Flow, heat and mass transfers during solidification under traveling/rotating magnetic field

摘要

In this paper, we present the relative problem of heat and mass transfer to adopt a means of imposing an electromagnetic field to improve solutal segregation (macrosegregation) during liquid metal solidification. A well-validated, quasi-two-dimensional solidifying experimental benchmark was introduced, which allowed us to observe the temperature field evolution and to provide the evident clues of phase transformation. We also observed naturally formed solutal segregations in the post-mortem sample. The idea of imposing a modulated magnetic field while optimizing modulation frequency and having a cable to suppress solutal segregation was confirmed by multiscale numerical modeling. Magnetohydrodynamics, flow driven by a modulated traveling magnetic field, was experimentally studied. Furthermore, a more practical cylindrical shape of liquid metal bulk driven by a permanent helical magnetic field has been achieved. The spatial flow behaviors suggested an appropriate magnetic field with optimized electromagnetic parameters for obtaining high-quality, low-defect casting products.