Provide reliable and affordable manufacturing technology for 100-foot lengths of ridged neodymium tape for use as the heat-exchange medium in cryogenic refrigeration applications.
The National Center for Excellence in Metalworking Technology (NCEMT) has developed a process to produce neodymium metal in ribbon form. This change in the form of the neodymium, from spherical powder to a ridged metal ribbon, would improve the flow characteristics of the cryocooler. Long lengths (450-foot) of various ribbon geometries were produced and tested for refrigerating cooling capacity. Prototype lengths will be evaluated by trials in the Advanced Lightweight Influence Sweep System (ALISS) magnet system.
Improved cryocooler efficiency would reduce weight and power requirements. The project goal was to increase cooling power from 2 watts to 3 watts at 4.2 Kelvin. Evaluation results show that the refrigeration capacity of the best-performing ribbon geometry nearly matched that of the powder while having only 45 percent of the heat transfer surface area. However, use of ribbon geometry has improved the flow characteristics of the cryocooler by decreasing the pressure drop across the medium by 40 percent as compared to that of the powder. This pressure drop improvement enables the cooler to operate at higher cycle speeds with no increase in energy consumption that would lead to increased cooling capacity. The demonstration of this heat exchange medium technology is directly applicable to all commercial cryogenic systems, such as magnet resonance imaging (MRI) cooling systems, and can be applied to advancing cryogenic materials.
Work was closely coordinated with the NSWC. Ribbon materials were created by the NCEMT and then evaluated under subcontract with Chesapeake Cryogenics, Inc., whose suggestions were then incorporated into optimizing the ribbons. The NCEMT also worked with a subcontractor and industry partner, Supercon Inc., on wire and ribbon development as an industry partner. Technical reports and presentations were used to transition the technology to the domestic cryogenics industry.