Sound Velocity, Phase Separation, and Lambda Transitions of He3[Single Bond]He4 Mixtures

Journal Article · Fri Jan 01 04:00:00 EST 1960 · Physics of Fluids (New York)

DOI:https://doi.org/10.1063/1.1706154· OSTI ID:4090135

Roberts, Thomas R.; Sydoriak, Stephen G.

The velocity of first sound was measured in saturated liquid He/sup 3/-- He/sup 4/ mixtures rangng in composition from 20 to 90% He/sup 3/ between 0.5 and 2.3 deg K. The velocities decrease with increasing He/sup 3/ concentration due to the large increase in compressibility. The temperature T/sub s/ at which a liquid mixture first begins to separate into two layers of different composition is identified by a break in the temperature derivative of the sound velocity. The values of T/sub s/ are compared with and found to agree well with all other recent direct measurements. Breaks also occur in the temperature derivatives of first sound velocity and signal amplidirect measuremeats. Breaks also occur in the temperature derivatives of first sound velocity and signal amplitude at temparatures which are in good agreement with most recent determinations of lambda transition temperatures for concentrations up to 30%. For higher concentrations, the values obtained are in good agreement with lambda points determined from second sound measurements but differ markedly from results based on the disappearance of boiling. Possible reasons for the differences are discussed. A smoothed table of lambda temperature as a function of concentration is given up to the intersection of the lambda line and the phase separation region at 68% He/sup 3/ and 0.86 deg K. The vaper pressure of pure He/ sup 4/ at its lambda point is 37.80 plus or minus 0.01 mm Hg (at 0 deg C and standard gravity) based on the measured vaper pressure at the minimum sound signal and a calculated displacement of the sound minimum from the lambda point.

• Research Organization: Los Alamos Scientific Lab., N. Mex.
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-005530
• OSTI ID: 4090135
• Journal Information: Physics of Fluids (New York), Journal Name: Physics of Fluids (New York) Journal Issue: 6 Vol. 3; ISSN 0031-9171; ISSN PFLDAS
• Publisher: American Institute of Physics
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BOILING
COMPRESSIBILITY
HELIUM
MIXING
PHYSICS
PRESSURE
SATURATION
SEPARATION PROCESSES
SOUND
TEMPERATURE
TENSILE PROPERTIES
VAPORS
VELOCITY