Skirted Leaf Seal for Gas Turbine Nozzle Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engine exhaust nozzles face inefficiencies due to leakage of core air through gaps between movable flaps and stationary sidewalls, which reduces thrust and efficiency, and existing dynamic seals struggle to effectively seal these gaps while accommodating sliding motion and thermal variations.
Innovation Solution
A dynamic skirted leaf seal assembly with resilient flap and wall arms that bias away from each other, forming an interior space and accommodating gap size variations, is used to seal the gap between the movable flap and stationary sidewall, reducing core air leakage and adapting to distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dynamic seal is used to seal the gap between movable flap and stationary sidewall, then core air leakage is reduced, but the seal must accommodate sliding motion and thermal variations which complicates the design
Solution Approach 1:
The seal assembly uses resilient arms (flap arm and wall arm) that can dynamically deflect and adapt to relative motion between the movable flap and stationary sidewall. The resilient nature allows the seal to accommodate sliding motion and thermal variations without requiring complex adjustment mechanisms, while maintaining effective sealing contact.
Solution Approach 2:
The seal assembly changes its physical parameters (deflection, contact pressure, gap distance) in response to thermal and mechanical conditions. The resilient arms naturally adjust their position and force application based on thermal expansion and relative motion, allowing the seal to adapt to varying operating conditions without complex control systems.
2Adaptability or versatility
If the seal structure is made more resilient to accommodate motion, then adaptability to thermal and motion variations improves, but the risk of excessive gap and reduced sealing effectiveness increases
Solution Approach 1:
The seal assembly extracts the sealing function from a single rigid component and distributes it across multiple resilient elements (flap arm, wall arm, and skirt). This distribution allows each element to independently adapt to motion while collectively maintaining sealing effectiveness, preventing excessive gap formation.
Solution Approach 2:
The skirt is positioned within the interior space formed by the flap arm and wall arm, creating a nested configuration. The skirt provides an additional sealing barrier that prevents core air from entering the interior space, while the resilient arms accommodate motion. This nested arrangement ensures redundant sealing protection.
3Adaptability or versatility
If existing dynamic seals are used, then some sealing capability is provided, but they struggle to effectively seal gaps while accommodating sliding motion and thermal variations
Solution Approach 1:
The seal assembly is segmented into distinct functional components: the flap arm attached to the movable flap, the wall arm attached to the stationary sidewall, and the skirt positioned within the interior space. This segmentation allows each component to independently respond to motion and thermal variations while collectively maintaining sealing effectiveness, outperforming conventional single-piece dynamic seals.
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 dynamic skirted leaf seal effectively seals the gap, reducing core air leakage and adapting to thermal and motion-induced distortions, thereby enhancing the engine's thrust and efficiency without adding weight or complexity.
Implementation Method 1
a first seal having a first proximal end portion, a first distal end portion with a first bend, and a first skirt extending away from the first bend; and a second seal having a second proximal end portion, a second distal end portion with a second bend, and a second skirt extending away from the second bend. The second seal opposite the first seal and forming an interior space therebetween, wherein the first seal biases away from the second seal to seal the gap
Data Source
AI summary
In some embodiments, apparatuses are provided herein useful to sealing a gap between a movable flap and a stationary structure, such as a gap between a gas turbine engine nozzle flap and a corresponding sidewall. An apparatus for sealing such a gap may be a dynamic skirted leaf seal which may include a flap arm and a wall arm opposite the flap arm. A distal end portion of the flap arm may comprise a first skirt and the distal end portion of the wall arm may comprise a second skirt that engages the first skirt. When positioned in a gap between the movable flap and the stationary structure, the skirted leaf seal may exert a force to urge the flap arm towards the flap and to urge the wall arm towards the structure to seal the gap.