Heat Exchanger Baffle Flow Restriction Thermal Strain

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Solution Overview

Problem

Heat exchangers in vehicles experience thermal strain due to temperature differentials, leading to material expansion and contraction, which can cause cracks and leaks, particularly at the juncture of coolant channels.

Innovation Solution

Incorporating a baffle within the header tanks of the heat exchanger to slow down coolant flow, reducing the volume flow rate and heat transfer, thereby minimizing temperature variations and mechanical strain by limiting the flow through slots or holes in the baffle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If coolant flows rapidly through the heat exchanger, then cooling efficiency is improved, but thermal strain increases causing material expansion and contraction

Engineering Contradiction:

Improvecooling efficiencyVSAvoidthermal strain

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The header tank is divided into multiple chambers by baffles with slots, which segments the coolant flow path. This segmentation allows the coolant to flow through multiple smaller openings rather than a single large opening, reducing the flow rate while maintaining distribution across the heat exchanger. The segmented flow path decreases thermal strain by preventing rapid temperature changes in specific areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The baffles are positioned at specific locations within the header tank to control flow distribution to different sections of the heat exchanger. By adjusting the location and configuration of baffles, the system achieves local flow rate control, ensuring that areas prone to thermal strain receive moderated coolant flow while other areas maintain adequate cooling.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If coolant flow rate is increased, then heat transfer efficiency is improved, but temperature variations across the heat exchanger increase causing mechanical stress

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidmechanical stress

Core Design Contradiction:

Use of energy by moving objectVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the flow rate parameter by introducing baffles that restrict coolant flow. By modifying the flow rate parameter through physical restriction rather than changing temperature or pressure parameters, the system reduces mechanical stress while maintaining heat transfer effectiveness through improved flow distribution.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a baffle is added to slow coolant flow, then thermal strain is reduced, but device complexity increases

Engineering Contradiction:

Improvethermal strainVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The baffles are designed with slots that allow coolant to pass through while restricting flow rate. This porous-like structure achieves flow control without requiring complex valves or regulators. The slots provide a simple geometric solution that reduces thermal strain while adding minimal complexity to the overall system.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The baffles act as intermediary elements between the coolant source and the heat exchanger channels. These intermediaries moderate the coolant flow before it reaches the heat exchanger, reducing thermal strain without requiring complex control systems. The baffles serve as a simple mechanical mediator that achieves flow rate control.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 baffle reduces thermal strain by minimizing temperature variations across the heat exchanger, leading to reduced mechanical stress and potential for leaks, enhancing the durability and efficiency of the heat exchanger.

Implementation Method 1

the baffle slows coolant flow in the first tube and fin section... by limiting the flow through slots or holes in the baffle

Methodology Applied

Scientific EffectFlow restriction through baffle slots/holes:

Implementation Method 2

Heat exchanger for transferring heat from a liquid

Methodology Applied

Scientific EffectHeat transfer:

Implementation Method 3

thermal strain may develop at specific locations of the heat exchanger... The baffle reduces thermal strain by minimizing temperature variations across the heat exchanger

Methodology Applied

Scientific EffectThermal strain reduction: Thermal Expansion

Data Source

PatentUS9115934B2Heat exchanger flow limiting baffle

Publication Date: 2015.08.25 DENSO INTERNATIONAL AMERICA INC

AI summary

A heat exchanger, such as a radiator, may transfer heat from a liquid and employ a first header tank, a second header tank, a plurality of tubes fluidly joining the first and second header tanks, and a baffle within one of the first or second header tanks. The baffle may be located in a header tank positioned substantially parallel or perpendicular to a surface upon which a vehicle employing the hear exchanger rests. The baffle may be a wall defining only one slot, a wall defining only one slot that is open through one side of the wall, a wall that defines a plurality of slots, or a wall that defines a plurality of holes. The heat exchanger may further employ fluidly isolated first and second tube and fin sections each defining a self-contained flow path for cooling different liquids. The baffle may slow coolant flow in a flow path.