Turbofan Bleed-Air Bypass for Part-Power Efficiency and Thrust
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face inefficiencies in specific fuel consumption due to sizing for maximum rated thrust, leading to higher consumption at part-power cruise, and are susceptible to erosion from particulate ingestion, particularly in the high-pressure compressor and turbine sections.
Innovation Solution
A turbofan gas turbine engine design with a bleed passage system that diverts airflow from the low-pressure compressor to bypass the high-pressure components, incorporating a bleed burner for increased thrust and variable pitch vanes to control airflow, along with a centrifuge mechanism to redirect particulates away from critical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the compressor is sized for maximum rated thrust, then the engine can deliver maximum power, but specific fuel consumption increases at part-power cruise conditions
Solution Approach 1:
The patent implements variable geometry components including variable stator vanes and variable pitch propeller blades that can adjust their configuration dynamically. This allows the engine to optimize aerodynamic performance across different operating conditions, improving part-power efficiency while maintaining maximum thrust capability when needed
Solution Approach 2:
The engine is divided into functionally independent sections with separate control systems for the compressor, combustor, turbine, and propeller. This segmentation allows each component to be optimized and controlled independently for its specific operating range, enabling better part-power cruise efficiency without sacrificing maximum power output
2Use of energy by moving object
If the engine operates at part-power cruise conditions with a compressor sized for maximum thrust, then fuel consumption increases, but the engine structure remains simple
Solution Approach 1:
Variable geometry components such as adjustable stator vanes and propeller pitch control mechanisms are incorporated to dynamically optimize performance. These dynamic adjustments allow the engine to achieve better part-power efficiency without requiring multiple compressors of different sizes, thus managing complexity while improving fuel consumption
3Power
If compressor bleed flow is used for thrust augmentation, then higher thrust is achieved, but thermal stress on engine components increases
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the compressor bleed flow and the combustion chamber. This heat exchanger preheats the bleed air using exhaust gas heat, allowing the bleed flow to be used for thrust augmentation while managing thermal loads on engine components and reducing direct thermal stress
4Reliability
If particulate matter is allowed to enter the core section, then the engine structure remains simple, but component erosion increases
Solution Approach 1:
A particulate separator is installed in the air intake system to extract and remove sand, dust, and other particulate matter from the incoming air before it enters the compressor. This extraction of harmful particles protects the compressor and downstream components from erosion, extending component life while adding a relatively simple separation stage to the overall engine structure
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
Reduces specific fuel consumption and extends component life by optimizing compressor size for part-power conditions and preventing erosion through particulate diversion, while enabling higher thrust without increased thermal stress.
Implementation Method 1
incorporating a bleed burner for increased thrust
Implementation Method 2
along with a centrifuge mechanism to redirect particulates away from critical components
Data Source
Figure 1
Figure 2
AI summary
A gas turbine engine (20) includes a core section including a compressor (44, 50), a main combustor (54), and a main turbine (46, 52). Combustion products from the main combustor (54) drive rotation of the turbine (46, 52) and the compressor (44, 50). A power turbine (40) is fluidly connected to the main turbine (46, 52) and driven by exhaust from the main turbine (46, 52). The gas turbine engine (20) further includes a fan section (22) having a fan rotor (38) located fluidly upstream of the core section. The power turbine (40) is operably connected to the fan rotor (38) to drive rotation of the fan rotor (38) via rotation of the power turbine (40). The gas turbine engine (20) includes a bleed arrangement having one or more bleed passages (56) configured to divert a bleed airflow (62) from the compressor (44, 50) around the main combustor (54) and main turbine (46, 52), and reintroduce the bleed airflow (62) into the power turbine (40).