Aircraft Electric Propulsion Cooling Inlet Positioning

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Solution Overview

Problem

Existing electric propulsion units for aircraft have suboptimal aerodynamic performance due to oversized air inlets and outlets, which are designed for maximum cooling during take-off but result in inefficient airflow during other phases of flight.

Innovation Solution

The electric propulsion unit incorporates a main cooling circuit with the main air inlet positioned behind the propeller, eliminating the need for a fan and minimizing aerodynamic impact. The main air outlet is configured to generate additional thrust, and the secondary cooling circuit is designed to enhance cooling capacity during high-demand phases like take-off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the air inlet, air outlet, intake duct and exhaust duct are sized for maximum cooling during take-off, then the cooling capacity is sufficient for critical phases, but the aerodynamic performance deteriorates during cruising phases due to oversized dimensions

Engineering Contradiction:
Improvecooling capacityVSAvoidaerodynamic performance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the air inlet and air outlet dimensions adjustable rather than fixed. The air inlet can be positioned in different locations (front fairing or side fairing) and the air outlet can be adjusted, allowing the cooling system to adapt its configuration based on the flight phase. This enables optimal cooling capacity during take-off while minimizing aerodynamic drag during cruising phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by modifying the geometric parameters of the cooling system components. Specifically, the air inlet area, air outlet area, and duct dimensions are made variable through adjustable positioning mechanisms. This allows the system to change its effective cooling parameters according to operational requirements, balancing cooling needs with aerodynamic performance across different flight phases.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the air inlet is positioned on the side face of the nacelle to enable cooling, then the cooling circuit can function, but a fan is required to control air mass flow, increasing device complexity

Engineering Contradiction:
Improvecooling functionVSAvoidfan requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the self-service principle by positioning the air inlet in a location where it can utilize the aircraft's forward motion to generate sufficient air flow for cooling without requiring additional mechanical assistance. The air inlet is positioned in the front fairing or side fairing where the oncoming air flow during flight provides the necessary mass flow for the cooling circuit, eliminating the need for a fan and reducing device complexity.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If the air inlet is positioned behind the propeller, then aerodynamic performance is optimized and fan is eliminated, but the cooling capacity may be reduced

Engineering Contradiction:
Improveaerodynamic dragVSAvoidcooling capacity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies dynamics by providing multiple air inlet positioning options that can be selected or adjusted based on operational needs. The air inlet can be positioned in the front fairing, side fairing, or behind the propeller, allowing the system to dynamically optimize between aerodynamic performance and cooling capacity depending on the flight phase and thermal management requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by creating different air inlet configurations in different locations (front fairing, side fairing, rear fairing) each optimized for specific conditions. The front fairing position maximizes cooling capacity, the side fairing position balances cooling with aerodynamics, and the rear position optimizes aerodynamics while eliminating fan requirements, allowing local optimization based on operational needs.

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 optimizes cooling capacity according to flight phase needs, reducing drag and enhancing thrust efficiency, particularly during cruising phases, while maintaining effective heat removal during critical phases like take-off.

Implementation Method 1

a cooling system which includes two cooling circuits positioned for example on both sides of the nacelle. Each cooling circuit comprises, depending on the direction of the air flow, an air inlet, an intake duct, a heat exchanger, an exhaust duct and an air outlet.

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a propeller driven in rotation by the electric motor

Methodology Applied
Scientific EffectAerodynamic thrust: Aerofoil

Implementation Method 3

an electric motor powered by the electric power system, a propeller driven in rotation by the electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 4

at least an electric power system, such as a set of fuel cells for example

Methodology Applied
Scientific EffectElectrochemical energy conversion: Fuel Cell

Data Source

PatentEP4086176B1Electric propulsion unit of an aircraft comprising a cooling system incorporating at least one front air inlet and aircraft comprising at least one such electric propulsion unit
Publication Date: 2025.03.05 AIRBUS (SAS)
  • EP4086176B1 patent drawingFigure 1~3
  • EP4086176B1 patent drawingFigure 4~5
  • EP4086176B1 patent drawingFigure 6~7

AI summary

The invention relates to an electric propulsion unit of an aircraft comprising a nacelle (22) housing an electric power system (16), an electric motor (18) and a cooling system for the electric power system (16); the nacelle comprising a central fairing (32), a front fairing (34) which extends from the central fairing (32) to a front end (34.1) and a rear fairing (36) which extends from the central fairing (32) to a rear end (36.1). According to the invention, the front fairing (34) comprises a protrude (52) positioned in a lower part of the front fairing (34), said protrude (52) having a front face (54) in a transverse plane, a main air inlet (42) of the cooling system being positioned on the front face (54).