A three resistance model for thermal transport measurements in {sup 3}He superfluid {sup 4}He mixtures

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Bulletin of the American Physical Society

OSTI ID:374894

Olafsen, J S; Behringer, R P

Previous DC measurements have indicated a deviation from the K{sub eff}{proportional_to}X{sup {minus}1} dependence predicted for the effective thermal conductivity in superfluid mixtures as a function of the {sup 3}He impurity, X. Recent measurements for X = 1.2X10{sup {minus}4} using an AC heat flux of the form Q(t) = Q{sub 0}exp(i{omega}t) demonstrate a third thermal resistance, R{sub 0}, that is separate from the fluid resistance and the ordinary Kapitza resistance. The mass diffusion of the {sup 3}He`s, the Kapitza resistance, and a diffusivity D{sup 0}, corresponding to R{sub 0}, all manifest themselves on different time scales. The apparatus allows the height of the fluid layer, d, to be varied continuously from 0.02mm {le} d {le} 2.50 mm. Using the smallest d`s available, the authors obtain only the response of the Kapitza resistance and R{sub 0}. This additional thermal effect at lower frequencies accounts for the deviations detected in previous DC, or transient, heat flux measurements.

• OSTI ID: 374894
• Report Number(s): CONF-9304297--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
HEAT TRANSFER
HELIUM 3
HELIUM 4
MIXTURES
SUPERFLUIDITY
THERMAL CONDUCTIVITY