Multi-stage Co-rotating Variable Pitch Fan for Reverse Thrust
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Solution Overview
Problem
Existing gas turbine engines face challenges in producing reverse thrust efficiently, as traditional thrust reversal devices are large and cumbersome, necessitating alternative approaches for decelerating aircraft during landing without excessive brake wear.
Innovation Solution
A fan design with multiple stages of fan blades that can pivot from forward to reverse pitch angles, utilizing idler gears for synchronized movement and a hub-to-tip ratio within 0.20 to 0.28, allowing for efficient redirection of air flow to achieve reverse thrust without the need for large thrust reversal devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional thrust reversal devices are used to redirect air forward for reverse thrust, then reverse thrust capability is achieved, but the device size becomes large and cumbersome
Solution Approach 1:
The fan blades are designed with variable pitch capability, allowing them to dynamically change their angle of attack from forward pitch (producing forward thrust) to reverse pitch (producing reverse thrust). This dynamic adjustment eliminates the need for separate, large thrust reversal devices by making the fan itself adaptable to different operational modes.
Solution Approach 2:
The fan system is designed to perform multiple functions: it can produce forward thrust during normal operation and reverse thrust during landing. By integrating reverse thrust capability directly into the fan blades through variable pitch mechanisms, the system eliminates the need for dedicated thrust reversal devices, achieving multi-functionality with a single component.
2Adaptability or versatility
If fan blades are designed with variable pitch capability for reverse thrust, then reverse thrust production is enabled, but device complexity increases
Solution Approach 1:
Multiple fan blades are coupled together through a common mechanism that synchronizes their pitch angle adjustments. By merging the pitch control of multiple blades into a single coordinated system, the design achieves variable pitch capability while reducing the overall complexity compared to independently controlling each blade.
Solution Approach 2:
The fan blade assembly is divided into multiple discrete blades that can be independently pitched but are synchronized through coupling mechanisms. This segmentation allows for modular design and maintenance while achieving coordinated variable pitch control across all blades.
3Productivity
If multi-stage fan blades are used for reverse thrust, then operational efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The fan is divided into multiple stages with blades spaced axially at different positions along the central axis. Each stage can be manufactured and assembled separately, then integrated into the complete fan system. This segmentation facilitates manufacturing and assembly while achieving the performance benefits of multi-stage configuration for improved reverse thrust efficiency.
Data Source
AI summary
A fan for a gas turbine engine is disclosed. The fan includes a fan disk and a plurality of fan blades coupled to the fan disk. The fan disk is adapted for rotation about a central axis. The fan blades are coupled to the fan disk for rotation therewith about the central axis.