Spoke-Supported Superconducting Rotor for Low-Heat Cryogenic Cooling
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Solution Overview
Problem
Existing superconducting electric motors for aerospace applications face significant challenges due to the weight, complexity, and bulk of cryogenic cooling systems, which are necessary for maintaining high efficiency and light weight.
Innovation Solution
A rotor design with a spoke-supported structure that minimizes heat transfer and cooling demands by using high thermal resistance spokes and a cryocooler integrated into the rotor, allowing direct conductive cooling and reducing the need for complex fluid cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If superconducting coils are used to replace permanent magnets, then efficiency and specific power are improved, but cooling system weight and complexity increase
Solution Approach 1:
The invention extracts the cooling function from a separate complex external system and integrates it directly into the rotor structure. The cryocooler is mounted on the rotor shaft and provides localized cooling at the source, eliminating the need for external cooling infrastructure and fluid handling systems.
Solution Approach 2:
The invention introduces a thermal isolation intermediary system using low-thermal-conductivity spokes and vacuum insulation to separate the cryogenic rotor from the warmer stator and shaft. This intermediary thermal barrier enables independent temperature zones, allowing the rotor to be cooled locally without cooling the entire motor structure.
2Temperature
If conventional fluid cooling systems are used, then heat removal is effective, but system weight and bulk increase
Solution Approach 1:
The invention replaces the mechanical fluid cooling system with a solid-state conductive cooling system. Instead of pumping fluids through channels, the design uses direct thermal conduction through the rotor shaft and spokes to transfer heat from the superconducting coils to the cryocooler, eliminating pumps, valves, and fluid handling components.
Solution Approach 2:
The rotor structure itself serves the dual function of mechanical support and thermal management. The spokes and shaft that provide structural support also serve as thermal pathways for heat removal, and the vacuum envelope that provides structural containment also provides thermal insulation, eliminating the need for separate cooling system components.
3Temperature
If the rotor is thermally isolated from the shaft, then cooling demands are reduced, but structural fixation becomes more difficult
Solution Approach 1:
The invention applies different thermal properties to different parts of the connection system. The spokes use low-thermal-conductivity materials for thermal isolation while maintaining mechanical strength, whereas the cryocooler mounting points use high-thermal-conductivity pathways for effective heat removal. This localized differentiation of thermal properties resolves the contradiction between isolation and fixation.
Solution Approach 2:
The invention employs composite material structures, particularly in the spokes that combine mechanical strength with low thermal conductivity. The vacuum envelope acts as a composite insulation barrier, and the cryocooler assembly integrates multiple materials with different thermal properties to achieve both structural fixation and thermal management.
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 achieves reduced cooling requirements, lighter weight, and improved efficiency by isolating the rotor within a vacuum envelope and using a self-contained mechanical cooling system, maintaining high thermal isolation and structural rigidity.
Implementation Method 1
suspending the rotor on the rotor shaft with high thermal resistance tensile spokes
Implementation Method 2
direct conductive cooling of the rotor coils using a cryocooler, for example, extending partially into the shaft and communicating with the coils through radially-extending conductive straps
Implementation Method 3
confining the cooling to the rotor (which may be isolated in a rotor-specific vacuum envelope)
Data Source
AI summary
A lightweight superconducting machine suitable for aerospace applications provides a wound-field rotor suspended from a driveshaft by insulating tensile spokes. The resultant reduction in heat transmission allows a cryocooler positioned centrally within the rotor to cool the machine coils through radially conducting straps.