Physics of Microfluidics
Pressure vs Flow Rate
- A few inches of H2O gives 100’s of mm/sec in typical channels (l=1 cm, r=50 mm).
Reynolds Number
- Typically Re<< 1, no turbulence.
Time
- Flow is reversible, no inertia.
Diffusion Coefficients, typical values
- Small Molecule D = 500 mm2/sec. 25 mm in 1 sec
- Protein D = 70 mm2/sec. 8 mm in 1 sec
- 0.5 mm sphere D = 0.5 mm2/sec. 0.7 mm in 1 sec