Abstract-
When a fluid filled pliant tube is connected to tubing of a different
impedance, a net flow in either direction can be induced by periodically
compressing the pliant section asymmetrically from the ends. An experimental
analysis of the characteristic behaviors of such a pump has been done
demonstrating interesting results not predicted by prior analytical and
computation results. Measurements show a complex non-linear behavior in
response to the compression frequency including distinct resonance peaks and
reversals in flow direction. Ultrasound imaging provided a unique view of the
tube wall and flow within allowing us to visualize the wave propagation and
reflection. Measurements include transient responses, resonant responses and
bulk flow behaviors for a variety of configurations. Net flow rates can
exceed the volumetric displacement done by active compression demonstrating
that as a first approximation, this pump can have a higher efficiency than
peristaltic pumping. Elasticity has been shown not to be a necessary factor
in stimulating net forward flow.
Results from this study have helped show that a zebrafish
(a model for human cardiac development) may utilize impedance pumping to to
drive circulation in early embryonic stages prior to valve formation as
opposed to peristaltic pumping as was once thought. Additional research
is being undergone to develop a micro-scaled version with applications in
medicine, heat transfer, lab-on-chip technology and micro-mixing.
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