Flow rate variations in microfluidic circuits with free surfaces
Résumé
We investigate analytically and experimentally the flow rate through
a biochip in a circuit involving a peristaltic pump and reservoirs with
liquid/air interfaces. Peristaltic pumps are a convenient way to achieve
recirculation in microfluidic circuits. We consider different cases: reservoirs in contact with ambient air, tight reservoirs, and imperfect tightness
leading to air or liquid leaks. We demonstrate that if changes in
hydraulic resistance are slow enough, i.e. if cells do not proliferate too
fast, the system may reach an equilibrium, with a difference in liquid height between inlet and outlet reservoir compensating the pressure
drop in the biochip. We compute the flow rate through the biochip
in the transient regime as well as the characteristic time. We also
show that depending on the circuit dimensions, this equilibrium may
never be reached. We provide guidelines to design tubings and reservoirs to avoid this situation and ensure a smooth recirculation at a
desired flow rate, which is a necessary condition for dynamic cell culture.
Domaines
Sciences de l'ingénieur [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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