Segmented Heat Exchanger for Gas Turbine Bypass Ducts
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Solution Overview
Problem
Gas turbine engines face significant pressure losses and reduced cooling efficiency due to heat exchanger blockages in fan bypass ducts, which can lead to decreased engine thrust and airflow issues at varying airflow rates.
Innovation Solution
The arrangement of heat exchangers with increased cold-side frontal area and variable geometry to minimize blockage, allowing for adaptive control of airflow through the engine, including a forward-facing scoop and pivotally attached heat exchanger segments, reduces pressure losses and enhances cooling capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat exchangers are distributed around the entire circumference of the fan bypass duct, then the cooling capability is improved, but the engine air stream blockage increases resulting in pressure drop and decreased engine thrust
Solution Approach 1:
The heat exchanger is divided into multiple discrete segments distributed around the fan bypass duct circumference rather than forming a continuous ring. This segmentation reduces the total blockage area while maintaining cooling capability through distributed heat rejection zones.
Solution Approach 2:
Heat exchanger segments are strategically positioned at specific circumferential locations where they can effectively reject heat without creating excessive blockage. The local arrangement optimizes the balance between cooling performance and airflow preservation by placing heat exchangers where they intercept minimal engine air stream.
2Productivity
If heat exchanger blockage is increased to draw more air through the heat exchangers, then the cooling rate improves, but the pressure drop across the heat exchangers becomes excessively large or chokes the engine stream flow
Solution Approach 1:
The heat exchanger segments are designed to provide sufficient cooling capacity without creating excessive blockage. By using multiple partial segments rather than a complete ring, the system achieves adequate cooling rate while maintaining acceptable pressure drop levels that prevent flow choking.
3Stress or pressure
If heat exchanger blockage is decreased to reduce pressure drop, then the engine thrust is improved, but the pressure difference across the heat exchangers becomes insufficient to draw adequate air through for cooling
Solution Approach 1:
Multiple discrete heat exchanger segments create distributed pressure differences that collectively provide sufficient driving force for airflow through the heat exchangers without requiring excessive total blockage. Each segment generates local pressure differential that contributes to overall cooling performance.
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 configuration reduces airstream blockage by one-third while increasing the cold-side frontal area, improving cooling efficiency and minimizing pressure losses, thereby maintaining engine thrust and reducing fuel consumption.
Implementation Method 1
heat exchangers arranged within the duct to reject a heat load
Implementation Method 2
the airstream may pass through the heat exchangers in an axial direction of the engine
Implementation Method 3
The heat exchangers create a blockage in the fan bypass duct and produce a pressure difference, thereby drawing air through the heat exchangers in the axial direction
Data Source
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AI summary
One embodiment of an engine may include an enclosure surrounding an engine having an engine centerline, and the enclosure defining a passage for a cold-side airflow. The engine may also include one or more contiguous heat exchangers having a cold side inlet surface receiving a cold-side airflow. The heat exchanger may be disposed within the passage, such that a surface normal relative to the cold side inlet surface is offset by at least 30 degrees from the engine centerline.