Study of thermal convection in liquid metal using modified lattice Boltzmann method

PurposeThis study aims to extend the application of the lattice Boltzmann method (LBM) to solve solid-to-liquid phase transition problems involving low Prandtl number (Pr) materials. It provides insight about the flow instability in a cavity undergoing melting. This work further report interface development and thermal transport against the Boussinesq number.Design/methodology/approachThis study modifies the lattice Bhatnagar-Gross-Krook model by including correction components in the energy and density distribution functions. To prevent numerical instability, a tuning parameter in the flow domain is set in the range of 0.15-0.7 for the range of Rayleigh number and Prandtl number. To the best of the authors' knowledge, the modified LBM is being used for the first time to examine the low Pr domain melting behavior of liquid metals.FindingsThe interaction with complicated flow structure with natural convection, studied in a square enclosure, has a significant impact on the melting of metals in the low Pr range. Results show that the melting rate and the length of the interface between two phases are significantly influenced by the Boussinesq number (Bo), the product of Pr and Rayleigh number (Ra). For changing Ra, the maximum interface length is almost constant in the in the Boussinesq number range up to 100 and beyond this range the interface length increases with Bo.Originality/valueThe effects of Pr on melting rate, Ra and Pr together on the length of the solid-liquid interface and the thermofluidic behavior in the melt zone are explained. This work also includes mapping the maximum melt interface size with Bo.