Qualification of MHD effects in dual-coolant DEMO blanket and approaches to their modelling

Valls, E. Mas de les; Batet, L.; Medina, Vicente; Fradera, J.; Sedano, L.

doi:10.1016/j.fusengdes.2011.03.071

Cited by 10 publications

(5 citation statements)

References 19 publications

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“…Although a sidewall Reynolds number of 10 5 provided both very large growth, and slow relaminarization, at a realistic magnetic field strength, the corresponding Reynolds number based on the half duct height would be around 10 7 . This is well beyond what is currently expected for reactor operation, which range from 10 4 to 10 6 [7, 58,59]. Furthermore, no assessment of the sensitivity to wall properties on the formation of the arched TS wave has been performed, which given the thermal, electrical and slip issues considered in magnetohydrodynamic coolant duct flows [60][61][62][63], provides an important avenue for future work for self-cooled reactor designs.…”

Section: Discussionmentioning

confidence: 99%

Subcritical route to turbulence via the Orr mechanism in a quasi-two-dimensional boundary layer

Camobreco¹,

Pothérat²,

Sheard³

2020

Preprint

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A subcritical route to turbulence via purely quasi-two-dimensional mechanisms, for a quasi-twodimensional system composed of an isolated exponential boundary layer, is numerically investigated. Exponential boundary layers are highly stable, and are expected to form on the walls of liquid metal coolant ducts within magnetic confinement fusion reactors. Subcritical transitions were detected only at weakly subcritical Reynolds numbers (at most ≈ 70% below critical). Furthermore, the likelihood of transition was very sensitive to both the perturbation structure and initial energy. Only the quasi-two-dimensional Tollmien-Schlichting wave disturbance, attained by either linear or nonlinear optimisation, was able to initiate the transition process, by means of the Orr mechanism. The lower initial energy bound sufficient to trigger transition was found to be independent of the domain length. However, longer domains were able to increase the upper energy bound, via the merging of repetitions of the Tollmien-Schlichting wave. This broadens the range of initial energies able to exhibit transitional behaviour. Although the eventual relaminarization of all turbulent states was observed, this was also greatly delayed in longer domains. The maximum nonlinear gains achieved were orders of magnitude larger than the maximum linear gains (with the same initial perturbations), regardless if the initial energy was above or below the lower energy bound. Nonlinearity provided a second stage of energy growth by an arching of the conventional Tollmien-Schlichting wave structure. A streamwise independent structure, able to efficiently store perturbation energy, also formed.

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Section: Discussionmentioning

confidence: 99%

Subcritical route to turbulence via the Orr mechanism in a quasi-two-dimensional boundary layer

Camobreco¹,

Pothérat²,

Sheard³

2020

Preprint

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show abstract

“…The scheme has been employed to conduct 3D direct simulation of MHD flows by solvers of HIMAG, OpenFOAM, CDP, CFX et al HIMAG [25,29] is a parallel code on an arbitrary collocated mesh developed by HyperComp Inc. with strong technique supports from UCLA. OpenFOAM (see http://www.openfoam.com/) is an open source code for parallel algorithm used on an unstructured collocated mesh with module developed in Europe for 3D MHD simulations [14,15,19]. CDP (http://www.stanford.edu / group / cits / research / combustor / cdp.…”

Section: On a Collocated Meshmentioning

confidence: 99%

Recent advances in computational techniques for MHD flow and application to fusion

2012

Fusion Engineering and Design

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“…The liquid metal domain has been discretised into 1.4×10 5 nodes, what has proved to provide good accuracy, as demonstrated in [1]. Very briefly, boundary conditions include an inlet temperature of 450 • C and velocity of 0.2 m/s; the non-slip boundary condition is applied at walls.…”

Section: Model and Boundary Conditionsmentioning

confidence: 99%

“…Such analyses include MHD studies, mainly concerning to liquid metal MHD thermofluid issues such as MHD pressure drop, Q2D turbulence and buoyancy, among others. In this direction, a preliminary study was carried out by the authors [1], where a qualification of MHD effects under TECNO FUS blanket design specifications and some approaches to their modelling were exposed. The analysis first summarised the main flow parameters and characteristics by means of a dimensionless study, then, some preliminary numerical results were shown.…”

Section: Introductionmentioning

confidence: 99%

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Influence of thermal performance on design parameters of a He/LiPb dual coolant DEMO concept blanket design

Valls

Batet

Medina

et al. 2012

Fusion Engineering and Design

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Qualification of MHD effects in dual-coolant DEMO blanket and approaches to their modelling

Cited by 10 publications

References 19 publications

Subcritical route to turbulence via the Orr mechanism in a quasi-two-dimensional boundary layer

Subcritical route to turbulence via the Orr mechanism in a quasi-two-dimensional boundary layer

Recent advances in computational techniques for MHD flow and application to fusion

Influence of thermal performance on design parameters of a He/LiPb dual coolant DEMO concept blanket design

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