Aircraft Environmental Control System with Offset Turbine-Compressor Shaft
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Solution Overview
Problem
Current aircraft environmental control systems face limitations in efficiency regarding engine fuel burn, as they either rely on bleed air, electrical compression, or lower engine pressure, which do not fully optimize energy usage.
Innovation Solution
An aircraft environmental control system that mixes bleed air, fresh air, and cabin discharge air to power a ram air circuit and dehumidification system, using a combination of heat exchangers and compressing devices to achieve efficient cabin pressurization and cooling, with the compressing devices including turbines and compressors coupled via a shaft and a fan offset from the axis of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If bleed air is used to power the environmental control system, then cabin pressurization and cooling can be achieved, but engine fuel burn increases
Solution Approach 1:
The environmental control system is divided into two separate but coordinated packs, each capable of independent operation. This segmentation allows the system to use cabin outflow air for one pack and bleed air for the other pack, optimizing fuel efficiency while maintaining operational redundancy through the ability to operate with either pack independently
Solution Approach 2:
The system changes the operational parameters by using cabin outflow air (a waste resource) instead of bleed air as the primary power source for the compressing devices. This parameter change reduces engine fuel burn while the dual-pack configuration ensures reliability through operational redundancy
2Use of energy by moving object
If electrical power is used to compress outside air, then engine fuel burn is reduced, but system efficiency is limited
Solution Approach 1:
The system uses cabin outflow air (a waste resource) to self-power the compressing devices through the turbine-compressor assembly. This self-service approach converts waste energy into useful work, driving the compression process without requiring external electrical power while maintaining high system efficiency
Solution Approach 2:
The system recovers energy from cabin outflow air that would otherwise be discarded. The outflow air is directed through the turbine to drive the compressor, converting waste kinetic energy into useful compression work, thereby reducing the need for electrical power while maintaining high productivity
3Use of energy by moving object
If lower engine pressure is used, then fuel burn is reduced, but the energy available for environmental control is limited
Solution Approach 1:
The system converts the harmful waste resource of cabin outflow air into a beneficial power source. The outflow air, which would normally be discarded, is captured and used to drive the turbine-compressor assembly, providing sufficient power for environmental control while allowing the engine to operate at lower, more fuel-efficient pressures
4Weight of moving object
If a single integrated pack is used, then component count and weight are reduced, but operational redundancy is lost
Solution Approach 1:
The system merges two separate environmental control packs into a single integrated unit that shares common components such as the heat exchanger, ducting, and control systems. This merging reduces overall component count and weight while maintaining operational redundancy through the dual-pack configuration that can operate independently
5Adaptability or versatility
If the fan axis is offset from the shaft axis, then mounting flexibility is improved, but mechanical complexity increases
Solution Approach 1:
The system employs asymmetric mounting where the fan axis is deliberately offset from the shaft axis. This asymmetric configuration provides mounting flexibility to accommodate various installation positions and orientations within the aircraft, while the offset is designed into the overall mechanical layout to minimize complexity
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 system achieves high fuel burning efficiency by effectively utilizing different air sources to power the environmental control system, reducing component count and weight, and allowing for more flexible mounting configurations within the aircraft.
Implementation Method 1
one or more heat exchangers positioned within the ram air circuit
Implementation Method 2
at least one compressing device includes a turbine and a compressor operably coupled via a shaft
Implementation Method 3
a compressor operably coupled via a shaft
Data Source
Figure 1
AI summary
An environmental control system (20) of an aircraft includes a ram air circuit (30) including a ram air shell (32) having at least one heat exchanger positioned therein. A dehumidification system (42) is arranged in fluid communication with the ram air circuit (30) and at least one compressing device (60) is arranged in fluid communication with the ram air circuit (30) and the dehumidification system (42). The at least one compressing device (60) includes a turbine (64) and a compressor (62) operably coupled via a shaft (68). A fan is operably coupled to the ram air circuit (30). At least one compressing device (60) is arranged non-linearly with the ram air circuit (30) such that an axis of rotation of the fan is offset from the axis of the shaft (68).