جستجوی مقالات مرتبط با کلیدواژه « Rectangular microchannels » در نشریات گروه « مکانیک »

We investigate the phenomenon of electrokinetics in microchannels. Electroosmotic is one of the four electrokinetic effects. Electroosmotic flow (EOF) is caused by the application of an electric field to an aqueous solution. The characteristics of the EOF depend on the nature of the surface potential distribution. EOF in microfluidic systems is limited to low Reynolds. As a result, species mixing in EOF systems is primarily due to diffusion. The surface heterogeneous of the microchannel walls causes the production of micro vortexes in the liquid. In this study, A two-dimensional microchannel is used to study the electroosmotic/pressure driven in Newtonian fluids. The equations governing the fluid flow in a rectangular microchannel are obtained based on the Lagrangian approach and using the density-based weakly compressible smoothed particle hydrodynamics (WCSPH) method. We have analyzed the vortexes due to surface potential heterogeneity and investigated increasing the surface potential on the flow. The results show that increasing the surface potential causes the vortexes to grow and strengthens the velocity and mixing fields more.

Electroosmotic is one of the four electrokinetic phenomena that is formed by applying an electric field to an ionized electrolyte near the charged dielectric surface. Due to the applying of this electric field change the arrangement of ions within the electrolyte, and eventually a region called the Electric double layer is formed near the surface. The thickness of this layer is approximated by the Debye length. In this study, the Because the Reynolds number in in microfluidic devices is usually very low. Therefore, achieving to sufficient mixing in electroosmotic microchannel flow has been a challenge. For this purpose, a non uniform distribution of surface potential for flow mixing is considered. This type of charge distribution is very efficient for mixing purposes by creating circulations in the microchannel. Lagrangian description is used to solve the governing equations. The method used in this research is the constant density weakly compressible particle hydrodynamics method. In order to improve the mixing, the effect of changing the Debye length has been analyzed. The results show that increasing the Debye length causes smaller vortexes to be produced and mixing efficiency is reduced.