Dielectric coefficient and density of subcooled liquid oxygen

The results of high precision dielectric coefficient measurements of subcooled liquid oxygen in the temperature range from 56 to 91 K and under pressures up to 1 MPa are reported. The measurements are performed using a three-terminal flat plate capacitor and a single-frequency, ultra-precision capacitance bridge. Measurement results are combined with the previously published data in different pressure and/or temperature ranges to express the dielectric coefficient and the Clausius-Mossotti relation in an equation form. This new expression covers both the liquid and the gaseous state, and predicts the density of oxygen to better than 0.1% over the entire range of interest. The results reported in this paper are expected to be especially useful for capacitance-based measurements involving fluid oxygen such as liquid level and void fraction measurements of two phase flow.