Baffled Heat Exchanger Assembly for Micrometeorite Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heat exchangers in the aeronautical and spatial fields face challenges with assembly industrialization due to welding or tender brazing, which leads to thermal dilation issues and vulnerability to micro-meteorites, requiring a solution for mechanical integrity and thermal constraint management.
Innovation Solution
A heat exchanger design featuring two profiled bars around a fluid circulation tube with a chicane interstice and vacuum brazing, reducing thermal stresses and providing protection against micro-meteorites, along with a manufacturing process using a vacuum brazing oven and optional metallic layer application for enhanced assembly and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welding or soft soldering is used to assemble the heat exchanger, then assembly is simpler, but industrialization becomes difficult and thermal stresses are not properly managed
Solution Approach 1:
The patent changes the assembly parameter from welding/soft soldering to brazing, which operates at intermediate temperatures (450-600°C) between soft soldering and welding. This parameter change enables industrialization through furnace-based processing while managing thermal stresses better than soft soldering, resolving the contradiction between assembly simplicity and industrialization capability.
2Productivity
If brazing is used to assemble the heat exchanger, then industrialization is facilitated through furnace use, but thermal stresses from differential expansion cause decohesions and compromise mechanical strength
Solution Approach 1:
The patent applies local quality by using a multi-layer brazing structure with different materials at different locations. The first brazing layer uses a filler metal with intermediate melting point between the tube and first bar materials, while the second brazing layer uses a different filler metal between the first and second bars. This localized material differentiation manages thermal stresses at each interface, preventing decohesion while maintaining industrialization benefits.
Solution Approach 2:
The patent employs composite materials by combining multiple brazing layers with different filler metals, each selected for specific thermal and mechanical properties. This composite brazing structure accommodates differential thermal expansion between dissimilar materials (tube and bars) while maintaining joint integrity, thus preserving mechanical strength during industrial brazing processes.
3Reliability
If the heat exchanger is used in space domain, then heat exchange function is achieved, but the tube becomes vulnerable to micrometeorite impacts causing damage or fluid leaks
Solution Approach 1:
The patent implements beforehand cushioning by placing a sacrificial second bar between the tube and the external space environment. This second bar absorbs micrometeorite impacts before they can reach the tube, protecting the critical fluid circulation pathway. The sacrificial bar can be replaced if damaged, while the tube remains intact, thus maintaining heat exchange reliability while protecting against micrometeorite harm.
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 enables a simpler, industrializable assembly with improved thermal management and protection against micro-meteorites, enhancing the mechanical integrity and thermal exchange efficiency of the heat exchanger.
Implementation Method 1
a joining surface distributed on either side of the recess and configured to form a junction with the other profiled bar following brazing of the bars
Implementation Method 2
The brazing element is advantageously created by brazing a brazing strip inserted into at least part of the gap during the manufacture of the heat exchanger
Implementation Method 3
Brazing is preferably vacuum brazing, particularly using a vacuum brazing furnace
Implementation Method 4
the assembly by brazing of elements of two materials of different nature generates differential expansions between the two materials due to their different coefficients of thermal expansion
Implementation Method 5
a tube for circulating a fluid and configured to allow heat exchange between the fluid circulating in the tube and a casing surrounding the tube
Implementation Method 6
heat exchange between the fluid circulating in the tube and a casing surrounding the tube
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a heat exchanger comprising a fluid circulation tube (14) configured to allow heat exchange between the fluid circulating in the tube and a casing surrounding the tube and formed of two profiled bars (112a, 112b) configured to surround the tube (14) in at least part of its length, each comprising a recess (16a, 16b) for receiving the tube, and a junction surface (18a, 18b) configured to form a junction with the other profiled bar, and in that the junction surfaces (18a, 18b) of the profiled bars form a gap (20) between them, and the junction surfaces (18a, 18b) of the profiled bars are arranged in different planes so that said gap forms at least one baffle (24a, 24b) on each side of the tube (14).