34. A length effect in the heat transport in helium II

✍ Scribed by H. Forstat

• Publisher: Elsevier Science
• Year: 1958
• Weight: 67 KB
• Volume: 24
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(58)80549-2

✦ Synopsis

LIgUID HELIUM S 143 heat transport by liquid 4He through a narrow slit at eleven temperatures between 1. I°K and 2. I°K for values of AT up to 1000 millidegrees. The slit (1.9 cm long and 2 microns wide) connects two reservoirs of liquid helium, one thermally isolated and fitted with a heater, the other intimately coupled to the helium bath. Two ½-watt carbon resistors serve as thermometers. All measurements are made with the isolated reservoir completely filled. Upon heating, the fountain pressflre compresses the liquid in this reservoir causing a drop of the liquid level in the colder (reference temperature) reservoir. Observations of this level change together with information on the liquid density 1) and compressibility 2) allow a calculation of Pf.

The results show two important divergences from previous similar experiments 3) : (1) initial slopes of heat current vs AT are not linear, but concave upward; and (2) plots of heat current vs PI are also concave upward in disagreement with the Allen-Reekie rule. These results will be discussed in relation to present theories.