Gas Turbine Heat Exchanger Cross-Flow Cooling

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Solution Overview

Problem

As gas turbine engines operate at higher pressures, the compressed air becomes increasingly hot, leading to thermal stress on engine components, and existing heat exchangers struggle to effectively cool the air to prevent material threshold violations.

Innovation Solution

A heat exchanger design featuring a shroud encasing tubes with a flow area less than 5% of the intake manifold, utilizing air from bypass and low-pressure compressor paths, and coupled to both intake and outtake manifolds, facilitates cross-flow heat transfer to efficiently cool air, mitigating thermal stress through convective heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If higher pressures are achieved in compressors, then engine power and efficiency are improved, but the temperature of compressed air increases causing thermal stress on components

Engineering Contradiction:
Improveengine powerVSAvoidcompressed air temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent extracts the cooling function from the main compressor system by introducing a separate heat exchanger unit. The heat exchanger removes excess heat from compressed air before it enters the combustor, effectively decoupling the pressure generation function from the temperature control function. This allows the compressor to operate at high pressures for improved power while the heat exchanger independently manages the temperature to prevent thermal stress.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a heat exchanger is added to cool compressed air, then thermal stress on components is reduced, but device complexity increases

Engineering Contradiction:
Improvecomponent thermal stress resistanceVSAvoidheat exchanger system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the heat exchanger with existing engine components, specifically integrating it with the compressor outlet and combustor inlet pathways. The heat exchanger is positioned to utilize existing structural elements and flow paths, combining the cooling function with the existing air intake and compression system. This integration approach reduces the need for separate, standalone cooling systems and minimizes overall device complexity while still providing effective thermal management.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If the flow area of the heat exchanger tube is reduced, then heat transfer efficiency is improved, but the pressure drop across the heat exchanger increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidpressure drop
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The patent applies local quality by varying the tube flow area along the length of the heat exchanger. The tube cross-sectional area is reduced in regions where heat transfer coefficient needs enhancement, while maintaining larger areas in regions where pressure drop would be excessive. This non-uniform tube design allows optimized heat transfer in critical zones without imposing excessive pressure drop across the entire heat exchanger, balancing cooling efficiency with acceptable pressure loss.

Inventive Principle:
Principle #3Local quality

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 design effectively cools air to prevent thermal stress, maintaining material safety and improving engine efficiency by managing high operating temperatures within material thresholds, thus enhancing fuel efficiency and reducing component wear.

Implementation Method 1

a heat exchanger (HEX) may be provided to cool hot air in a gas turbine engine

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

facilitates cross-flow heat transfer to efficiently cool air, mitigating thermal stress through convective heat transfer

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3130781B1Heat exchanger for cooled cooling air
Publication Date: 2018.12.12 UNITED TECH CORP
  • EP3130781B1 patent drawingFigure 1
  • EP3130781B1 patent drawingFigure 2
  • EP3130781B1 patent drawingFigure 3

AI summary

A heat exchanger (HEX) (400) for cooling air in a gas turbine engine (110) is provided. The HEX (400) may comprise an intake manifold (412) in fluid communication with a compressor section (224) and configured to receive air from the compressor section (224), an outtake manifold (414) in fluid communication with the intake manifold (412) via a tube (432), and a cooling air flow path (F) defined by at least one of an outer surface of the tube (432), an outer surface (516) of the intake manifold (412), and an outer surface (518) of the outtake manifold (414), wherein the cooling air flow path (F) is orthogonal to said tube (432). The air from the intake manifold (412) may travel through the tube (432) to the outtake manifold (414) and from the outtake manifold (414) to a portion of the gas turbine engine (110).