Segmented Fan Outlet Guide Vanes for Distorted Airflow Control
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Solution Overview
Problem
Fan blades in gas turbine engines 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, allowing for flexible management of distorted airflows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed outlet guide vane assembly 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 assembly is divided into multiple independently controllable vanes, each capable of being positioned at different angles. This segmentation allows each vane to be optimized for specific airflow conditions, enabling the assembly to adapt to varying intake airflow patterns and pressure fluctuations while maintaining manageable structural complexity through modular design
Solution Approach 2:
The outlet guide vane assembly transitions from a fixed structure to a dynamic, adjustable system where individual vanes can be actively positioned based on real-time airflow conditions. This dynamic capability enables the system to respond to and accommodate variations in intake airflow and pressure fluctuations, improving adaptability while the control system manages the complexity of actuation
2Reliability
If the outlet guide vane assembly is made adjustable, then fan operability is enhanced, but the device complexity increases
Solution Approach 1:
The adjustable outlet guide vane assembly is segmented into multiple independently controllable vanes, each with its own actuation mechanism. This segmentation enhances fan operability by allowing precise control over airflow direction for different operational conditions, while the modular nature of the segmented design helps manage overall system complexity through standardized components and control logic
Solution Approach 2:
The outlet guide vane assembly utilizes parameter changes by adjusting the angular position of individual vanes to optimize performance across different operating conditions. This parameter adjustment capability enhances fan operability and reliability, while the use of standardized actuation mechanisms and control algorithms helps mitigate the increase in device complexity
3Reliability
If segmented variable vanes with independent rotation are used, then stall margin is improved, but manufacturing complexity increases
Solution Approach 1:
The outlet guide vanes are segmented into multiple sections that can rotate independently, allowing each segment to be optimized for specific airflow conditions. This segmentation improves stall margin by enabling better flow control and delaying separation, while the modular segmented design facilitates manufacturing through standardized components and assembly procedures
Solution Approach 2:
The segmented vanes incorporate dynamic rotation capability that allows each segment to adjust its position to maintain optimal airflow angles. This dynamic adjustment improves stall margin by preventing flow separation under varying conditions, while the use of standardized rotational joints and actuation mechanisms helps manage manufacturing complexity
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 thrust losses.
Implementation Method 1
a 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 first actuation assembly arranged radially outward of the leading edge portion and including a first actuation head coupled to the first tip segment, a second actuation head, and a first actuation rod coupled to the second actuation head and to the first hub segment
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 actuation assembly having a pass through actuation rod enabling the single actuation assembly to rotate both of the tip and hub segments.