Simulation of particles dissolution in the shear flow: A combined concentration lattice Boltzmann and smoothed profile approach

Abstract

In the present study, the combination of the Concentration Lattice Boltzmann Method and the Smoothed Profile Method (CLBM–SPM) was used to simulate the dissolution of circular particles between parallel plates moving in opposite directions. The hydrodynamics and fluid concentration simulation were performed based on the single relaxation time Lattice Boltzmann Method. LBM convection–diffusion equation was then used to solve the concentration of the solute in the fluid phase. Additionally, SPM was employed to apply the no-slip boundary condition at the solid–fluid interface and to calculate the concentration forces. Initially, the results of the numerical solution were compared with the ones presented in the literature. Then the effects of the initial solid volume fraction, the Schmidt number, the Reynolds number, and particle size were studied to examine the behavior of particles dissolution. The results showed that the smallest dissolution time in the systems with different volume fractions was in a one with the least solid volume fraction. As the volume fraction was increased, the solid–fluid mass transfer driving force was decreased in the system. Also, with the rise of the Schmidt number, the dissolution time was increased, due to the decrease of the diffusion coefficient of the fluid flow. Moreover, by increasing the Reynolds number, the time required for the volume fraction ratio to reach 0.05 of its initial value was reduced. Finally, the particle size in this system was studied. The results indicated that with the decrease in particle size (or increase in the surface area), we could significantly alter the dissolution time.