Truss-Supported Multilayer Insulation for Cryogenic Motor Rotors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High power-to-weight electric motors for aerospace applications face challenges in maintaining cryogenic temperatures due to the weight, complexity, and bulk of cryogenic coolers and plumbing, which are necessary for superconducting coils, while existing systems lack fault tolerance and efficient heat management.
Innovation Solution
A multilayer insulation (MLI) using low-emissivity sheets separated by a truss-structure to reduce thermal conduction, which is self-supporting and resistant to centrifugal forces, providing a lightweight thermal barrier for superconducting coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cryogenic coolers and plumbing are used to cool superconducting coils, then the coils can maintain cryogenic temperatures, but the system weight and complexity increase significantly
Solution Approach 1:
The patent extracts the cooling function from a centralized cryogenic cooler system and distributes it through passive thermal insulation layers integrated directly into the rotor structure. The multilayer insulation with low-emissivity surfaces and truss separators provides localized thermal protection without requiring bulky external cooling plumbing.
Solution Approach 2:
The patent introduces multilayer insulation with low-emissivity surfaces and truss-structure separators as intermediary thermal barriers between the superconducting coils and the external environment. These intermediate layers block radiative and conductive heat transfer, reducing the cooling load without requiring heavy active cooling systems.
2Loss of energy
If dense insulation material is used to reduce heat transfer, then thermal insulation improves, but the weight increases
Solution Approach 1:
The patent employs a truss-structure separator that creates a porous, open-cell architecture with high air-filled void space. This porous structure provides excellent thermal insulation by trapping stationary air (which has low thermal conductivity) while maintaining extremely low weight, as the truss material itself occupies only a small fraction of the total volume.
Solution Approach 2:
The patent creates a composite insulation system combining low-emissivity surface layers with a truss-structure separator. This composite approach integrates radiative barrier properties of the low-emissivity surfaces with the conductive barrier properties of the truss structure, achieving superior overall insulation performance per unit weight.
3Weight of moving object
If the insulation structure is made lightweight, then weight is reduced, but structural integrity under centrifugal force deteriorates
Solution Approach 1:
The patent segments the insulation into multiple thin layers separated by truss-structure spacers, rather than using a single solid block. This segmentation allows each layer and separator to be optimized independently for minimal weight while maintaining structural integrity. The distributed truss separators provide localized support points that collectively maintain the insulation structure under centrifugal loading.
Solution Approach 2:
The patent uses composite construction combining low-emissivity surface materials with a truss-structure framework. This composite structure achieves high strength-to-weight ratio by concentrating structural material only where needed for support (at the truss nodes and members) while leaving the majority of the volume as low-weight insulation space.
4Strength
If solid insulation structure is used to resist centrifugal force, then structural strength improves, but thermal conductivity increases
Solution Approach 1:
The patent deliberately uses a porous, open-structure truss separator rather than solid material. The porosity (high void fraction) ensures low thermal conductivity by minimizing solid conduction paths and trapping insulating air, while the truss geometry (long slender members connected at nodes) provides sufficient structural strength to resist centrifugal forces through efficient load distribution.
Solution Approach 2:
The patent employs curved and tapered truss member geometries that optimize both structural strength and thermal insulation. The curved members better distribute centrifugal loads, while the tapered sections reduce material usage at locations where less structural support is needed, thereby minimizing thermal conduction paths while maintaining strength.
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 MLI effectively reduces heat transfer to superconducting coils by minimizing thermal conductivity and weight, maintaining efficient cooling and structural integrity under high centrifugal forces.
Implementation Method 1
The multilayer insulation is constructed of multiple low-emissivity surfaces separated by a truss-structure which provides light weight and low thermal conductance between the layers
Implementation Method 2
This spoke system reduces conductive heat transfer to the superconducting windings, improving cooling efficiency
Implementation Method 3
The separating structure provides light weight and low thermal conductance between the layers because of its open mesh and truss-form while supporting the low-emissivity material against high centrifugal forces
Data Source
AI summary
A lightweight, multilayer cryogenic insulator is formed by successive layers of low-emissivity sheeting and a separating truss-structure operating to resist circumferential deflection of the low-emissivity sheeting.