Cooling Tube Deflection Control in Superconducting Rotor Machines
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Solution Overview
Problem
Electric machines with superconducting rotors face damage from shock loads due to increased deflection of cooling tubes, which can lead to contact with the rotor, as existing solutions either increase thermal load or require costly mounting methods.
Innovation Solution
Introducing additional bearings outside the cryogenic area at ambient air temperature to stabilize the cooling tube, ensuring maximum deflection is reduced and maintaining a residual radial gap to prevent contact, using conventional and inexpensive bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radial gap is enlarged to prevent cooling tube contact with the rotor, then shock load resistance is improved, but thermal load increases due to greater heat conduction path and enhanced convection
Solution Approach 1:
The cooling tube is divided into multiple segments with individual bearings at different axial positions, allowing each segment to be independently supported and reducing overall deflection without increasing the radial gap
Solution Approach 2:
Instead of solving the contact problem by increasing the radial gap (radial dimension), the invention adds axial support points along the cooling tube length, transitioning from a single radial gap solution to a multi-point axial support system
2Reliability
If the cooling tube length is reduced to prevent deflection under shock load, then shock load resistance is improved, but cooling efficiency deteriorates
Solution Approach 1:
The cooling tube is segmented with multiple bearing support points along its length, allowing the tube to maintain its full cooling length while being divided into smaller supported sections that deflect less under load
3Ease of manufacture
If conventional bearings are used to mount the cooling tube, then ease of manufacture is improved, but shock load resistance deteriorates due to bearing failure at cryogenic temperatures
Solution Approach 1:
Different axial sections of the cooling tube are assigned different bearing configurations - conventional bearings in the warm first longitudinal section and superconducting magnetic bearings in the cryogenic second longitudinal section, optimizing each location for its specific temperature conditions
Solution Approach 2:
A hybrid bearing system acts as an intermediary between conventional mechanical bearings and pure superconducting magnetic bearings, using conventional bearings where temperatures permit and magnetic bearings where cryogenic conditions require
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
Significantly reduces cooling tube deflection by an order of magnitude, enhancing shock resistance without altering the cooling tube, rotor, or radial gap, and allowing for inexpensive, conventional bearing usage.
Implementation Method 1
a so-called cooling tube in order to transfer liquid coolant from a thermosiphon system to the rotating machine and to return the evaporated coolant to the condenser
Implementation Method 2
to return the evaporated coolant to the condenser
Implementation Method 3
The conduit 109 slopes slightly from the B-side B to the area 114 in the direction of gravitation
Implementation Method 4
cool the rotor winding down to the operating temperature
Implementation Method 5
The axial section 124 has a temperature range from the ambient air temperature of the section 122 to the cryogenic temperature of the area 114
Implementation Method 6
the inlet pipe in the first section is mounted in the rotor so it can be rotated by at least two bearings at different axial positions
Implementation Method 7
upon exposure to a maximum radial force corresponding to a maximum possible shock load, this effected a maximum deflection on the inlet pipe
Data Source
AI summary
An electric machine contains a rotor which contains a first longitudinal section at the ambient air temperature and a second longitudinal section cooled at least partially to cryogenic temperature, a coolant inlet pipe extending into the second longitudinal section, wherein the inlet pipe is set at a distance from the rotor by a radial gap, wherein the inlet pipe in the first longitudinal section is mounted by at least two bearings, wherein the bearings are distributed on axial positions in such a way that upon action of a maximum radial force on the inlet pipe the pipe has a maximum deflection which is smaller than the radial gap. In a method for determining the axial positions, various batches of potential locations are chosen for the axial positions of the bearings, according to potential locations which has a minimum gap greater than zero.