MRI: A Tool For Measuring Turbulent Intensities
In Flow Systems
Author(s)
O. Adegbite, L. Kadem & B. Newling
Abstract
Understanding the fluid-structure interaction and fluid dynamics downstream of
an obstruction is crucial in the design and fabrication of devices that find
application in both medicine and industry. It is known that the fluid flow patterns
downstream of an obstruction may be very complex and are three dimensional,
including the formation of vortices, recirculating flow, flow separation and the
onset of turbulence. The development of any such pattern of flow might be
detrimental to the optimal performance of the flow system. In this work we have
used the magnetic resonance imaging (MRI) technique to investigate flow
dynamics downstream of an artificial heart valve. MRI is a naturally threedimensional,
non-invasive technique that finds application in clinical, biomedical
research and materials research. It has the capability to visualize the internal
structure of materials and also to quantify mass transport properties. In this
in vitro study, we have measured the turbulent diffusivity and velocity
downstream of the valve in two configurations (fully opened and partially
opened). Our particular implementation of the MRI measurement (known as
SPRITE imaging) is unusually robust to fast turbulent flows and has been
demonstrated effective at Reynolds numbers on the order 105, much higher than
possible with most conventional, clinical MRI techniques. The results showed a
low turbulent diffusivity downstream of the fully opened valve configuration,
while the turbulent diffusivity is higher downstream of the partially opened valve
coupled with a high-velocity fluid jet and recirculating flow. There are distinct
Keywords
mechanical heart valve, aorta, spiral-SPRITE, turbulent flow, turbulence, velocity, gradient, MRI
Related Book
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