Compact Hydraulic Manifold Shear Rate Control
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Solution Overview
Problem
Existing technologies fail to maintain blood health by controlling wall shear rates within a limited range in organ assist devices, which can lead to clotting or hemolysis, and require a compact channel network architecture for safely transporting blood and other shear-sensitive fluids.
Innovation Solution
A compact hybrid hydraulic manifold structure with a microfluidic device featuring a network of channels within substrates, including primary, secondary, and tertiary channels, designed to maintain shear rates between 200 and 2000 s^-1, using flow dividers and curvature to manage fluid flow and pressure, and materials like thermoplastics and nanotubes for stability and biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact channel network architecture is used, then device size is reduced, but maintaining shear rate control becomes more difficult
Solution Approach 1:
The channel network is divided into primary, secondary, and tertiary channels with distinct functions. Primary channels handle main flow with controlled shear rates, secondary channels provide branching with flow dividers, and tertiary channels deliver fluid to processing zones. This segmentation allows each section to be optimized for shear rate control while maintaining overall compactness.
Solution Approach 2:
Flow dividers are designed with curved surfaces having radii of curvature between 0.5-5mm to guide fluid smoothly from primary to secondary channels. This curvature eliminates sharp corners that would create high shear rates, maintaining blood health while enabling compact channel routing.
2Volume of moving object
If channels are made compact, then device volume is reduced, but flow distribution uniformity deteriorates
Solution Approach 1:
Different channel sections have locally optimized geometries. Primary channels have larger cross-sections (2-10mm²) for main flow, secondary channels have intermediate sizes (0.5-5mm²), and tertiary channels have smaller cross-sections (0.1-1mm²). Flow dividers at branching points create localized low-pressure zones to ensure uniform flow distribution to multiple secondary channels.
Solution Approach 2:
Channel dimensions are systematically varied along the flow path. The hydraulic diameter decreases from primary to tertiary channels to maintain appropriate shear rates (200-2000 s⁻¹) in each section. This parameter gradient allows compact design while preserving flow distribution uniformity through careful dimensioning.
3Ease of manufacture
If channel network is simplified for compactness, then manufacturing complexity is reduced, but shear rate management capability is lost
Solution Approach 1:
Multiple channel functions are merged into integrated components. Flow dividers serve both as structural elements dividing primary channels into secondary channels and as flow control elements with curved surfaces that manage shear rates. The substrate integrates support structure and channel definition, reducing part count while maintaining shear rate management capabilities.
Solution Approach 2:
The design utilizes hydraulic principles to achieve flow control without mechanical actuators. Low-pressure zones are created at flow divider locations to naturally distribute flow uniformly to secondary channels. The curved surfaces of flow dividers leverage fluid dynamics to maintain appropriate shear rates, eliminating the need for complex mechanical flow control mechanisms.
Data Source
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AI summary
An compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device.