Nested Tabs Heat Transfer Surface for Pressure Drop Control
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Solution Overview
Problem
Existing heat transfer surfaces in heat exchangers enhance heat transfer performance but often increase pressure drop, necessitating a solution that improves heat transfer without negatively impacting pressure drop.
Innovation Solution
A heat transfer surface with a corrugated member featuring parallel ridges and planar fin surfaces, where the planar fin surfaces have triangular tabs projecting out of the plane, forming counter-rotating vortices and allowing for increased fin density through tab nesting, which enhances heat transfer performance without significantly increasing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat transfer surfaces with louvered fins are used to increase heat transfer performance, then heat transfer performance is improved, but pressure drop through the fluid channel increases
Solution Approach 1:
The patent applies nesting by positioning tabs on adjacent fins such that tabs on one fin extend into openings formed by tabs on neighboring fins. This nested arrangement allows multiple fins to be closely spaced without excessive interference, increasing fin density and heat transfer surface area while controlling pressure drop by optimizing the inter-fin flow passages.
Solution Approach 2:
The patent transitions from traditional planar louvered fins to three-dimensional tabs that project out of the fin plane at specific angles. This dimensional change creates counter-rotating vortices that enhance heat transfer through improved fluid mixing, while the optimized tab geometry and spacing maintain acceptable pressure drop characteristics.
2Productivity
If fin density is increased to improve heat transfer performance, then heat transfer performance is improved, but pressure drop increases
Solution Approach 1:
By nesting tabs from adjacent fins into each other's openings, the patent achieves higher fin density within the same space envelope. This nested configuration maximizes the heat transfer surface area while the optimized tab geometry maintains adequate flow passages, thereby controlling pressure drop despite increased fin density.
Solution Approach 2:
The patent optimizes multiple geometric parameters including tab angle, tab spacing, tab projection distance, and fin spacing to achieve the desired balance between heat transfer performance and pressure drop. These parameter changes allow increased fin density while maintaining acceptable pressure characteristics.
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 heat transfer surface achieves improved heat transfer performance and reduced pressure drop compared to traditional louvered fin structures, with increased fin density that maintains the effectiveness of counter-rotating vortices, outperforming known fin structures at their manufacturing limits.
Implementation Method 1
the planar fin surfaces have triangular tabs projecting out of the plane, forming counter-rotating vortices
Implementation Method 2
The tabs serve to disrupt boundary layer growth along the length of the planar surfaces and increase mixing in the fluid flowing over/through the heat transfer surface
Implementation Method 3
heat transfer surfaces, such as fins, positioned between, adjacent to and/or inside fluid flow passages in the heat exchanger to increase heat transfer performance
Implementation Method 4
increase mixing in the fluid flowing over/through the heat transfer surface in an effort to increase overall heat transfer performance
Data Source
AI summary
A heat transfer surface for a heat exchanger has a corrugated member having parallel spaced apart ridges and planar fin surfaces extending the ridges. Tabs are formed in the planar fin surfaces for forming counter-rotating vortices in the fluid flowing over the heat transfer surface, the tabs being lifted out of the surface of the planar fin surface and extending into or nesting within the openings formed by the corresponding tabs in the adjacent planar fin surface so as to achieve high fin density.