Aircraft Nacelle Cowl Deflection Limiter for Burst Duct Pressure Relief
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Solution Overview
Problem
Existing aircraft propulsion systems face structural damage risks due to uncontrolled pressure relief in the event of a highly-pressurized duct burst, which current systems fail to adequately mitigate.
Innovation Solution
The implementation of a deflection limiter system within the aircraft propulsion system, which includes a core cowl that can flex and move radially to accommodate increased fluid flow during a burst duct condition, while being limited by deflection limiters to prevent over-flexing and structural damage, ensuring controlled pressure relief and maintaining system integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core cowl is allowed to flex and move radially to accommodate increased fluid flow during a burst duct condition, then pressure relief is improved, but structural damage may occur due to over-flexing
Solution Approach 1:
The core cowl is designed with dynamic flexibility to move radially in response to pressure changes during a burst duct condition, allowing the structure to adapt and relieve pressure while maintaining integrity through controlled movement
Solution Approach 2:
The deflection limiter acts as an intermediary component between the core cowl and the fixed structure, mediating the radial movement to prevent over-flexing while still allowing necessary pressure relief through controlled deflection
2Strength
If the core cowl is constrained to prevent over-flexing, then structural damage is prevented, but pressure relief capability is reduced
Solution Approach 1:
The deflection limiter serves as a mediator that allows controlled radial movement of the core cowl for pressure relief while simultaneously preventing excessive deflection that would cause structural damage
Solution Approach 2:
The deflection limiter changes the movement parameter of the core cowl from unrestricted radial movement to controlled deflection within specific limits, enabling pressure relief while maintaining structural integrity
3Strength
If a deflection limiter is introduced to control core cowl movement, then structural damage is prevented, but device complexity increases
Solution Approach 1:
The deflection limiter is segmented into discrete components including the limiter body, pivot pin, and engagement features that can be manufactured and assembled separately, reducing overall system complexity while providing the necessary protection
Solution Approach 2:
The deflection limiter is designed to automatically engage and disengage based on the operational conditions, providing self-regulating protection without requiring external control systems or complex actuation mechanisms
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 deflection limiter system effectively manages pressure changes during a burst duct event, preventing structural damage by allowing controlled radial movement of the core cowl, thus maintaining system integrity and preventing excessive pressure relief.
Implementation Method 1
in the event of a highly-pressurized duct burst... to thereby permit the pressure relief door to assume an open condition in accordance with an occurrence of a burst duct event to relieve excess pressures
Implementation Method 2
a deflection limiter that is configured to enable a predetermined amount of radial movement of the core cowl... configured to limit radial movement of the core cowl
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An assembly is provided for an aircraft propulsion system (20). This assembly includes a nacelle inner structure (42) and a deflection limiter (78). The nacelle inner structure (42) includes an internal compartment (68) and a cowl (72). The internal compartment (68) is configured to house a core (49) of a gas turbine engine (22). The cowl (72) is configured to form an outer radial periphery of the internal compartment (68). The cowl (72) is also configured to form an outer radial periphery of a compartment exhaust (70) to the internal compartment (68) at an aft end (76) of the cowl (72). The deflection limiter (78) is attached to the cowl (72). The deflection limiter (78) is configured to limit radial outward movement of the cowl (72).