Aircraft Engine Accessory Box Venting for Fugitive Fuel Gas
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Solution Overview
Problem
Existing systems for managing gaseous fuels in aircraft engines, such as hydrogen gas, are inadequate in preventing ignition and detonation risks due to fugitive fuel gas accumulation and lack effective ventilation strategies.
Innovation Solution
A system and method for passive and active ventilation of gaseous fuel in aircraft engines, utilizing vents, air scoops, compressor bleed conduits, and blast doors to manage fugitive fuel gas, including sensors and controllers for real-time detection and purging, and a blast door for detonation relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gaseous fuel is handled in aircraft engines, then fuel efficiency and environmental performance are improved, but ignition and detonation risks increase due to fugitive fuel gas accumulation
Solution Approach 1:
The patent extracts and removes fugitive fuel gas from the accessory box interior space through dedicated venting systems. Vents are positioned at strategic locations to extract accumulated fuel gas before it can reach ignition sources, thereby separating the harmful substance from the potential ignition environment.
Solution Approach 2:
The patent introduces inert or less flammable air into the accessory box through vents and air scoops, creating an inerted atmosphere that dilutes the concentration of fuel gas. This reduces the oxygen-fuel mixture to below flammable limits, effectively preventing ignition and detonation while allowing gaseous fuel systems to operate.
2Object-affected harmful factors
If ventilation systems are added to prevent fuel gas accumulation, then ignition risks are reduced, but device complexity increases
Solution Approach 1:
The ventilation system is segmented into multiple independent vent openings distributed at different locations within the accessory box. Each vent handles a specific zone, allowing the system to manage fuel gas accumulation through simple, modular openings rather than a complex centralized ventilation mechanism.
Solution Approach 2:
The venting system operates passively using natural convection and pressure differentials created during engine operation. Air scoops and vents automatically draw air through the accessory box without requiring active fans, motors, or controlled mechanisms, thereby preventing fuel gas accumulation through self-regulating natural forces.
3Device complexity
If passive ventilation is used, then device complexity is minimized, but ventilation effectiveness is reduced compared to active systems
Solution Approach 1:
The patent combines multiple passive venting mechanisms (vents, air scoops, and natural convection paths) into an integrated ventilation system. The synergistic effect of these combined elements compensates for the lack of active components, achieving effective fuel gas removal through coordinated passive airflow paths.
Solution Approach 2:
The ventilation system utilizes three-dimensional airflow patterns created by air scoops positioned at strategic angles and locations. By leveraging spatial dimensionality and directional airflow, the passive system achieves comprehensive coverage of the accessory box interior, effectively removing fuel gas without requiring active mechanical ventilation.
4Object-affected harmful factors
If the accessory box is positioned above the engine, then fuel gas accumulation is reduced due to buoyancy, but access for maintenance becomes more difficult
Solution Approach 1:
The patent extracts fuel gas from the accessory box through strategically positioned vents that leverage the elevated position. By placing vents at the highest points and using air scoops to draw air upward, the system takes advantage of the natural buoyancy of fuel gas to extract it efficiently, while the top position itself facilitates access for vent maintenance.
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
Effectively prevents the spread of fugitive fuel gas, minimizes ignition risks, and safeguards against detonations by actively purging and safely exhausting gaseous fuel, thereby protecting the engine and surrounding components.
Implementation Method 1
allowing buoyancy forces to drive fuel gas upward out of the interior space through the vent
Implementation Method 2
purging the interior space with air drawn through the interior space by a downstream jet pipe
Implementation Method 3
exhausting the interior space with an exhaust flow directed outward from the engine nacelle
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A system (200; 300; 400; 500; 600) for an aircraft engine (100) includes an accessory box (220) and a fuel accessory (116) located in an interior space (222) within the accessory box (220), where a vent (230; 330; 430; 530; 630) is defined through a wall (226, 242) of the accessory box (220). In embodiments, the vent (230... 630) includes a plurality of holes or slots (236; 340) in an outer wall (226) of the accessory box (220) for passage of gaseous fuel from the interior space (222). In embodiments, the vent (230... 630) is configured for passive ventilation of the interior space (222).