Influence of channel geometry on the mixing performance in microchannels using non-isothermal liquid streams

Abstract

Microfluidic systems play a pivotal role in various fields, including biotechnology and chemistry, due to their ability to efficiently mix small volumes of fluids. Achieving rapid and precise mixing is essential for applications such as chemical reactions and diagnostics. These microfluidic systems need to efficiently mix different substances at the microliter or nanoliter scale. The importance of microfluidic mixing lies in its applications across various fields, including chemical analysis, drug development, biology, and diagnostics. In this study, an attempt has been made to study the mixing performance of rectangular, trapezoidal, semi-circular, and triangular or V-shaped channels at a fluid velocity of 0.01 m/s and to identify which cross-section among them exhibits the best mixing, followed by the fabrication of microchannels using a laser on polymethyl methacrylate (PMMA). The models were analyzed using ANSYS, and studied turbulence kinetic energy, velocity streamlines, and mixing time. The mixing efficiency of semi-circular, rectangular, trapezoidal, and triangular channels was 81.43%, 70.26%, 90.52%, and 93.5%, respectively. Triangular microchannels have exhibited better mixing performance than the other designs. The triangular cross-section microchannels were fabricated using a CO₂ laser on PMMA, and their surface morphological studies, such as scanning electron microscopy (SEM), contact angle, and mechanical probe scanning for channel profile, were carried out.