Thermal Resistance Across a Copper/Kapton/Copper Interface at Cryogenic Temperatures
The high-Tc superconductor current lead heat intercept connection, which is utilized as a thermal intercept to remove the Joule heat from the upper stage lead to a heat sink operating at 50 – 77 K, consists of a structure where a 152-µm film is sandwiched between two concentric copper cylinders. The material chosen for the insulating film is Kapton MT,* a composite film which has a relatively low thermal resistance, but yet a high voltage standoff capability. Here, the measured thermal conductance of a copper/Kapton MT/copper junction in a flat-plate geometry is compared to the results obtained from the actual heat intercept connection. Increasing the contact pressure reduces the thermal resistance to a minimum value determined by the film conduction resistance. A comparison between the resistance of the copper/Kapton MT/copper junction and a copper/G-10/copper junction demonstrates that the Kapton MT layer yields a lower thermal resistance while still providing adequate electrical isolation.
KeywordsHeat Flux Thermal Resistance Contact Pressure Argonne National Laboratory Thermal Contact Resistance
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- 2.M.A. Lambert and L.S. Fletcher, “A Review of Thermal Contact Conductance of Junctions with Metallic Coatings and Films,” AIAA Paper 92–0709, AIAA 30th Aerospace Meeting, Reno, NV (1992).Google Scholar
- 3.P.E. Phelan, R.C. Niemann and T.H. Nicol, “Thermal Contact Resistance for a Cu/G-10 Interface in a Cylindrical Geometry,” ASME Proceedings of the 31st National Heat Transfer Conference, 5:185 (1996).Google Scholar
- 5.C.V. Madhusudana, “On Heat Flow across Cylindrical Joints,” Proceedings of the 8th International Heat Transfer Conference, 2:651 (1986).Google Scholar
- 6.J.P. Holman, “Experimental Methods for Engineers,” McGraw-Hill, Inc., New York (1994), p. 66.Google Scholar
- 7.D.L. Rule, D.R. Smith and L.L. Sparks, “Thermal Conductivity of a Polymide Film between 4.2 and 300K, with and without Alumina Particles as Filler”, NISTIR 3948 (1995), p.40.Google Scholar