Trimmed Outlet Guide Vanes for Gas Turbine Particle Extraction
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Solution Overview
Problem
Conventional variable bleed valves in gas turbine engines are ineffective in extracting larger particles and amounts of foreign matter such as sand and ice, leading to erosion and stress on compressor vanes and blades, as these particles often fail to be sufficiently drawn into the bleed duct.
Innovation Solution
The system employs multiple variable bleed valve doors with trimmed trailing edges on the outlet guide vane assembly, positioned between the low and high pressure compressors, and circumferentially-spaced support struts to direct flow into the bleed valves, enhancing the extraction of foreign particles into a bypass flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional variable bleed valves are used with standard outlet guide vanes, then the system structure is simple, but foreign matter extraction efficiency is insufficient
Solution Approach 1:
The outlet guide vane assembly is divided into multiple sections, with at least one section having trimmed trailing edges. This segmentation allows the system to enhance foreign matter extraction in specific critical areas while maintaining the overall structure, resolving the contradiction between extraction efficiency and device complexity.
Solution Approach 2:
The patent applies trimmed trailing edges to specific sections of the outlet guide vanes rather than uniformly across all vanes. This local modification concentrates the foreign matter extraction capability where it is most needed (in the bleed duct region) while keeping other parts of the system simple, thus improving extraction efficiency without proportionally increasing overall complexity.
2Productivity
If conventional bleed duct configuration is used, then the device complexity is low, but larger particles are not sufficiently drawn into the bleed duct
Solution Approach 1:
The trimmed trailing edges on the outlet guide vanes preliminarily direct the flow and particles toward the bleed duct before the flow reaches the variable bleed valves. This preliminary action prepares the flow path to enhance particle draw-in efficiency, addressing the insufficiency of conventional configurations without requiring major redesign of the bleed duct itself.
3Reliability
If standard outlet guide vanes are used, then manufacturing is simpler, but erosion and stress on compressor vanes and blades increase
Solution Approach 1:
The trimmed trailing edges are applied selectively to specific sections of the outlet guide vanes that are most effective for directing flow into the bleed duct. This localized manufacturing modification protects critical compressor components from erosion and stress while minimizing the overall manufacturing complexity compared to redesigning the entire outlet guide vane assembly.
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 configuration improves foreign particle extraction efficiency by about 10%, reducing ingestion in the high pressure compressor, leading to enhanced operability, durability, and cost savings through reduced maintenance needs.
Implementation Method 1
each pairs of adjacent support struts comprises at least one VBV door therebetween and a section of the OGV assembly located at an upstream side of the fan hub frame before the each pairs of adjacent support struts. The section of the OGV assembly includes a first side with one or more guide vanes with trimmed trailing edges configured for directing flow into the at least one VBV door without impacting the one or more guide vanes at the first side.
Data Source
AI summary
A system for extracting foreign matter in a gas turbine includes multiple variable bleed valve (VBV) doors disposed on the outer engine casing between a low pressure compressor and a high pressure compressor for bleeding a portion of flow from a core engine flow path into a bypass flow path. The system includes an outlet guide vane (OGV) assembly having multiple guide vanes disposed within the core flow path and multiple support struts positioned downstream from the multiple guide vanes. Each pairs of adjacent support struts comprises at least one VBV door therebetween and a section of the OGV assembly located at an upstream side of the fan hub frame before the each pairs of adjacent support struts. Each section of the OGV assembly includes a first side with one or more guide vanes with trimmed trailing edges configured for directing flow into the at least one VBV door.