Fig. 2: Two possible representations of the triple phase problem.
From: Simulation of intercalation and phase transitions in nano-porous, polycrystalline agglomerates
In the diffuse boundary approach (a) the regularized indicator function ψ parametrizes the active material and does not evolve. The order parameter φ distinguishes high- and low-concentration phases and evolves within the whole computational domain. The multi-phase field approach (b) employs three volume fractions ϕα, ϕβ and ϕelyte which fulfill the sum constraint \(\mathop{\sum }\nolimits_{0}^{N}{\phi }_{i}=1\).
