Session: 11-17-01: Micro/Nanofluidics 2025 - Fluid Engineering in Micro- and Nanosystems

Paper Number: 166063

Theoretical Study of an MHD Viscous Micropump With a Phan-Thien-Tanner Fluid Driving a Newtonian Fluid 

Hydrodynamic analysis of micropumps in microfluidic systems (bioMEMS - biological microelectromechanical systems, microTAS - micro total analysis systems, LOCs - labs on chips) requires precise pumping techniques to control the transport of complex fluid samples. Magnetohydrodynamics (MHD) is a technology that deploys magnetic and electric fields to manipulate the behavior of electrically conducting fluids. This pumping method presents significant advantages in miniaturized systems by reducing the risk of clogging and damage to molecular materials, which is essential for fluid analysis and diagnostics in medical, chemical, and biological applications. In addition, MHD micropumps have a simple and compact design with no moving parts, are silent, and can withstand high temperatures. Some fluids with low electrical conductivity cannot react to magnetic and electric fields, and therefore, they cannot be transported directly by MHD effects. In these cases, viscous micropumps allow the transport of non-conducting fluids through the viscous drag forces of a neighboring conducting fluid that responds to magnetic and electric fields. In this sense, the study of viscous micropumps contributes to understanding the pumping techniques of electrically non-conducting fluids by MHD effects of a conducting fluid, which is relevant for the design and hydrodynamic analysis of MHD pumps. Therefore, this work analyzes the hydrodynamic behavior of a viscous micropump that transports two immiscible fluids in a parallel flat plate microchannel under combined magnetohydrodynamic and pressure effects. The displacement of an electrically conducting fluid described by the Phan-Thien-Tanner model and an electrically non-conducting Newtonian fluid represent the flow field. The Lorentz forces, produced by the interaction between magnetic and electric fields, are the primary pumping source to drive the conducting fluid. Then, the conducting fluid drives the non-conducting fluid by viscous drag effects. Nevertheless, both fluid layers are affected by a constant pressure gradient. Here, the pressure drop comes from a syringe pump incorporated into the MHD micropump to enhance the flow, although the principal focus of the work is the MHD effect on the conducting fluid to drive the non-conducting fluid. The mathematical model to describe the movement of fluids is based on the continuity and momentum equations, the rheological models, the no-slip boundary conditions at the walls, and the velocity continuity and stress balance conditions at the liquid-liquid interface. The dimensionless parameters that control the magnitude and shape of the velocity profiles are the pressure gradient, the viscoelastic parameter, the viscosity ratios, and the Hartmann number. This research explores the non-Newtonian rheology of the conducting fluid in favor of pumping a non-conducting Newtonian fluid.

Presenting Author: Juan R. Gómez Instituto Politécnico Nacional, SEPI-ESIME Unidad Azcapotzalco, Departamento de Termofluidos

Presenting Author Biography: Mechanical Engineer and MSc in Thermofluids by the Instituto Politécnico Nacional in Mexico. Currently studying a PhD in Thermofluids at the Escuela Superior de Ingeniería Mecánica y Eléctrica of the Instituto Politécnico Nacional in Mexico. Areas of interest in electrokinetic and magnetohydrodynamic flows, transport phenomena in heat transfer and fluid flow, micropumps, fluid rheology, and magnetorheological dampers. Several publications in journals indexed in the Master Journal List of Web of Science. Participation in ASME conferences since 2017.

Authors:

Juan R. Gómez Instituto Politécnico Nacional, SEPI-ESIME Unidad Azcapotzalco, Departamento de Termofluidos
Juan P. Escandón Instituto Politécnico Nacional, SEPI-ESIME Unidad Azcapotzalco, Departamento de Termofluidos
Edson M. Jimenez Instituto Politécnico Nacional, SEPI-ESIME Unidad Azcapotzalco, Departamento de Termofluidos
Clara G. Hernández Instituto Politécnico Nacional, SEPI-ESIME Unidad Azcapotzalco, Departamento de Termofluidos