Actuation Assembly for Gas Turbine Fan Blade Spacing
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Solution Overview
Problem
Gas turbine engines without an outer nacelle face issues with misaligned airflow causing uneven force distribution on fan blades, leading to undesirable 1P loads during operations like takeoff or in strong cross-winds.
Innovation Solution
An actuation assembly with a first linkage connected to a fan blade, a pivot point, and a control point that moves relative to the pivot point to adjust the fan blade's position, allowing for equal force distribution by changing the circumferential spacing of the fan blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the outer nacelle is removed to increase fan diameter, then fan diameter is improved, but force distribution uniformity deteriorates due to misaligned airflow causing uneven 1P loads
Solution Approach 1:
The patent applies dynamics by making the fan blade positions adjustable rather than fixed. The actuation assembly allows the circumferential spacing between fan blades to be dynamically changed based on airflow conditions. When misaligned airflow is detected, the system adjusts blade positions to achieve uniform force distribution, thus resolving the contradiction between large fan diameter and force distribution uniformity.
Solution Approach 2:
The patent changes the parameter of fan blade circumferential spacing from a fixed value to a variable parameter that can be adjusted in response to airflow misalignment. By modifying this geometric parameter, the system optimizes force distribution across the fan assembly while maintaining the benefits of a larger fan diameter without an outer nacelle.
2Ease of manufacture
If fan blades are fixed in uniform circumferential spacing, then manufacturing simplicity is improved, but performance under misaligned airflow deteriorates due to uneven 1P loads
Solution Approach 1:
The system transitions from a static blade spacing configuration to a dynamic one where the actuation assembly can adjust circumferential spacing. This allows the fan to adapt to misaligned airflow conditions during operation, improving reliability without significantly complicating manufacturing, as the adjustment mechanism uses standard mechanical components.
Solution Approach 2:
The actuation assembly serves multiple functions: it adjusts blade spacing to optimize performance under misaligned airflow, and can potentially operate in both ducted and unducted configurations. This multi-functionality improves reliability across different operating conditions while maintaining ease of manufacture through a versatile design.
Data Source
AI summary
A fan assembly is provided for a gas turbine engine including: a plurality of fan blades, the plurality of fan blades including a first fan blade; and an actuation assembly including: a first linkage connected to the first fan blade; a first pivot point rotatable with the first fan blade, the first linkage further connected to the first pivot point; a control point moveable relative to the first pivot point and connected to the first linkage for changing a relative position of the first fan blade within the plurality of fan blades.