Serpentine Flow Channel for Laminarizing Fluid in Miniaturized Sensors
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Solution Overview
Problem
Miniaturized flow sensors face challenges in maintaining laminarized fluid flow and achieving a strong signal-to-noise ratio due to issues like turbulent flow and eddies, which result in low and non-monotonic sensor outputs at high flow rates.
Innovation Solution
The flow sensor assembly employs a housing with serpentine channels, inclined ramps, and a sensor chamber that promotes laminarized flow by guiding fluid around corners and confining it close to the sensor die, increasing the signal strength and reducing turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the flow sensor is miniaturized, then the sensor size is reduced, but the flow becomes turbulent and eddies form resulting in low signal-to-noise ratio
Solution Approach 1:
The patent employs serpentine flow channels with optimized curvature radii and rounded corners throughout the flow path. The inlet and outlet channels feature curved transitions rather than sharp angles, which reduces flow separation and eddy formation. This curvature-based design allows the miniaturized sensor to maintain laminar flow conditions despite the reduced overall size, thereby preserving signal-to-noise ratio.
Solution Approach 2:
The flow channel is segmented into distinct functional zones: an inlet region with gradual expansion, a sensor chamber with controlled flow paths, and an outlet region. This segmentation allows each zone to be optimized independently for laminar flow conditions. The sensor chamber specifically incorporates multiple serpentine passages that segment the flow into controlled streams, preventing turbulence and eddies while maintaining compact dimensions.
2Length of moving object
If the flow channel is shortened for miniaturization, then the sensor size is reduced, but turbulent flow and eddies occur resulting in non-monotonic sensor output
Solution Approach 1:
The flow channel incorporates multiple serpentine sections with carefully controlled curvature radii. These curved paths replace straight-line distances, allowing the flow to navigate turns smoothly without creating eddies or turbulent zones. The curvature is optimized to maintain laminar flow even though the overall channel length is shortened for miniaturization, ensuring stable and monotonic sensor output across the measurement range.
Solution Approach 2:
The patent optimizes key geometric parameters of the flow channel including curvature radius, channel width, and aspect ratio. By adjusting these parameters, the design achieves laminar flow conditions in a compact configuration. The serpentine channels use specific radius-to-width ratios that prevent flow separation and maintain stable flow patterns despite the reduced channel length required for miniaturization.
3Volume of stationary object
If the sensor chamber is made compact, then the sensor size is reduced, but flow turbulence increases resulting in low sensor output
Solution Approach 1:
The sensor chamber incorporates serpentine flow paths with optimized curvature radii that allow compact volume while preventing flow turbulence. The curved channels guide fluid smoothly through the sensor chamber without creating eddies or separation zones, maintaining laminar flow conditions that are essential for accurate measurement in the miniaturized sensor chamber.
Solution Approach 2:
The serpentine flow channels utilize three-dimensional routing within the sensor chamber, allowing the flow path length to be extended in multiple dimensions rather than requiring a large linear space. This dimensional approach enables the compact sensor chamber volume to accommodate sufficiently long flow paths for laminar flow development, thereby maintaining measurement precision despite reduced volume.
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
This design achieves laminarized fluid flow and enhances signal strength, leading to a higher signal-to-noise ratio and monotonic sensor output across varying flow rates.
Implementation Method 1
Flow channel for laminarizing flow in flow sensor
Implementation Method 2
an inlet ramp that transitions between a bottom of an inlet of the sensor chamber to a spit portion of the planar region
Data Source
AI summary
Embodiments relate generally to a system comprising a flow sensor assembly. The flow sensor assembly includes a housing defining a flow channel. The flow channel has an inlet serpentine portion fluidly coupled to an inlet port, and an outlet serpentine portion fluidly coupled to an outlet port. The housing further defines a sensor chamber fluidly coupling the inlet serpentine portion to the outlet serpentine portion, where the sensor chamber has a split planar region. The flow sensor assembly further includes a sensor die located proximate to the split planar region and configured to sense a measure related to a flow rate of a fluid.