Aircraft Active Flow Control System Using Heat Exchanger Cooling Airflow
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Solution Overview
Problem
Existing aircraft flow control systems, such as blown flaps, have limitations in managing boundary layer separation and lift coefficients, particularly at low speeds and high aerodynamic loads, and require additional cooling systems that consume significant energy and resources.
Innovation Solution
An active flow control system that utilizes a heat exchanger to circulate a cooling airflow, which is used to affect the boundary layer flow of flight control surfaces, enhancing control and efficiency by providing active flow management and reducing the need for dedicated fans or additional heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dedicated cooling system with additional heat exchangers and fans is used, then cooling efficiency is improved, but device complexity and weight increase
Solution Approach 1:
The patent merges the cooling system and boundary layer control system into a single integrated system. The same heat exchanger and airflow path are used for both cooling the engine component and providing boundary layer control to the wing, eliminating the need for separate dedicated cooling equipment and reducing overall system complexity
Solution Approach 2:
The cooling airflow serves dual purposes: it cools the engine component by absorbing heat through the heat exchanger, and simultaneously provides boundary layer control to the wing surface to prevent flow separation. This multi-functionality reduces the number of required system components
2Ease of operation
If compressed air is bled from the engine compressor for boundary layer control, then active flow control is improved, but fuel consumption increases
Solution Approach 1:
The patent converts the waste heat from the engine component into a useful resource. Instead of dissipating this heat to the environment, the system uses it to pre-heat the boundary layer control airflow, improving the thermal energy utilization and reducing the energy penalty of the active flow control system
Solution Approach 2:
The system uses its own waste thermal energy to improve the effectiveness of the boundary layer control. The heated airflow from the heat exchanger provides better thermal conditions for flow control, allowing the system to serve its own needs without external energy input
3Strength
If the boundary layer control system is activated, then lift coefficient is improved, but drag increases due to additional airflow
Solution Approach 1:
The patent changes the thermal parameter of the boundary layer control airflow by heating it through the heat exchanger. This thermal parameter change modifies the airflow characteristics, allowing for more effective boundary layer control at lower mass flow rates, thereby reducing the drag penalty associated with injecting large amounts of cold air
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 system improves stall angles, reduces stall speeds, and enhances lift coefficients, while also optimizing cooling efficiency and reducing fuel consumption by utilizing waste air for boundary layer control, thus enhancing aircraft performance and reducing weight and size.
Implementation Method 1
cooling the liquid coolant in the heat exchanger by circulating a cooling airflow through the heat exchanger in heat exchange relationship with the liquid coolant
Implementation Method 2
providing fluid communication between the cooling airflow and a boundary layer flow of at least one flight control surface of the aircraft, the cooling airflow affecting the boundary layer flow
Data Source
AI summary
A method of providing active flow control for an aircraft includes cooling a liquid coolant in a heat exchanger by circulating a cooling airflow through the heat exchanger, and providing fluid communication between the cooling airflow and a boundary layer flow of at least one flight control surface of the aircraft. The cooling airflow affects the boundary layer flow of the flight control surface(s) to provide active flow control. A method of cooling an engine core of an engine assembly includes circulating a cooling fluid through the engine core, and cooling the cooling fluid with a cooling airflow used to provide active flow control to a flight control surface of the aircraft. An active flow control system for an aircraft is also discussed.