Simulation of flow through
a mechanical heart valveThe heart is the vital
part of the human body which functions as a pump to
circulate blood throughout the body. Heart valves are
very important, since they prevent backflow of blood to
ensure that the heart pumps blood in a specific
direction efficiently. There are numerous complications
and diseases associated with natural (human) heart
valves that prevent them from working efficiently, such
as regurgitation, stenosis and sclerosis. The defective
valves have to be replaced by prosthetic valves in some
cases, although medication is considered to be the best
alternative. Approximately 170,000 individuals worldwide
receive prosthetic heart valves every year, and over
half receive mechanical heart valves (MHV). One of the
advantages of MHVs is their durability compared to
bio-prosthetic valves. They typically last for the
lifetime of the patient.
Bi-leaflet heart valves are currently the most
commonly implanted type of MHV. The current designs are
far from being optimal and, due to non-physiological
flow characteristics, significant complications often
arise after implantation. The new tools that are being
used to improve MHV design include accelerated wear
testing, advanced blood contact property testing,
computer-aided design and manufacturing, and coatings to
reduce the chance of infection. MHVs are geometrically
very complex and the motion of their bileaflet is not
predictable. Due to the complexity of the flow through
such a device, sophisticated fluid dynamic testing
requires close synergy between advanced experimental and
computational techniques.
The MHV shown in the schematic below was calculated
with AEROFLO in an LES framework using 18 overset
blocks. The reference Reynolds number for the numerical
simulations is 7300. The 3D computational model and
sample simulation results are shown below.
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