Background:
Cardiac functions and support modes of left ventricular assist device (LVAD) will influence the pump inner flow field and blood damage potential.
Methods:
Computational fluid dynamics (CFD) method and lumped-parameter-model (LPM) were applied to investigate the impacts of cardiac functions under full (9000 rpm) and partial (8000 rpm) support modes in an axial pump.
Results:
The constitution of hemolysis index (
) in different components of the pump was investigated.
was found to be more sensitive to positive incidence angles (
) compared with negative incidence angles in rotors. Negative incidence angles had little impact on
both in rotors and the outlet guide vanes. The improved cardiac function made only a minor difference in
(estimated average
in one cardiac cycle) by 9.88%, as the flow rate expanded mainly to higher flow range. Switching to partial support mode, however, would induce a periodic experience of severe flow separation and recirculation at low flow range. This irregular flow field increased
by 47.97%, remarkably increasing the blood damage potential.
Conclusion:
This study revealed the relationship between the blade incidence angle
and
, and recommended negative-incidence-angle blade designs as it yielded lower
. Moreover, to avoid flow range below 50% of the design point, careful evaluations should be made before switching support modes as weaning procedures in clinical applications.