Regenerator Channel Layout in Engine Displacers for Swirling Flow

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Solution Overview

Problem

Existing Stirling engines face challenges in efficiently transferring heat to and from the working fluid, which affects the expansion and compression of the working fluid and ultimately the engine's performance.

Innovation Solution

A displacer with regenerator channels that include angled components in the azimuthal direction to force the working fluid to swirl, enhancing heat transfer by increasing the velocity of the fluid and promoting convective heat exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional straight channels are used in the displacer, then the structure is simple and easy to manufacture, but heat transfer efficiency is insufficient

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidchannel structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies curvature by designing channels with azimuthal angular components instead of straight radial paths. The channels follow curved trajectories that force the working fluid to swirl as it flows through the displacer, increasing convective heat transfer efficiency between the working fluid and the displacer body.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from simple radial channels (one-dimensional flow) to three-dimensional curved channels with radial, azimuthal, and axial components. This dimensional enhancement creates a more complex flow path that improves heat transfer by increasing fluid velocity and promoting turbulent mixing while still maintaining manufacturability through standard machining operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Use of energy by moving object

If the working fluid flows in straight radial paths, then the flow path is simple, but convective heat exchange is insufficient

Engineering Contradiction:
Improveconvective heat exchangeVSAvoidchannel flow path complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The channels are designed with curved paths that include azimuthal angular components, forcing the working fluid to follow spiral trajectories rather than straight radial lines. This curvature induces swirling flow patterns that significantly enhance convective heat exchange between the working fluid and the displacer channels.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent utilizes fluid dynamics principles by designing channels that exploit the swirling motion of the working fluid to improve heat transfer. The angular components of the channels create centrifugal forces and turbulent flow patterns that enhance convective heat exchange without requiring additional mechanical components.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 angled channels in the displacer enhance heat transfer efficiency by allowing the working fluid to swirl, resulting in improved performance of the Stirling engine.

Implementation Method 1

enhancing heat transfer by increasing the velocity of the fluid and promoting convective heat exchange

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4624741A1Engine displacer with regenerator channels
Publication Date: 2025.10.01 EKSTERA INC
  • EP4624741A1 patent drawingFigure 1
  • EP4624741A1 patent drawingFigure 2~3
  • EP4624741A1 patent drawingFigure 4~6

AI summary

A displacer for an engine includes a body extending along a displacer longitudinal axis from a displacer first end surface to a displacer second end surface. At least one channel extends between a first opening in the displacer first end surface and a second opening in the displacer second end surface and has sidewalls therebetween defining a channel flow path. The first opening is located at a first radial distance from the displacer longitudinal axis in a first radial direction and the second opening is located at a second radial distance from the displacer longitudinal axis in a second radial direction. At least a portion of the channel flow path has a component in an angular direction that is at an angle to both the first and second radial directions.