A phase field model for reactive liquid-solid systems

Chemical precipitation is widely employed in industry, and improving the understanding of its underlying mechanisms is crucial for optimizing chemical engineering processes. The phase field method is frequently utilized to simulate multiphase processes; however, traditional phase field models encounter significant difficulties when simulating chemical precipitation, particularly in constructing multivariable free energy functions for complex, reactive liquid-solid transition systems. Here, a novel phase field framework is proposed to describe the microstructure evolution in reactive liquid-solid systems. In this model, an independent single-variable free energy function is constructed for each reaction in a multi-reaction system, replacing the complex multi-variable chemical free energy function shared by all reactions in the traditional phase field models, significantly reducing the difficulty of constructing the free energy functions. Inclusion growth during the steel refining process is employed as a benchmark case to demonstrate the capability of our new model. Simulation results show that the model successfully characterizes the shift in reaction equilibrium and the non-uniform spatiotemporal distribution of solutes and phases during the chemical precipitation process, unravelling a series of coupling effects arising from these phenomena.