Temperature Controlled Nitrogen Generation for Aircraft Fuel Inerting
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Solution Overview
Problem
Membrane-based nitrogen generation systems for aircraft fuel tanks require larger and heavier units to maintain adequate inerting throughout flight due to fixed permeability and selectivity of polymeric membranes, limiting performance.
Innovation Solution
A temperature-controlled nitrogen generation system that adjusts the temperature of the air separation module's membrane to manipulate permeability and selectivity, using a heat exchanger, flow control valves, and sensors to control the flow rate and oxygen concentration of nitrogen-enriched air based on aircraft flight phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a membrane-based nitrogen generation system uses a polymeric membrane with fixed permeability and selectivity, then the system structure is simple, but the system requires larger volume and greater weight to provide adequate fuel tank inerting throughout the flight profile
Solution Approach 1:
The patent applies the dynamics principle by transforming the static membrane system into a dynamic one through temperature control. The membrane temperature is actively adjusted during flight to change its permeability and selectivity characteristics, allowing the same membrane area to provide varying nitrogen enrichment levels as needed during different flight phases, thereby reducing the overall system volume required
Solution Approach 2:
The patent implements parameter changes by modifying the membrane's operating temperature to alter its physical properties (permeability and selectivity). By controlling the temperature parameter, the system can optimize nitrogen generation performance for different flight conditions without changing the membrane's physical dimensions, thus reducing the volume required for adequate inerting
2Device complexity
If a membrane-based nitrogen generation system uses a polymeric membrane with fixed permeability and selectivity, then the system structure is simple, but the system requires greater weight to provide adequate fuel tank inerting throughout the flight profile
Solution Approach 1:
The system transitions from a static to a dynamic configuration by implementing temperature control of the membrane. This allows the membrane to adapt its performance characteristics during flight, enabling a lighter membrane structure to provide adequate inerting across varying flight conditions rather than requiring an oversized, heavy membrane designed for maximum demand
Solution Approach 2:
By changing the membrane temperature parameter, the system optimizes nitrogen generation efficiency. This parameter control allows a smaller, lighter membrane area to achieve the required nitrogen enrichment levels during different flight phases, thereby reducing overall system weight
3Volume of moving object
If the membrane temperature is controlled to manipulate permeability and selectivity, then the system performance is enhanced and volume/weight are reduced, but the system complexity increases
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary component between the air separation module and the environment. This heat exchanger enables temperature control of the membrane by facilitating heat transfer, allowing performance optimization without directly complicating the membrane structure itself
Solution Approach 2:
The system implements feedback control by monitoring nitrogen enrichment levels and adjusting membrane temperature accordingly. Sensors detect oxygen concentration or nitrogen flow rate, and the controller modifies heat exchanger operation to maintain optimal membrane temperature for current flight conditions, automating the complexity management
4Weight of moving object
If the membrane temperature is controlled to manipulate permeability and selectivity, then the system weight is reduced, but the system complexity increases
Solution Approach 1:
The heat exchanger serves as a lightweight intermediary that enables temperature control without adding significant weight. By placing the heat exchanger in the airflow path, the system achieves membrane temperature control using existing air streams, minimizing additional weight while enabling performance optimization
Solution Approach 2:
Automatic feedback control reduces the need for heavy manual intervention and oversized safety margins. The controller continuously monitors nitrogen generation performance and adjusts membrane temperature to maintain optimal operation, allowing the system to be both lightweight and reliable
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
This approach enhances the performance of the nitrogen generation system, allowing for a reduction in volume and weight while meeting varying demands for nitrogen-enriched air during an aircraft's flight profile.
Implementation Method 1
a heat exchanger for receiving supply air and cooling air and providing temperature conditioned supply air
Implementation Method 2
a polymeric membrane which separates air into NEA and oxygen-enriched air (OEA)... permeability (defined as the transport flux of a gas through the membrane per unit driving force)
Implementation Method 3
selectivity (selectivity α AB is defined as the ratio of permeability of one gas component A to the permeability of another gas component B in a gas mixture)
Data Source
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AI summary
A nitrogen generation system includes a heat exchanger (12, 112, 212) for receiving supply air and cooling air and providing temperature conditioned supply air, a flow control valve (16, 116, 216) for controlling a flow of the cooling air through the heat exchanger, and an air separation module (26, 126, 226) for receiving the temperature conditioned supply air and generating nitrogen-enriched air. The nitrogen generation system also includes a sensor (34, 134, 234) for measuring a parameter of the nitrogen-enriched air selected from the group consisting of a temperature, a flow rate, an oxygen concentration, and combinations thereof, and a controller connected to the sensor and the flow control valve for controlling the flow of the cooling air through the heat exchanger based on the parameter of the nitrogen-enriched air measured by the sensor.