and contemporary heat transfer. The drag force exerted on the dust by a moving fluid due to the viscous surface shear stress and pressure distribution around the dust particles depends mainly on the Reynolds number, i.e. property of the fluid (kinematic viscosity), its mean velocity and characteristic length of the geometry. For a fixed geometry, the key parameter for the dust mobilization is the velocity field of the continuous phase, and its thermodynamics properties, inside the vacuum vessel. In this contribution, the authors present and discuss the results of numerical simulations of air jet flow field during a LOVA with particular attention to the comparison with the experimental data and differences arising from the use of different types of grid resolution and turbulence models (Zero-Equation, k-ω and SST). © 2014 Elsevier B.V.

Lupelli, I., Gaudio, P., Gelfusa, M., Malizia, A., Belluzzo, I., Richetta, M. (2014). Numerical study of air jet flow field during a loss of vacuum. FUSION ENGINEERING AND DESIGN, 89(9-10), 2048-2052 [10.1016/j.fusengdes.2014.03.064].

Numerical study of air jet flow field during a loss of vacuum

LUPELLI, IVAN;GAUDIO, PASQUALINO;GELFUSA, MICHELA;MALIZIA, ANDREA;RICHETTA, MARIA
2014-01-01

Abstract

Air leakage into tokamaks vacuum vessel during plasma burning or maintenance operations may lead to the fast pressurization of the vacuum vessel. A fraction of the dust inventory present in the vacuum vessel can be mobilized threatening the safety of staff and workers on site, the local population and the environment. A numerical analysis of the physical phenomena involved in such accidents is necessary in order to predict the thermal-fluid dynamics into the vacuum vessel after air ingress and consequent dust mobilization. Accuracy of the numerical results is also required in order to provide a sufficient margin in the design of the safety systems. The numerical simulation of Loss of Vacuum Accident (LOVA) scenarios is a challenging task for today numerical methods and models because it involves large volumes, multiphase flows ranging from highly supersonic to nearly incompressible and contemporary heat transfer. The drag force exerted on the dust by a moving fluid due to the viscous surface shear stress and pressure distribution around the dust particles depends mainly on the Reynolds number, i.e. property of the fluid (kinematic viscosity), its mean velocity and characteristic length of the geometry. For a fixed geometry, the key parameter for the dust mobilization is the velocity field of the continuous phase, and its thermodynamics properties, inside the vacuum vessel. In this contribution, the authors present and discuss the results of numerical simulations of air jet flow field during a LOVA with particular attention to the comparison with the experimental data and differences arising from the use of different types of grid resolution and turbulence models (Zero-Equation, k-ω and SST). © 2014 Elsevier B.V.
2014
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/01 - FISICA SPERIMENTALE
Settore ING-IND/06 - FLUIDODINAMICA
English
Accident prevention; Accidents; Computational fluid dynamics; Computer simulation; Dust; Flow fields; Jets; Magnetoplasma; Numerical models; Reynolds number; Thermodynamics; Turbulence models; Velocity, Characteristic length; LOVA; Maintenance operations; Nearly incompressible; Numerical results; Physical phenomena; Surface shear stress; Thermodynamics property, Vacuum technology
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Lupelli, I., Gaudio, P., Gelfusa, M., Malizia, A., Belluzzo, I., Richetta, M. (2014). Numerical study of air jet flow field during a loss of vacuum. FUSION ENGINEERING AND DESIGN, 89(9-10), 2048-2052 [10.1016/j.fusengdes.2014.03.064].
Lupelli, I; Gaudio, P; Gelfusa, M; Malizia, A; Belluzzo, I; Richetta, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/117859
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