  A blood turbine-pump system (iATVA), resembling a turbocharger was proposed
as a mechanical right-heart assist device without external drive power. In this
study, the iATVA system is investigated with particular emphasis on the blood
turbine flow dynamics. A time-resolved 2D particle image velocimetry (PIV)
set-up equipped with a beam splitter and two high speed cameras, allowed
simultaneous recordings from both the turbine and pump impellers at 7 different
phased-locked instances. The iATVA prototype is 3D printed using an optically
clear resin following our earlier PIV protocols. Results showed that
magnetically coupled impellers operated synchronously. As the turbine flow rate
increased from 1.6 to 2.4 LPM, the rotational speed and relative inlet flow
angle increase from 630 to 900 rpm, and 38 to 55% respectively. At the trailing
edges, backflow region spanned 3/5 of the total passage outlet flow, and an
extra leakage flow was observed at the leading edge. For this initial turbine
design, approximately, 75% of the turbine blade passage was not contributing to
the impulse operation mode. The maximum non-wall shear rate was ~2288 s-1 near
to the inlet exit, which is significantly lower than the commercial blood
pumps, encouraging further research and blood experiments of this novel
concept. Experimental results will improve the hydrodynamic design of the
turbine impeller and volute regions and will be useful in computational fluid
dynamics validation studies of similar passive devices.
