Multi-physical field coupling numerical investigation of alumina dissolution

•A solution module for alumina dissolution was established coupling heat and mass transfer.•A multi-physics field coupling process including flow field, temperature field and concentration field was modeled and simulated.•Particle shrinkage and thermal response in bath during dissolution were considered in this study.•The critical diameter which can identify the dominant mechanism between heat and mass transfer was proposed and investigated.•Optimal feeding quantity of alumina for 300 kA aluminum electrolytic cell was obtained.