Cryocooler Assembly With Thermosiphon Cooling and Nested Torque Tubes
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Solution Overview
Problem
Conventional superconducting generators face challenges with bulky and costly cooling systems, inefficient torque transfer assemblies, and increased space requirements due to large torque tubes and lids, which affect thermal isolation and heat transfer efficiency.
Innovation Solution
A cryocooler assembly with a thermosiphoning system and a torque assembly featuring stiffening members, which includes a first torque tube within a thermal shield and a second torque tube outside, thermally isolates the rotor and stator while transferring torque, using a compact design to reduce space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If forced-flow cooling systems are used to cool superconducting generators, then cooling effectiveness is improved, but device complexity and cost increase due to bulky equipment such as helium pumps, blowers and refrigeration systems
Solution Approach 1:
The patent replaces the mechanical forced-flow cooling system (helium pumps, blowers, refrigeration systems) with a thermosiphon-based passive cooling system. The thermosiphon uses natural convection and phase change of the cooling agent to achieve cooling without mechanical pumps or complex refrigeration equipment, thereby reducing device complexity while maintaining cooling effectiveness.
Solution Approach 2:
The thermosiphon cooling system is self-regulating and requires no external power or control systems. The cooling agent automatically circulates through evaporation in the hot region and condensation in the cold region, providing self-service cooling that eliminates the need for complex mechanical cooling systems.
2Force
If large torque tubes are used in conventional torque transfer assemblies, then torque transfer capability is improved, but volume of stationary object increases leading to larger space footprint
Solution Approach 1:
The patent divides the torque transfer function into multiple discrete torque tubes instead of using one large torque tube. This segmentation allows the same torque transfer capability to be achieved with smaller individual components that occupy less total volume, reducing the space footprint while maintaining force transfer capability.
Solution Approach 2:
The patent nests multiple torque tubes within each other, with inner torque tubes positioned within outer torque tubes. This nested arrangement allows efficient use of space while maintaining the required torque transfer capability through the combined effect of multiple tubes, reducing the overall volume required.
3Force
If conventional torque tubes are used, then torque transfer is achieved, but heat transfer efficiency decreases due to inefficient coupling to heat loads
Solution Approach 1:
The patent applies different properties to different parts of the torque tube system. The torque tubes are positioned and configured with specific thermal characteristics to optimize heat transfer from the coil windings to the cooling agent, while maintaining their torque transfer function. This local optimization of thermal properties reduces heat transfer losses.
Solution Approach 2:
The torque tubes serve as intermediary components that simultaneously perform torque transfer and heat transfer functions. By coupling the torque tubes directly to the coil windings and positioning them within the cooling agent flow paths, they efficiently mediate heat transfer from the heat loads to the cooling system.
4Force
If lids are added to couple coil windings to coil formers, then electromagnetic force resistance is improved, but air gap between rotating and stationary components increases
Solution Approach 1:
The patent integrates multiple functions into the torque tubes, which simultaneously provide torque transfer, structural support for the coil windings, and electromagnetic force resistance. This eliminates the need for separate lids, maintaining a compact design with reduced air gap while still providing the required force resistance.
Solution Approach 2:
The patent merges the functions of the lid and torque tube into a single integrated structure. The torque tube assembly performs both the mechanical support function previously requiring a lid and the torque transfer function, thereby eliminating the need for additional components that would increase the air gap.
5Strength
If lids are used to couple coil windings, then structural support is improved, but heat transfer from coil windings decreases
Solution Approach 1:
The torque tubes provide multiple functions simultaneously: structural support for the coil windings, torque transfer, and heat transfer pathways. By eliminating the need for separate lids, the system maintains structural integrity while preserving direct thermal coupling between the coil windings and cooling agent.
Solution Approach 2:
The patent removes the lid component from the design, extracting its structural support function and redistributing it to the torque tube system. This elimination of the lid prevents the heat transfer barrier it would create while maintaining the required structural support through the integrated torque tube assembly.
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 enables efficient cooling of superconducting generators by thermosiphoning a cooling agent, reducing heat transfer losses, and minimizing space requirements while maintaining effective thermal isolation and torque transfer.
Implementation Method 1
Each flow member is configured to thermosiphon the cooling agent in a first state from the reservoir and in a second state to the reservoir
Implementation Method 2
Each flow member is configured to thermosiphon the cooling agent in a first state from the reservoir and in a second state to the reservoir
Implementation Method 3
A thermal shield that is configured to enclose the stationary assembly
Implementation Method 4
A torque assembly is coupled to the field winding assembly and configured to receive torque experienced by the field winding assembly
Data Source
AI summary
A cryocooler assembly for cooling a field winding of an electrical machine having an axis of rotation is provided. The assembly includes a cryocooler and a reservoir coupled in flow communication to the cryocooler and configured to contain a cooling agent. A flow assembly is coupled in flow communication to the reservoir. The flow assembly includes a first flow loop coupled in flow communication to the reservoir; a second flow loop coupled in flow communication to the reservoir; and a plurality of flow members coupled in flow communication to the first flow loop and the second flow loop and coupled to the field winding. Each flow member is configured to thermosiphon the cooling agent in a first state from the reservoir and in a second state to the reservoir.