Rotating Multilayer Insulation for Lightweight Superconducting Motors
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Solution Overview
Problem
Existing superconducting electric motors for aerospace applications face challenges in maintaining cryogenic temperatures efficiently due to the weight, complexity, and bulk of cryogenic coolers and necessary plumbing, which affect heat transfer and fault tolerance.
Innovation Solution
A multilayer insulation (MLI) is used, comprising alternating layers of low-emissivity sheets and high-tensile modulus mesh to minimize thermal conductance and resist hoop stresses, reducing heat transfer through radiative means rather than direct conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cryogenic coolers and plumbing are used for heat transfer, then cooling capability is improved, but weight and device complexity increase significantly
Solution Approach 1:
The patent extracts the heavy cryogenic cooler and plumbing systems from the motor design, replacing them with passive multilayer insulation barriers. This removes the active cooling infrastructure while maintaining the necessary thermal isolation, thereby reducing weight and complexity while preserving cryogenic temperature maintenance capability.
Solution Approach 2:
The patent introduces multilayer insulation (MLI) as an intermediary thermal barrier between the superconducting coils and the external environment. This MLI system acts as a passive mediator that blocks heat transfer without requiring active cooling components, thus maintaining cryogenic temperatures while eliminating the need for heavy coolers and plumbing.
2Temperature
If cryogenic coolers and plumbing are used for heat transfer, then cooling capability is improved, but device complexity increases significantly
Solution Approach 1:
The patent extracts the complex active cooling infrastructure (coolers and plumbing) and replaces it with passive multilayer insulation. This eliminates pumps, valves, fluid lines, and control systems associated with active cooling, thereby dramatically reducing device complexity while maintaining thermal isolation.
Solution Approach 2:
The multilayer insulation system is self-service in that it passively provides thermal isolation without requiring external control systems, power input, or maintenance. The MLI structure inherently performs the cooling function through its physical barrier properties, eliminating the need for complex active cooling management.
3Object-affected harmful factors
If low-emissivity sheet material is used alone, then radiative heat transfer is reduced, but the material cannot resist high hoop stresses
Solution Approach 1:
The patent employs a composite multilayer structure combining low-emissivity sheet material with high-strength mesh or foil layers. The low-emissivity sheets (such as aluminized Mylar) provide radiative heat transfer reduction, while the interwoven mesh or foil layers (such as stainless steel or Inconel) provide mechanical strength to resist hoop stresses, creating a synergistic composite that delivers both thermal and mechanical performance.
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, maintaining cryogenic temperatures while minimizing weight and material stress, enhancing efficiency and fault tolerance.
Implementation Method 1
The multilayer insulation is constructed of multiple low-emissivity surfaces separated by a high-tensile modulus mesh, the latter which minimizes thermal conductance between the layers because of its open mesh structure
Implementation Method 2
multiple low-emissivity surfaces separated by a high-tensile modulus mesh
Implementation Method 3
the high-tensile modulus mesh minimizes thermal conductance between the layers because of its open mesh structure
Data Source
AI summary
A lightweight, multilayer cryogenic insulator is formed by successive layers of low-emissivity sheeting and high elastic modulus mesh, the latter which provide thermal separation of the sheets while resisting high hoop stresses.