Bi-directional Ram Air System for Aircraft Cooling
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Solution Overview
Problem
Aircraft designs with multiple openings on the outer mold line for air supply increase drag, vulnerability, and maintenance issues, and existing air off-take arrangements within the engine inlet can lead to undesirable operational characteristics, especially at low airspeeds where suction prevents air from flowing into the off-take.
Innovation Solution
A bi-directional flow ram air system with an engine air pathway and an auxiliary air pathway that includes internal and external intakes, utilizing check valves and air movers to ensure air flows in the desired direction, regardless of aircraft speed, and a bi-directional air flow pathway to maintain desired airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple openings are provided on the outer mold line to supply air to aircraft systems, then air supply is improved, but drag increases and vulnerability increases
Solution Approach 1:
The patent combines the engine air intake and auxiliary air intake into a single integrated opening on the outer mold line. The engine air pathway and auxiliary air pathway share a common intake structure, allowing both systems to access atmospheric air through one opening rather than requiring separate openings for each function, thereby reducing the total number of openings while maintaining adequate air supply to both engine and auxiliary systems
Solution Approach 2:
The patent segments the air flow paths into distinct engine air pathway and auxiliary air pathway after the common intake opening. By dividing the air flow into separate channels with independent control mechanisms (check valves, air movers), the system can independently regulate air supply to each component while using a single external opening, thus reducing vulnerability and drag
2Device complexity
If an air off-take is provided within the engine inlet, then the number of openings on the outer mold line is reduced, but air flow is prevented at low airspeeds due to suction
Solution Approach 1:
The patent introduces a check valve as an intermediary component at the engine inlet off-take. The check valve acts as a mediator that prevents backward flow of air caused by engine suction at low speeds, while allowing forward flow when ram air pressure is sufficient. This intermediary mechanism enables the off-take to function reliably across all airspeed conditions without requiring multiple external openings
Solution Approach 2:
The patent employs dynamic control mechanisms including check valves and air movers that can actively regulate flow direction based on operating conditions. At low airspeeds, the check valve closes to prevent suction-induced flow reversal, while at higher airspeeds the ram air pressure opens the check valve to allow cooling air intake, making the system adaptively responsive to varying flight conditions
3Device complexity
If an air off-take is provided within the engine inlet, then the number of openings on the outer mold line is reduced, but maintenance increases due to foreign objects entering the opening
Solution Approach 1:
The patent extracts the auxiliary air intake function from the external environment and routes it through the engine inlet off-take. By taking the auxiliary air intake path inside the engine inlet structure, the system uses the engine inlet's existing protective geometry to shield the auxiliary intake from direct exposure to foreign objects, thereby reducing maintenance requirements while maintaining a reduced opening configuration
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 effectively directs air flow through air flow branches even at low speeds, preventing undesirable suction and maintaining airflow direction, thus reducing drag and vulnerability while minimizing the number of openings on the aircraft fuselage.
Implementation Method 1
A first check valve is provided at the first intake opening. A second intake is the second source. The second intake is disposed externally to the engine air pathway. A plurality of branches provide cooling air to at least one of the ancillary aircraft components. Each of the plurality of branches includes a check valve and an air mover.
Implementation Method 2
Each of the plurality of branches includes a check valve and an air mover. The air mover is configured to move air through a respective branch to cool the at least one ancillary aircraft component.
Implementation Method 3
The auxiliary air pathway is configured to draw in cooling air to cool ancillary aircraft components from at least one of the first intake and the second intake based on the airspeed of the aircraft.
Data Source
AI summary
A ram air system for an aircraft having an engine and a fuselage with an outer mold line. The ram air system includes an engine air pathway having an opening in the outer mold line defining an engine inlet. The engine air pathway is configured to supply operating air for combustion in the engine. An auxiliary air pathway includes a first intake disposed inside the outer mold line in the engine inlet and a second intake disposed externally to the engine air pathway. The auxiliary air pathway is configured to draw in cooling air to cool ancillary aircraft components from at least one of the first intake and the second intake based on the airspeed of the aircraft.