Prediction of Shear and Discharge Rate of Proteins in Microfluidic Junctions

Changes of hydrodynamic parameters in microchannel branches affect the suspended biological samples in blood. To prevent denaturation and hemolysis, we have numerically investigated the effect of divergence angle on shear rate and velocity at branch entrance (discharge rate), under electroosmotic flow. In such flow, hydrodynamic properties are also affected by zeta potential at the microchannel walls. We have also studied the effect of change of zeta potential (ξ) proportion at main channel wall (ξ1) to that of branch channel (ξ2), on the discharge rate to find its maximum for different divergence angles. In the divergence angle of 60° and while zeta potential at the branch wall is equal to its value at main channel wall, the tendency of particles to pass through the branch is the highest among all examined degrees. At the zeta potential proportion of ( ξ1/ξ2 =0.5), the change of divergence angle has almost no effect on the maximum velocity in the branch. In addition, with increase of divergence angle from 60° to 150°, the shear rate at the branch will become 2.1 times higher.