Compressor Bleed Air Ducting Into Heat Exchanger
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Solution Overview
Problem
Gas turbine engines operating at higher pressures and temperatures pose challenges for the bypass duct, which is not designed to withstand these conditions, especially when high volumes of bleed air are dumped into it, leading to potential damage.
Innovation Solution
A compressor bleed valve system that directs the bleed air into a heat exchanger duct designed to withstand high temperatures, where it mixes with cooler air, thereby avoiding the temperature-sensitive regions of the bypass duct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If bleed air is dumped directly into the bypass duct, then the compressor stability is maintained, but the bypass duct is damaged by high temperature and pressure
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary component between the bleed air source and the bypass duct. The heat exchanger receives hot bleed air from the compressor, exchanges heat with cooler air from the bypass duct, and outputs tempered air that is safe for the bypass duct while maintaining compressor stability. This mediator resolves the contradiction by allowing the beneficial function (compressor stability) without the harmful effect (thermal damage).
Solution Approach 2:
The patent segments the air flow path into distinct zones: a first region receiving hot bleed air, a second region receiving cooler bypass air, and a mixing region where the two streams combine within the heat exchanger. This segmentation allows temperature and pressure management at different stages, enabling the system to maintain compressor stability while protecting the bypass duct from thermal damage through controlled gradual mixing.
2Stability of the object's composition
If high volume bleed air is dumped, then compressor stability is maintained, but the bypass duct cannot withstand the high temperature
Solution Approach 1:
The heat exchanger serves as a thermal intermediary that decouples the high-temperature bleed air from the temperature-sensitive bypass duct. It allows high-volume bleed air to be processed at elevated temperatures while the bypass duct only encounters tempered, lower-temperature air, thus maintaining compressor stability without exceeding the bypass duct's temperature tolerance.
Solution Approach 2:
The heat exchanger changes the temperature parameter of the bleed air progressively as it moves through the exchanger. The air enters at high temperature, undergoes heat exchange with cooler bypass air, and exits at a reduced temperature that is safe for the bypass duct. This parameter transformation enables high-volume dumping while protecting the bypass duct from thermal damage.
3Object-affected harmful factors
If bleed air is directed through heat exchanger duct, then the bypass duct is protected from damage, but the system complexity increases
Solution Approach 1:
The heat exchanger duct is designed to perform multiple functions: it serves as both the heat exchange medium and the delivery conduit for tempered air to the bypass duct. By integrating these functions into a single component rather than separate systems, the patent reduces overall system complexity while still providing bypass duct protection from thermal damage.
Solution Approach 2:
The patent merges the heat exchanger and the air delivery duct into an integrated structure. The heat exchanger duct combines the thermal management function with the air transport function, eliminating the need for separate cooling systems and delivery pathways. This consolidation protects the bypass duct while minimizing the increase in system complexity.
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 solution effectively accommodates high-pressure and high-temperature bleed air by directing it into a heat exchanger duct, ensuring the air is cooled and distributed in a way that avoids damaging the bypass duct, enhancing the engine's stability and longevity.
Implementation Method 1
the heat exchanger includes an air inlet to pass air through the heat exchanger to cool a fluid in the heat exchanger
Data Source
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AI summary
A gas turbine engine (20) includes a compressor section (106), a combustor (108), and a turbine section (110). A bleed tap (116) taps air from the compressor section (106) through a bleed valve (112). The bleed valve (112) is selectively opened by a control to dump air from the compressor section (106) to a dump outlet (118). A heat exchanger duct (119) includes a duct air inlet (104) to cool a fluid in a heat exchanger (124) and a duct air outlet (122). The dump outlet (118) is within the heat exchanger duct (119).