Date on Master's Thesis/Doctoral Dissertation


Document Type

Master's Thesis

Degree Name

M. Eng.


Mechanical Engineering

Committee Chair

Lian, Yongsheng


Fluid dynamics--Mathematical models


This thesis looks at the optimization of fluid flow and mass transfer using computational fluid dynamics (CFD) in a micro fluidic coulter counter. CFD will be used to solve equations of fluid flow and mass transfer to see how molecules within the microchannel will react with different flow ratios. Choosing a sheath stream to sample stream flow ratio will optimize the channel by increasing the concentration level of the sample stream near the electrodes; resulting in a clearer and more precise signal. Optimization will provide cell separation between each passing cell to improve counting efficiency. Analysis of the microcytometer shows the numerical solution of the fluid flow is greatly affected by a changing the x directional grid lines while having grid lines stretched in the y direction towards the microcytometer walls. The numerical diffusion solution is greatly affected by increasing or decreasing the y directional grid lines. While a sheath stream to sample stream flow ratio between 6.643 and 5.056 proved to have the highest sample stream concentration level and a focused stream width the same width as the cell diameter. Also a three dimensional numerical solution shows viscous effects of the fluid on the wall. This is represented by an hour glass shape of the diffusion.