Rocket Nozzle Overlapping Flap Seals for Gimbaling and Reentry
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Solution Overview
Problem
Existing rocket engines face challenges in providing sufficient control authority during all phases of operation, particularly in sealing the interface between the engine nozzle and the rocket due to movement, and protecting the base area of reusable rockets during reentry into the atmosphere.
Innovation Solution
The use of overlapping flaps, including a first flap for sealing and a second flap for thermal protection, which are biased against the rocket's heat shield to maintain integrity during engine movement and thermal loads, and are designed to be reusable with passive forcing elements like springs to facilitate multiple launches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is provided at the interface between the engine nozzle and the rocket, then sealing effectiveness is improved, but the seal must accommodate nozzle movement which complicates the sealing mechanism
Solution Approach 1:
The seal is designed with flexible elements including a biasing spring that allows the seal to dynamically adapt to nozzle movement. The spring-loaded mechanism maintains continuous contact between the seal and the nozzle interface while accommodating gimbal motion, transforming a static sealing problem into a dynamic solution that follows the moving parts.
Solution Approach 2:
The sealing system uses parameter changes through the spring force that adjusts the contact pressure between the seal and nozzle interface. As the nozzle moves during gimbaling, the spring compresses and expands, automatically adjusting the sealing force to maintain effective sealing across the full range of motion without requiring complex mechanical linkages.
2Object-affected harmful factors
If the rocket base is protected during reentry, then damage to the rocket interior is reduced, but adding protection structures increases device complexity
Solution Approach 1:
The heat shield is nested within the rocket structure, positioned to extend over the engine nozzle and seal assembly during reentry. This nested configuration allows the heat shield to protect the rocket interior from thermal and mechanical damage during atmospheric reentry without requiring separate external protection systems, as it integrates with the existing rocket architecture.
Solution Approach 2:
The heat shield serves multiple functions: it protects the rocket interior from thermal damage during reentry, shields the seal mechanism from heat exposure, and maintains structural integrity of the nozzle assembly. This multi-functionality reduces the need for additional dedicated protection structures, simplifying the overall design.
3Reliability
If seals are designed for single use, then sealing reliability is improved, but replacement after each launch increases maintenance time and cost
Solution Approach 1:
The seal is designed with a biasing spring and flexible elements that allow it to self-adjust and maintain sealing effectiveness throughout repeated use. The spring-loaded mechanism automatically compensates for wear and thermal expansion, enabling the seal to serve multiple launches without replacement, eliminating the need for frequent maintenance while maintaining reliable sealing performance.
Solution Approach 2:
Instead of discarding the seal after single use, the design recovers the seal for repeated use by incorporating durable materials and a self-adjusting spring mechanism that maintains sealing effectiveness over multiple thermal and mechanical cycles, allowing the same seal component to be recovered and reused across multiple launches.
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 seals effectively reduce damage to the rocket interior, simplify refurbishment processes, and enable multiple reuse cycles without the need for seal replacement, thereby reducing costs and maintenance time.
Implementation Method 1
One or more flaps can be biased against the heat shield (either directly, or by acting on an overlapping flap) so as to maintain the integrity of the seal
Data Source
AI summary
Seals for gimbaling and/or fixed rocket engine nozzles, and associated systems and methods are disclosed. A representative rocket propulsion system includes a rocket engine having an exhaust nozzle, a seal plate carried by the exhaust nozzle, and a seal engaged with the seal plate. The seal includes at least one support, multiple pivotable first flaps, carried by the at least one support and positioned to contact the seal plate, and multiple pivotable second flaps, with an individual second flap positioned to shield a corresponding individual first flap. At least one forcing element is operatively coupled to at least one of the individual first flap or the individual second flap, to apply a pivoting force to the at least one of the individual first flap or the individual second flap.