MRT-lattice Boltzmann Simulation of High Schmidt and Low Prandtl Number Fluids with Heterogeneous Reaction on Surfaces

Document Type

Article

Publication Date

5-1-2020

Publication Title

Heat Transfer Research

Volume

51

Issue

5

First page number:

433

Last page number:

445

Abstract

An efficient algorithm based on the multiple-relaxation-time (MRT) lattice Boltzmann method (LBM) is developed to overcome instability in the simulation of heterogeneous reaction on surfaces exposed to liquid metals which have low Prandtl (Pr) and high Schmidt (Sc) numbers. The obtained simulation result from the model is in good agreement with previous works in which the single-relaxation-time (SRT) LBM model with reactive boundary condition was implemented for moderate Pr number liquids. A two-dimensional Poiseuille flow with heterogeneous reaction on surfaces is simulated using the developed MRT-LBM model for different Prandtl numbers and Schmidt numbers ranged from 7 x 10(-1) to 7 x 10(-3) and 10(3) to 10(1), respectively. Temperature and concentration distributions along with the Nusslet number Nu and Sherwood number Sh are presented as results. The findings show that the developed model is stable and robust to simulate a heterogeneous reaction on surfaces in low Pr and high Sc number flows. The relation between Pr and Sc numbers with thermal and mass transfer boundary layers is investigated. The fast-growing thermal boundary layer is observed for a lower Pr number. A higher reaction rate was spotted for liquids with the lower Sc number which leads to a stronger dissolution rate due to the high mass diffusion. Also, the obtained simulation results indicate the interest in using liquid metals in heat exchangers as compared to conventional fluids.

Keywords

Lattice Boltzmann method; MRT method; Low Prandtl number; Reactive boundary condition

Disciplines

Engineering | Mechanical Engineering

Language

English

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