Effect of heating modes on melting performance of a solid-liquid phase change using lattice Boltzmann model

摘要

The effects of heating modes on melting processes of pure tin and gallium are simulated using the enthalpy-based lattice Boltzmann method (LBM) with multi-relaxation time in a square cavity. Five different wall-heating modes including the uniform wall-temperature (UWT), increment wall-temperature (IWT), decrease wall-temperature (DWT), convex wall-temperature (CWT) and sink wall-temperature (SWT) are simulated at the left-wall and bottom-wall heaters of the cavity. The natural convective heat transfer is simulated with the change of Fourier numbers and Rayleigh numbers. The melting rate, melting efficiency and synergy angle are compared with the left-wall heater and the bottom-wall heater at the different heating modes. The dimensionless melting times decrease and the melting efficiencies increase with the increase of Rayleigh numbers. The dimensionless melting times are largest at the CWT heating mode, and lowest at the UWT heating mode. The synergy angles are lowest at the CWT heating mode and largest at the UWT heating mode at the bottom-wall and left-wall heaters. Comprehensive comparison shows that the melting process at the CWT heating mode is faster than the other heating modes because of the better field synergy at the hot wall.