Heat Exchanger Tube-to-Header Joint Reinforcement Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heat exchangers suffer from joint fatigue failure and limited life due to high stresses at tube-to-header joints, primarily caused by thermal and mechanical stresses resulting from non-uniform dimensional changes.
Innovation Solution
The introduction of an intermediate plate with flanges that conform to the sidewalls of heat exchange tubes, reinforcing the tube-to-header joints to enhance mechanical resistance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tubes are rigidly attached to header by soldering, brazing or welding, then joint strength is improved, but thermal and mechanical stresses cause joint fatigue failure
Solution Approach 1:
The header is divided into two distinct parts: a rigid header body providing structural support and fluid distribution, and a flexible header portion that can elastically deform to accommodate thermal expansion and contraction of tubes. This segmentation allows the rigid portion to maintain joint strength while the flexible portion absorbs thermal stresses, preventing fatigue failure.
Solution Approach 2:
The header material composition is changed to create a flexible header portion with different mechanical properties than the rigid header body. The flexible portion has higher elasticity and lower stiffness, allowing it to deform under thermal stress while maintaining the overall structural integrity and strength of the joint through the rigid portion.
2Strength
If tubes are rigidly attached to header, then mechanical resistance is improved, but dimensional changes due to heating cause high stresses
Solution Approach 1:
The header is segmented into a rigid header body that provides mechanical resistance and structural support, and a flexible header portion that specifically accommodates thermal dimensional changes. This allows the system to maintain high mechanical resistance while reducing thermal stress concentration at the tube-to-header joints.
Solution Approach 2:
The flexible header portion acts as an intermediary element between the rigid header body and the tubes. It mediates the thermal expansion and contraction forces, allowing dimensional changes without transmitting high stresses to the rigid header body or the tube-to-header joints, while still providing adequate mechanical resistance.
3Reliability
If flexible header portion is added, then stress resistance is improved, but device complexity increases
Solution Approach 1:
The flexible header portion is merged with the rigid header body to form a single integrated header component. This combining approach maintains stress resistance through the flexible portion while avoiding the complexity of separate flexible and rigid header components, reducing manufacturing steps and assembly complexity.
Solution Approach 2:
The header is designed as a multi-functional component where the rigid header body provides structural support, fluid distribution, and mechanical strength, while the flexible header portion provides thermal stress accommodation. This universal header design achieves multiple functions simultaneously without requiring separate specialized components, thereby limiting the increase in device complexity.
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 solution increases the mechanical strength at the joints, thereby enhancing the service life and reliability of the heat exchanger by mitigating stress-induced failures.
Implementation Method 1
The heat exchanger transfers thermal energy between the fluids as a result of the heating or cooling of the tubes
Implementation Method 2
The first fluid flows from the inlet manifold to the outlet manifold through the plurality of heat exchange tubes. Further, a second fluid flows around the heat exchange tubes across the fins
Implementation Method 3
The thermal difference may cause non-uniform dimensional changes to the interconnected parts of the heat exchanger. For example, the tubes may increase in length
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention discloses a heat exchanger (100) comprising a first manifold (102), a second manifold (108) and a plurality of heat exchange tubes (114) providing a fluidal communication between the first and second manifold (102, 108). Each of the tubes (114) comprises an interior surface (118) defined by a sidewall (120), a first end (116A) and a second end (116B) opposite to the first end (116A). Each of the manifolds (102, 108) comprises a tank member (106, 112) and a header plate (104, 110) comprising a plurality of apertures (144) to receive the respective end (116A, 116B) of the tubes (114). At least one intermediate plate (122) is arranged at least at one end (114A, 114B) of the tubes (114). The intermediate plate (122) comprises a plurality of orifices (128) aligning with the arrangement of the tubes (114) and the apertures (144) of the header plate (104, 110).