| Abstrak/Abstract |
Spatiotemporal distribution visualization of solid volume fraction φ(r,θ,T(t)) (r: radial coordinate, θ: azimuthal coordinate, T: temperature, t: time) has been visualized during LiCl-KCl molten salt solidification by thermal-compensated electrical resistance tomography (tcERT). The visualization process by tcERT is composed of three steps which are 1) conductivity interpolation step, 2) conventional conductivity reconstruction step, and 3) phase-fraction conversion step. In the first step, interpolated liquid conductivity (_ ^L)σ(x,T) is defined under mole fraction x of KCl and measured temperature T by conductivity interpolation diagram (CID). In the second step, conventional heat-resistant ERT reconstructs solid-liquid conductivity (_ ^(S+L))σ(r,θ,T(t)). In the third step, solid-liquid conductivity model (SLCM) converts (_ ^(S+L))σ(r,θ,T(t)) into φ(r,θ,T(t)) by referring to (_ ^L)σ(x,T). The tcERT was applied to a composition of 85mol%LiCl–15mol%KCl in a crucible with platinum-wire electrodes under the initial temperature (_ ^0)T= 700 ˚C and at cooling rate γ= 4.44 ˚C/min. As the results, inhomogeneous and unsteady φ(r,θ,T(t)) are precisely visualized with a maximum relative error ζ= 0.763 of space-mean 〈φ〉(T(t)), in which inhomogeneity is the spatial gradient in the direction perpendicular to the crucible wall, and fluctuation is the transition of nucleation region to crystal growth region. |
