Heat Exchanger Flow Path Design for Stagnation

Solution Overview

Problem

Existing heat exchangers suffer from reduced heat recovery performance due to stagnation of the second fluid, which leads to boiling and erosion of the members forming the flow path, as they do not adequately address the flow path for the second fluid.

Innovation Solution

The heat exchanger design includes a heat recovery member positioned such that its axial central portion is downstream of the inner cylinder's central portion, and its downstream end is upstream of the second fluid's flow path end, with optional boiling suppression features like flow path blocking members or high-thermal resistant processed portions to prevent stagnation and boiling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the heat exchanger uses a conventional design without specific attention to the second fluid flow path, then the structure is simpler, but the heat recovery performance is reduced due to stagnation and boiling of the second fluid

Engineering Contradiction:

Improveheat recovery performanceVSAvoidflow path design complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing specific structural features (such as inclined surfaces, protrusions, or recesses) at particular locations within the flow path where stagnation is most likely to occur. These localized modifications create turbulence and prevent dead zones without requiring a complete redesign of the entire flow path, thus improving heat recovery performance while minimizing added complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by designing the flow path structure in advance to prevent stagnation before it occurs. The inclined surfaces and geometric features are configured to guide fluid flow and eliminate dead zones from the outset, preventing the accumulation and boiling of the second fluid before it can negatively impact heat recovery performance.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the heat exchanger operates without preventing second fluid stagnation, then the operation is simpler, but boiling occurs causing erosion of flow path members

Engineering Contradiction:

Improveflow path member durabilityVSAvoidoperational complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies local quality by providing specific structural features (such as inclined surfaces, protrusions, or recesses) at particular locations within the flow path where stagnation is most likely to occur. These localized modifications create turbulence and prevent dead zones without requiring a complete redesign of the entire flow path, thus improving heat recovery performance while minimizing added complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary anti-action by designing the flow path structure to counteract the tendency toward stagnation and boiling before they can cause erosion. The geometric features are configured to maintain fluid motion and prevent the conditions that lead to boiling, thereby protecting flow path members from erosion without requiring complex operational controls.

Inventive Principle:

Principle #9Preliminary anti-action

3Productivity

If the second fluid flows freely without flow path optimization, then the flow rate is higher, but stagnation zones form causing boiling and reduced heat transfer efficiency

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidfluid flow rate distribution

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The patent applies local quality by providing specific structural features (such as inclined surfaces, protrusions, or recesses) at particular locations within the flow path where stagnation is most likely to occur. These localized modifications create turbulence and prevent dead zones without requiring a complete redesign of the entire flow path, thus improving heat recovery performance while minimizing added complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by designing the flow path with geometric features that actively promote fluid motion and prevent stagnant zones. The inclined surfaces and protrusions create dynamic flow patterns that adapt to the fluid flow, ensuring continuous movement and preventing the formation of dead zones where boiling could occur, thereby maintaining high heat transfer efficiency.

Inventive Principle:

Principle #15Dynamics

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 enhances heat recovery performance and prevents erosion of the flow path members by minimizing the boiling of the second fluid, thereby improving overall heat transfer efficiency and extending the lifespan of the heat exchanger components.

Implementation Method 1

a heat recovery member (1) through which a first fluid can flow; an inner cylinder (10) configured to house the heat recovery member (1)... a flow path for a second fluid being formed between the outer cylinder (20) and the inner cylinder (10)

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS20230288144A1Heat exchanger

Publication Date: 2023.09.14 NGK INSULATORS LTD

AI summary

A heat exchanger includes: a heat recovery member through which a first fluid can flow; an inner cylinder configured to house the heat recovery member; an outer cylinder having a feed port capable of feeding a second fluid and a discharge port capable of discharging the second fluid, the outer cylinder being disposed on a radially outer side of the inner cylinder with a distance such that a flow path for the second fluid is formed between the outer cylinder and the inner cylinder; a feed pipe connected to the feed port; and a discharge pipe connected to the discharge port.