(6lv) Electrokinetically enhanced particle focusing in Non-linear microfluidic flows

Particle focusing in non-linear flows: Cross-stream migration of particles suspended in fluid flows occurs due to inherent non-linearity: inertia or polymeric stresses. This physics, in the past, has been utilized in microfluidics to focus cells in biological fluids. Recent experimental studies, towards the manipulation of focusing via external fields, have drawn my attention to ask: how electrokinetics affects the particle migration in non-linear flows? Use of classical mathematical techniques (such as perturbation theory and asymptotics in conjunction with Lorentz reciprocal theorem) has helped me gain fundamental insights into the migration of charged particles and reveal the primary source behind the breaking of symmetry in weakly inertial [P5, P3] and viscoelastic flows [P4]. I am currently examining this behavior in high Reynolds number flows.

Other research interests and experience

Swimmers in complex fluids: Synthetic swimmers such as Janus particles and rods can propel themselves by generating concentration gradients along their surface. This results in a 'diffusio-osmotic' slip which consequently propels the particle autonomously. A significant portion of the potential applications lies in drug-delivery and biological fluid systems which exhibit non-Newtonian behavior. This led me to study the changes in the slip and swimming of Janus particles in complex fluids. [P6]

Process intensification in microreactors: Microchannels are known to offer small length scale for rapid heat and mass transport. Despite of this, several reaction processes are limited by slow diffusion, which causes formation of undesired products and safety hazards. I am interested in intensification methods and modeling of such systems through CFD simulations. For instance, a gently curved channel produces vortices which generates cross-section mixing and enhancement in heat and mass transport. [P2]

Teaching Interests:

Graduate Courses: Mathematical Methods in Chemical Engineering, Multiphase flows, Dynamical Systems.

During the course of my PhD at IIT Madras, I was a teaching assistant of the aforementioned courses and had numerous opportunities to give lectures. Although I enjoyed teaching a subject related to my research interests, I also learned to give lectures outside my research. Apart from theoretical lectures, I also conducted seminars (as a part of the course work) which introduced first year graduate students to computational techniques using Matlab and Mathematica.

Publications:

[P6] A. Choudhary, T. Renganathan and S. Pushpavanam, "Non-Newtonian effects on the slip and mobility of a self-propelling active particle”, (Under review process in Journal of Fluid Mechanics)

[P5] T. Krishnaveni, A. Choudhary, T.Renganathan and S. Pushpavanam, “Inertial migration of a particle in flows with transverse viscosity variation” (Under review process in Physics of Fluids)

[P4] A. Choudhary, Di Li, T. Renganathan, Xiangchun Xuan, S. Pushpavanam, “Electrokinetics Enhances Cross-stream Particle Migration in Viscoelastic Flows” (Under review process in Journal of Fluid Mechanics)

[P3] A. Choudhary, T. Renganathan, S. Pushpavanam, “Inertial migration of an electrophoretic rigid sphere in a 2D Poiseuille flow”, Journal of Fluid Mechanics vol. 874(2019) 856-890

[P2] A. Choudhary and S. Pushpavanam, “Process intensification by exploiting Dean vortices in catalytic membrane microreactors” Chemical Engineering Science Volume 174, 31 December 2017, 413-425

[P1] C. Sun, Z. Luo, A. Choudhary, P. Pfeifer and R. Dittmeyer, “Influence of the Condensable Hydrocarbons on an Integrated Fischer−Tropsch Synthesis and Hydrocracking Process: Simulation and Experimental Validation” Ind. Eng. Chem. Res.2017564513075-13085