Convergent Flap Roller Assembly for Gas Turbine Nozzle Friction Reduction
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Solution Overview
Problem
Convergent-divergent nozzles in gas turbine engines face challenges in accommodating significant applied loads and elevated temperatures, leading to frictional resistance and misalignment issues during flap movement, which necessitate stronger and heavier linkages and actuators, and can result in binding and reduced operational efficiency.
Innovation Solution
A convergent flap roller assembly is introduced, comprising a first and second hanger flange, a roller, and a pivot axle, which engages with a guide track to reduce frictional forces and accommodate misalignment, utilizing self-lubricating bearings and track tabs to maintain engagement and facilitate smooth movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If convergent flaps engage with guide tracks to constrain axial and radial movement, then movement control is improved, but frictional forces increase and binding occurs
Solution Approach 1:
The patent replaces traditional sliding contact with rolling contact by introducing rollers at the engagement points between convergent flaps and guide tracks. This curvature-based solution transforms the friction mechanism from sliding friction to rolling friction, significantly reducing the frictional forces that resist flap movement while maintaining effective movement control through the guide track geometry.
2Strength
If stronger linkages and actuators are used to overcome frictional forces, then movement capability is improved, but device weight increases
Solution Approach 1:
The patent substitutes a purely mechanical sliding system with a roller-based system that reduces frictional resistance. By introducing rolling elements, the system requires significantly less actuation force to overcome friction, allowing for lighter linkages and actuators while maintaining the capability to move the convergent flaps against substantial loads.
3Manufacturing precision
If guide tracks are used to constrain flap movement, then positional control is improved, but misalignment causes binding
Solution Approach 1:
The roller elements provide a more tolerant engagement mechanism compared to sliding contact. The rolling contact geometry allows for slight misalignments between the convergent flaps and guide tracks without causing binding, as the rollers can accommodate minor angular deviations while maintaining smooth movement along the guide track path.
Solution Approach 2:
The rollers act as intermediary elements between the convergent flaps and guide tracks, mediating the interaction to reduce the harmful effects of misalignment. This intermediary rolling contact mechanism transforms direct sliding contact into a more forgiving rolling engagement that maintains positional control while reducing binding issues.
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
The roller assembly significantly reduces the actuation force required for nozzle operation, minimizes maintenance, and operates effectively in high-temperature environments, addressing the issues of friction and misalignment while maintaining performance and efficiency.
Implementation Method 1
each convergent flap is engaged to slide along a guide track during the translation, and therefore is subject to frictional forces resisting the sliding movement
Implementation Method 2
utilizing self-lubricating bearings and track tabs to maintain engagement and facilitate smooth movement
Data Source
AI summary
A convergent flap roller assembly is provided that includes a first hanger flange, a second hanger flange, a roller, and a pivot axle. Each hanger flange has a panel, a roller shaft, and at least one track tab. Each roller shaft extends outwardly from the respective panel, and includes a roller shaft bore. The roller has a center bore and an exterior contact surface. The roller shafts are received within the roller center bore and are in contact with each other, and the pivot axle extends through the roller shaft bores.