Offset Duct Heat Exchanger for Constrained Airflow
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Solution Overview
Problem
Aircraft propulsion systems face challenges in achieving desired airflow and thermal transfer efficiencies due to the constrained size of ducts within the aircraft structure, limiting the amount of airflow available for cooling and thermal management.
Innovation Solution
The implementation of heat exchanger assemblies in the inlet ducts with increased thermal transfer area without increasing duct size, utilizing diverging and converging configurations to enhance airflow pressures and velocities, and incorporating offset heat exchanger designs to increase cross-sectional areas for improved thermal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the duct size is increased to provide more airflow for cooling, then the airflow quantity improves, but the aircraft structure constraints are violated
Solution Approach 1:
The heat exchanger is nested within the existing duct structure, with the core positioned inside the duct and heat exchanger passages formed within the available duct volume. This allows thermal management functionality to be added without increasing the overall duct size, effectively nesting the cooling system within the constrained airflow path.
Solution Approach 2:
The heat exchanger utilizes the radial dimension of the duct by forming passages that extend from the inner wall toward the center, and the core positioned at the center creates radial airflow paths. This three-dimensional utilization of the duct cross-section maximizes thermal transfer area without increasing the duct's external dimensions.
2Temperature
If the thermal transfer area is increased to improve thermal efficiency, then the heat exchange capability improves, but the duct size must be increased
Solution Approach 1:
The heat exchanger creates radial airflow passages that utilize the vertical and radial dimensions of the duct cross-section. The core positioned at the center with passages extending outward maximizes the thermal transfer surface area within the available duct volume, effectively using the third dimension to increase heat exchange capability without increasing duct size.
Solution Approach 2:
The heat exchanger core may utilize porous materials or finned structures to dramatically increase the thermal transfer surface area within the limited volume of the core itself, allowing extensive heat exchange surfaces to be packed into the central region of the duct without increasing overall duct dimensions.
3Adaptability or versatility
If the duct size is constrained to fit aircraft structure, then the aircraft integration improves, but the airflow for cooling is insufficient
Solution Approach 1:
The complete heat exchanger assembly including core, passages, and inlet/outlet structures is nested within the existing duct geometry, allowing the system to adapt to various duct sizes and shapes while maintaining effective thermal management. The compact nested design ensures the heat exchanger fits within constrained aircraft structural envelopes.
Solution Approach 2:
The heat exchanger is divided into distinct functional segments: the core at the center, radial passages for airflow, inlet and outlet regions, and end walls. This segmentation allows each component to be optimized independently and facilitates integration into different duct configurations and aircraft structures.
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 provides enhanced thermal transfer capabilities and propulsive efficiencies while maintaining duct size constraints, improving overall engine performance and adaptability to different aircraft structures.
Implementation Method 1
heat exchanger assemblies in the inlet ducts with increased thermal transfer area
Implementation Method 2
utilizing diverging and converging configurations to enhance airflow pressures and velocities
Data Source
Figure 1
Figure 2
Figure 3~9
AI summary
A heat exchanger system for a propulsion system inlet duct (36) includes a heat exchanger assembly that is disposed within an inlet duct assembly (34). The heat exchanger assembly includes a heat exchanger with a front facing area that is greater than an area of the inlet duct (34) that is transverse to a longitudinal length of the inlet duct (34).