Dielectric coefficient and density of subcooled liquid hydrogen Original Research Article

Here we present precision dielectric coefficient measurements of subcooled equilibrium liquid hydrogen in the temperature range from 15 to 23 K and under pressures up to 1 MPa. The measurements were performed using a three-terminal flat plate capacitor and a single-frequency, ultra-precision capacitance bridge. These results are combined with the previously published data to express the dielectric coefficient in the form of the Clausius–Mossotti relation with a new correlation. The results reported in this paper are expected to be especially useful for capacitance-based measurements involving fluid hydrogen such as liquid level, mass gauging and void fraction measurements in two phase flow. Also, a new equation of state gives the density as a function of pressure and temperature for the subcooled liquid phase.