Separation Membrane Element With Vortex-Forming Flow Channel
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Solution Overview
Problem
Existing separation membrane elements suffer from pressure loss and concentration polarization due to low-speed regions on the membrane surface, which hinder efficient fluid separation.
Innovation Solution
A separation membrane element design featuring a supply-side flow channel material with intersecting fibrous rows and specific geometric relationships to create a vortex on the membrane surface, reducing pressure loss and preventing concentration polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional supply-side flow channel material is used, then the structure is simple, but concentration polarization occurs and pressure loss increases due to low-speed regions on the membrane surface
Solution Approach 1:
The supply-side flow channel material is designed with locally varied fiber bundle diameters: larger diameters in low-speed regions to increase flow velocity and reduce concentration polarization, and smaller diameters in high-speed regions to minimize pressure loss. This local differentiation of structural properties optimizes both productivity and energy efficiency.
Solution Approach 2:
The flow channel material structure is designed to dynamically adapt to flow conditions by varying fiber bundle diameters according to local flow velocity. The larger diameters in low-speed regions create turbulence to enhance mixing, while smaller diameters in high-speed regions reduce resistance, making the system dynamically responsive to flow patterns.
2Productivity
If conventional supply-side flow channel material is used, then manufacturing is simple, but concentration polarization phenomenon is insufficiently prevented
Solution Approach 1:
The flow channel material incorporates local quality variations through differentiated fiber bundle diameters in different regions. This local structural differentiation targets specific flow problems in specific areas, effectively preventing concentration polarization while maintaining overall structural manageability.
Solution Approach 2:
The flow channel structure employs asymmetric fiber bundle arrangements with different diameters oriented in different directions (first and second directions perpendicular to each other). This asymmetric design creates targeted turbulence patterns that effectively prevent concentration polarization without requiring complex overall restructuring.
3Reliability
If fiber bundle diameters are increased to prevent concentration polarization, then salt rejection improves, but pressure loss increases
Solution Approach 1:
The solution applies local quality differentiation by using larger fiber bundle diameters only in low-speed regions where concentration polarization occurs, while maintaining smaller diameters in high-speed regions. This localized approach ensures reliable salt rejection where needed without incurring unnecessary pressure loss elsewhere.
Solution Approach 2:
Instead of uniformly increasing fiber bundle diameters throughout the entire flow channel, the invention applies the diameter increase only partially in specific low-speed regions. This partial action is sufficient to prevent concentration polarization and ensure reliable salt rejection while avoiding the excessive pressure loss that would result from a uniform increase.
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 design enhances water production and salt rejection rates by effectively preventing concentration polarization and pressure loss, promoting efficient fluid separation.
Implementation Method 1
forming a vortex of supply water on a surface of a separation membrane
Data Source
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AI summary
This separation membrane element has a thread diameter of a supply side flow channel material other than intersections of a net shape, the thread diameter being smaller than a thread diameter of the intersections, has θ×(1-Lp/Lq)2>15, wherein, in a plane parallel to the flow direction of supply water and vertical to the planar direction of the supply side flow channel material, P is a point on the outer circumference of a cutting plane other than the intersections where the distance between the cutting plane and a separation membrane is minimum, Q is a point on the outer circumference of the cutting plane where the distance on the same side as the separation membrane on the downstream side of supply water from P is maximum, Lp is the distance between P and the separation membrane, Lq is the distance between Q and the separation membrane and θ is an elevation angle from P to Q, and has the proportion of the area of the cutting plane relative to the area of a diagram formed with a line forming a convex hull enclosing, among the outer circumference connecting P with Q on the cutting plane, the outer circumference closer to the separation membrane surface and the outer circumference further from the separation membrane surface of 70% or more and Lp of 15% or less of the thickness of the supply side flow channel.