Two-Lobe Swirl Duct Design Template for Blood Flow

SCEBE-20-018-DMSF

Background

The first design of swirl-inducing duct was patented in 1899 to improve the dredging of river sediments. The novel two-lobe design is a recent development to affect the swirl number.
Blood vessels curve naturally in three dimensions, causing laminar swirl. This keeps cells in suspension, mixes them and elevates wall shear on endothelial cells forming the innermost layer of the vessel wall. The action promotes oxygen diffusion into the wall, protects against the build up of atherosclerotic plaques and ‘restenosis’ (the re-narrowing of a previously narrowed vessel following, for example, the insertion of a stent). The traditional design of stent is a largely straight duct inserted, in a plane and at an angle to the vessel. This does not embody the important swirling action and can lead to shear stress anomalies, for example regions of low shear stress which in turn lead to thickening of the wall of the vessel (“intimal hyperplasia”) and said restenosis.

Aim and scope of work

The project centres on creating an efficient design template for a novel two-lobe swirl-inducing duct for blood flow and surgical stenting. There are many degrees of freedom in the design: throat position, final lobe radius, rate of increase of spatial frequency, total twist, which need to be applied to the specifics of blood flow and stenting. The research work will involve repeated use of Computational Fluid Dynamics (CFD) models, experimentation with blood simulant and application of fabrication techniques.