Electric Machine Cooling Using Turbine Engine Intake Airflow

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Solution Overview

Problem

Existing cooling systems for electric motors in powerplants, such as aircraft auxiliary power units, lack efficiency in heat dissipation, necessitating an improved method to effectively cool the electric machines during operation.

Innovation Solution

A powerplant configuration that integrates a turbine engine with a fluid circuit, where the turbine engine draws air through an internal passage of the electric machine to cool it, utilizing a flowpath extending through compressor, combustor, and turbine sections, and includes ports and conduits to facilitate air flow for cooling, both during startup and regular operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a separate cooling system is used for the electric motor, then cooling effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvecooling effectivenessVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling function for the electric motor with the existing turbine engine air intake system. Air is drawn through the electric motor via ports in the compressor housing and conduits, integrating the cooling pathway into the engine's existing airflow structure. This eliminates the need for a completely separate cooling system while maintaining effective heat dissipation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The turbine engine's air intake system serves dual functions: providing air for combustion in the engine and simultaneously cooling the electric motor. The same airflow path and components (compressor housing, ports, conduits) are used for both engine operation and motor cooling, maximizing system efficiency and reducing redundancy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If air is drawn through the electric machine for cooling, then heat dissipation is improved, but airflow resistance increases

Engineering Contradiction:
Improveheat dissipationVSAvoidairflow resistance
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates cooling passages and ports specifically at locations where heat generation is highest in the electric motor, such as near the windings and core. The airflow path is optimized to target these hot spots directly, maximizing cooling effectiveness while minimizing the total airflow resistance across the entire motor structure.

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

This configuration enhances cooling efficiency by utilizing the turbine engine's airflow to dissipate heat from the electric machine, improving operational performance and reducing thermal stress, while also allowing for flexible operation as both a generator and motor.

Implementation Method 1

The turbine engine is configured to draw air through the internal passage and into the core flowpath during operation

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

air through an internal passage of the electric machine into a flowpath of the turbine engine to cool the electric machine

Methodology Applied
Scientific EffectHeat dissipation: Convection

Data Source

PatentEP4484714A1Cooling an electric machine of a gas turbine engine powerplant
Publication Date: 2025.01.01 RTX CORP
  • EP4484714A1 patent drawingFigure 1
  • EP4484714A1 patent drawingFigure 2
  • EP4484714A1 patent drawingFigure 3

AI summary

A powerplant (10) is provided that includes an electric machine (14), a turbine engine (12) and a fluid circuit (16). The turbine engine (12) is operatively coupled to the electric machine (14). The turbine engine (12) includes a flowpath (30), a compressor section (32), a combustor section (33) and a turbine section (34). The flowpath (30) extends through the compressor section (32), the combustor section (33) and the turbine section (34) from an inlet (40) into the flowpath (30) to an exhaust (42) from the flowpath (30). The compressor section (32) includes a shroud (64) forming a peripheral boundary of the flowpath (30). The fluid circuit (16) includes a passage (106A, 106B, 106C), a port (90) and a conduit (112). The passage (106A, 106B, 106C) is within the electric machine (14). The port (90) extends through the shroud (64) to the flowpath (30). The conduit (112) fluidly couples the passage (106A, 106B, 106C) to the port (90).