Floating Core Heat Exchanger Deflector Eliminates Stagnation
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Solution Overview
Problem
Heat exchangers in EGR systems face thermal fatigue due to stagnation regions at the floating end, leading to reduced durability and efficiency, especially with differential expansion between the shell and bundle of tubes causing stress and failure.
Innovation Solution
A heat exchange device with a floating core configuration, featuring a deflector that eliminates stagnation regions by modifying the coolant flow trajectory, ensuring effective heat transfer and reducing thermal stresses through a parallel velocity field, and an elastically deformable conduit to accommodate longitudinal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a floating core configuration is used to accommodate differential expansion, then thermal expansion stress is reduced, but stagnation regions form at the floating end causing thermal fatigue
Solution Approach 1:
The invention introduces a deflector element that redirects coolant flow in a different direction (parallel to the floating baffle) to eliminate stagnation regions. This dimensional change in flow trajectory prevents thermal fatigue while preserving the floating core's expansion accommodation capability
Solution Approach 2:
The deflector acts as an intermediary element between the coolant flow and the floating baffle, modifying the flow pattern to prevent direct stagnation against the baffle surface. This intermediary structure resolves the contradiction by mediating the interaction between thermal expansion needs and flow-induced thermal fatigue
2Volume of moving object
If the heat exchanger size is reduced to meet packaging requirements, then space efficiency improves, but temperature gradients increase causing higher thermal stresses
Solution Approach 1:
The invention applies local quality modification by introducing a deflector at the specific location of the floating end where stagnation occurs. This localized intervention addresses thermal fatigue at the critical region without requiring overall size increase, thus maintaining compact dimensions while managing local thermal stress concentrations
3Reliability
If the coolant flow rate is increased to reduce thermal fatigue, then heat transfer efficiency improves, but energy consumption increases
Solution Approach 1:
The deflector dynamically redirects coolant flow to eliminate stagnation regions, ensuring efficient heat transfer at lower flow rates. This dynamic flow management achieves thermal fatigue prevention without requiring excessive coolant energy input, optimizing the balance between reliability and energy consumption
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 significantly increases the thermal fatigue resistance and service life of the device by preventing stagnation points and enhancing cooling efficiency, demonstrated through numerical simulations and prototype testing.
Implementation Method 1
an elastically deformable conduit establishing the fluid continuity of the hot gas conduit
Implementation Method 2
the combination of the shape of the shell and of a deflector... results in a low-cost exchanger... preventing stagnation points and enhancing cooling efficiency
Implementation Method 3
a bundle of heat exchange tubes extending according to a longitudinal direction X-X' between a first fixed baffle and a second floating baffle for passage of the hot gas to be cooled
Implementation Method 4
adapted for cooling a hot gas by means of a coolant liquid
Data Source
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AI summary
The present invention relates to a heat exchange device of the so-called floating core type, having a special configuration which allows increasing its durability as it increases its thermal fatigue resistance. This invention is characterized by a configuration having high thermal fatigue resistance due to the special configuration of the end where the floating side of the core is located since stagnation regions that are usually produced in the baffle of the floating end are eliminated by means of the combination of the shape of the shell and of a deflector. This configuration furthermore results in a low-cost exchanger.