Oscillating Heat Pipe for Gas Turbine Thermal Management

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Solution Overview

Problem

Existing heat transfer devices in gas turbine engines are bulky, difficult to position, and incur additional drag penalties when using fan air as a heat sink, especially as the fan pressure ratio decreases.

Innovation Solution

The use of an oscillating heat pipe, a passive heat transfer device, to efficiently transfer heat from the engine core to the fan exit guide vane, reducing the need for bulky heat exchangers and minimizing weight and pressure drop penalties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a traditional heat exchanger is used to transfer heat from the engine core to the heat sink, then heat transfer function is achieved, but the device becomes bulky and difficult to position within the gas turbine engine

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidheat exchanger size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The oscillating heat pipe utilizes phase transitions of the working fluid (evaporation at the hot end, condensation at the cold end) to transfer heat efficiently. This phase change mechanism enables high heat transfer capability in a compact structure, resolving the contradiction between heat transfer effectiveness and device volume

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The heat pipe employs periodic oscillation of the working fluid between liquid and vapor phases, creating a cyclic heat transfer process. This periodic action allows continuous heat transfer with compact dimensions, addressing the contradiction between thermal performance and size

Inventive Principle:
Principle #19Periodic action

2Temperature

If fan air is used as the heat sink, then heat transfer is achieved, but an additional drag penalty is incurred

Engineering Contradiction:
Improveheat dissipationVSAvoiddrag penalty
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a secondary fluid system as an intermediary between the engine core and fan air. This intermediate fluid transfers heat from the core to the heat sink, reducing the direct interaction between fan air and the heat transfer process, thereby minimizing drag penalty while maintaining effective heat dissipation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If the fan pressure ratio is reduced, then engine efficiency is improved, but the allowable pressure drop in the heat exchanger decreases

Engineering Contradiction:
Improveengine efficiencyVSAvoidallowable pressure drop
Core Design Contradiction:
Use of energy by moving objectVSStress or pressure

Solution Approach 1:

The patent replaces the traditional mechanical heat exchanger system with an oscillating heat pipe system that relies on thermal-driven phase changes rather than mechanical pressure differentials. This substitution eliminates the constraint of allowable pressure drop, allowing the engine to operate at reduced fan pressure ratios for improved efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Temperature

If a traditional heat exchanger is used, then heat transfer function is provided, but weight penalty is incurred

Engineering Contradiction:
Improveheat transferVSAvoidheat exchanger weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The oscillating heat pipe uses phase transitions of a small amount of working fluid to achieve heat transfer, eliminating the need for large metal heat exchanger structures. This approach provides effective heat transfer with dramatically reduced weight

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention extracts the essential heat transfer function from the bulky heat exchanger structure and concentrates it in the oscillating heat pipe system, removing unnecessary structural weight while maintaining thermal performance

Inventive Principle:
Principle #2Taking out (Extraction)

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 oscillating heat pipe effectively transfers heat with high thermal conductivity and fast response, reducing weight and volume compared to traditional heat exchangers, and eliminating up to 0.5% of the combined weight and pressure drop penalties on engine fuel burn.

Implementation Method 1

Gas turbine engines with oscillating heat pipe for thermal management

Methodology Applied
Scientific EffectHeat pipe: Heat Pipe

Implementation Method 2

The oscillating heat pipe effectively transfers heat with high thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2935832B1Gas turbine engines with oscillating heat pipe for thermal management
Publication Date: 2025.04.23 RTX CORP
  • EP2935832B1 patent drawingFigure 1
  • EP2935832B1 patent drawingFigure 2~3

AI summary

An oscillating heat pipe of a gas turbine engine includes a plurality of channels that define a continuous loop through which a fluid flows, and an evaporator of a gas turbine engine. The fluid flows through the evaporator to accept heat from a first fluid. The first fluid is located near or in an engine core. The oscillating heat pipe also includes condenser of the gas turbine engine. The fluid flows through the condenser to reject heat to a second fluid, and the second fluid is located outwardly of the engine core.