Aircraft Inert Gas Turbocompressor Cooling With Regenerative Exhaust
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current on-board inert gas generation systems for aircraft fuel tanks face challenges in efficiently producing inert gas while minimizing disruptive exhaust conditions, particularly at high altitudes and fast-moving aircraft, where temperature and pressure variations can affect flight performance and increase the risk of explosions due to combustible oxygen and fuel vapor mixtures.
Innovation Solution
A turbocompressor-based gas generation system with a thermal control module that includes a turbine wheel, regenerative heat exchanger, and compressor, utilizing bleed air to generate compressed air and nitrogen-enriched gas, which is then introduced into the fuel tank ullage space, while stabilizing pressure ratios and controlling temperature variations through a control valve and ozone removal system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a regenerative heat exchanger is used to cool pressurized air, then the efficiency of inert gas generation is improved, but the device complexity increases
Solution Approach 1:
The regenerative heat exchanger utilizes the turbine exhaust air (which is already cooled and pressurized) to pre-cool the incoming pressurized air before it enters the compressor. This self-service approach recovers energy from the exhaust stream to improve the efficiency of the inert gas generation process without requiring additional external cooling resources.
Solution Approach 2:
Instead of discarding the turbine exhaust air directly into the ambient, the system recovers its cooling capacity by using it to pre-cool the incoming pressurized air in the regenerative heat exchanger. This recovery process improves overall system efficiency while the exhaust is eventually discharged through the ejector into ram air flow.
2Ease of operation
If the turbine exhaust air is discharged directly into ambient, then the system operation is simplified, but the flight performance is disrupted due to temperature and pressure variations
Solution Approach 1:
The ejector serves as an intermediary device that facilitates the discharge of turbine exhaust air into the ram air flow rather than directly into the ambient environment. This intermediary approach allows the exhaust to be mixed and diluted with the high-velocity ram air, reducing the disruptive effects of temperature and pressure variations on flight performance while maintaining operational simplicity.
3Adaptability or versatility
If the pressure ratio across the turbine wheel varies with altitude, then the system adapts to different flight conditions, but the inert gas generation efficiency decreases
Solution Approach 1:
The system dynamically adjusts to different altitude conditions by allowing the pressure ratio across the turbine wheel to vary with altitude changes. The regenerative heat exchanger and ejector configuration maintains stable operation across this dynamic range, ensuring that inert gas generation efficiency is preserved despite the varying pressure conditions encountered during different phases of flight.
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 reduces oxygen levels in aircraft fuel tanks, minimizing explosion risks and maintaining efficient flight performance by generating sufficient inert gas while managing temperature and pressure fluctuations, thus enhancing safety and operational stability.
Implementation Method 1
The bleed air is cooled by passing turbine exhaust air in thermally conductive proximity to the bleed air
Implementation Method 2
the pressurized air from the pressurized air supply rotating the turbine wheel becomes cooled air
Implementation Method 3
The rotating compressor receives the cooled air from the regenerative heat exchanger and generates compressed air
Implementation Method 4
The primary heat exchanger cools the compressed air by passing the compressed air in thermally conductive proximity to ram air
Data Source
AI summary
The present invention provides a system and method for cooling the bleed air supply in an on-board inert gas generation system. The gas generation system cools the bleed air using a turbocompressor in conjunction with heat exchangers. Exhaust from a regenerative heat exchanger providing air to the turbocompressor is ported to a ram air outlet using a flow-restriction/ejector unit.