Computational design approach to hydrodynamic focusing in a flow cytometer

A two-fluid theoretical model was developed to simulate the hydrodynamic focusing process formed by the coflowing sample and sheath fluids in a flow cytometer. The analysis consists of two groups of time-dependent three-dimensional conservation equations of mass and momentum. To validate the computer code, the predicted focused width in the two-dimensional test configuration was compared with Lee et al.'s measured data. The present study also examines the pressure distribution of the three-dimensional hydrodynamic focusing flowfield. For the u(Sh)/u(S) ratio ranging from 10 to 80, the focused width was determined to explore the applicability of the proposed flow cytometer.