Application of the lattice Boltzmann method for simulation of the mold filling process in the casting industry

Abstract

The aim of this work is the development of the lattice Boltzmann model for simulation of the mold filling process. The authors present a simplified approach to the modeling of liquid metal-gas flows with particular emphasis on the interactions between these phases. The boundary condition for momentum transfer of the moving free surface to the gaseous phase is shown. Simultaneously, the method for modeling influence of gas back pressure on a position and shape of the interfacial boundary is explained in details. The problem of the lattice Boltzmann method (LBM) stability is also analyzed. Since large differences in viscosity of both fluids are a source of the model instability, the so-called fractional step (FS) method allowing to improve the computation stability is applied. The presented solution is verified on the bases of the available reference data and the results of experiments. It is shown that the model describes properly such effects as: gas bubbles formation and air back pressure, accompanying liquid-gas flows in the casting mold. At the same time the proposed approach is easy to be implemented and characterized by a lower demand of operating memory as compared to typical LBM models of two-phase flows.

Memory-efficient Lattice Boltzmann Method for low Reynolds number flows

“…From practical point of view, the LBM1 algorithm discussed here should be useful in applications where the original BGK Lattice Boltzmann was combined with the relaxation time τ = 1. For example, in [33,12,6,28,17,13,9,34,25,3,10,14,15,22] it is possible to save more than 75% of the memory by using LBM1 described here.…”

“…In the standard LBM BGK algorithm the relaxation time τ may range from nearly 1/2 up to 1 (highly viscous flows), however, the choice τ = 1 is a popular choice for single relaxation time BGK approximation [33,20,12]. For example, τ = 1 was chosen in the gray LBM model used for porous media flows [6], to compute first predictor step and fictitious viscosity solution in the simulation of the mold filling process [28], in the LBM multicomponent flow simulation with comparison to Finite Volume Methods [21], the immersed-boundary LBM for particles suspended in fluids [17]. It was shown that the value of τ influences the accuracy of the LBM solver in flow through narrow pores and τ = 1 case was in the best agreement with advanced multi-relaxation time schemes [18,20].…”

Physical and Numerical Modeling of the Impeller Construction Impact on the Aluminum Degassing Process

“…The liquid could fill them freely, and the air surrounding the system was considered by the atmospheric pressure exerted on the free surface. This approach is often used in modeling foundry and metallurgical processes [ 24 ].…”

Experimental validation of numerical simulations of free-surface flow within casting mould cavities

“…This decreases its computational demands. Although twophase flow LBM models of the casting processes exist, Szucki et al (2017), Kharmiani and Passandideh-Fard (2018), a single phase model with free-surface boundary, Ginzburg and Steiner (2003), Zhang et al (2019), is considered within this work in order to keep the computational simplicity and cost efficiency.…”