Cryogenic Pipe Assembly With FRP Outer Tube for Thermal Stability
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Solution Overview
Problem
The integration of cryogenic fluid pipes into the primary structure of aerospace systems poses challenges due to significant thermal expansion and insulation difficulties, which affect structural stability and increase heat flow, complicating the dual use of pipes as both structural elements and fluid conduits.
Innovation Solution
A pipe design comprising a fiber-reinforced polymer outer tube with a gas-proof inner tube and insulation layer, where the inner tube has a low thermal expansion coefficient, allowing it to be integrated into the primary structure while minimizing length changes and heat ingress, with flanges for secure connections and thermal stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If pipes are integrated into the primary structure for load transfer, then mass savings are achieved, but thermal expansion and contraction cause deformation that compromises structural stability
Solution Approach 1:
The pipe system is segmented into multiple sections with expansion joints positioned at strategic locations. Each segment can expand and contract independently, allowing the overall structure to maintain stability while accommodating thermal deformation. The expansion joints act as isolated segments that absorb dimensional changes without transmitting stress to the primary structure.
Solution Approach 2:
The patent utilizes materials and design features that change physical parameters to accommodate thermal expansion. Expansion joints incorporate flexible elements and clearance gaps that allow dimensional changes in response to temperature variations, enabling the pipe to maintain both structural integration and thermal adaptability.
2Stability of the object's composition
If compensators are used to accommodate thermal deformation, then structural stability is maintained, but the number of connection points increases and heat flow into the pipes is augmented
Solution Approach 1:
The expansion joint serves as an intermediary element between the pipe sections. It mediates the thermal deformation by providing a flexible connection that accommodates expansion and contraction while maintaining structural continuity. This intermediary design reduces the need for multiple rigid connection points, thereby minimizing heat transfer pathways.
3Temperature
If thermal insulation is applied to limit heat flow, then cryogenic fluid temperature is maintained, but attachment points create conductive connections that increase heat ingress
Solution Approach 1:
The insulation system is designed with local quality variations to address heat transfer at different locations. Attachment points and expansion joints incorporate localized insulation features such as insulating boots, thermal breaks, or vacuum gaps at specific hot spots, while other sections use continuous insulation. This targeted approach maintains thermal performance without compromising the necessary conductive connections for structural attachment.
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 facilitates weight-saving utilization of pipes as structural elements, reduces thermal expansion, and maintains insulation integrity, enabling efficient fluid conduction with minimal heat transfer and secure mounting to other structures.
Implementation Method 1
an (thermal) insulation layer in-between
Implementation Method 2
a significant cooling of the pipes occurs during operation. This change in temperature between the state of assembling on the one hand and operating states on the other hand leads to large, material-dependent changes in length
Data Source
AI summary
A pipe for conducting a cryogenic fluid. The pipe includes a rigid outer tube at least partially made of a fiber-reinforced polymer, a gas-proof inner tube running within the outer tube, an insulation layer arranged between the inner tube and the outer tube, and at least one flange formed at a respective end of the inner tube. The at least one flange connects the inner tube with the outer tube. Also a pipe assembly with at least two such pipes which are connected or configured to be connected at their respective flanges, and an aerospace system with at least one such pipe.