Electrokinetic effects of charged nanoparticles in microfluidic Couette flow

The behavior of Couette flow of nanofluids composed of negatively-charged nanoparticles dispersed in aqueous NaCl solutions is studied theoretically. The equation for calculating the Couette flow velocity profiles is derived. The induced electric fields and velocity profiles are calculated as a function of key parameters including nanoparticle size and volume fraction. We have found for the first time that the velocity profile of nanofluids containing charged nanoparticles deviates significantly from the classical linear velocity profile for Couette flow. This previously unseen flow phenomenon is attributed to the dominance of the electric field strength induced by the flow of charged nanoparticles. This new mechanism of nanoparticle-induced microfluidic transport could lead to novel microfluidic and tribological applications.

Velocity profile of aqueous solutions with charged nanoparticles deviates significantly from the classical linear velocity profile for plane Couette flow due to the electrokinetic flow enhancement effects of charged nanoparticles.Figure optionsDownload high-quality image (74 K)Download as PowerPoint slideHighlights
► Plane Couette flow of nanofluids containing charged nanoparticles is modeled.
► Effects of charged nanoparticles on flow velocity are studied for the first time.
► The velocity profile of nanofluids deviates from the classical linear profile.
► This is due to electrokinetic flow enhancement effects of charged nanoparticles.