Evaluation of the temperature-dependent rheology of non-Brownian particle suspensions via direct numerical simulation

This paper presents the recent development and testing of a LBM-DEM model of fluid-particle systems which can predict suspension rheology in the presence of conjugate heat transfer. A total energy formulation of the dual-population thermal lattice Boltzmann method (TLBM) has been extended to include a model of temperature-dependent fluid viscosity. The TLBM-DEM model was then applied to predict the rheology of a range of non-Brownian suspensions in a process referred to as numerical rheometry. Isothermal results at high solid volume fractions demonstrated a pronounced increase in relative viscosity. They were also able to highlight the influence of particle friction on suspension behaviour. The inclusion of temperature-dependent fluid viscosity showed a reduced perturbation of the velocity field due to the presence of particles in areas of thinner fluid. Temperature profiles exhibited nonlinearity due to viscous heating stemming from increasing particle solid volume fraction, which increased when conjugate heat transfer was allowed to take place. In the future, this modelling work-flow will be applied to investigate temperature-dependent suspension transport in a number of industrially-relevant flows