MHD forced convection flow in dielectric and electro-conductive rectangular annuli

Abstract

Abstract The Breeding Blanket is a fundamental component of a nuclear fusion reactor and the Water-Cooled Lead Lithium (WCLL) blanket is one of the possible solutions proposed. In this concept, liquid lithium-lead eutectic alloy (PbLi) serves as tritium breeder, tritium carrier and neutron multiplier. The liquid metal is distributed within the breeding zone by two co-axial rectangular channels and, interacting with the reactor magnetic field, leads to the arising of MagnetoHydroDynamic (MHD) effects. In this work, the general-purpose CFD code Ansys CFX 18.2 is used to study this uncommon configuration, modelled as a prototypical square annular channel. The study covers a wide range of magnetic field intensity (up to H a = 2000 ) and two values for the wall conductance ratio ( c w = 0 and c w = 0.1 ) representing, respectively, the ideal insulated case and one more closely approaching the WCLL manifold actual conditions. For both these scenarios, characteristic flow features and their evolution with increasing magnetic field are discussed. A correlation is found linking the pressure loss in the studied configuration and an equivalent square channel through a corrective factor e , which exhibits an asymptotic behavior for H a > 1000 equal to e c w = 0 ≅ 2.44 and e c w = 0.1 ≅ 1.12 .