Variable-Passage Heat Exchanger Design for Uniform Heat Transfer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing heat exchangers experience non-uniform heat transfer profiles and resulting thermal gradients that lead to uneven stress distribution and structural integrity issues.

Innovation Solution

Modifying the cross-sectional flow area of heat exchanger passages with augmentation features that vary along the longitudinal length to tailor thermal transfer and reduce mechanical stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional uniform flow passages are used, then manufacturing is simple, but heat transfer coefficient is non-uniform causing thermal gradients and stress

Engineering Contradiction:

Improvestructural integrityVSAvoidpassage geometry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the cross-sectional flow area at different locations along the passage. Specifically, the flow area is modified in the inlet region compared to the outlet region, creating location-dependent flow characteristics that optimize heat transfer uniformly across the heat exchanger surface, thereby reducing thermal gradients and improving structural integrity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter of the flow passage by varying the cross-sectional area along its length. This parameter change is achieved through augmentation features that modify the passage dimensions, allowing control over flow velocity and heat transfer coefficient distribution to achieve more uniform thermal conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If cross-sectional area is varied to optimize heat transfer, then heat transfer uniformity improves, but manufacturing complexity increases

Engineering Contradiction:

Improveheat transfer uniformityVSAvoidpassage fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The augmentation features are applied locally at specific regions of the passage (inlet vs outlet) rather than uniformly throughout, allowing targeted modification of heat transfer characteristics where needed while maintaining simpler geometry in other regions, thus balancing manufacturing ease with heat transfer performance.

Inventive Principle:

Principle #3Local quality

3Reliability

If flow velocity is increased to improve heat transfer coefficient, then heat transfer improves, but pressure drop increases

Engineering Contradiction:

Improveheat transfer coefficientVSAvoidpressure drop

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies different cross-sectional areas at different locations to create location-specific flow velocities. By having larger cross-sectional area in the inlet region and smaller area in the outlet region, the flow velocity is optimized at each location to maintain adequate heat transfer coefficient without excessive pressure drop, achieving a balanced distribution rather than uniform high velocity throughout.

Inventive Principle:

Principle #3Local quality

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

Achieves a more uniform heat transfer coefficient across the exchanger, reducing thermal stresses and enhancing structural integrity by strategically controlling flow velocities and thermal gradients.

Implementation Method 1

the first augmentation feature varies a cross-sectional area in a direction along the first longitudinal length... to optimize the heat transfer coefficient

Methodology Applied

Scientific EffectFlow velocity modification through area variation: Bernoulli Effect

Implementation Method 2

As the two working fluids pass through the heat exchanger the hotter working fluid transfers thermal energy to the colder working fluid

Methodology Applied

Scientific EffectHeat transfer: Convection

Implementation Method 3

the outer surface being in heat transfer communication with the inner surface

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the first region includes portions of both the inner surface and the outer surface adjacent at least a portion of the first inlet end... Thermal gradients present in the sheet material create stresses

Methodology Applied

Scientific EffectThermal gradient: Temperature Gradient

Data Source

PatentUS12372313B2Variable passages to optimize delta p and heat transfer along flow path

Publication Date: 2025.07.29 RTX CORP

AI summary

A heat exchanger including an internal passage extending from a first inlet end to a first outlet end; a first longitudinal length extending from the first inlet end to the first outlet end; an inner surface of the passage including a first augmentation feature disposed along the first longitudinal length across the inner surface; an outer surface extending from a second inlet end to a second outlet end, the outer surface being in heat transfer communication with the inner surface; and a first region including portions of both the inner surface and the outer surface adjacent at least a portion of the first inlet end, wherein the first augmentation feature varies a cross-sectional area in a direction along the first longitudinal length and within the first region.