Sw. Day et al., Particle image velocimetry measurements of blood velocity in a continuous flow ventricular assist device, ASAIO J, 47(4), 2001, pp. 406-411
The third prototype of a continuous flow ventricular assist device (CFVAD3)
is being developed and tested for implantation in humans. The blood in the
pump flows through a fully shrouded four-bladed impeller (supported by mag
netic bearings) and through small clearance regions on either side of the i
mpeller. Measurements of velocities using particle image velocimetry of a f
luid with the same viscosity as blood have been made in one of these cleara
nce regions. Particle image velocimetry is a technique that measures the in
stantaneous velocity field within an illuminated plane of the fluid field b
y scattering light from particles added to the fluid. These measurements ha
ve been used to improve understanding of the fluid dynamics within these cr
itical regions, which are possible locations of both high shear and stagnat
ion, both of which are to be avoided in a blood pump. Computational models
of the pump exist and these models are currently being used to aid in the d
esign of future prototypes. Among other things, these models are used to pr
edict the potential for hemolysis and thrombosis. Measurements of steady fl
ow at two operating speeds and flow rates are presented. The measurements a
re compared with the computed solutions to validate and refine, where neces
sary, the existing computational models.