Joule-Thomson coefficient measurements

Reliable equations of state need accurate reference data. As part of the cryogenic-mixtures work I carried out large-pressure-drop Joule-Thomson coefficient measurements, characterising how the temperature of a gas mixture changes as it expands across a large pressure difference. These isenthalpic measurements probe a region of the thermodynamic surface that is otherwise poorly constrained, providing data to test and refine the equations of state for helium, neon and argon mixtures.