why is mixing difficult in microfluidc devices describe 2 a

why is mixing difficult in microfluidc devices ? describe 2 approaches to achive good mixing

Solution

Mixing is difficult in microfluidic devices because of low reynold\'s number that poses diffuculty while mixing.Due to low Reynold\'s number, viscous forces are more and they dominate over the inertial forces that arise within the flow.This intensity of the flow irregularities that helps in fluid mixing becomes less and mixing becomes difficult This also results in failure of turbulent mixing required for macro-scale systems.

Two approaches that can be used to achieve good mixing are:

Passive mixing : Passive mixing is used by changing the structure of fluid channels.The advantage of passive mixing is that moving parts within the mixer are not used that results proper mixing. The disadvantage is that this is type of mixing cannot be controlled by users externally.

Active mixing : Active mixing applies external energy for mixing in microfluidics.The advantage of active mixing is that it includes microstirrers, acoustic mixers, and flow pulsation that are attached to microfluidic devices to aid in mixing and that too in a controlled manner.The disadvantage is that it is very costly.