Aircraft Nacelle Heat Exchanger Layout for Low-Drag Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aircraft turbojet cooling systems are susceptible to performance losses due to aerodynamic disruptions from heat exchangers and are vulnerable to damage from bird strikes and debris impacts, leading to reduced reliability and increased fuel consumption.
Innovation Solution
A nacelle design incorporating a heat exchanger positioned in a proximal upper quadrant of the nacelle, away from potential impact zones, and a closed-loop heat transfer fluid system with dual heat exchangers and a leak detection mechanism to ensure continuous lubricant cooling without aerodynamic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a finned heat exchanger is used in the secondary intake or compressor, then lubricant cooling is achieved, but airflow is disrupted causing pressure drops and increased fuel consumption
Solution Approach 1:
The heat exchanger is extracted from the airflow path (secondary intake or compressor) and relocated to the nacelle structure itself. The nacelle fairing acts as the heat exchanger surface, eliminating airflow disruption while maintaining cooling function through direct thermal contact between the lubricant cooling circuit and the fairing structure.
Solution Approach 2:
The nacelle fairing structure serves as an intermediary between the lubricant cooling circuit and the external environment. Instead of using fins to exchange heat with airflow, the fairing itself becomes the heat exchange surface, mediating thermal transfer without disrupting the aerodynamic flow.
2Temperature
If scoops are added to the external fairing for air intake, then cold air is available for cooling and de-icing, but aerodynamic performance is degraded
Solution Approach 1:
The nacelle fairing is given multiple functions: it serves as both the aerodynamic outer shell and the heat exchanger surface for the lubricant cooling circuit. This eliminates the need for separate scoops or air intake structures, maintaining clean aerodynamics while providing adequate cooling capability through the fairing's thermal exchange function.
3Temperature
If heat exchangers are placed in the nacelle, then lubricant cooling is provided, but the heat exchangers are vulnerable to bird strikes and debris impacts
Solution Approach 1:
The heat exchanger function is merged with the nacelle fairing structure itself. The fairing, which is already designed to withstand external impacts and environmental conditions, becomes the heat exchange surface. This integration protects the cooling function by shielding it within the robust nacelle structure while maintaining effective thermal contact with the lubricant cooling circuit.
4Temperature
If a closed-loop heat transfer fluid system is used, then cooling efficiency is improved, but system complexity increases
Solution Approach 1:
The cooling system uses a closed-loop heat transfer fluid circuit with flexible routing through the nacelle structure. The fluid circulates through channels or conduits integrated into the fairing, providing efficient heat transfer while accommodating the compact space constraints and movement of the nacelle during operation.
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 solution enhances aircraft performance by minimizing aerodynamic losses and maintaining cooling efficiency while protecting the heat exchanger from impacts, thus improving fuel efficiency and reliability.
Implementation Method 1
a first heat exchanger (14) arranged in the turbojet engine (126) between the lubricant (H) to cool and the heat transfer fluid (C)... a second heat exchanger (12) arranged in the nacelle (100) in contact with the external and/or internal fairing (103a, 103b) so as to form a cold source between the heat transfer fluid (C) to cool and the external environment
Implementation Method 2
the heat transfer fluid (C) circulates in the first heat exchanger (14) via a first portion (15a) of the circulation line (15), and it circulates in the second heat exchanger (12) via a second portion (15b) of the circulation line (15)
Data Source
Figure 1~3B
Figure 4~5
Figure 6~7
AI summary
The invention relates to a nacelle (100) for an aircraft (123) comprising a fuselage (124) arranged in a longitudinal plane (p) and two propulsion assemblies (125a, 125b) arranged in a plane transverse to the longitudinal plane, on either side of the fuselage, the nacelle comprising: - A proximal upper quadrant, - A distal upper quadrant, - A proximal lower quadrant, - A distal lower quadrant, - An upstream section, - A mid-section, - A downstream section comprising a trailing edge, and - At least one surface heat exchanger, called a cold source exchanger, between a heat transfer fluid and a cold air stream, integrated in a closed circuit in which the heat transfer fluid circulates, and disposed in any one of the proximal upper quadrants, distal upper quadrants and/or distal lower quadrants, and in the mid-section and/or downstream section.