39 Numerical Simulation for Nature Convection Heat Transfer of Liquid Metal Flow with Fusion Magnetic Fields

The liquid metal, LiPb flow, as only tritium breeder is characterized by lower flow velocity in the separated-cooled blanket concept of fusion reactor. The LiPb magnetohydrodynamic (MHD) flow in the cubic enclosure of the blanket has been numerical simulated by special MHD code. The walls may have arbitrary electrical conductance. The enclosure was differentially heated at two opposite vertical walls, all other walls being adiabatic, and a uniform magnetic field was applied orthogonal to the temperature gradient and to the gravity vector. The study covers the range of the Rayleigh number, Ra, from 102 to 103, the Hartmann number, Ha, from 20 to 102. The temperature distribution of the LiPb flow in the cubic enclosure is changed due to the magnetic field in Y vector. There is a strong thermal coupling, modifying importantly the magnitude of the flow. The effect of the magnetic field on buoyancy-driven flows has been investigated. The nature convection was found to be sufficiently strong to impose its flow pattern on the cross flow in the region of intense heating.