Angled Ducted Heat Exchanger for Aircraft Engine Cooling
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Solution Overview
Problem
Modern aircraft engines face increasing heat loads due to larger fan diameters and additional electrical components, which overwhelm existing heat exchanger designs, leading to reduced efficiency and increased thrust and fuel consumption, while traditional heat exchanger designs either disrupt airflow or occupy excessive space.
Innovation Solution
A compact ducted heat exchanger assembly with a heat exchanger angled relative to the inlet duct airflow direction, featuring a constant area inlet duct and a fairing that forms both the inlet and outlet duct upper walls, allowing for efficient heat transfer without the need for a diffuser, and is mounted in various configurations to minimize footprint and maximize integration with the engine casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional heat exchanger designs are used, then heat transfer function is provided, but pressure loss increases and aerodynamic performance deteriorates
Solution Approach 1:
The heat exchanger is positioned at an angled orientation relative to the bypass duct flow direction, transitioning from a traditional axial alignment to a three-dimensional angled configuration. This dimensional change allows the heat exchanger to be integrated into the bypass duct structure without creating flow disruption or pressure loss, as the angled positioning enables heat transfer functionality while maintaining smooth airflow through the duct.
2Temperature
If heat exchanger size is increased to handle higher heat loads, then heat transfer capacity improves, but assembly footprint increases
Solution Approach 1:
The heat exchanger assembly is nested within the bypass duct structure, with the heat exchanger core integrated into the duct walls. The inlet and outlet ducts are configured to connect with the bypass duct, creating a nested arrangement where the heat transfer function is provided within the existing duct volume rather than requiring additional external space. This nesting approach allows increased heat transfer capacity while maintaining a compact overall footprint.
3Loss of energy
If diffuser is added to reduce approach velocity, then pressure loss decreases, but assembly length increases
Solution Approach 1:
The diffuser component is extracted and removed from the heat exchanger assembly. Instead of using a traditional diffuser to reduce approach velocity, the invention relies on the angled positioning of the heat exchanger relative to the bypass duct flow. This extraction eliminates the need for additional length while maintaining acceptable pressure loss characteristics through the geometric orientation of the heat transfer surfaces.
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
This design enhances heat transfer efficiency, reduces pressure loss, and minimizes the overall size of the heat exchanger assembly, addressing the increasing heat load demands while maintaining aerodynamic performance and reducing the impact on thrust and fuel consumption.
Implementation Method 1
heat transfer efficiency
Data Source
AI summary
A heat exchanger assembly that in a preferred embodiment comprises: an inlet duct lower wall interfacing with a bypass duct; an outlet duct lower wall interfacing with a bypass duct; a heat exchanger coupled between the inlet duct lower wall and the outlet duct lower wall wherein the heat exchanger is at a compound angle with respect to an inlet duct air flow direction; and a fairing coupled to the top of the heat exchanger wherein the fairing forms the inlet duct upper wall and the outlet duct upper wall.