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Bioparticle - Fluid Separation in Micro-Channels

Blood, an analyte frequently used for various diagnoses is non-Newtonian fluid transporting oxygen, carbon dioxide, nutrients, salts, hormones, metabolites and various other components to all parts of human body. The process of separation of the cellular components of blood from the plasma is called Plasmapherisis.This is routinely carried out for preparative, analytical and therapeutic purposes. Many experimental techniques were developed for the separation of particles from fluids and one such technique is by using pulsatile pressure in micro-channels. It is observed that the Red Blood Cells (RBC) accumulate at the front of the blood column due to the effect of non-Newtonian viscosity, while the opposite is observed in water.

The objective of the present work is to find the reasoning behind the separation and cause for the difference in behavior for water and blood. The effect of blood viscosity and particle density and volume fraction is also being studied. The governing equations for multiphase flow are used to delineate the effect of non-Newtonian shear-thinning viscosity of blood from Newtonian viscosity of water.

Figure 1 shows the geometry of the micro-channel with the medium and the particles. Figure 2 shows the variation of percentage of liquid free from particles with number of pressure pulses applied and the validation with the experimental data.


Figure 1 :Geometry and the components in the micro-channel


Figure 2 : Volume of liquid free from particles for different number of pulses

Figure 3 shows the concentration of the RBC along the width of the micro-channel, it can be observed that the RBC stay in the centre and move to the front of the plasma.


Figure 3 : The concentration of particles along the width of the channel.

The present work involves the numerical simulation of the particle separation in a plug flow with non-Newtonian fluids in a micro-channel. This research is being conducted in collaboration with the Department of ECECS (BioMEMS Lab) and the Department of Biomedical Engineering of University of Cincinnati.

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by zopeown last modified 2007-12-05 11:41