Aircraft Flammability Reduction System Dynamic ASM Control
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Solution Overview
Problem
Conventional on-board inert gas generation systems (OBIGGS) face challenges in reducing parasitic load on aircraft, inefficient air separation module (ASM) performance over its service life, and oversized heat exchangers due to inconsistent air flow and pressure demands, leading to increased weight and operational costs.
Innovation Solution
A flammability reduction system with a pressure limiting valve and electronic controller that dynamically controls air pressure and flow to the ASM, predictive monitoring of ASM health, and heat load management to optimize system performance and component sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ASM is sized to deliver adequate inert gas at the end of service life, then sufficient inerting performance is maintained throughout service life, but additional inlet flow is consumed during early service life creating parasitic burden and requiring oversized components
Solution Approach 1:
The patent applies dynamics by making the ASM inlet flow rate variable rather than constant. The system dynamically adjusts the inlet flow rate based on the ASM's age and performance characteristics, using control logic that modifies operational parameters to match the membrane's declining performance over time, thereby optimizing flow consumption across the service life
Solution Approach 2:
The patent changes operational parameters (inlet flow rate, pressure, temperature) based on the ASM's service life stage. By monitoring operational data and adjusting these parameters dynamically, the system adapts to the membrane's aging characteristics, reducing flow rate when the membrane is new and maintaining adequate flow when performance degrades
2Reliability
If additional inlet flow is provided to account for ASM performance variation, then adequate inert gas production is ensured, but parasitic drag on the aircraft increases
Solution Approach 1:
The system dynamically adjusts inlet flow rate based on real-time monitoring of ASM performance and operational conditions. By using feedback control that adapts flow rate to actual membrane performance and flight conditions, the system minimizes unnecessary flow consumption and associated parasitic drag while ensuring adequate inert gas production
Solution Approach 2:
The patent implements feedback control by monitoring operational data from the ASM and using this information to adjust inlet flow rate. The control system continuously evaluates performance metrics and modifies operational parameters to optimize the balance between inert gas production and flow consumption, thereby reducing parasitic drag
3Reliability
If components are sized to handle maximum ASM inlet flow, then adequate capacity is provided for entire service life, but component weight and cost increase
Solution Approach 1:
The patent applies dynamics by enabling components to operate at variable flow rates rather than requiring constant maximum capacity. By dynamically adjusting inlet flow rate based on ASM performance, the system allows components to be sized for average rather than peak demand, reducing weight while maintaining reliability through adaptive operation
Solution Approach 2:
The system uses partial action by providing adequate inert gas production only when needed, rather than continuously operating at maximum capacity. By adjusting flow rate to match actual requirements based on ASM performance and flight conditions, the system avoids the need for oversized components designed for worst-case scenarios
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
Reduces parasitic drag, extends ASM life, minimizes component size and weight, and lowers operational costs by optimizing air flow and pressure, while predicting ASM failure and adjusting heat load for efficient operation.
Implementation Method 1
The OBIGGS may produce NEA using permeable membranes in an air separation module (ASM). Pressurized air enters the ASM inlet and, as the air passes through the membranes, oxygen is separated from the air stream
Implementation Method 2
With an engine bleed system, compressed hot air is usually cooled by a heat exchanger before being ported or sent to the ASM
Data Source
AI summary
A flammability reduction system and method for controlling air pressure and allowing an air separation module (ASM) to consume less pressurized air includes a pressure limiting valve that is dynamically controlled based upon a defined pressure setpoint. A flammability reduction system and method for predictively monitoring the ASM's health and its remaining useful life includes a flow and/or oxygen sensor that are used to detect trends in ASM flow rate and/or oxygen content in the inert gas produced by the ASM. A flammability reduction system and method for controlling heat load includes flow and temperature sensors for calculating heat load of a component, and controls one or more valves to adjust temperature and/or flow rate to control the heat load based upon a heat load setpoint.