Effect of microchannel sizes on 3D hydrodynamic focusing of a microflow cytometer

Hydrodynamic focusing is an important method used in microfluidics cell sorting devices. A design of flow cytometer has been developed and simulated using COMSOL Multyphysics software. The device is capable of creating a self-aligned stream by manipulating the flow rate, Q in both sheath channel. The objective of this research is to study the effect of channel size variation on the fluid flow in the micro flow cytometer device. The flow rate ratio Qs/Qi is applied in order find the best flow rate ratio value between sheath channel and sample channel. Simulated results showed that when Qs is smaller than Qi, the stream size is bigger and the length of the stream is longer. However, Qs is equal to Qi, the stream becomes smaller and the length of the stream is shorter. Similary, when Qs is bigger than Qi, the stream becomes smaller and shorter. The results showed that fluid flow is better when the size of the channel is bigger.