Dynamic Seal Assembly for Twisting Rocket Engine Duct Joints
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Solution Overview
Problem
Rocket engine ducts with flexible joints face leakage issues due to twisting movement between torsional rings, which existing dynamic seals fail to adequately address, especially under high pressures and varying temperatures.
Innovation Solution
A duct design featuring first and second torsional rings with dynamic seals, including internal coils and fluoropolymer outer jackets, and a spacer ring, allowing for twisting movement while maintaining dynamic sealing, with the seals being continuous rings and the outer polymer jacket having non-symmetrical arms with controlled surface roughness to enhance sealing at cryogenic temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing dynamic seals are used in ducts with torsional rings, then the duct can accommodate twisting movement, but fluid leakage occurs between the torsional rings
Solution Approach 1:
The seal assembly is designed to be dynamic rather than static, allowing it to accommodate torsional movement between duct sections. The bellows structure enables angular displacement while the dynamic seal maintains continuous contact with the mating surface, adapting to the changing geometry during twisting motion without compromising sealing integrity.
Solution Approach 2:
The dynamic seal employs a composite structure combining a resilient sealing element (such as elastomer or polymer) with a supportive metallic or rigid framework. This composite construction allows the seal to deform elastically during torsional movement while maintaining structural integrity and consistent sealing pressure against the mating flange surface.
2Ease of manufacture
If the outer polymer jacket is made with smooth surface, then assembly is easy, but sealing effectiveness at cryogenic temperatures is reduced
Solution Approach 1:
The outer polymer jacket exhibits different surface characteristics at different locations or scales. The bulk surface remains relatively smooth for assembly purposes, while the contact surface with the mating flange features controlled roughness elements or increased surface area that enhance sealing effectiveness at cryogenic temperatures by conforming to surface irregularities and maintaining seal pressure.
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 design effectively limits fluid leakage between torsional rings by providing primary and backup sealing, maintaining sealing integrity under twisting forces and temperature variations, ensuring reliable operation of steerable rocket engines.
Implementation Method 1
The flexible joints may include bellows that can stretch, compress, or angularly displace to provide the required movement
Implementation Method 2
The outer polymer jacket includes a base and first and second spaced-apart arms extending from the base and between which the internal coil is disposed
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A duct includes first and second bellows sections. First and second torsional rings are attached to, respectively, the first and second bellows sections. First and second dynamic seals are sandwiched between the first and second torsional rings.