Heat Exchanger with Transversely Offset Ribs for Turbulent Mixing

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Solution Overview

Problem

Existing heat exchangers face challenges in achieving high efficiency and simplicity in design and manufacturing while effectively transferring heat from fluids, particularly in applications like motor vehicle exhaust systems, where overheating can occur and heat needs to be dissipated or utilized.

Innovation Solution

The heat exchanger features a heat dissipation body with alternating sections of ribs that are transversely offset relative to each other, creating turbulence and enhancing heat transfer efficiency, and is manufactured using structurally identical segments that can be easily produced and assembled, promoting uniform fluid flow and mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the heat exchanger uses a simple cylindrical cavity without internal structures, then the manufacturing is simple, but the heat transfer efficiency is low

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The heat dissipation body incorporates a porous core structure within the cylindrical cavity. This porous material provides extensive internal surface area for heat transfer while maintaining a simple external cylindrical shape that is easy to manufacture. The porous structure allows fluid to flow through while maximizing contact area between the fluid and heat exchange surfaces.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention nests the porous core structure inside the cylindrical cavity, creating a concentric arrangement where the porous material is positioned coaxially within the outer cylindrical housing. This nested configuration maximizes heat transfer surface area within the constrained cylindrical geometry while maintaining manufacturing simplicity through standardized assembly of nested components.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If the heat exchanger incorporates complex internal structures to enhance heat transfer, then the heat transfer efficiency increases, but the manufacturing complexity increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The porous core provides complex internal surface area for heat transfer without requiring complex external structures. The porous material's inherent internal geometry delivers high heat transfer efficiency while the external cylindrical shape remains simple and easy to manufacture using standard processes.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention optimizes parameters such as the porous material's pore size, porosity, and thermal conductivity to achieve high heat transfer efficiency. By adjusting these material parameters rather than complicating the structural geometry, the design maintains manufacturing simplicity while maximizing heat transfer performance.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If the heat exchanger uses a compact design with small dimensions, then the space requirement is reduced, but the heat transfer surface area is limited

Engineering Contradiction:
Improveheat exchanger volumeVSAvoidheat transfer surface area
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The porous core structure provides extensive internal surface area within a compact cylindrical volume. The three-dimensional porous network allows the heat exchanger to achieve high heat transfer surface area density, maximizing heat transfer capability while maintaining a compact external dimensions suitable for space-constrained applications.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention transitions from two-dimensional heat transfer surfaces to three-dimensional porous structures. This dimensional transformation enables the heat exchanger to pack significantly more heat transfer surface area into a compact cylindrical volume by utilizing the internal pore structure of the porous material.

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

4Ease of manufacture

If the heat exchanger uses uniform rib spacing throughout, then the manufacturing is simple, but the fluid mixing and turbulence are insufficient

Engineering Contradiction:
Improvemanufacturing uniformityVSAvoidfluid mixing efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention introduces asymmetric or non-uniform spacing of ribs or fins on the porous core structure. This asymmetric arrangement disrupts laminar flow patterns, promotes turbulence, and enhances fluid mixing while maintaining relatively simple manufacturing processes. The non-uniform spacing creates varying flow resistance that induces rotational and turbulent flow characteristics.

Inventive Principle:
Principle #4Asymmetry

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 high heat transfer rates with a simple and cost-effective manufacturing process, preventing overheating in exhaust systems and allowing for efficient heat utilization, applicable beyond vehicle applications.

Implementation Method 1

The inner surface of the heat dissipation body has a first portion with at least two fins that are transversely offset relative to each other; and a second section contiguous to the first section having at least two ribs transversely offset relative to each other... This promotes the formation of turbulence at the boundary between the sections and thus promotes mixing of parts of the fluid near the surface with parts of the fluid remote from the surface

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

the heat exchanger is used in an exhaust line of a motor vehicle in order to dissipate as much heat as possible from the hot exhaust gas generated in the engine of the motor vehicle, for example by transferring it to a heat transfer fluid

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP3077751B1Heat exchanger and method for producing a heat exchanger
Publication Date: 2019.08.14 WEBASTO AG
  • EP3077751B1 patent drawingFigure 1
  • EP3077751B1 patent drawingFigure 2
  • EP3077751B1 patent drawingFigure 3

AI summary

The invention relates to a heat exchanger (10) with an inner guide (32) for guiding a fluid and with a heat discharging element (12, 12') for discharging heat of the fluid. The heat discharging element (12, 12') has a cavity (14, 14') which extends in a longitudinal direction (36) and within which at least one end piece (34) of the inner guide (32) extends, said end piece (34) having an opening (42) which faces a base surface (44) of the cavity (14, 14') in order to introduce the fluid into a base region (46) of the cavity (14, 14'). A flow chamber for guiding the fluid away from the base region (46) is formed between an outer casing surface (48) of the inner guide (32) and an inner casing surface (20, 20') of the heat discharging element (12, 12'), said flow chamber extending in the longitudinal direction (36). The inner casing surface (20, 20') of the heat discharging element (12, 12') has a first portion (20), which has at least two ribs (22) that are transversely offset relative to each other, and a second portion (20'), which adjoins the first portion (20) and which comprises at least two ribs (22') that are transversely offset relative to each other. At least one rib (22') of the second portion (20') is transversely offset relative to each rib (22) of the first portion (20), or at least one rib (22) of the first portion (20) is transversely offset relative to each rib (22') of the second portion (20'). The invention further relates to a method for producing such a heat exchanger.