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RESEARCH PRODUCT
Heat transport of helium II in restricted geometries
H. WiechertR. Schmidtsubject
Materials scienceThermal conductivityThermal resistanceHeat transferThermodynamicsRate of heat flowLaminar flowHeat transfer coefficientCondensed Matter PhysicsThermal conductionThermal diffusivityElectronic Optical and Magnetic Materialsdescription
The linear heat transport of helium II contained in porous powder samples with mean pore diameters of 1.25µm, 0.17µm and 0.02µm was systematically studied in the temperature range between 0.8 K and 2 K. The effective thermal conductivity was determined by steady-state heat flow measurements and the effective thermal diffusivity by transitory temperature measurements. The experimental results are interpreted by a simple theoretical model. In the framework of this model the linear heat transport consists of two contributions: the laminar flow of the normal fluid (T≳1.4 K) and a diffusion mechanism (T≲1.4 K). At low temperatures (T≲1.2 K) the mean free paths of the elementary excitations of helium II become greater than the pore diameters. In this range, the heat flow is limited by scattering of the elementary excitations with the walls of the pores and can be described by a kinetic model. Good agreement between theory and experiment is obtained in the total temperature range investigated.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1979-03-01 | Zeitschrift f�r Physik B Condensed Matter and Quanta |