Heat Exchanger Header Movable Manifold Thermal Stress
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Solution Overview
Problem
Conventional heat exchangers, such as charge air coolers, face reduced service life due to thermal shock caused by differential expansion and contraction of header plates brazed to end plates, leading to potential cracking and stress on the tank and header, which affects the engine's optimal operating conditions and fuel efficiency.
Innovation Solution
A heat exchanger design featuring a movable manifold with non-continuous connections between end plates and the header, allowing independent movement to mitigate stress and cracking, while maintaining thermal shock resistance without increasing dimensions or weight, through the use of parallel plates with anti-brazing sections and recessed portions to prevent brazing at specific areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the header plate is brazed to the end plates along its length, then the structural strength and rigidity are improved, but thermal shock resistance deteriorates due to differential expansion and contraction causing cracking
Solution Approach 1:
The header plate is divided into a first portion and a second portion by a transverse partition wall, creating separate fluid circuits. This segmentation allows each portion to expand and contract independently, reducing thermal stress at the brazed joints while maintaining structural integrity.
Solution Approach 2:
The end plates are designed with localized brazing only at specific regions (first and second regions) rather than along the entire length of the header plate. This selective brazing maintains structural strength at critical joints while allowing other areas to move freely during thermal expansion, preventing cracking.
2Stability of the object's composition
If the header plate is rigidly connected to end plates, then structural stability is improved, but service life deteriorates due to stress accumulation from thermal expansion
Solution Approach 1:
The header plate is segmented into multiple portions by transverse partition walls, allowing each segment to respond independently to thermal changes. This reduces cumulative stress while maintaining overall structural stability of the heat exchanger assembly.
Solution Approach 2:
The connection between the header plate and end plates is made dynamic through selective brazing, allowing the structure to adapt to thermal expansion and contraction. The brazed joints provide stability where needed while permitting controlled movement, extending service life by preventing fatigue failure.
3Weight of moving object
If aluminum alloys are used for heat exchange tubes, then weight is reduced and corrosion resistance is improved, but manufacturing complexity increases due to brazing requirements
Solution Approach 1:
Brazing is applied locally only at the regions where the header plate contacts the end plates, rather than along the entire length. This reduces manufacturing complexity and cost while maintaining the weight and corrosion resistance benefits of aluminum alloys throughout the heat exchange tubes.
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 design enhances thermal shock resistance and extends the service life of the heat exchanger by preventing cracks and maintaining optimal engine performance without adding weight or complexity, ensuring efficient heat exchange and fuel efficiency.
Implementation Method 1
a stack of spaced apart heat exchange elements (106), which form a first fluid circuit for the first fluid
Implementation Method 2
The charge air cooler may dissipate heat from the charged air flowing from the turbocharger
Implementation Method 3
the header and the second section are able to move independently with respect to each other during operational mode of the heat exchanger
Implementation Method 4
thermal shock resistance of the heat exchanger
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates a heat exchanger for heat exchange between a first fluid and a second fluid, having a stack of heat exchange elements forming a first fluid circuit for the first fluid, a header adapted to receive first ends of the heat exchange elements and a housing. The housing is adapted to encapsulate the heat exchange elements to form a second fluid circuit for the second fluid. Further, the housing includes a first plate and a second plate disposed parallel with respect to the first plate. Further, at least one of the plates includes a first section that is in contact with the header and a second section that is free from the contact with the header, so that the header and the second section are able to move independently with respect to each other during operational mode of the heat exchanger.