Further On the Fountain Effect in Superfluid Helium

TL;DR

This paper revises thermodynamic data for superfluid helium, resolving previous discrepancies between theory and experiment, and explains the fountain effect through energy minimization principles.

Contribution

It corrects thermodynamic data related to superfluid helium, achieving better agreement with experimental fountain pressure measurements and providing a physical explanation for the fountain effect.

Findings

Corrected thermodynamic data aligns theory with experiment.

Energy minimization drives the fountain effect.

Almost exact agreement between theory and measurements.

Abstract

In the previous paper (Attard 2022d)on the fountain pressure in superfluid helium, it was shown that the experimentally confirmed expression of H. London (1939) was thermodynamically equivalent to equality of chemical potential. However this theoretical equivalence was not reflected in the experimental data. The problem has now been traced to errors in the enthalpy and entropy derived from the measured heat capacity by Donnelly and Barenghi (1998). In this paper the corrected thermodynamic data yields almost exact agreement between the two expressions and the measured fountain pressure. A physical explanation is given for energy minimization as the principle that drives the fountain effect and superfluid flow more generally.