Superconducting Rotor Cooling Loops for Uniform Stationary Cooling
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Solution Overview
Problem
Conventional superconducting rotors with cooling tube systems face challenges in achieving uniform cooling when stationary, as coolant flows only through half of the tubes without rotation, leading to thermally induced stresses and the need for continuous rotor rotation during cooling processes.
Innovation Solution
The rotor design incorporates connecting tubes between cooling tube loops, allowing coolant to circulate between opposite loops through a bubble pump effect, ensuring uniform cooling even when stationary by using evaporation to drive coolant flow, potentially eliminating the need for additional supporting devices and continuous rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotor is cooled without rotation, then the cooling process is simpler, but the coolant flows through only half of the cooling tubes resulting in non-uniform cooling and thermal stresses
Solution Approach 1:
The cooling tube system is segmented into multiple independent loops (first cooling tube loop and second cooling tube loop) that are radially opposite to each other. Each loop can be independently connected to the coolant reservoir, allowing selective activation of cooling paths based on rotor orientation, thereby ensuring uniform cooling distribution.
Solution Approach 2:
The cooling system dynamically adapts to the rotor's rotational position by selectively activating different cooling tube loops. A switching mechanism changes the coolant flow path according to whether the first or second cooling tube loop is in the lower position, ensuring continuous uniform cooling during both stationary and rotating states.
2Reliability
If the rotor rotates continuously or at intervals to ensure coolant flow through the entire cooling tube system, then uniform cooling is achieved, but additional drive equipment is required increasing device complexity
Solution Approach 1:
The cooling system uses the rotor's own weight and gravitational force to drive coolant flow through the cooling tubes. By positioning cooling tube loops radially opposite each other and connecting them to a reservoir, the system automatically activates the appropriate cooling path based on rotor orientation, eliminating the need for external drive equipment during cooling operations.
Solution Approach 2:
The cooling tube loops serve dual functions: they provide cooling during both stationary and rotating states of the rotor. The same cooling infrastructure is used regardless of rotor motion state, eliminating the need for separate drive mechanisms specifically for cooling purposes.
3Reliability
If multiple cooling tube loops are provided radially opposite to each other, then uniform cooling during rotation is improved, but the system becomes more complex without a solution for stationary cooling
Solution Approach 1:
The cooling system is divided into multiple radially opposite cooling tube loops, each independently connectable to the coolant reservoir. This segmentation allows selective activation of cooling paths based on rotor orientation, managing complexity through modular design while ensuring comprehensive cooling coverage.
Solution Approach 2:
The cooling system dynamically switches between different cooling tube loops based on rotor position. During rotation, both loops contribute to uniform cooling; during stationary phases, the switching mechanism activates only the lower loop, simplifying operation while maintaining cooling effectiveness.
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
This design enables uniform cooling of the superconducting rotor winding during stationary phases without the need for continuous rotation, reducing thermal stresses and start-up complexity, and enhances cooling efficiency by maintaining coolant flow through both loops.
Implementation Method 1
the still hot rotor causes the coolant in the geodetically lower cooling tube loop to evaporate
Implementation Method 2
liquid coolant is conveyed via the connecting tube(s) into the geodetically higher cooling tube loop in the manner of a bubble pump
Implementation Method 3
The coolant is caused to circulate by the centrifugal force produced by rotation of the rotor
Data Source
AI summary
A rotor form electric machine is provided including a rotor body that rotates about an axis of rotation, the rotor body having a superconducting rotor winding and cooling arrangement provided for cooling the rotor winding having at least one pair of cooling tube loops disposed substantially radially opposite each other on the rotor body, wherein a cryogenic coolant is transported in the axial direction in the coolant tube loops from a first axial rotor end to a second, opposite axial rotor end and back when the rotor rotates about the axis of rotation. One or more connecting tubes are provided in the cooling arrangement and connect one cooling tube loop to the other cooling tube loop of the at least one pair of cooling tube loops.