Thermal effects on two-phase flow in 2D mixers using SPH

摘要

The present study is concerned with the numerical simulation of thermal effects of blades on the mixing process in micromixers with circular and elliptical chambers. Simulation of the problems including moving objects, sharp corners and small gaps, which are significant challenges in CFD, is performed here by applying the meshfree Lagrangian particle method of Smoothed Particle Hydrodynamics (SPH). To ensure the accuracy of the modified computational code, validations are carried out for the heat conduction in a slab and Taylor-Couette flow and the numerical results are successfully compared with the analytical solutions. As there is a limited knowledge of thermal effects of blades on the mixing process in micromixers with circular and elliptical chambers, numerical investigations are conducted for different temperature ratios and mixer geometries. In liquids, temperature and mass diffusion are inversely related to the viscosity. Therefore, it will be shown that the local Schmidt number decreases as the temperature increases, which will lead to an increase in the mixing rate. Furthermore, in elliptical mixers, the reduction of the mixing index occurs with a higher gradient compared to the circular mixers.