Liquid Rocket Engine Joint Structure for Thermal Expansion
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Solution Overview
Problem
Conventional liquid rocket engine assemblies face performance and integrity issues due to thermal expansion differences between materials used in nozzles and thrust chambers, leading to potential failures during temperature and pressure fluctuations, and require complex cooling systems which increase costs and complexity.
Innovation Solution
A joint structure comprising a seal element, an attachment ring, and fasteners is used to securely attach the nozzle and thrust chamber, accommodating different coefficients of thermal expansion, thereby reducing the need for active cooling and ensuring a seal between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling systems are added to accommodate thermal expansion differences, then structural integrity is improved, but device complexity increases
Solution Approach 1:
A joint structure serves as an intermediary component between the nozzle and thrust chamber, accommodating thermal expansion differences without requiring complex cooling systems. The joint structure includes a first flange connected to the nozzle, a second flange connected to the thrust chamber, and a biasing element that allows for differential thermal expansion while maintaining structural integrity.
Solution Approach 2:
The joint structure changes its physical parameters (dimensional relationships between flanges and biasing element) based on temperature conditions. The biasing element is configured to permit relative movement between the nozzle and thrust chamber flanges, allowing the assembly to adapt to thermal expansion differences automatically without active cooling control.
2Temperature
If active cooling systems are implemented, then thermal management is improved, but manufacturing cost increases
Solution Approach 1:
The joint structure provides passive thermal management by allowing the nozzle and thrust chamber to thermally manage themselves through controlled relative movement. The biasing element automatically adjusts the connection as temperatures change, eliminating the need for active cooling systems and associated manufacturing costs.
Solution Approach 2:
The invention extracts the thermal management function from the joint structure itself rather than adding separate cooling systems. By incorporating thermal accommodation directly into the connection mechanism, the design eliminates complex cooling infrastructure and reduces manufacturing complexity.
3Adaptability or versatility
If materials with different coefficients of thermal expansion are used, then component performance is improved, but reliability deteriorates due to thermal expansion differences
Solution Approach 1:
The joint structure transitions from a rigid fixed connection to a dynamic connection that allows controlled movement. The biasing element enables the joint to flex and accommodate dimensional changes as the nozzle and thrust chamber expand at different rates, maintaining connection integrity despite material differences.
Solution Approach 2:
The connection system is segmented into distinct components (first flange, second flange, biasing element) that can independently respond to thermal expansion. This segmentation allows each component to be optimized for its specific material and function while the overall assembly accommodates differential expansion.
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 solution effectively secures the nozzle to the thrust chamber, provides insulation, and eliminates the need for separate cooling systems, resulting in improved performance, reduced costs, and simplified design while maintaining structural integrity under extreme conditions.
Implementation Method 1
Since the nozzle, thrust chamber, and fasteners are made from different materials having markedly different coefficients of thermal expansion (CTE), the liquid rocket engine assembly may experience a loss in performance and integrity during its use and operation, particularly if the engine is cycled on and off repeatedly, creating wide temperature swings.
Data Source
AI summary
A liquid rocket engine assembly comprising a thrust chamber, a nozzle, and a joint structure. The joint structure attaches the thrust chamber and the nozzle and comprises at least one seal element and an attachment ring interposed between the thrust chamber and the nozzle. Fasteners extend between the nozzle and the thrust chamber through the at least one seal element and the attachment ring. Materials of the thrust chamber and of the nozzle comprise different coefficients of thermal expansion. A method of forming a liquid rocket engine assembly is also disclosed.