Heat Exchanger Mixing Chambers With Fins for Boundary-Layer Control
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Solution Overview
Problem
Existing aircraft engine heat exchangers face inefficiencies due to boundary layer buildup, which reduces heat transfer as fluids flow through conduits, leading to decreased performance over time.
Innovation Solution
Incorporation of a mixing chamber with fins and convergent-divergent sections within the heat exchanger design to disrupt boundary layers, combined with features like swirl-inducing apertures and movable louvers or protrusions to enhance turbulence and mixing of fluid flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat exchanger conduits are used without mixing chambers, then the structure is simple, but boundary layer buildup reduces heat transfer efficiency over time
Solution Approach 1:
The conduit is segmented into multiple sections by inserting a mixing chamber that divides the flow path. This segmentation disrupts the continuous boundary layer formation along the conduit length, allowing fresh fluid contact with heat exchange surfaces and maintaining thermal efficiency without requiring complete conduit replacement.
Solution Approach 2:
A mixing chamber acts as an intermediary element inserted within the conduit system. This intermediary component introduces turbulence and remixes the fluid flow between upstream and downstream sections, preventing boundary layer stagnation while maintaining the overall conduit structure and enabling continuous operation.
2Reliability
If mixing chambers with fins are added to disrupt boundary layers, then heat transfer efficiency is enhanced, but pressure drop increases
Solution Approach 1:
Fins are applied locally within specific sections of the mixing chamber rather than along the entire conduit length. This localized fin configuration creates turbulence and disrupts boundary layers only where needed for heat transfer enhancement, while minimizing the overall pressure drop that would result from continuous turbulence generation throughout the system.
Solution Approach 2:
The mixing chamber with fins provides partial mixing action rather than complete turbulence throughout the entire flow path. The fins are positioned to create sufficient disruption of boundary layers at critical locations while allowing smoother flow in other sections, achieving an optimal balance between heat transfer enhancement and pressure loss minimization.
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
Enhances heat transfer efficiency by improving mixing of boundary layer and core flows, reducing pressure drop, and maintaining effective heat exchange across the length of the conduits.
Implementation Method 1
Incorporation of a mixing chamber with fins and convergent-divergent sections within the heat exchanger design to disrupt boundary layers, combined with features like swirl-inducing apertures and movable louvers or protrusions to enhance turbulence and mixing of fluid flows.
Implementation Method 2
Existing aircraft engine heat exchangers face inefficiencies due to boundary layer buildup, which reduces heat transfer as fluids flow through conduits
Implementation Method 3
a heat exchanger for exchanging heat with a fluid flowing through the aircraft component
Data Source
AI summary
A system for an aircraft engine, has: an aircraft component; and a heat exchanger having: a housing defining a first inlet, a first outlet, a second inlet, and a second outlet; first conduits within the housing, the first conduits fluidly connecting the first inlet to the first outlet; one or more second conduit within the housing, the one or more second conduits fluidly connecting the second inlet to the second outlet, the one or more second conduit in heat exchange relationship with the first conduits; a mixing chamber intersecting two or more of the first conduits, the mixing chamber having a peripheral wall extending around a mixing volume and a central axis; and fins protruding from the peripheral wall into the mixing volume, the fins extending in a direction having an axial component relative to the central axis, the fins defining flow passages interspaced between the fins.