PRECISION, SELF-CONSISTENT THERMODYNAMICS FOR SUPERFLUID HELIUM FROM SOUND VELOCITY MEASUREMENTS
Titel:
PRECISION, SELF-CONSISTENT THERMODYNAMICS FOR SUPERFLUID HELIUM FROM SOUND VELOCITY MEASUREMENTS
Auteur:
Maynard, J. D.
Verschenen in:
Chemical engineering communications
Paginering:
Jaargang 6 (1980) nr. 4-5 pagina's 191-214
Jaar:
1980
Inhoud:
Measurements of the different sound velocities of superfluid 4He have been used to sell-consistently determine all the equilibrium thermodynamic properties of the superfluid. The precision of the results, typically 0.3%, represents an order-of-magnitude improvement over a significant portion of the existing data and has eliminated some discrepancies as large as (10-15)%. The sound velocity data consists of first-, second-, and fourth-sound velocities measured simultaneously at more than 400 points in the P-T plane about 1.2 K. Equations of two-fluid hydrodynamics are used to convert the sound velocities to thermodynamic quantities, including the density, thermal expansion coefficient, normal-fluid fraction, entropy, specific heats, and compressibility.
Tijdschrift beschrijving