Turbo Air Cycle Machine for Aircraft Bleed Air Pre-Cooling
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Solution Overview
Problem
Aircraft bleed air systems waste excess heat, and existing systems lack efficiency in providing variable bleed air to meet dynamic environmental control demands, leading to suboptimal performance and increased fuel costs.
Innovation Solution
A bleed air system utilizing a turbo air cycle machine with a proportional mixing-ejector valve assembly and dual compressor sections, which allows for the selection and combination of low and high-pressure bleed air to precondition air for environmental control systems, recovering energy and reducing waste heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pre-cooler heat exchanger is used to pre-condition hot bleed air, then the air temperature is reduced to sustainable levels for ECS, but waste heat is exhausted without utilization and energy efficiency decreases
Solution Approach 1:
The patent converts the harmful waste heat from the pre-cooler into a useful resource by routing it through a heat exchanger that transfers thermal energy to the conditioned air stream. This transforms the previously wasted thermal energy into a benefit that reduces the workload on the ECS and improves overall system efficiency.
Solution Approach 2:
Instead of discarding the heat from the pre-cooled bleed air, the system recovers this thermal energy through a secondary heat exchanger arrangement. The recovered heat is then utilized to pre-condition the ambient air or assist the ECS, thereby eliminating the energy loss that would otherwise occur.
2Device complexity
If bleed air systems provide fixed pressure and temperature, then system design is simplified, but adaptability to dynamic ECS demands is reduced
Solution Approach 1:
The patent implements dynamic control capabilities in the bleed air system by incorporating variable geometry components and controllable valves that can adjust pressure and temperature outputs in real-time. This allows the system to adapt to varying ECS demands while maintaining manageable design complexity through standardized control architecture.
Solution Approach 2:
The bleed air system is designed with multi-functional capabilities that allow it to serve different ECS requirements across various flight conditions. By integrating adjustable pressure regulators, temperature control valves, and multiple extraction ports, the system can universally meet diverse environmental control demands without requiring separate dedicated systems.
3Stress or pressure
If high-pressure bleed air is extracted from the engine, then sufficient pressure is provided for ECS, but engine efficiency decreases and fuel consumption increases
Solution Approach 1:
The patent employs parameter changes by utilizing multiple bleed air extraction ports at different pressure stages along the compressor. This allows the system to select the optimal pressure level based on ECS requirements, thereby minimizing the impact on engine efficiency and fuel consumption while still providing sufficient pressure for environmental control functions.
Solution Approach 2:
The bleed air system is segmented into multiple extraction points at different compressor stages, each providing air at different pressure levels. This segmentation allows the ECS to receive bleed air at the minimum necessary pressure, reducing the burden on the engine and lowering fuel consumption compared to extracting all high-pressure air from a single point.
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 achieves efficient bleed air conditioning that meets variable demands, reduces fuel costs, and extends flight range by utilizing energy recovery and parallel compressor operation, enhancing performance and reducing waste heat.
Implementation Method 1
a first turbine section (40a) receives the high-pressure bleed air and emits a cooled air stream
Implementation Method 2
a first turbine section (40a) receives the high-pressure bleed air and emits a cooled air stream
Implementation Method 3
a second turbine section (40b) receives the cooled air stream and emits a further cooled airflow
Implementation Method 4
a set of compressor sections (42a, 42b) compresses low-pressure air to a higher pressure
Implementation Method 5
The pre-cooler heat exchangers produce waste heat
Data Source
Figure 1
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Figure 3
AI summary
A method and aircraft for providing bleed air to environmental control systems of an aircraft using a gas turbine engine, including determining a bleed air demand for the environmental control systems, selectively supplying low pressure and high pressure bleed air to the environmental control systems, wherein the selectively supplying is controlled such that the conditioned air stream satisfies the determined bleed air demand.