The effect of geometry on mixing efficiency for microfluidic device

Abstract

Micromixers have had a huge growth in past few decades and the fabrication of simple devices leads us to have so many results on different micromixer devices with a variety of techniques. They perform as one of the most important elements in attaining microfluidic system for biological and medical applications. Liposomes are one of the most noticeable nanoparticles used as a carrier in drug delivery for medical applications. The production of liposomes using micromixers and microfluidic devices have overcome so many barriers in this field. Enhancement in mixing process by adding a barrier on the channel walls such as periodic disturbance mixer (PDM), micromixer which we are introducing in this work, would reduce the mixing length and lead us to a higher mixing efficiency. A novel passive-micromixer design has been used for this part of research which named PDM micromixer. A well designed micromixer has rapid mixing and compact size and always must have this in mind that the time of mixing is the key element specially for industrial usage. The shape of the microchannels is another important parameter in designing a micromixer and they are usually connected to a series of planar channel engaging in sudden changes in the flow direction. The two main categories for micromixers are active and passive which for active micromixers an external energy force is applied to perturb the samples and for the passive, the contact area and contact time of the samples are increasing through the configuration of the design. In this dissertation, numerical modeling was used to evaluate and investigate the micromixing process for mixing efficiency through microfluidic devices and a comparison between different geometries which are simple Y and PDM structures, and different sizes of each geometry have been done. A set of controlling parameters have been chosen to identify the optimum geometry and size which were a range of flow rate ratio (FRR) and total flow rate ratio (TFR), and three different aspect ratios for two different designs to see which one has the best efficiency for fluid mixing. As a part of evaluation of the design, a set of measurements for produced liposomes has been conducted to see what the effect of the aspect ratio is, TFR and FRR on the size range of produced liposomes since medical applications have a huge interest in microfluidic devices due to the ability in producing controlled-size liposomes and size distribution.

Date	20 Dec 2020
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Vahé Nerguizian (Supervisor)