Turbine Engine Bleed System Segmentation for Fuel Efficiency
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Solution Overview
Problem
Existing turbine engine bleed systems face challenges in efficiently providing bleed air to aircraft systems and low-pressure turbines while minimizing fuel burn penalties and preventing hot gas path ingestion, which can lead to component durability issues.
Innovation Solution
The implementation of a bleed system with three separate bleed flowpaths from successive stages of the high-pressure compressor, allowing for independent control of bleed air distribution to aircraft systems and turbines, and adjusting bleed air quantities based on altitude to optimize fuel efficiency and prevent hot gas ingestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bleed air is extracted from the high-pressure compressor to supply aircraft systems, then aircraft system requirements are met, but fuel burn penalty increases
Solution Approach 1:
The bleed system is divided into multiple independent flowpaths (first bleed flowpath, second bleed flowpath, third bleed flowpath) that can be selectively activated. This segmentation allows the system to extract bleed air from different compressor stages depending on operational requirements, optimizing the balance between meeting aircraft system needs and minimizing fuel consumption penalties.
2Quantity of substance
If bleed air is extracted from the high-pressure compressor, then aircraft systems receive required air, but hot gas path ingestion risk increases
Solution Approach 1:
The system uses separate bleed flowpaths for different purposes: the first flowpath supplies aircraft systems while the second and third flowpaths supply turbines. This segmentation prevents hot compressed air from the high-pressure compressor from being directed to the low-pressure turbine, thereby eliminating hot gas path ingestion risks while still meeting all air supply requirements.
Solution Approach 2:
A bleed air mixing assembly acts as an intermediary component that can mix bleed air from different stages or introduce cooling air to reduce the temperature of bleed air before it reaches the turbine. This mediator prevents hot gas ingestion by ensuring that air supplied to the low-pressure turbine remains below the threshold for hot gas path ingestion.
3Device complexity
If single bleed flowpath is used, then system complexity is reduced, but independent control of bleed air distribution is limited
Solution Approach 1:
The bleed system is divided into multiple independent flowpaths with individual control capabilities. The first bleed flowpath, second bleed flowpath, and third bleed flowpath can be independently activated or deactivated based on operational conditions, providing versatile control over bleed air distribution to different destinations (aircraft systems or turbines) while maintaining a relatively simple overall system architecture.
Data Source
AI summary
A turbine engine includes a high-pressure (HP) compressor and a bleed system. The HP compressor includes an HP compressor flowpath and a plurality of stages of HP compressor rotor blades and HP compressor stator vanes. The bleed system includes a plurality of bleed flowpaths including at least three bleed flowpaths in fluid communication with the HP compressor flowpath. The plurality of bleed flowpaths direct compressed air from the HP compressor flowpath. At least two of the bleed flowpaths are at successive stages of the plurality of stages.