Low melting point metals (LMPMs) are a new kind of phase change materials (PCMs) which exhibit excellent heat extraction capability due to their high thermal conductivity. Such a characteristic renders it distinctive melting mode which hardly exists in conventional paraffin PCMs. In this paper, comprehensive numerical investigation is carried out to reveal the melting process of LMPMs. First, comparative simulations of typical paraffin eicosane and typical LMPM gallium is conducted. Then, dimensionless analysis is performed based on a series of parametric studies and corresponding dimensionless correlations are given under both constant wall temperature condition and constant heat flux condition. Further, the critical dimensionless values within which the correlations are applicable are suggested. Finally, a preliminary exploration is performed to illustrate the influence of natural convection under relatively high Ra number condition. This study can serve as a valuable reference for future practical thermal design of LMPMs based thermal management systems and thermal energy storage systems. (C) 2016 Elsevier Ltd. All rights reserved.