The thermal transport properties of dilute sup 3 He- sup 4 He mixtures near the superfluid transition temperatures

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5246938

Zhong, Fang

Measurements of the average thermal conductivity, {kappa}{sub exp} = hQ/{Delta}T, were made for dilute mixtures of {sup 3}He in {sup 4}He around their superfluid transitions. The temperature difference was measured with germanium resistors across a layer of fluid mixture. Here c and X are mass and molar concentration respectively. The ratio is k{sub T}* in superfluid phase and k{sub T} in normal fluid phase. The measurements covered the reduced temperature range of 10{sup {minus}6} {le} {vert bar}{var epsilon} = (T - T{sub {lambda}})/T{sub {lambda}}{vert bar} < 0.3, and the heat current range up to 46{mu}W/cm{sup 2}. The anomalous Kapitza boundary resistance for {sup 4}He was observed. The result was consistent with those by Duncan and Ahlers. The {kappa}{sub eff} data were consistent with those by Dingus et al, which deviate from the theoretical prediction of {kappa}{sub eff} {approximately} X{sup {minus}1}. The deviation was less than that by Dingus et al.. The finite heat effect of {kappa}{sub exp} was observed, and it was internally consistent with the deviation as predicted by Behringer. The dilute mixtures offer an ideal test for Khalatnikov's theory of two fluid model. The disagreement for {kappa}{sub eff} and k{sub T}* with the theory indicates that further improvement is needed in the two fluid model especially for very small X. The size and geometry of the sample may have to be considered in order to compare experimental results with the theory.

• Research Organization: Duke Univ., Durham, NC (United States)
• OSTI ID: 5246938
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPARATIVE EVALUATIONS
DATA
DISPERSIONS
EVALUATION
EVEN-EVEN NUCLEI
FLUIDS
HELIUM 4
HELIUM II
HELIUM ISOTOPES
INFORMATION
ISOTOPES
KAPITZA RESISTANCE
LIGHT NUCLEI
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MIXTURES
NUCLEI
PHYSICAL PROPERTIES
QUANTUM FLUIDS
STABLE ISOTOPES
SUPERFLUIDITY
THERMAL BOUNDARY RESISTANCE
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE