Segmented Variable Outlet Guide Vanes for Fan Incidence Control
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Solution Overview
Problem
Gas turbine engine fan blades experience operability issues due to variations in intake airflow and pressure fluctuations, leading to inefficiencies and performance degradation.
Innovation Solution
A fan assembly with a variable leading edge outlet guide vane assembly that includes independently rotating tip and hub segments, controlled by actuation assemblies, to adjust the direction of fan exit air and reduce incidence, using air manipulating members like winglets or seals to manage airflow distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed outlet guide vane is used, then the structure is simple, but it cannot accommodate variations in intake airflow and pressure fluctuations
Solution Approach 1:
The outlet guide vane is divided into multiple independently controllable segments (first outlet guide vane segment, second outlet guide vane segment, etc.) that can be adjusted separately to accommodate varying airflow conditions, resolving the contradiction between adaptability and structural simplicity
Solution Approach 2:
The fixed outlet guide vane is replaced with variable outlet guide vanes that can dynamically adjust their positions based on real-time airflow and pressure conditions, enabling the system to adapt to changing operating conditions while maintaining manageable structural complexity through modular design
2Reliability
If the outlet guide vane angle is fixed, then manufacturing is easier, but fan operability deteriorates under varying intake conditions
Solution Approach 1:
The outlet guide vane assembly is segmented into multiple adjustable segments, each capable of independent angle adjustment, which improves fan operability under varying conditions while keeping the manufacturing process manageable through standardized modular components
Solution Approach 2:
The fixed outlet guide vane angle parameter is changed to variable angles that can be adjusted based on operating conditions, enhancing fan operability and reliability while using standardized adjustment mechanisms to control manufacturing complexity
3Object-affected harmful factors
If a single outlet guide vane is used, then the device complexity is low, but it cannot reduce incidence effectively across the entire fan outlet
Solution Approach 1:
The single outlet guide vane is segmented into multiple segments distributed across the fan outlet, each capable of independent adjustment to locally reduce incidence, achieving effective incidence reduction across the entire outlet while maintaining manageable overall device complexity
Solution Approach 2:
Different segments of the outlet guide vane can be adjusted to different angles based on local airflow conditions, allowing targeted incidence reduction at specific locations while keeping the overall device complexity manageable through localized adjustments rather than uniform changes
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
Enhances fan operability and performance by accommodating complex intake and inlet duct geometries, improving stall margin, efficiency, and reducing fan forcing debits through flexible airflow management.
Implementation Method 1
the first tip segment configured to rotate about a leading edge pitch axis and a first hub segment located radially inward of and separate from the first tip segment, the first hub segment configured to independently rotate about the leading edge pitch axis relative to the first tip segment
Implementation Method 2
a radial gap is formed between the radially inner side of the first tip segment and the radially outer side of the first hub segment, and wherein the first air manipulating member has a radial extent that is sized so as to seal off the incoming fan exit air from flowing through the radial gap
Implementation Method 3
a fan comprising a plurality of fan blades that extend radially outward relative to the central axis and that are adapted to rotate about the central axis to force fan exit air toward an aft end of the fan duct
Data Source
AI summary
A fan assembly for a gas turbine engine includes a fan duct, a fan, and an outlet guide vane assembly located in the fan duct axially downstream of the fan. The outlet guide vane assembly includes a first variable leading edge outlet guide vane that extends radially relative to the central axis and includes a leading edge portion and a fixed aft portion, the leading edge portion including a tip segment configured to rotate about a leading edge pitch axis and a hub segment located radially inward of and separate from the tip segment, the hub segment configured to independently rotate about the leading edge pitch axis relative to the tip segment. The assembly further includes an air manipulating member arranged radially between the tip and hub segments and at least one actuation assembly configured to rotate one of the tip and hub segments.