Thermal transport properties in dilute sup 3 He- sup 4 He mixtures near the superfluid transition

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5162432

Tuttle, J G

The author describes measurements of various transport properties of dilute liquid {sup 3}He-{sup 4}He mixtures in two different sample cells. One cell was designed to measure the temperature drop {Delta}T across a fluid layer due to an applied heat flux Q, and the other allowed measurement of both {Delta}T and {Delta}X, the molar concentration drop. He studied the anomalous boundary resistance, {Delta}R{sub b}, in superfluid {sup 4}He near T{sub {lambda}} for Q between 4 and 100{mu}W/cm{sup 2}. He presents results for both the weakly divergent and the heat dependent, more strongly divergent contributions. He compares his data with those of Duncan and Ahlers and with theoretical predictions by Frank and Dohm. He also presents similar R{sub b} data for a mixture with X = 2.5 {times} 10{sup {minus}6}. He determined the relaxation time {tau} for transients observed during thermal conductivity {kappa}{sub eff} and thermal diffusion k{sub T}{asterisk} measurements in superfluid mixtures between 1.7K and T{sub {lambda}} with X ranging from 10{sup {minus}6} to 5 {times} 10{sup {minus}2}. He compares these results, taken with a fluid layer thickness h = 1.81 mm, with theoretical predictions and with earlier data for h = 1.47 mm. He shows the mass diffusion coefficient D computed both from {tau} and from {kappa}{sub eff} data for 0.001 < X < 0.01 between 1.7 K and T{sub {lambda}}, and he compares the results of these two different determinations. In addition, he presents the {sup 3}He-roton scattering cross section calculated using D results. In the normal phase he measured the thermal diffusion ratio k{sub T} and the thermal conductivity {kappa} for 0.009 {le} X {le} 0.05 near T{sub {lambda}}, and he compares these results with predictions by Dohm and Folk.

• Research Organization: Duke Univ., Durham, NC (United States)
• OSTI ID: 5162432
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HELIUM II
THERMAL CONDUCTIVITY
THERMAL DIFFUSION
COMPARATIVE EVALUATIONS
MIXTURES
RELAXATION TIME
SUPERFLUIDITY
THICKNESS
DIFFUSION
DIMENSIONS
DISPERSIONS
EVALUATION
EVEN-EVEN NUCLEI
FLUIDS
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
PHYSICAL PROPERTIES
QUANTUM FLUIDS
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
665420* - Superfluidity- (1992-)