Split Fan Exit Guide Vanes for Back Pressure and Fan Stress Control
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Solution Overview
Problem
Current gas turbine engine designs with non-variable fan exit guide vanes are not optimized for a wide range of operating conditions, leading to inefficiencies and increased stress on fan blades due to fixed installation angles and airflow back pressure.
Innovation Solution
The implementation of split variable fan exit guide vanes with independently adjustable upper and lower sections, each controlled by actuators, allows for dynamic adjustment of incidence and installation angles in response to operating conditions, optimizing airflow direction and reducing back pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-variable fan exit guide vanes with fixed installation angles are used, then the structure is simple and easy to manufacture, but the engine cannot be optimized for different operating conditions leading to increased fan stress and reduced efficiency
Solution Approach 1:
The fan exit guide vanes are made variable through actuators that can change the installation angle of individual vanes or groups of vanes in response to different operating conditions. This dynamic adjustment capability allows the engine to optimize performance across various flight regimes while managing fan stress effectively.
Solution Approach 2:
The fan exit guide vane system is divided into multiple independently controllable segments or groups. This segmentation allows different portions of the vane array to be adjusted to different angles simultaneously, enabling optimized airflow distribution for various operating conditions while maintaining structural manageability.
2Stress or pressure
If fixed installation angles are used for fan exit guide vanes, then the manufacturing and installation process is simplified, but airflow back pressure adversely affects fan blades causing increased stress
Solution Approach 1:
Variable fan exit guide vanes with adjustable installation angles allow the system to dynamically optimize airflow angles to minimize back pressure on fan blades under different operating conditions, thereby reducing fan blade stress while maintaining manufacturing feasibility through modular actuator designs.
3Productivity
If variable fan exit guide vanes are implemented, then engine efficiency is improved across different operating conditions, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The implementation of variable fan exit guide vanes with actuators enables dynamic optimization of engine efficiency across different operating conditions. The system manages complexity through controlled variableity, where only necessary portions of the vane array are made adjustable based on specific performance requirements.
Solution Approach 2:
By segmenting the fan exit guide vane system into controllable groups rather than making the entire system variable, the design achieves improved engine efficiency while managing manufacturing and control complexity through a modular approach.
Data Source
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AI summary
A gas turbine engine (10) with split variable fan (12) exit guide vanes includes a fan duct (14) supporting, or having supported therein, a circumferential pattern of split variable fan exit guide vanes (18). The split variable fan exit guide vanes include an upper section (30) and a lower section (32), the upper section and the lower section each being adjustable about an axis extending along a span (38) of each of the split variable fan exit guide vanes. The split variable fan exit guide vanes also include an upper actuator (34) in operative communication with the upper section, the upper actuator configured to independently adjust an incidence angle (44) of the upper section responsive to predetermined gas turbine operating conditions, and a lower actuator (36) in operative communication with the lower section, the lower actuator configured to independently adjust an incidence angle (44) of the lower section responsive to the predetermined gas turbine operating conditions.