Turbine Bleed System Segmentation for Fuel Efficiency
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Solution Overview
Problem
Existing turbine engine bleed systems face challenges in balancing fuel efficiency and component durability, particularly due to hot gas path ingestion in the low-pressure turbine, which occurs when insufficient pressure bleed air is provided from upstream stages of the high-pressure compressor.
Innovation Solution
The implementation of a bleed system with three distinct bleed flowpaths from successive stages of the high-pressure compressor, including a first bleed flowpath at the third stage for aircraft systems, a second bleed flowpath at the fourth stage for the low-pressure turbine, and a third bleed flowpath at the sixth stage for the high-pressure turbine, ensures efficient air distribution and maintains positive back flow margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If bleed air is extracted from upstream stages of the high-pressure compressor to reduce fuel burn penalties, then fuel efficiency is improved, but insufficient pressure bleed air is provided causing hot gas path ingestion in the low-pressure turbine
Solution Approach 1:
The bleed system is segmented into multiple distinct bleed flowpaths (first, second, and third bleed flowpaths) tapping air from different stages (third, fourth, and sixth stages) of the high-pressure compressor. This segmentation allows independent optimization of each bleed path's pressure and flow rate, enabling sufficient pressure delivery to the low-pressure turbine while extracting adequate air from upstream stages to reduce fuel burn penalties.
Solution Approach 2:
Different bleed flowpaths provide air with different pressure characteristics to different destinations. The first bleed flowpath provides lower pressure air to aircraft systems, while the second and third bleed flowpaths provide higher pressure air to the low-pressure and high-pressure turbines respectively. This local quality differentiation ensures each component receives the specific pressure level it requires.
2Reliability
If bleed air pressure is increased to prevent hot gas path ingestion, then component durability is improved, but fuel burn penalties increase
Solution Approach 1:
By segmenting the bleed system into multiple flowpaths from different compressor stages, the invention can provide high-pressure air to the low-pressure turbine from the fourth and sixth stages without requiring excessive bleed air extraction from upstream stages, thus preventing hot gas path ingestion while minimizing fuel burn penalties.
Solution Approach 2:
The invention changes the pressure parameter of bleed air by tapping from different compressor stages. The second and third bleed flowpaths utilize higher pressure air from downstream stages (fourth and sixth stages) to ensure sufficient pressure margin for the low-pressure turbine, while the first bleed flowpath uses lower pressure air from the third stage for aircraft systems, optimizing the balance between component protection and fuel efficiency.
3Productivity
If multiple bleed flowpaths are implemented from successive stages, then air distribution efficiency is improved, but system complexity increases
Solution Approach 1:
The bleed system is divided into three separate bleed flowpaths (first, second, and third) with distinct functions and pressure requirements. Each flowpath is equipped with its own control valve (first, second, and third bleed flowpath valves), allowing independent control and optimization of air distribution to different components without requiring complex interaction between the flowpaths.
Solution Approach 2:
The system employs variable geometry diffusers in each bleed flowpath that can dynamically adjust their opening based on operating conditions. The diffusers are controlled by actuators that respond to sensor inputs, enabling real-time optimization of air flow distribution efficiency while managing the complexity through automated control rather than mechanical complexity.
Data Source
AI summary
A method of operating a turbine engine. The turbine engine includes a high-pressure compressor including a high-pressure compressor flowpath and a plurality of stages, and a bleed system. The bleed system includes a plurality of bleed flowpaths including a first bleed flowpath from one stage of the plurality of stages and a second bleed flowpath from another stage of the plurality of stages. The method includes directing compressed air through the high-pressure compressor flowpath, directing a first portion of the compressed air through the first bleed flowpath, the first portion of the compressed air having a first mass flow, directing a second portion of the compressed air through the second bleed flowpath, determining an altitude of the turbine engine, and changing the first mass flow of the first portion of the compressed air through the first bleed flowpath based on the altitude of the turbine engine.