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Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
December, 14-17, 2023, Bihar, India

Study of Natural Convection in Corner Melting of Low Prandtl Number Materials using Modified Lattice Boltzmann Method

Get access (open in a dialog) DOI: 10.1615/IHMTC-2023.1290
pages 797-802

摘要

In this work, the lattice Boltzmann method (LBM) has been used to conduct a numerical analysis of the melting phenomena of low Prandtl number materials in a square enclosure with two adjacent heated walls. The energy equation and the incompressible Navier-Stokes equation's lattice Boltzmann Bhatnagar-Gross-Krook (LBGK) models are modified to address numerical instabilities for the simulation of low Pr fluids. Using a total enthalpy-based lattice Boltzmann approach, the flow field and the thermal behaviour in the melt zone are numerically modelled for corner melting problem. The investigation has been performed in a wide range of Prandtl number Pr ∈ [0.001, 0.01] and high Rayleigh number Ra ∈ [105,106]. The evolution of the melting front with thermo-fluidic behaviour in the melt zone for low Pr materials is reported. For parametric values of Stefan number Ste=0.01, the impact of Rayleigh number on the convective flow field with the variation of Pr is assessed. The outcomes demonstrate discrete convection rolls at the melt zone for various situations and, over time, a preference for convection heat transfer over conduction. Set of isotherms and streamlines have been used to explain the thermal behaviour of the fluid flow in the melt zone. The interface front is observed is initially convex and gradually becomes concave in the direction of melting against different time and Pr. The turning of a convex to concave interface front requires more time as Pr rises. With an increase in Pr, the average Nusselt number (Nuavg.) near the interface rises.