Multi-Objective Optimization of a Passive Micromixer Based on Periodic Variation of Velocity Profile

Abstract

This paper presents a multi-objective optimization procedure for the design 
of a sigma micromixer. The procedure combines three-dimensional analyses 
of fluid flow and mixing, polynomial approximation of objective functions, and 
a multi-objective genetic algorithm (MOGA). MATLAB Optimization Toolbox 
(version 7.7, The Mathworks, Inc., MA, USA) was used to invoke MOGA for 
optimization. A brief discussion on the application of Toolbox is introduced in 
the paper. Three geometric design parameters concerning the shape of the 
sidewalls were exploited for optimization. Mixing index and non-dimensional 
pressure loss were selected as objective functions. For mixing analysis, steady 
Navier-Stokes equations with a convection-diffusion model for scalar transport 
were solved at the Reynolds number Re=0.91. The design space was explored 
through parametric study, and the Latin hypercube sampling method was used as 
a design-of-experiment technique for selection of the design points in the design 
space. Surrogate modeling was performed for the objective functions using response 
surface approximation. Pareto-optimal solutions in the functional space lying on the 
Pareto-optimal curve were obtained.