Aircraft Thermal Management Using Compressed Air Work Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal management systems for propulsion systems, such as geared turbomachines and variable pitch fans, face inefficiencies due to fan stream blockage and inadequate thermal load attenuation, particularly in reduction gearboxes and lubricant systems, leading to reduced engine performance and efficiency.
Innovation Solution
A method and system that extracts a flow of compressed fluid from a compressor section of a propulsion system, utilizing a turbine downstream of the compressor to generate output torque and adjust fluid flow through a flow control device, allowing independent adjustment of heat exchange fluid relative to operating conditions, and incorporating a heat exchanger to manage thermal loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an air stream is used to provide thermal attenuation of fuel or lubricant, then thermal management is achieved, but fan stream blockage occurs reducing engine performance and efficiency
Solution Approach 1:
The patent extracts the thermal management function from the main fan stream by diverting a portion of compressed air through a separate cooling system. This allows thermal attenuation to occur without blocking the primary fan stream, thereby maintaining engine performance while achieving temperature control for fuel and lubricant.
Solution Approach 2:
The cooling system is segmented into separate pathways: one for thermal attenuation of fuel and another for cooling of load devices. This segmentation allows independent optimization of each cooling function without interfering with the main propulsion stream, resolving the contradiction between thermal management and engine efficiency.
2Temperature
If conventional cooling configurations are used, then simple structure is maintained, but thermal loads from reduction gearboxes and variable pitch fans are inadequate to be attenuated
Solution Approach 1:
The cooling system is designed with multi-functionality to handle diverse thermal loads including reduction gearboxes, variable pitch fans, and lubricant systems through a unified architecture. The system uses a common compressed air source that can be distributed to multiple cooling zones, achieving comprehensive thermal load attenuation without proportionally increasing system complexity.
Solution Approach 2:
The cooling system incorporates variable geometry components such as adjustable guide vanes and controllable flow paths that can dynamically adapt to different operating conditions. This allows the system to effectively attenuate varying thermal loads from different components while maintaining a relatively simple base structure that only becomes complex when adaptability is required.
3Productivity
If compressed fluid flow is extracted and expanded through turbine, then work extraction is maximized improving efficiency, but system complexity increases
Solution Approach 1:
The system uses self-service by utilizing excess compressed air that would otherwise be wasted or require active management. The turbine expands this available compressed fluid to generate useful work for driving cooling fans and other accessories, turning a potential waste stream into a productivity enhancement without requiring external energy inputs or significantly increasing system complexity.
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
Improves overall system and vehicle efficiency by maximizing work extraction from compressed fluid, enhancing heat transfer from lubricants and load devices, and allowing independent adjustability of cooling fluid based on operating conditions, thereby optimizing thermal management.
Implementation Method 1
generating an output torque via expanding at least a portion of the flow of compressed fluid across a turbine
Implementation Method 2
incorporating a heat exchanger to manage thermal loads
Data Source
AI summary
A thermal management system for a propulsion system of an aircraft includes a fluid circuit configured to provide a flow of a compressed fluid from a compressor section of the propulsion system to, in serial flow order, a first turbine, a compressor, a second turbine, a thermal load, and an exhaust sink. A heat exchanger is disposed in a fan stream of the propulsion system at a location along the fluid circuit between the compressor and the second turbine. The fluid circuit extends through and is in thermal communication with the heat exchanger.