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@PHDTHESIS{GroHardt:795760,
author = {Groß-Hardt, Sascha},
othercontributors = {Steinseifer, Ulrich and Karagiannidis, Christian},
title = {Über die numerische {B}estimmung der {B}lutschädigung in
{R}otationsblutpumpen},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2020-08537},
pages = {1 Band (verschiedene Zählungen)},
year = {2020},
note = {Dissertation, Rheinisch-Westfälische Technische Hochschule
Aachen, 2020, Kumulative Dissertation},
abstract = {Despite decades of research related to blood damage and
numerical blood damage estimation, the accuracy of
prediction algorithms for complex flows could not be
improved significantly. Nonphysiologically high shear
stresses are associated with blood trauma and many of the
complications in mechanical circulatory support devices, but
direct blood damage predictions (e.g. hemolysis or
thrombosis) with Computational Fluid Dynamics (CFD) tend to
be inaccurate. An important, but often underestimated factor
for the accuracy of the entire simulation is mesh
generation, describing the subdivision of a continuous
geometric space into discrete geometric and topologic cells.
The first publication details the strong dependency of mesh
resolution on shear stress prediction within a generic
rotary centrifugal blood pump. To avoid under prediction and
to maintain a consistent quantification of the actual shear
stress, much finer mesh resolutions were required, compared
to the current state of the art. Accordingly, the
mesh-induced error in subsequent hemolysis prediction was
minimized. The second publication highlights crucial aspects
for improved numerical accuracy with respect to result
validation, choice of turbulence model and setup
verification. Simulation results of a benchmark centrifugal
blood pump from the FDA Critical Path Initiative were
compared with experimental data, demonstrating that the
simulation accuracy depends highly on the validation of both
pump pressure head and internal velocity field. Furthermore,
shear stress quantification demanded particularly high
near-wall mesh resolutions, which were not required for the
validation of pressure heads or velocity. Using the findings
from the previous two publications, the third publication
demonstrates the high risk of increased bleeding or clotting
complications of currently used rotary blood pumps when
operated at blood flow rates below 2 L/min, as in recent
clinical use for ECCO2R systems or neonatal and pediatric
ECMO applications. Using high resolution CFD analysis, it
was observed that the pump internal flow recirculation rate
increases 6-12-fold in these flow ranges, potentially
increasing adverse effects due to multiple exposures to high
shear stress. This dissertation discusses the importance of
systematic model verification and result validation as
decisive prerequisites for improved simulation accuracy. The
findings will support the development of more advanced and
more credible blood damage models in the future.
Furthermore, CFD could contribute to the understanding of
the deleterious consequences that present with the low-flow
operation of current rotary blood pump systems, stressing
the urgent need to design blood pumps dedicated for low flow
applications.},
cin = {811001-1},
ddc = {610},
cid = {$I:(DE-82)811001-1_20140620$},
typ = {PUB:(DE-HGF)11},
url = {https://publications.rwth-aachen.de/record/795760},
}
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