Rocket Engine Extendable Divergent Nozzle Thermal Protection
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Solution Overview
Problem
Deployable divergent rocket engine nozzles face issues with mechanical integrity due to high thermal radiation, which can lead to overheating and damage of deployment mechanisms during operation.
Innovation Solution
A deployable diverging rocket engine design featuring a rigid thermal protection screen with a convex wall and lateral fins, along with a flexible heat shield strip, is introduced to mitigate thermal radiation effects on the deployment mechanism. The rigid screen is made of refractory metallic materials like tungsten or molybdenum alloys, while the flexible strip is composed of borosilicate cloth and alumina fibers, providing enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a deployable divergent nozzle is used to adapt outlet section to ambient pressure, then thrust optimization is improved, but the deployment mechanism is exposed to high thermal radiation causing overheating and mechanical property degradation
Solution Approach 1:
A rigid thermal protection screen made of refractory metallic material (tungsten or molybdenum alloy) is introduced as an intermediary element between the divergent nozzle and the deployment mechanism. This screen intercepts thermal radiation from the nozzle, preventing it from reaching the deployment mechanism, thereby protecting mechanical components while preserving the deployable divergent design for thrust optimization
Solution Approach 2:
The thermal protection screen is designed as a sacrificial component that can be replaced if necessary. By using a relatively simple refractory metallic screen rather than making the entire deployment mechanism thermally resistant, the solution provides cost-effective protection while maintaining the complexity of the deployment mechanism to a minimum
2Device complexity
If the deployment mechanism is placed close to the divergent for compact design, then device complexity is reduced, but thermal radiation exposure increases causing temperature rise and potential destruction
Solution Approach 1:
The rigid thermal protection screen serves as a physical barrier positioned between the divergent nozzle and the deployment mechanism, allowing the mechanism to remain in its compact position close to the divergent while blocking harmful thermal radiation from reaching it
Solution Approach 2:
The thermal protection system combines a rigid refractory metallic screen (tungsten or molybdenum alloy) for high-temperature radiation resistance with a flexible heat shield strip (borosilicate cloth and alumina fibers) for additional thermal protection and adaptability, creating a composite protective structure
3Reliability
If thermal protection is added to protect the deployment mechanism, then reliability is improved, but device complexity increases
Solution Approach 1:
The thermal protection system is divided into two functional segments: a rigid thermal protection screen made of refractory metallic material for blocking intense thermal radiation from the divergent, and a flexible heat shield strip made of borosilicate cloth and alumina fibers for additional protection and adaptability. This segmentation allows each component to be optimized for its specific protective function while keeping the overall structure manageable
Solution Approach 2:
The rigid thermal protection screen is positioned specifically where thermal radiation exposure is most severe - between the divergent nozzle and the deployment mechanism. The flexible heat shield strip extends over the entire height of the first fixed diverging section, providing localized protection where needed rather than uniformly protecting the entire mechanism
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 thermal protection system effectively reduces overheating and mechanical stress on the deployment mechanism, ensuring the integrity and reliability of the rocket engine by directing thermal radiation away from critical components and maintaining mechanical properties.
Implementation Method 1
emits by thermal radiation a flux which can reach, in certain places, 250 kW per m2
Implementation Method 2
the thermal protective screen has a convex wall on its turned face towards the first section of fixed diverging
Implementation Method 3
a rigid thermal protection screen interposed between the deployment mechanism and the first section of fixed divergent
Implementation Method 4
the rigid screen is made of refractory metallic materials like tungsten or molybdenum alloys
Implementation Method 5
a flexible heat shield strip disposed between the rigid heat shield and the deployment mechanism
Implementation Method 6
the flexible strip is composed of borosilicate cloth and alumina fibers
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a rocket engine with an extendable divergent which includes an exhaust nozzle for the gases coming from a combustion chamber, the nozzle having a longitudinal axis (ZZ') including a first portion defining a nozzle throat and a first fixed divergent section (12), at least one second extendable divergent section (16) with a larger cross-section than the first fixed divergent section (12) and a mechanism (18) for extending the second extendable divergent section (16) arranged outside the first and second divergent sections (12, 16). A rigid thermal protection screen (102) is positioned between the extending mechanism (18) and the first fixed divergent section (12). The thermal protection screen (102) has a convex wall (104) on the surface thereof that faces the first fixed divergent section (12).