Vortex Generators for Blood Flow Shear Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medical devices such as prosthetic heart valves, stents, and blood pumps induce adverse effects like blood damage and thrombus formation due to non-physiological shear stresses, leading to thromboembolic events and platelet activation.
Innovation Solution
Incorporation of passive surface modifications with vortex generators that alter fluid flow to reduce shear stress, including conformable and flexible elements that adapt to flow cycles, and surface irregularities to minimize boundary layer formation and enhance cross-stream mixing, thereby reducing platelet activation and thrombogenic responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth surfaces are used in blood-contacting devices, then manufacturing is easier, but shear stress-induced platelet activation and thrombus formation increase
Solution Approach 1:
The patent applies vortex generators only in specific locations where flow separation and recirculation occur, rather than modifying the entire surface. This localized approach reduces platelet activation at critical zones while maintaining manufacturing simplicity for the overall device structure.
Solution Approach 2:
The vortex generators utilize curved or angled surfaces to generate beneficial vortices that enhance mixing and reduce stagnant flow regions. The curved geometry promotes physiological flow patterns that decrease shear stress on platelets compared to flat surfaces.
2Object-affected harmful factors
If vortex generators are added to reduce shear stress, then platelet activation decreases, but device complexity increases
Solution Approach 1:
The vortex generator surface is divided into multiple discrete elements or zones rather than a continuous complex structure. This segmentation allows for easier manufacturing and assembly while achieving the flow manipulation effect to reduce thrombus formation.
Solution Approach 2:
The vortex generators are designed to passively utilize the existing blood flow to generate beneficial vortices without requiring external power or control systems. The flow itself activates the vortex generators, simplifying the overall device complexity.
3Object-affected harmful factors
If boundary layer formation is enhanced to protect surfaces, then shear stress is reduced, but cross-stream mixing decreases leading to flow stagnation
Solution Approach 1:
The vortex generators create periodic or oscillating flow patterns that alternately enhance boundary layer protection and promote cross-stream mixing. This periodic action prevents flow stagnation while maintaining reduced shear stress through controlled vortex formation.
Solution Approach 2:
The vortex generators induce mechanical disturbances in the flow that enhance mixing without creating excessive shear stress. The controlled vibrations or oscillations promote cross-stream transport while the vortex structure protects against harmful shear forces on blood elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of vortex generators and surface irregularities significantly reduces shear stress, leading to lower thrombin-anti-thrombin concentrations, diminished platelet activation, and reduced blood damage, enhancing the safety and efficacy of blood-contacting medical devices.
Implementation Method 1
Incorporation of passive surface modifications with vortex generators that alter fluid flow to reduce shear stress
Implementation Method 2
surface modifications with vortex generators that alter fluid flow to reduce shear stress, including conformable and flexible elements that adapt to flow cycles, and surface irregularities to minimize boundary layer formation
Implementation Method 3
adverse events (such as blood element or cell damage, thrombus formation, and platelet activation) can be caused by flow-induced shear stresses
Data Source
AI summary
A device for use in combination with a fluid flow having a biologic component and subject to an adverse response to shear stress includes a surface in contact with the flow of the fluid. The surface has a longitudinal direction extending from a leading end toward a trailing end and aligned with a direction of the flow. The surface is susceptible to inducing boundary layer formation within the flow sufficient for a resulting shear stress to induce the response. The surface includes a surface feature sufficient to induce boundary layer tripping in the flow to retard growth of boundary layer formation along the length.